I want to build a new exhaust for the monsta. Currently I have a Quat D- Xbox on it.
I love the look of an under engine exhaust but the X Box is robbing heaps of power, my guess is because there is no crossover inside it. The exhaust just goes in, has a change of direction and comes out. I'm thinking because there is no crossover, there is no scavenging.
So, the plan is to build an an under engine exhaust of similar styling, but with a crossover inside.
I have an old exhaust from a 600 that I plan on cutting up to use the crossover and any other bits needed.
(http://i133.photobucket.com/albums/q41/monsta904/CIMG2409.jpg)
The problem I have is that I want the exhaust to narrow like the xbox, but the 600 headers (like the 900) exit the crossover and make a wide radius toward the back, which will make the fab'd exhaust also wide.
(http://i133.photobucket.com/albums/q41/monsta904/CIMG2406.jpg)
I could cut off the pipework as it exits the crossover, but I'm thinking that it would probally ruin the scavenging effect of the unit?? because it would need that run-on to help draw the gas through. any ideas?
(http://i133.photobucket.com/albums/q41/monsta904/CIMG2404.jpg)
Maybe I should just go and get some tighter radius bends from an exhaust shop and fab it from scratch, or reposition the crossover somehow?
Any experts here that may have some suggestions?
swap the inlets and outlets so to speak, or rotate it 45 degrees so you can have more exit length in the same space. or run the vert down and foward and loop it back towards the back so you can y the horiz in there. they'll be different lengths tho.
you theory will be overruled by the reality of making it fit. make what you want fit and asthetics wise, then throw it away if it doesn't work and start again on something different.
maybe try two uncollected pipes with mufflers on them. dyno it with std headers and slip ons (the control) then the x box then try other things. two single pipes of the right size might work ok. ok enough for the simplicity to suffice.
exhaust formula here - http://www.mvagusta.net/forum/showthread.php?t=43891 (http://www.mvagusta.net/forum/showthread.php?t=43891)
thanks Brad. I have a bit of spare stainless sheet, so yeah, there will be a bit of trial and error.
That link is good. I offten wondered if there was a formula or was it hit n miss.. and why Ducatis had different lengths!
Tomorrow I'm gunna try n get an exhaust donut locally and cut it up to see if I can make it fit.
exhaust donut = tighter radius...
(http://www.pro-werks.com/images/parts/DonutsFull.jpg)
Thanks for the link to that site.
how do you order from them?
i couldn't see how to order either.. but thay arn't local, I hope to get on local so I dont have to wait...
Quote from: brad black on February 17, 2012, 03:02:10 AM
swap the inlets and outlets so to speak, or rotate it 45 degrees so you can have more exit length in the same space. or run the vert down and foward and loop it back towards the back so you can y the horiz in there. they'll be different lengths tho.
you theory will be overruled by the reality of making it fit. make what you want fit and asthetics wise, then throw it away if it doesn't work and start again on something different.
maybe try two uncollected pipes with mufflers on them. dyno it with std headers and slip ons (the control) then the x box then try other things. two single pipes of the right size might work ok. ok enough for the simplicity to suffice.
exhaust formula here - http://www.mvagusta.net/forum/showthread.php?t=43891 (http://www.mvagusta.net/forum/showthread.php?t=43891)
hey brad, im just playing with the formulae on that page, but dont have cam specs. with your experience in ducati, do u have a exhaust bbdc value for an 800?
EDIT: found cam specs on your site of all things.. haha cheers!
looking at your site, i assume the figures posted are btdc? your listing 57 for the 800. looking at his formula, do u think i should just use your 57 instead of his [bbdc+180]? same thinG?ok so that obviously didnt work at 6 inches primaries.. ill now assume your reading is bbdc.
his formula for length is
850x [exh bbdc+180] / rpm @peak power
850x [57+180] / 8500 = 23.7 in long
that seems fair....
for diameter of pipe
2x the square root of swept cylinder volume[in cc]/8.2/L/Pi
2x square root of 400/8.2/23.7/3.14
2x square root of 0.655
2x 0.809
1.618 inch
so for an 800. my ideal is 41mm id pipe, 60cm length before merge/crossover. im thinking that seems quite doable with the rear primary going down, forwards then hooking at the right point (prob a touch tight a bend but unavoidable) to make them merge a bit before the 60 cm mark to accomodate for the length of the head port.
but what diameter pipe should be used when you combine two 41mm primaries would depend on the phase of the cylinders wouldnt it? but that i dunno mucha bout that, so discarding the phase of the cylinders, with the tapering rule for exhaust to maintain air speed id want to go a little smaller than the combined area of the primaries after the merge.
41mm pipe = 13.2cm2
2 pipes = 26.4cm2
so 58mm pipe= 2x 41mm pipes
common sizes for mild steel exhaust is 41.3 and 57.15 how convenient! now to find it in thin wall stainless....
mild steel exhaust tubing comes in 1/8 increments and has 1/16 wall thickness. so one size will slip nicely over the next smaller and nicely into the next bigger. get it ceramic coated and forget about stainless. i say. did that on my sport 1100i.
i'd be more inclined to make the merge smaller, just cutting a 1/3 or so off each pipe and welding them together. check out a 2004 - 2008 aprilia rsvr or 2006 - 2008 tuono with the 2-2 exhaust.
I can get the sizes needed in 409 stainless. not the best grade but worth a shot. i have brought off these guys before when i extended my s-pipes and they are very helpful.
http://www.sassales.com.au/catalogues/Muffler%20Flyer%20211106.pdf (http://www.sassales.com.au/catalogues/Muffler%20Flyer%20211106.pdf)
http://www.suncoastcyclesports.com/servlet/the-142872/04-dsh-09-Aprilia-RSV-RSVR/Detail (http://www.suncoastcyclesports.com/servlet/the-142872/04-dsh-09-Aprilia-RSV-RSVR/Detail)
u talking about this one? it is very similar to what i was thinking except i was intending to merge and have a single outlet from there. but I'm not too fussed as long as its short and low. is there a benefit to a 2 to 2 system over a 2 to 1?
The main reason i want this exhaust change is to have a short low exhaust that allows me to remove the huge spacers I've had to use to make my rizoma rear sets clear the high mount dp setup. and i don't like regular low mount pipes.
http://www.apriliaforum.com/forums/attachment.php?attachmentid=157939&stc=1&thumb=1&d=1306264795 (http://www.apriliaforum.com/forums/attachment.php?attachmentid=157939&stc=1&thumb=1&d=1306264795)
this one, the tuono is like what i was thinking
Quote from: Roaduser on February 20, 2012, 05:23:44 AM
http://www.suncoastcyclesports.com/servlet/the-142872/04-dsh-09-Aprilia-RSV-RSVR/Detail (http://www.suncoastcyclesports.com/servlet/the-142872/04-dsh-09-Aprilia-RSV-RSVR/Detail)
not a 2-2 pipe. has a crossover where the pipes are cut and welded together.
must be a terminology difference there. i thought a 2-2 was two header pipes, a crossover, two tail pipes. or do u call that a 2-1-2?
Quote from: Roaduser on February 20, 2012, 06:34:07 AM
must be a terminology difference there. i thought a 2-2 was two header pipes, a crossover, two tail pipes. or do u call that a 2-1-2?
2-2 is two separate pipes
2-1-2 is two pipes that crossover/xpipe/etc.
2-1 combine but never separate
the d-16 GP exhaust 4-2 for example. so 2 of the cylinders combine into single pipes but then never combine or separate after that.
a lot of I4 bikes are 4-2-1
pretty much standard I've seen for ducati 2-1-2 with either a crossover or x-pipe.
what I didnt know was the 600SS in europe was a 2-1 or so i've seen them as such.
i am trying to perfect my 2-2 with some anti-reversion chambers (possibly that fat part you are seeing in that 2-1 system in this thread http://www.ducatimonsterforum.org/index.php?topic=55169.0 (http://www.ducatimonsterforum.org/index.php?topic=55169.0) ) to alleviate the need for the crossover.
Quote from: Raux on February 20, 2012, 06:46:05 AM
i am trying to perfect my 2-2 with some anti-reversion chambers (possibly that fat part you are seeing in that 2-1 system in this thread
Very interesting reading, this thread.
