Something's been bugging me for the last few weeks so let me throw it out there for everyone to comment:

Since the newer Monsters run closed loop ECU in stock state, does that mean you can open up the airbox and the OEM ECU will tune it to the factory state of lean-ness with more HP?  My thinking is with an open airbox and stock exhaust, you are pushing through more air which will be read by the O2 sensor as lean which will cause the ECU to increase fuel mixture which increases HP.  Granted this would only work if the stock O2 sensor is working properly.  That means, for now, only the stock exhaust and ExBox could work.

Comments? Anyone with a stock bike that is willing to test out this theory? 


P.S. I will be happy to test pony if someone can help me figure out how to keep the air filter in place w/out drilling the airbox cover.

You could tape the air filter on, the blue masking tape that painters use is pretty sticky, but not *too* sticky.

Exactly which bikes have a closed loop ecu?

The O2 sensor is only closed loop for low throttle openings to meet emissions. When you open the throttle wide it goes open loop and fuelling is based on the inbuilt map which is designed for the stock airbox so removing the lid will result in a lean mixture.

Quote from: CDawg on October 09, 2008, 10:35:25 AM
Something's been bugging me for the last few weeks so let me throw it out there for everyone to comment:

Since the newer Monsters run closed loop ECU in stock state, does that mean you can open up the airbox and the OEM ECU will tune it to the factory state of lean-ness with more HP?  My thinking is with an open airbox and stock exhaust, you are pushing through more air which will be read by the O2 sensor as lean which will cause the ECU to increase fuel mixture which increases HP.  Granted this would only work if the stock O2 sensor is working properly.  That means, for now, only the stock exhaust and ExBox could work.

Comments? Anyone with a stock bike that is willing to test out this theory? 


P.S. I will be happy to test pony if someone can help me figure out how to keep the air filter in place w/out drilling the airbox cover.

Within (unknown) tolerance, yes.  You would need to remove the lid and monitor 0₂ voltage to confirm.  If the volt meteror scope spensd too much time on the rich or lean side then the answer is no.

Quote from: Jethro on October 09, 2008, 12:00:56 PM
The O2 sensor is only closed loop for low throttle openings to meet emissions. When you open the throttle wide it goes open loop and fuelling is based on the inbuilt map which is designed for the stock airbox so removing the lid will result in a lean mixture.

That is a VERY good point!  Case closed.  It doesn't work with RPM>5100 and throttle>20%.
Thanks for the everyone's input!

I can tell you based on my butt dyno, that the answer is no.

I run cored pipes and no lid. (filter is taped to the airbox)

Quote from: Jethro on October 09, 2008, 12:00:56 PM
The O2 sensor is only closed loop for low throttle openings to meet emissions. When you open the throttle wide it goes open loop and fuelling is based on the inbuilt map which is designed for the stock airbox so removing the lid will result in a lean mixture.

Doh!  Jethro is totally correct.  Somehow I missed his post and forgot about the open loop simultaneously.

Quote from: CDawg on October 09, 2008, 10:35:25 AM


P.S. I will be happy to test pony if someone can help me figure out how to keep the air filter in place w/out drilling the airbox cover.

If you've got the clips on the lid like I do, leave them mounted in the bottom of the airbox and run zip ties across to the other side. I've got about 10k miles on like this.

i id that, and i lost a pin. i used plyers to pull it as tight as i could too.

Duct tape is better.