[Monsterlover]

9000 M900ie

My thinking is that if i build a straight pipe exhaust (not really straight, just no mufflers) the air fuel ratio shouldn't change much at all, since the factory head pipes are still in place. Right or wrong?

Kevin

 

[Speeddog]

It will change the mixture running straight pipes. Essentially no flow restriction compared to the stock mufflers. It will definitely run leaner, as the engine will flow more air for a given throttle/RPM combination, but the ECU won't know to add more fuel.

There was someone here that ran with just the header for a while, but I can't remember who....