Just curious, could you please explain anti-reversion chambers? I´m not familiar with this expression.
Also, the exhaust donuts are new to me, never seen that before. Where could I find out more about them? Finding tight-radius tube bends is a problem.
I´ve been buying my stainless tubing and other stuff from SR Racing in Germany, beautiful pieces and great quality craftmanship. But I´ve never seen the exhaust donut before
(http://h7.abload.de/img/archamber022ngy.jpg)
ok Raux, I get the anti reversion thing... but that wont do any scavenging. I would have thought scavenging was pretty important?
HPD, Australian links, but donuts can be got here... http://www.mantapro.com.au/index.html (http://www.mantapro.com.au/index.html)
http://www.bestmufflers.com/ (http://www.bestmufflers.com/)
Quote from: monsta on February 22, 2012, 02:47:21 PM
ok Raux, I get the anti reversion thing... but that wont do any scavenging. I would have thought scavenging was pretty important?
HPD, Australian links, but donuts can be got here... http://www.mantapro.com.au/index.html (http://www.mantapro.com.au/index.html)
http://www.bestmufflers.com/ (http://www.bestmufflers.com/)
This is all theory... the antireversion would eliminate the reverse pulse that stops the flow out of the cylinder. by allowing the cylinder to continue to flow the exhaust the need for scavenging can be reduced. In addition valve overlap may help push the exhaust a bit through the cylinder as well...
so antireversion with 1100 cams (more overlap) and variable ergal cam gears. yeah i'm crazy.
Quote from: Raux on February 22, 2012, 03:06:45 PM
This is all theory... the antireversion would eliminate the reverse pulse that stops the flow out of the cylinder. by allowing the cylinder to continue to flow the exhaust the need for scavenging can be reduced. In addition valve overlap may help push the exhaust a bit through the cylinder as well...
so antireversion with 1100 cams (more overlap) and variable ergal cam gears. yeah i'm crazy.
Thanks for the links on the donuts, I´ve never seen those before. I will have to look around if someone is doing them a bit closer to here (Sweden).
I would also like to see the whole document about the anti-reversion thing, looks like it is out of a patent application?
However, if I had just seen the picture, I would have assumed rather the opposite: By supplying this area increase, the sonic overpressure wave sent down the header pipe on exhaust valve opening would reach the area increase and reflect an opposite-sign, i.e. underpressure wave towards the exhaust valve.
Correctly timed thru header length this would arrive at the still-open exhaust valve, helping suck residual gasses out of the cylinder during valve overlap.
This was my reasoning behind the design of the 2-1 system shown in another thread on more or less the same subject, the aim beeing to have the presumed correct header length and still having a convenient (if not very pretty) installation .
Since this reasoning is more pro-reversion than anti-reversion, the full document would be very interesting to read. Where can it be found?
[popcorn]
Quote from: koko64 on February 24, 2012, 02:03:30 AM
[popcorn]
Beeing a not very experienced forum user, I´m not sure what this smiley exactly means, but I´d be hard pressed to assume something positive.
I figured these tech&mod forums were for discussing tech and mods for the mutual benefit of everyone, myself included, with an open mind and an interest in technical matters.
Well, maybe I was wrong....?
Anyway, for anyone interested in learning exhaust system basics, this is a better place to start than most:
http://www.burnsstainless.com/techarticles.aspx (http://www.burnsstainless.com/techarticles.aspx)
This is an excellent topic, no negative is implied.
[popcorn] often means someone is interested or entertained, watching closely and waiting for more. If someone is building a bike project it is often a vote of interest in the project and a compliment.
[popcorn] means in this context, an interesting technical topic. So I am watching with interest and waiting for the next contribution.
I have a particular interest in performance oriented topics.
Quote from: koko64 on February 25, 2012, 01:25:01 AM
This is an excellent topic, no negative is implied.
[popcorn] often means someone is interested or entertained, watching closely and waiting for more. If someone is building a bike project it is often a vote of interest in the project and a compliment.
[popcorn] means in this context, an interesting technical topic. So I am watching with interest and waiting for the next contribution.
I have a particular interest in performance oriented topics.
OK, sorry, my misinterpretation :-[ . I´ve also found this topic very interesting so I hope more is to come [thumbsup]
No worries. [beer]
[thumbsup]
[popcorn]
in reality, what kind of %'s of loss are we talking about here?
i.e. if i continue to use the DP slip-on system i have compared to running two formula derived header pipes with a small expansion chamber of sorts at the length determined to be most suited into two stylised mufflers. are we talking in the region of 3-5 or 10+ hp or torque loss? would u need an expansion chamber or would a fat muffler be enough to have a similar effect?
for the use, looks, and fitment to my bike id ideally like an independent twin system but I'm a Little scared of the implications. i don't wanna throw away power unnecessarily, after all it is just an 800, but a few hp isn't an issue as its a city commuter with the occasional country/hill run a few hp isn't going to worry me.
I'm looking into gettin access to a dyno at a fair price. id be happy to use my bike and make a twin exhaust out of mild steel (completely impractical mainly straight with minimal bends just to get the pipe away from the engine) and test and cut and test to see what happens...
i imagine it being a case of making two header pipes the max length thought to be practical, make a slip on clamp style expansion chamber and muffler setup. run it, then remove the slip on section, cut the header and try again. with 2 inch increments id hazard 5-10 tests would give a good curve of power and torque changes vs length. my guess would be near a full day on the dyno. I'm thinking i could set the base fuel mixture setting for the initial length and then do all tests at that setting. if i found one length to be ideal i suppose you could set it again to see the potential at that length...
anyone see any major flaws or reasoning not to do this?
I'm happy to see this done. i have the two into two. with no back pressure i was having issues i think the expansion chamber at the stock crossover point will fix it
Quote from: Roaduser on February 27, 2012, 08:31:17 PM
anyone see any major flaws or reasoning not to do this?
None whatsoever ..... partly because I´ve done more or less the same thing myself even if it did not turn out as thorough as I might have liked (I suppose you´ve seen the parallel thread about torque cones in he Tech section?).
I for one will be very interested in the results you´ll get. [thumbsup]
had a reply from burns stainless about their recommendations for a 2 into 1 using their "x-design" program. the results confirm my theory practiced earlier about length and diameter too a t!!
only thing is they don't take into account the port length (admittedly i didn't give them that information) nor do they account for what appears to be another inch or so of pipe in their collectors. combined, this would could add 3inches to the headers. not that i think the change in results would be dramatic at all but just out of interest itd be nice to check such things
(http://img688.imageshack.us/img688/5676/headerpdw.png) (http://imageshack.us/photo/my-images/688/headerpdw.png/)
Uploaded with ImageShack.us (http://imageshack.us)
the collector they sell and recommend uses a expanding transition after the collection of headers out to a 2.5inch tail pipe! that's a big tailpipe for a 800cc engine....
Very interesting, it´s the first time I see the result from the Burns X-design.
It pretty well matches what I´ve been doing. This does not indicate any particularily high level of knowledge on my part, rather it implies that they also use the same basic and generally well-known theories. But the header section is big for an 800 cc motor....
The 2-1 for the Monster uses the stock 37 mm id headers for the first bit, then 38 mm pipes for the rest, and a 54 mm id collector. Header length is about 680 mm from valve face to where the header ends into the id 54 mm bit.
The Rain Bike 2-1 uses pretty much the same setup, but header length 800 mm ending in the Y connection tapering up to the 54 mm id collector.
I´ve been trying to find some thin-wall tubing with 40 mm id, but so far no luck. I think if you stick to the Burns basic design, and do not go any bigger on the header id, I think it will work just fine.
I have not checked yet, but if it is possible to fit the megaphones I have to the headers on the Monster without cutting them up, I might do a dyno check on what will happen with 400 mm (open) megaphones on 700 mm headers. if nothing else, the noice will be interesting ... ;D
I have a dyno lined up and my exhaust guy is ready with some 41mm mild steel. Now i just need to get to the local engineer and have him cut up some exhaust flanges and rings to weld onto the headers and ill be set to test. Thinking if i want a stylised/finned design or just smooth flanges.... I might get a small section of 2 or 2.25 inch and make a dodgy expansion chamber to try out too, for the effort to build it itll give an answer to the theory but for a split system i think the cans will server the same purpose anyway.
