I was curious about the ECU mod involving crossing the two wires under the seat to remove the rev limiter and fuel cutoff. I noticed that it said the only noticeable difference is above 13k rpm. Well the stock rev limiter is somewhere between 15k and 15.5k, so why would there be a difference under the rpm? Also, why would you want to go past that rpm? Thanks.

 

There is a certain RPM in which maximum horsepower is achieved. You go anything past that and you're just "spinning your wheels" - .

So basically you've got 13k until 15.5k (if that) to make your money.. or in this case, more money.

 

The ECU JUMPER MOD affects Top-End power such as when racing at WOT.

 

Correct, but after 15.5k, there is only power to be lost (hence why we shift). Also, only a few more RPM and you hit the float point for the engine, which in turn destroys it. As far as I can tell, having the fuel cut and RPM limited at 15.5k saves the engine while not affecting lap times. Am I wrong?

 

That 15.5K redline is only indicated and not actual. The actual redline is 14,750 rpm. The Race ECU raises it by 500rpm which is really made for the ZX6RR's because of the forged pistons. The 636's have cast pistons which can't really handle prolonged extremely high rpms. Like dc said, the valves start floating and you start losing power or could smack the top of the pistons with the valves resulting in catastrophic engine failure. That is why you should never free rev the engine to redline or during a burnout. There is no resistance and it will easily over-rev past redline.

 

Ok, I understand now. Thanks for the clearity man.