Im thinking i wont get much variation from the lengths or expansion chamber but at approx $200 cost to build and test (including 2hrs dyno time, wont do too many different lengths) ill have piece of mind that its as good as ill get it, i wont waste a full stainless system on what could be a dud idea, ill get dyno figures for my bike, and ill have some fun along the way. Then itll prob cost another $500 or so in materials to make the final exhaust if its a viable design. Still to decide the style of cans i want, prob just get something from ebay/danmoto but for testing ill slip on the remus dp cans i have already.
The dyno operator thinks we could see a minor improvement with a correct sized split exhaust, based mainly off his experience with harleys, but im not holding any hopes of a gain. Minimal loss will do me fine. I do wonder on the sound itll make tho.... ive never heard a split system ducati.
the split systems are definitely louder ;D
http://new01.ugc.ducati.kontain.com/video/20110721/prod_da32f2d7-8ce2-4a6e-b4d4-4bc0a64663ff/af40f15c-7062-4864-8d6d-41fb5d5e862c.mp4 (http://new01.ugc.ducati.kontain.com/video/20110721/prod_da32f2d7-8ce2-4a6e-b4d4-4bc0a64663ff/af40f15c-7062-4864-8d6d-41fb5d5e862c.mp4)
remember just a 696
been a little slow getting things done as its actually been sunny!!
i had a engineer turn me some steel flanges for the tester. if all goes well he will make the next set in stainless for me. will go see my exhaust guy tmr and press bend the tester setup leaving it oversized length, and then once back from the easter break ill be on the dyno. fingers crossed
with the ducati headers being 1.3mm wall 40mm pipe, when i use 1.8mm wall 41.3 ill actually only be going up 0.8 mm in diameter. ill check my supplier, and if i can i might go for some 1.2 or even 0.8 wall stainless.
(http://img52.imageshack.us/img52/5572/photo19qq.jpg) (http://imageshack.us/photo/my-images/52/photo19qq.jpg/)
Uploaded with ImageShack.us (http://imageshack.us)
I'll jump on the subscribing bandwagon.
[popcorn]
Also, raux, I know you fabbed up the exhaust yourself, but mind if I ask where you bought your megaphones?
Quote from: Buckethead on April 03, 2012, 11:11:36 PM
I'll jump on the subscribing bandwagon.
[popcorn]
Also, raux, I know you fabbed up the exhaust yourself, but mind if I ask where you bought your megaphones?
ebay
$100
Very nice. Will be real interesting to see the results.
TEASER WARNING!!
i have results!! i did runs with the shortened dp high mount remus cans, then went to split headers of 1000, 800, and 600 ml volume with some brand new danmoto conical cans. have logs for power, torque, and afr.
im bout to go out for dinner now, so ill start a thread later on with all the details.
quick tip for anyone looking for cheap cans/testing on a dyno. DONT USE DANMOTO CANS!! filled the whole damned dyno room with fibreglass!! covered me, the bike and the dyno in snow after only 2 runs and continued to spew more all the way till finished haha. can see there is only about 10% of the packing remaining in the cans now! on a plus side, they are damn light cans now but more than a little too loud... haha and im still itchy!!
TO BE CONTINUED........
I think the DanMoto are using the same packing as a dirt bike. loose fill, instead of wrap fill.
looking forward to seeing results Roaduser...
well since I started the thread about building an exhaust I better add to it.
Finally got a bit done. I've had the donut, some straight tube and 1.5mm stainless sheet for a while, what I havn't had is time.
anyhow, yesterday I made a start....
(http://i133.photobucket.com/albums/q41/monsta904/P1000108.jpg)
I dont have access to machinery anymore because I've moved on from my previous job, so I have to buy my own.
here is a cheap chinese TIG/Plasma cutter I bought..
(http://i133.photobucket.com/albums/q41/monsta904/P1000246.jpg)
I used it to cut out from a template made from the X-Box. I dont mind the shape of the xbox, but a couple of things I'll change, I'll tweek it as I go.
First time that I've used the plasma, so there is a few rough edges where I wasn't moving fast enough and the cardboard burnt which let the cutter go off track.
(http://i133.photobucket.com/albums/q41/monsta904/P1000240.jpg)
I hand bent the sheet to shape in this...
(http://i133.photobucket.com/albums/q41/monsta904/P1000244.jpg)
To end up with this...
(http://i133.photobucket.com/albums/q41/monsta904/P1000245.jpg)
So, its a start... I'll try to keep some momentum, but this will be a slow project...
I've come to the conclusion that I'm probably going to have to build the exhaust I want. :P
You mind if I ask about your TIG/Plasma cutter setup?
Quote from: Buckethead on May 09, 2012, 05:30:20 PM
You mind if I ask about your TIG/Plasma cutter setup?
no, what do you want to know?
there's heaps of em on ebay, was about $600 Aus.
First off, what sort of specs did you look for? Amperage, wattage, etc.
Secondly, I don't know if you've used the TIG portions of it yet, but how would you rate the one you bought for what you're doing? Adequate? Barely so? Any features you'd look for if you had to buy another one?
I've only done a few small TIG welds to see if it works ok...
I just wanted something to be able to do light ally and small welds. Its 200 amp so that should be ok for most things I want to do.
Also has stick welder function.
So far I rate it ok, you wouldn't expect pro quality for the $600.
There's a few on ebay that dont have the plasma cutter, I'll use the plasma a bit so I made sure the one I bought had it.
ok, so I've made a bit more progress and the design has changed a bit.
But I have a question.. I'm wondering if I should bring the exit (inside the box) around a bit more to help draw the gases through to help scavenge?
I could add a bit more to the radius that I welded on before I button it up...
I'm thinking that the exit from the X peice is not long enough....
Any guru advise?
(http://i133.photobucket.com/albums/q41/monsta904/P1000298.jpg)
(http://i133.photobucket.com/albums/q41/monsta904/P1000297.jpg)
(http://i133.photobucket.com/albums/q41/monsta904/P1000299.jpg)
yeah I've been a bit busy lately and haven't done a write up. one day soon... i have some new flanges made up in stainless and alloy for the final version to collect tmr and the bends should be already waiting so ill get to work on it soon.
MONSTA: i think the take home message i have gained is the theory is only a basis to start from, the proof is in the pudding and we don't really have a means to test it thoroughly enough at every step so i wouldn't stress the small stuff like the length of those pipes, also we are both quite possibly going to be running a slight loss in anyway. I think you should focus on the aesthetics of your design and making sure you don't run too much restriction in whatever baffle design your going to choose for inside that enclosure and you'll on a winner in my eyes.
as for the theory on scavenging, my understanding is that it wont make any difference changing that end part of pipe as any real scavenging effect will take place from where the two cylinders headers first meet. this will still be at the same point as oem for you as you have the original headers and joiner in your design. so with those pipes your effectively dealing with the length of tailpipe on a car when the scavenging is happening at the headers.
if those two pipes did somehow have a scavenging effect on each other it would be to no purpose as it would effectively be scavenging from itself... this is because a scavenging effect (or negative pressure) at that point would have its effects on the whole system and not just the opposite cylinder because the two cylinders pressures have already met and are both already at play.
hope that makes sense, and just be aware it is only my "un-footnoteable" understanding.
yes, I think I get what your saying. And I think your totally wrong... no offence... :)
"if those two pipes did somehow have a scavenging effect on each other it would be to no purpose as it would effectively be scavenging from itself... this is because a scavenging effect (or negative pressure) at that point would have its effects on the whole system and not just the opposite cylinder because the two cylinders pressures have already met and are both already at play"
I think, without a doubt there is some scavenging.. whether its miss-timed because of lenght prior to the cross-over is another thing.. what you say would be true if both cylinders fired at the same time...
"as for the theory on scavenging, my understanding is that it wont make any difference changing that end part of pipe as any real scavenging effect will take place from where the two cylinders headers first meet. this will still be at the same point as oem for you as you have the original headers and joiner in your design. so with those pipes your effectively dealing with the length of tailpipe on a car when the scavenging is happening at the headers."
'my theory' is that scavenging would need some follow-on from the cross over to provide a negative pressure at the opposed cylinder?? thats why I welded the radius bend from the cross-over. Otherwise I would have just let it exit straight into the box.
Quote
yes, I think I get what your saying. And I think your totally wrong... no offence... :)
'my theory' is that scavenging would need some follow-on from the cross over to provide a negative pressure at the opposed cylinder?? thats why I welded the radius bend from the cross-over. Otherwise I would have just let it exit straight into the box.
Are you going to test this on the dyno when it´s finished? I´ve never really understood the reason for the cross-over design, so your experiment is very interesting. Especially since it is somewhat opposed to my own thinkings on the subject :-\ (also no offense).
I noticed on my M900 when I still had the stock headers on that the right-hand silencer was louder and getting warmer than the lefthand side, indicating more waste products ended up through that exit. Looking at the header entries, I did not find that surprising.
I would tend towards very little scavenging effect through the cross-over design, but I have no hard evidence one way or the other ... so please keep us posted. Exhaust systems are always good for a surprise or two .
Interesting that there is now 2 people that dont think there is scavenging... I may have to eat my words! :)
But, I wonder why Ducati would use a cross-over if it wasn't for a purpose?
Anyhow, yes I will be dynoing and yes I will keep you posted... [thumbsup]
[popcorn]
I like it when people design and test stuff. You never know if you dont have a go. Goodonya Monsta. [thumbsup]
There are tuners that have shown that the stock headers work surprisingly well. The stock crossover and twin exhaust muffler set up provides ample volume for big bore twins. Exhaust scavenging is another issue again related to engine configuration.
I have been surprised by dyno tests (in relation to airbox mods), when one principle you think will influence an outcome is overshadowed by another principle you may not have considered.
Those into this thread should check out Doug Lofgrens MPS site. Brad Blacks bikeboy site also has a saga or two.
Looking forward to the testing results.
Quote from: monsta on June 25, 2012, 04:30:41 PM
Interesting that there is now 2 people that dont think there is scavenging... I may have to eat my words! :)
But, I wonder why Ducati would use a cross-over if it wasn't for a purpose?
Anyhow, yes I will be dynoing and yes I will keep you posted... [thumbsup]
We might have different theories, but we have the urge to build and test in common ;D
Looking forward to your dyno runs, as well as those from Roaduser [thumbsup]
I'm not saying there is no scavenging effect at play in this setup, I'm saying the scavenging effect is not at play in the area you are playing with. this may simply turn out to be more of a terminology difference between us, but after reading what your doing and your explanation i still disagree that those pipes after the merge are having any effect on scavenging.
when one header has a pressure force that passes the merge it creates a negative pressure in the non firing header and helps remove waste and, depending on cam profiles, possibly suck more inlet gases into the non firing cylinder. that theory prevailing, your scavenging is happening at the merge and dependant on the header pipes before the merge and the characteristics of the merge itself.
another theory is that where the pipe area increases dramatically (commonly the merge area, or in zoomies/split pipes the end of the pipe) there is a wave that returns back up the firing cylinders header till it hits the valve or cylinder, then returns again out the header and that can aid in scavenging of a firing cylinders own wastes/aid inlet gases. this theory is the tuning of a header pipe and thus the timing of the return wave is effected by the length and volume of the header pipe before the merge/termination of the pipe. this is thought to then only have a positive effect at one point in the rev-range and thus a different length of header can increase performance in a different area of the rev-range and have a negligible or negative effect at others. as the wave will be at a constant speed and timing from when the valve opens, it depends on the engine speed/valve timing as to when and wether the wave is synchronised and having a positive effect on the cylinder.
my thought on your design is that since both of your outlet pipes are after the merge and the same length/volume, they will theoretically both have the same pressures and waves that are split between them from both of the header pipes and will then effectively act like two simultaneously firing cylinders having no positive/scavenging effect on each other. its a difference in pressures and waves that causes the scavenging effect.
whats your theory on how those pipes will effect your exhaust? as others, I'm intersted in other peoples ideas and theories as much as anyone
ok, its very difficult to explain my thought's without drawing a diagram.
but... as the gas from one cylinder is split at the merge point (crossover) into 2 streams it interacts with the other cylinders also split stream (at the merge) to creats a venturi effect.
this will create a negative pressure, which will draw gases through the now open valves (valve over-lap) which helps remove spent fuel and bring in a fresh charge of fuel/air to the cylinder.
Without the extra length from the exit of the crossover, 'my thoughts' are there will a chance that the venturi wont be a efficient...
Anyhow, as I've stated previous, I know that the standard exhaust works better than the quat d.
What I'd like to achieve is similar performance as standard, with the under engine exhaust look...
Time will tell! [thumbsup] [beer]
Quote
.........
but... as the gas from one cylinder is split at the merge point (crossover) into 2 streams it interacts with the other cylinders also split stream (at the merge) to creats a venturi effect.
this will create a negative pressure, which will draw gases through the now open valves (valve over-lap) which helps remove spent fuel and bring in a fresh charge of fuel/air to the cylinder.
........
Just speculating on the scavenging theme .... I remember I once read an interview or something with Rob Muzzy (I think it was a Kevin Cameron story in an old Cycle Magazine) that the angle between the four headers as they joined the collector had a definite effect on torque / power. One theory as good as any other since I don´t know could well be a venturi effect beteen the active and passive pipes.
Just speculating again ...Should the cross-over design not work satisfactorily, one possible alternative design could be to join the 2 headers in a "regular" Y-piece inside the exhaust box. This would potentially also create a venturi effect. On the other hand, that would just be a normal 2-1 with a slightly different collector / silencer.
I don´t know what silencing you´re planning, but maybe some perforated inner skin with damping material between the walls would help dampen out "drum-skin" resonance of the flat-ish box walls?
Quote from: MonsterHPD on June 26, 2012, 10:56:00 AM
I don´t know what silencing you´re planning, but maybe some perforated inner skin with damping material between the walls would help dampen out "drum-skin" resonance of the flat-ish box walls?
that's another thing I have to work out.
At this stage I'm thinking of just, in... change of direction (twice) and out. Thats how the quat D is... I put a bore scope (camera) inside when it was new to have a looky...
I'm planning on have an inspection cover screwed onto the top side so that if I need to I can pack it with some stainless swarf.. or something.. to quieten it if needed. That may well be my downfall as well...
Your idea of an inner skin is a good one, I'll have to have a think about that, see what I can come up with. [thumbsup]
Don't make the mistake danmoto is making using loose packing with too large holes on the perforated tubing.
so... this is where I'm heading.
(http://i133.photobucket.com/albums/q41/monsta904/P1000301.jpg)
At this stage I only have one 90 deg elbow (the 2 offcuts lying in the center are just supporting the elbow sticking through the hole), I'll see if I can get something tomorrow. As you can see the gas has to change direction twice.
(http://i133.photobucket.com/albums/q41/monsta904/P1000302.jpg)
Quote
so... this is where I'm heading.
This is really nice [thumbsup]
Really shows how much effort has to go into any idea you might want to try out.
It´ll be a while, but I´ll add to this story when I get around to making up my 2-2 megaphone exhaust for my track St2 bike.
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/DSC_0359.jpg)
looks like I'm doomed to failure! :(
I wish I had thought of this before I started...
I've blown air down the exhaust to see what sort of vacume there is on the other exhaust inlet.
I used a little bit of paper and it sucked straight in then blew straight out the the outlet.
proves there is a vacume.
Problem is, when I do it to the exhaust that I've fabricated there is no vacume, it seems very neutral.
And when I put an extension on the bends that I welded onto the crossover it actually starts to blow out the other inlet! :'(
So, I guess the bends that welded on are too tight and causing a bit of restriction?
I might have to just cut them off bit by bit to try and get them to mimic the longer radius bend of the standard exhaust?
If that dosn't work... throw it in the bin and put it down to experience! [bang]
(http://i133.photobucket.com/albums/q41/monsta904/P1000303.jpg)
ok, so all's not lost...
I was playing around today trying to suss a solution and blew air down the quat d, same as I did to the standard and my fab'd one...
Its actually blowing air back up the other exhaust inlet at about the same thats coming out the outlets...
that cant be a good thing??
so.. if mine's is neutral, IE; is not blowing out the other inlet, it's gotta be better than the quat d?? anyone? ???
Great stuff guys! I have always wanted to do something similar, but did not think that header lengths, radii and crossovers were that important. Guess I should've been clued in by the huge exhaust aftermarket!
So Monsta, why make your exhaust gasses bend again in the outlet? Why not just have them cross again with perforations or whatever, so that the right side of the original crossover outlet exits out of the left side of your fabbed box and vice versa. That would seem like an easier to build/less restrictive flow to me....thoughts?
Quote from: monsta on July 01, 2012, 05:31:59 AM
ok, so all's not lost...
I was playing around today trying to suss a solution and blew air down the quat d, same as I did to the standard and my fab'd one...
Its actually blowing air back up the other exhaust inlet at about the same thats coming out the outlets...
that cant be a good thing??
so.. if mine's is neutral, IE; is not blowing out the other inlet, it's gotta be better than the quat d?? anyone? ???
put some mufflers on the ends of the std headers and try it again. i'd give both std and aftermarket a go if you have them hanging around.
the quat-d is a complete system (that allegedly doesn't work, from what i've read power wise anyway). open headers are not.
but if it is pushing air back up the other header it can't be good. i'd shitcan the idea right there.
here's where I'm at ATM. not finished yet, just been ground smooth and soon to be sent off to be ceramic coated on the inside. then ill cc the bent/vert cylinder header and cut the straight/horizontal cylinder to match, weld on my cans and see how it goes!!
(http://img528.imageshack.us/img528/8277/photo23e.jpg) (http://imageshack.us/photo/my-images/528/photo23e.jpg/)
(http://img443.imageshack.us/img443/1906/photo24k.jpg) (http://imageshack.us/photo/my-images/443/photo24k.jpg/)
as said above, the horizontal cylinder pipe is too long in this pic, i estimate it to be about 14cm too long in this pic, so the can should move to under the rearset. looks much better when moved under the rearset. im still undecided on the cans, i was going to modify these to the style i want but i think ill just put it together as is first and sort that out after
(http://img9.imageshack.us/img9/5485/photo25ky.jpg) (http://imageshack.us/photo/my-images/9/photo25ky.jpg/)
Uploaded with ImageShack.us (http://imageshack.us)
Uploaded with ImageShack.us (http://imageshack.us)
well it certainly looks super cool.
That looks awesome [thumbsup] I really like the simplicity and routing of the vertical header/pipe! Kind of a Sport Classic Zard look.
[popcorn]
Thanks guys!! ;D
my thoughts, given in the vein of having my right to express your opinion and you having the right to ignore me without prejudice.
i appreciate the parallel lines you're going for, but given the pipes are quite a long way apart and non symmetrical side to side wise anyway the angle of the bottom one looks a bit odd to me. how about running it at the angle of the frame rail above the rearset (50 degrees going by holding the iphone up to the screen)?
or maybe a contrasting colour on the swingarm to help set the muffler off/make it more visual. it sort of gets lost in the swingarm to me. perhaps moving the muffler forward when you shorten the header will help keep it more in the bike so the speak.
altho i get the impression the top muffler would look different to how it looks in the photo once you can get a real life perception of depth on it.
did you do some dyno testing of different pipes?
with angles, i did intend on the cans being parallel to each other and the rail under the seat, i have noticed on the zard (after it was pointed out my design is similar [bang] ) that they have them nonparallel and contrary to my original thoughts, it doesn't look "off" on their design.
so maybe this is the reason for them being nonparallel on the zards as i agree something does look a little off in that picture, hence the mild disclaimer about lengths. in the above pic the bottom can is hanging by tie wire so it is not set at any angle yet. both cans do also slightly angle out horizontally (equally) which cannot be seen in these pics but looks quite nice in person. ill cut the front header to length, dummy mount the can and take another pic with it in the position i originally intended under the rearset and still parallel, then try and crank it up to a more aggressive angle and see what that looks like then too.
always happy to hear opinions and ideas, cheers brad.
oh and as for colours, thats all likely to change soon ;) i have some new parts to colour/refinish and then the cans/headers should make a little more sence. and yeah that includes a black swingarm
and i did spend a coupla hrs on the dyno with various pipes and have results but not conclusions, hence ive been a little hessitant to put them up on the forum. i believe it mainly comes back to the factory tune not being good with the split headers, then with a less than ideal tune the change in results with the different volume headers wasnt exactly linear.
sooo yeah, i think if i want statistically significant results i would really need to retune individual cylinder maps with atleast one of the sets of split headers if not each, and then observe the changes of afr/hp/tq from there. not something this little black duck has the resources to do unfortunately. :'( as it was i did keep the room conditions and engine temps consistent atleast but yeah it wasnt really enough.....
Nice work.
As far as cosmetics go, I think we all design (or sometimes, sort of end up with ...) a design we like. If others like it, nice, if not, well ... nice as well, as long as the creator likes it.
Of course, on the other hand there´s that old aircraft industry saying, "if she looks nice she´ll fly nice"; in my humble view those exhausts look nice, so they could fly well enough [thumbsup].
Anyway, s lot of what "design" work I do is based on what I think might work, so I have a few questions concerning these exhausts:
Are the megaphones in the pictures empty; i.e. "real" megaphones?
Why will you have them ceramic coated on the inside?
I´m a bit confused abouth header length and volume; do you use header volume as a way to measure length, or is header volume itself the design criteria?
If volume is the criteria, what is the theory concerning header volume?
Even if you won´t publish the dyno results, were there any trends that could be of interest?
I have a theory of my own concerning the stock "X" header configuration:
Since the "X" piece splits 2 different-length headers into 2 mufflers, with each header splitting into 2 roughly half-diameter branches, I think the "X" piece is designed to kill off any wave / resonance activity that might take place in the exhaust.
This would render the motor pretty insensitive to any exhaust modifications (excepting back pressure due to silencer flow resistance), enabling Ducati (and anyone else) to sell any style slip-on exhausts they could dream up, with tolerable effects on engine behaviour, especially considering the improved sound compared to the dull-sounding stock mufflers.
After all, some exhaust are slip-on in the original position, others are under-seat (or beside-the-seat), adding maybe 50 cm of header length. Normally, this would affect an engine noticeably, but I think a Monster will run at least reasonably with any of the Ducati aftermarket slip-on exhausts even if you do not change the mapping? ??? Or am I just beeing paranoid...?
please publish the results. this thread is more tech than idiotic petty pointer out of non perfection as some can be, and there's enough serious people contributing to make the info very worthwhile.
did the exhaust formula from the mv forum reach here? i forget now. haven't been there for ages. http://www.mvagusta.net/forum/showthread.php?t=43891 (http://www.mvagusta.net/forum/showthread.php?t=43891)
here it is, been around for a long time
the formula;
Length= 850 x Exhaust opening [degrees BBDC+180]/rpm[power peak]
the Exhaust opening is effective opening ie; 0.040-0.050" exhaust valve opening point, i used 1mm lift.
Diameter, the pipe must hold, from the valve to the end of the head pipe twice the cylinder volume.
D = 2x the square root of swept cylinder volume[in cc]/8.2/L/Pi
yeah it did brad, by you, here was my reasoning
Quote from: Roaduser on February 19, 2012, 10:27:57 PM
his formula for length is
850x [exh bbdc+180] / rpm @peak power
850x [57+180] / 8500 = 23.7 in long
that seems fair....
for diameter of pipe
2x the square root of swept cylinder volume[in cc]/8.2/L/Pi
2x square root of 400/8.2/23.7/3.14
2x square root of 0.655
2x 0.809
1.618 inch
and yeah, i will post up the results i have. I'm off for the weekend so ill aim at getting it organised on monday.
but basically the rear cylinder appeared to be running lean on the oem tune with split headers and this was a bigger negative than the various lengths of pipe. because i can't do split maps with a power commander i have since brought the ingijet u sent me and will use that to tune my bike to suit the split equal headers. i think this will give me the best results
MonsterHPD, these are not really megaphones by your definition, they are glass packed with a perforated inner tube and thus i wouldn't say the effective volume really increases much.
i want to have the headers (not the cans) ceramic coated on the inside to try and reduce the heat/browning of the pipes while keeping the brushed stainless look on the outside, just a theory, may not work but ehh worth a shot...
and as for volume, yeah I'm basically using it as a more accurate measure to maintain equal headers, the length is an easier way for some to measure but with the various bends i find the volume easier. I've tried to explain my thoughts on volumes/length in the quote below but from my dyno time i decided that the volume isn't near as important as matching the headers to each other and then tuning accordingly. so i made the rear cylinder to look good and will cut the front to match its volume, and being the same diameter pipe they should then be equal length.
from the above formulae and link i believe the volume and length are both the determining factors in tuning pipes and the diameter is a by product. once you have done the theory and start building the diameter becomes a constant and the length becomes the variable. as for wether the volume or length is more important, i don't know, but it matters little now for my setup anyway. Equality is my goal
Quote from: Roaduser on June 26, 2012, 01:41:10 AM
when one header has a pressure force that passes the merge it creates a negative pressure in the non firing header and helps remove waste and, depending on cam profiles, possibly suck more inlet gases into the non firing cylinder. that theory prevailing, your scavenging is happening at the merge and dependant on the header pipes before the merge and the characteristics of the merge itself.
another theory is that where the pipe area increases dramatically (commonly the merge area, or in zoomies/split pipes the end of the pipe) there is a wave that returns back up the firing cylinders header till it hits the valve or cylinder, then returns again out the header and that can aid in scavenging of a firing cylinders own wastes/aid inlet gases. this theory is the tuning of a header pipe and thus the timing of the return wave is effected by the length and volume of the header pipe before the merge/termination of the pipe. this is thought to then only have a positive effect at one point in the rev-range and thus a different length of header can increase performance in a different area of the rev-range and have a negligible or negative effect at others. as the wave will be at a constant speed and timing from when the valve opens, it depends on the engine speed/valve timing as to when and wether the wave is synchronised and having a positive effect on the cylinder.
Roaduser,
thanks for the info.
I´ve used header length and id as the design parameters, altho different sources quote different formulaes or otherwise to determine the correct values. I´ve found some different formulaes over the years, and I´ve made a compilation as per below (hope the document comes out OK ...):
Edit: Did not come out that great, but at least marginally decipherable....
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/Headerlengthcopy.jpg)
M&S is Morrison and Smith, who wrote the book "Scientific design of intake and exhaust systems" long ago; their formula give a length that is not engine speed dependant. CW is a formula I found in an old issue of Cycle World.
I have basically used the orange "medel" (meaning average in swedish).
Whatever formula is used, the result is very dependant on the exhaust gas temperature, since the sonic wave speed is dependant on the temperature, values between 1400 fps and 1700 fps beeing quoted in different sources. Since exhaust temperature will vary with load, there is a further uncertainty here.
Several other sources I have found also recommend to aim for an engine speed approx. 1000 rpm below peak engine speed, since the scavenging effect will have effect maybe 1000 rpm each side of the "best" effect.
I do think that header diameter is important, and from all I have seen the 2V duc motors do not like too big headers. I have used 38 mm id tubing for the bikes with stock valve diameters, I would have liked to have 40mm or 41 mm for the big-valve ST2 engine but could only find 43 mm id.
The length and diameters you have chosen seem to be right in the rule-of-thumb ballpark ( 23.7" <=>602 mm; 1.618" <=> 41mm) . As you noted, getting better than that requires testing for which we as ordinary people do not hve the resources. I don´t think the results would justify the effort anyway, unless we´re dealing with heavily tuned engines.
To determine length of the headers I´ve used a piece of as-big-diameter-as-possible hose that I push through the header and mark up the ends of the header on the hose, pull it out again, and measure. Not exact down to the last mm, but easy to use and also easy to determine the length of each section before they are welded together, and assembled sections only tack-welded together.
The result of the ceramic coating will be interesting. I probably cn not use it even if it works, since I´ve never heard of anyone providing that in Sweden.....
seems you have done some research on the topic!! [thumbsup] so if I'm reading right, basically that graph is showing the ideal header length for max performance (hp or tq?) at a particular rpm assuming everything else is constant. supports the theory we have been discussing nicely. so theoretically i am in the right area, but as with my tests its everything else that is making more of an influence on the outcome than the actual header length/volume. so the conclusion I'm coming too is keep the diameter around the 38-40 mm range and the length anywhere between 1000 and 600 as long as the headers are equal and looking cool!! [Dolph]
here is the raw graphs from my testing, feel free to analyse and draw your own conclusions. And yes i realise how lean this engine is running, lets think of it as a calculated risk that i took when i decided to continue on with the testing... ;D
my basic conclusions from this is that my tune is crap, split headers make the std tune even less suiting, the length of headers is not significant in this test especially when compared to the effects of a bad oem tune, and i think/hope that when i finish my pipes and tune the individual cylinders to suit that i will be able to overcome the power loss shown in these graphs and possibly even improve on it a little..... but i dunno about the low end torque, there is a LOT being lost here.. :'(
Base run with shortened Remus DP highmounts, TPO beast inlet,
(http://img811.imageshack.us/img811/7834/baserun.png) (http://imageshack.us/photo/my-images/811/baserun.png/)
alltogether hp vs AFR
(http://img171.imageshack.us/img171/963/basevsallfrontcylinders.png) (http://imageshack.us/photo/my-images/171/basevsallfrontcylinders.png/)
altogether torque
(http://img716.imageshack.us/img716/4932/torque.png) (http://imageshack.us/photo/my-images/716/torque.png/)
600ml headers front vs rear cylinder
(http://img651.imageshack.us/img651/2622/600mlfrontvsrearcylinde.png) (http://imageshack.us/photo/my-images/651/600mlfrontvsrearcylinde.png/)
Uploaded with ImageShack.us (http://imageshack.us)
looking at this in a little more depth,
*i think its fair to say that once tuned, the 1000ml split headers would produce the highest top end power
*all sizes of split headers have a chance to produce more midrange power
*all sizes of split headers will probably lose bottom end torque unless i can pull it back with timing etc
*my clutch is starting to slip
*the front cylinder runs leaner
*with the 600 ml header comparison, the front cylinder was tested first and the rear second, so its possible that higher header temps could have had an influence on this.
Very interesting.
I´ve been digging in my files and dyno runs, unfortunately I´ve not been as thorough with making notes as I should.
I will post some dyno runs and pictures here, even though they´ve been on the forum in other threads already; I think they are relevant here so bear with me.
Concerning split headers, your claim that split headers will produce less bottom end torque seems valid (i.e., on a general level).
The link below will take you to a race team running (at the time) an 800, and dyno runs from an (unknown) 2-1 system, and a split-header (i.e., 2-2) system with megaphones: The 2-1 system is clearly better at low revs.
While you´re at it, take a look at the rest of their storys also, quite interesting.
http://beta-evo-db1.blogspot.se/p/2010-beta-evo-mk2-specs.html (http://beta-evo-db1.blogspot.se/p/2010-beta-evo-mk2-specs.html)
My own experiments with various-length open headers, and then the full 2-1 system, shows the same trend:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/HPDHeaderLengthComparo.jpg)
I have no real idea why the full system was also better on top end, but so it seems to be. Certainly room for more investigations here.
The next graph shows comparison between my 2-1, and stock with slip-on:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/graf900.jpg)
It´s not a direct comparison, since the 2-1 graph also shows the effects of an open air-box lid and PCIII.
They don´t start at the same RPM either, but at least it seems likely that they would be much the same below 3000 RPM or so. If the difference after that is down to exhaust or to airbox+PCIII, I don´t know but at least the 2-1 is not worse that the stock X-junction. I think.
Last, a comparison between my Monster 2-1, and the rain-bike 2-1:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/IndraHPDComparo.jpg)
The systems look quite different:
Monster 2-1:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Tv-tillett_1.jpg)
Rain bike 2-1:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/IndraExh1.jpg)
In spite of the systems beeing quite different in layout, they give pretty similiar results, maybe the better result on the rain bike at lower revs is due to the 2 headers ending close to each other in the Y junction.
Having looked into my "Scientific Design of Intake and Exhaust systems", I have a theory concerning the difference in low-end torque between 2-1 and 2-2 (please note: a theory, I don´t know).
The 2-1 system uses "independent" headers designed to be long enough to work without influencing the other, and returning a negative-pressure pulse to the exhaust valve during overlap.
On many 4-or 6-cylinder engines, Y-shaped headers connecting cylinders with even firing intervals are used; these systems are called "Interference headers". They often give better low-end torque since the "dead" branch of the Y acts as a resonator, increasing the amplitude of the pressure pulses and thus increasing the vacuum on the still-open exhaust valve at valve overlap.
This works well enough to have some people put a "dead" pipe on headers without a cylinder to connect to, just to get the resonator effect. Hard to incorporate on a bike without styling impact, though ...
Some of you might also remember the Y-type exhaust systems sold by Dunstall for Hondas, Nortons etc. in the 70´s. Worket great at the time, at least. They were designed by the late and great Gordon Blair at some university in GB.
My theory is that the non-working header in a 2-1 system work as such a resonator, working only at very low revs since it is so long.
In my case, I will be using the megaphones for a track bike, so a little loss below 4000 or so RPM is OK if I gain something at higher revs. For a commuter bike, this might not be so.
It will be very interesting to see if there is any change if you change timing etc., and also to hear your riding impressions.
i don't think there'd be enough in the tuning to make the short headers of any length better as such. but i'd say they'd not be much worse, if any. maybe under 4,500 rpm.
i think tuned right it'd be pretty good with any of the headers, although it's funny the long ones get hurt b/w 5,5 and 7.
how long or what volume are the std headers up to the stamped cross?
The stock system for the M800 mesures as follows:
Front header: 550 mm from flange to "stop" in the X stamping;
Rear header: 470 mm.
Measured very quickly with the hose-in-the-tube method, so maybe 10 mm tolerance either way. In any case, the rear header is markedly shorter.
On a very general level, the 1000 header (i.e., 1000 mm?) is better at low revs (<5000 rpm) and worse at higher revs, which is probably what could be expected. Not much of a difference between any of the configurations > 8000 rpm, though.
well the hose method says i need to trim off 5 cm, but by liquid volume i need to trim off 14cm. so the question is are "equal" headers better to be the same length or volume?? i can only assume that even tho they are mandrel bends they are still slightly resreicted and over the length of the header this is making a difference.
im leaning towards volume right now as that will give me a better looking system! [thumbsup]
Well,
you have your dyno curves and know what you get so no need to worry about that, I think [thumbsup]
I will also make a hose vs. volume test as soon as I have a loose header and some resonably accurate measuring glass os similiar, can´t see why there should be such a difference ....- ???
[popcorn]
Lovin' this thread.
hey monsterhpd, i finally got some time to read your above post properly!! it is interesting how clearly and how much more midrange torque that you got with the split headers, no small cookies there. Yet the loss your showing on the top end isnt small cookies either. Did u happen to log the AFR, maybe the fueling was way off on the top end? When did you do these dyno runs, was this in response to my tests or had you done this long ago? and were they back to back runs on the same day?
with your second graph, it is a pity thats combined with the pcIII but that is another great improvement to the midrange torque! your 900s are proving to be torque monsters!
on your last graph, that looks to be ahell of a flat spot at 6-7k. that isnt shown on any of your other runs, whats going on there?
http://www.accessnorton.com/pictures-dunstall-exhaust-t8494-15.html (http://www.accessnorton.com/pictures-dunstall-exhaust-t8494-15.html) some pictures of the dunstall exhaust you were talking about, for reference to future readers.
im too far in to pull out for any reason now. so we will know soon enough if the split system, properly tuned, will result in a significant enough low end loss to effect commuting. i can always make another or revert back to the remus system if all turns sour (SHUDDERS!!!) ill attach some upto date pics of mine below in a moment.
straight and long
(http://img191.imageshack.us/img191/6479/photo29hg.jpg)
straight and shorter
(http://img443.imageshack.us/img443/8545/photo30n.jpg)
angle to match rear can
(http://img152.imageshack.us/img152/5571/photo28ls.jpg)
agressive angle
(http://img827.imageshack.us/img827/6324/photo27qv.jpg)
slight kick up and walk around
(http://img208.imageshack.us/img208/3229/photo34p.jpg)
(http://img209.imageshack.us/img209/49/photo33rn.jpg)
(http://img829.imageshack.us/img829/1035/photo32cc.jpg)
(http://img99.imageshack.us/img99/7660/photo31do.jpg)
and that is what i ended up going with. the bottom of the can is level to the header so it shows a slight kick up. i didnt take a rear shot of the final but it is tucked in a bit more than the earlier trial shots. i ended up using a second exhaust seal ring thing in the front cylinder to give me a coupla mms extra needed to tuck it under the rear sets and have the header run true to the bike.
(http://img269.imageshack.us/img269/3681/photo26or.jpg)
maybe one day ill bother to walk back upstairs and get a decent camera... ;D
[clap]
Nice thread!
I have 2 thoughts (having only read this last page):
1) I'm still impressed by the foul looking X collector from 90's dual sided swingarm Ducatis. With MBP heads, Pongo made 104hp using the standard m900 header and 2" diameter mufflers.
2) any work done on previous generation 2V pantah heads with bent intake ports is wasted effort. Get a 796 engine & watch real results happen. All the old motors are handicapped by that intake port. :(
Oh, and 3: I have a set of MBP heads for 800 / s2r 800 that were intended for my bike sitting on the shelf. it'd be nice to sell them to help fund the projects we have in the works. Real projects, not me wasting time & $ on my bike that I don't ride enough. :P
Yaay,
Chris
Quote from: chris on August 09, 2012, 12:59:31 AM
Nice thread!
I have 2 thoughts (having only read this last page):
1) I'm still impressed by the foul looking X collector from 90's dual sided swingarm Ducatis. With MBP heads, Pongo made 104hp using the standard m900 header and 2" diameter mufflers.
2) any work done on previous generation 2V pantah heads with bent intake ports is wasted effort. Get a 796 engine & watch real results happen. All the old motors are handicapped by that intake port. :(
Oh, and 3: I have a set of MBP heads for 800 / s2r 800 that were intended for my bike sitting on the shelf. it'd be nice to sell them to help fund the projects we have in the works. Real projects, not me wasting time & $ on my bike that I don't ride enough. :P
Yaay,
Chris
if your reference to pantah heads was with concern to my bike, they arent pantah heads. they are the original m800 heads from the bike, so practically the same heads as the 796. i was just mucking around with some raw pantah belt covers i had sitting around. im looking at polishing them and a spare clutch cover i have just for something a little different to what everyone else is doing to the late model monsters.
what are MBP heads?
Yeah same heads as on my s2r 800 with pantah style bent intake ports. 100ds, 1100, 696, 796 are different casting and actually flow...
Yeah 796 is same bore & stroke but not the same engine...
Quote from: Roaduser on August 09, 2012, 01:42:04 AM
if your reference to pantah heads was with concern to my bike, they arent pantah heads. they are the original m800 heads from the bike, so practically the same heads as the 796. i was just mucking around with some raw pantah belt covers i had sitting around. im looking at polishing them and a spare clutch cover i have just for something a little different to what everyone else is doing to the late model monsters.
what are MBP heads?
pretty sure the 800 heads are similar to the 695. the bump from 695 to 696 in power comes from the new head configuration.
ahhh well there you go, i didn't know that. are the barrels the same, are the heads a bolt on?
from the sites i have checked so far, people are listing the 696 as about 5hp up, but torque as the same or slightly less than the 800. so from the impression I'm getting here, they may be similar in oem form but once tickled the later motor will go in leaps and bounds compared to the 800??. looking at the site for MBP it sounds good, but i guess expensive compared to just getting a 1000ds to start with! how much would u want for the heads u have Chris, just outa interest.... [evil]
I'm not really after more power, quite happy with what i have tbh, I'm just tinkering for tinkerings sake. basically because i got sick of tinkering with the car and getting nowhere so i started on the bike. ill get to that point on this bike soon too and move on. i have an xs650 sitting there begging to be played with and a nice old muscle car in the parents garage beggin to commandeered.
I had to search my memory in order to remember roughly how the dyno session went. All the runs were made on the same day; the mapping with the complete system was made first, then the header length runs were made with the same mapping.
I forgot to mention the complete system run was made with the, well, complete system, meaning the headers are 700 mm long. I could not run that version with the bare headers since that would have roasted the rear tire. This means that that run reflects the effects of the shortest headers as well as the collector / silencer.
I would like to repeat this test with a really large-diameter collector I could slip over the header ends on all versions, but I don´t have access to the dyno any more (the operator / friend has gone to another company).
We had some problems with the lambda equipment, but I don´t remember how we eventually did it. We also ran into the dreaded "Nemesis misfire", even if we did not know what it was at the time, so the testing was not quite as systematic as it could have been.
As an interesting side; when we did the header runs I was standing beside the rear wheel (stupidly), holding the exhaust extractor cone against the headers. The pressure on the cone from the exhaust at full throttle and 8000 rpm was amazing, making me understand why the F1 guys are (were) so hot on blown diffusors.
Anyway, here is the same graph, with AFR. Some of the AFR numbers I do not really believe.
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/HeadercomparowAFR.jpg)
With this result in mind, I have settled for 800 mm headers for any 2-1 system I might make in the future.
I do not have any explanation exactly why the full-system graph is so different, but there clearly would be some potential here.
On the stock-with-slip-on vs. 2-1 /PCIII/Open lid comparo, the slip-on is clearly quite lean, I don´t know how much that would affect torque. Maybe Brad could give us a hint here, I don´t know anyone with more Duc mapping experience than him.
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/Fuel900.jpg)
The last graph compares a 2-1/PCIII/Open lid Monster run with the Rain bike 800 mm header 2-1 with no-snorkels airbox and some unknown rather rich chip in it. (it has the old 1.5 or 1.6 ECU, so it´s not so easily mapped as the Nemesis). The different runs are just repeat runs to make sure the reults were reasonable; AFR is pretty OK.
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/IndraHPDAFRComparo.jpg)
I´m also pretty impressed with the stock X collector, as it seems to work very well; I think most of the improvement on a stock bike with a full system is due to lower back pressure. However, they do ground easily and I wanted a 2-1 as tight as possible on the bike along with the tucked-in rear-sets.
Your bike looks very nice with the split headers and megaphone silencers, I think it will work just OK [clap]
Nice also to hear you have an XS650. I had one for may years before getting the Monster, 860 cc, Mikuni 36´s, re-profiled cams and (you guessed it) a home-made 2-1. Since this is a Duc forum, send me a mail if there´s anything I can help you with.
And oh yea, Duc forum or not, a nice Commando is a very handsome bike. A pity they are no longer around :'(
(not counting the new version....)
No action on this thread for a while, so I figured I´d give the hose vs. water header length measurement methods a go.
The only header I had available is the stock Monster 800 rear header.
Hose method first:
Hose in header, mark with a few turns of plastic tape:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/DSC_00022_crop.jpg)
Pull out, and measure (the hose is stubbornly opposing staying straight, and I only have 2 hands):
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/DSC_0003_crop.jpg)
Measured this way, the header is a shade over 400 mm, including the part that will go into the "X" collector.
Next, the water:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/DSC_0004_crop.jpg)
The header took 432 ml (or cc) to fill. With an outside diameter of 40 mm, and a wall thickness of 1.5 mm resulting in an inner diameter of 37 mm, the length works out as L= 4*432 /(Pi*4*iD*iD) = 40.178 cm, or 402 mm.
In other words, in this specific case both methods give essentially the same results. For my personal use, I´ll use the hose method since it allows me to measure individual pieces as well as partially or fully assembled headers, push-jointed, tack-welded or finished. I will check the water method on a longer piece of header whan I have them off the bike, lets see what that might show.
Back again... [thumbsup] been awhile, but I've still been chipping away when I get a bit of time. (havn't been getting to much of that)
Anyhow, I've set up a system that I use to test the flow. Its far from perfect because there are many variables.
I'm doing the same as before with the a blower jammed into exhaust , but using a bit of paper held over inlet/outlet to observe what it does.
(http://i133.photobucket.com/albums/q41/monsta904/CIMG3123.jpg)
(http://i133.photobucket.com/albums/q41/monsta904/CIMG3124.jpg)
(http://i133.photobucket.com/albums/q41/monsta904/CIMG3125.jpg)
What I've found is that the standard header has a good suction from opposite exhaust(less with exhaust can fitted), but the cut down X section is fairly neutral.
When I fit a bit of tube to the cut off X section it draw's much better, showing that it needs a bit of length on the exit to make it work.
With the tight radius donut bends on the outlet it actually pushes air back up the other exhaust (like the quat d) showing (to me) that the bends create a bit of restriction.
Because I dont have the room to add a straight or large radius tube on the outet, I thought I might go down another path.
So, I cobbled up a Y peice that will fit inside the box and tested that.
(http://i133.photobucket.com/albums/q41/monsta904/CIMG3179.jpg)
It had similar results, also needing a bit of extra tubing on the exit to make it work, but probably not quiet as good as the X section.
I think there are other factors involved as well such as the angle they join at. But I'm not sure, I'm just bumbling around...
The other thing to factor is that I cant have the exit to close to the wall of the box, as that also creates a restriction send air back up the opposite exhaust.
Anyhow, I think I may go back to plan A and just button it up and hope for the best. I really would like to get it done and clean up my work bench! [roll]
Maybe the extra pressure the engine creates will make it work better than the low flow air blower I'm using? [beer]
well after about 18 months with this thing sitting on my bench at home I finally found some time to finish it off! [beer]
In the end I did 4 different configurations to try and get the air to flow. The one that I ended up with seemed to flow 'nearly' as good as the stock manifold.
Getting the pipe to create a vacume at the other cylinder was definately not as easy as I thought it would be!
I'm guessing it will be WAY better than the xbox but maybe not as good as stock!
I wont know for a while because I havn't put it on the bike and its getting ceramic coated at the moment, then I'll be away for about 5 weeks.
(cant wait tho! 8) )
heres a pic of the nearly finished job, just had to clean up the welds...
(http://i133.photobucket.com/albums/q41/monsta904/exhaust1_zps729103ae.jpg) (http://s133.photobucket.com/user/monsta904/media/exhaust1_zps729103ae.jpg.html)
Great job, I´m so pleased to see this one go live again [thumbsup]
Enjoy your 5 weeks away, but keep us posted when you get the system installed, and up and running. That will be SOO interesting.
well, finally got it on!
Mostly pretty happy with it, though it kinda loud! [evil]
Makes the power that I expected, a lot better than the X Box! second gear wheelies no problem and 3rd if I get the rev just right...
heres some pics,
in this one you can see the standard header and cut-off pipes that I originally had on it. The paper is neutral. doesn't really suck in or blow out. ( I've got a blower pumping air down the opposite exhaust)
(http://i133.photobucket.com/albums/q41/monsta904/P1030653_zpsa5507f84.jpg) (http://s133.photobucket.com/user/monsta904/media/P1030653_zpsa5507f84.jpg.html)
this is the one I made, pretty similar, paper is neutral...
(http://i133.photobucket.com/albums/q41/monsta904/P1030651_zps563befaf.jpg) (http://s133.photobucket.com/user/monsta904/media/P1030651_zps563befaf.jpg.html)
this is the Quat D, Blows out hard! that would be going back up the opposite exhaust. I'm no guru, but I don't think that's a good thing!
Hence the power loss.
(http://i133.photobucket.com/albums/q41/monsta904/P1030652_zps05955e36.jpg) (http://s133.photobucket.com/user/monsta904/media/P1030652_zps05955e36.jpg.html)
And here's how the finished product looks... I may try packing it with stainless gauze and see if I can quieten it a bit, but I think it will be a balance between noise and power because its so small? you can see I have put an inspection cover on it so that I can still play around with it...
(http://i133.photobucket.com/albums/q41/monsta904/exh_zpse7f282b8.jpg) (http://s133.photobucket.com/user/monsta904/media/exh_zpse7f282b8.jpg.html)
(http://i133.photobucket.com/albums/q41/monsta904/P1030667_zps3b04f61f.jpg) (http://s133.photobucket.com/user/monsta904/media/P1030667_zps3b04f61f.jpg.html)
Cool, looks great, exhaust, bike, all [thumbsup]
I think that´s a great bike you have there.