Floating a valve?

[MRPoopie]

how likely is it to float a valve with a rev box / performance CDI is it true that you have to replace valve springs with better ones to make up for the extra rpms?

much help appreciated

Thanks
Clayton

[SWIGIN]

the factory has a rev box for a reason....i say get spring

[smokinwrench]

I say very unlikely. Most rev boxes only raise the prm's 1,000rpm.

My question is does a rev box help? If the mfgr. designed the quad with a 9,500 rpm rev limiter, then shouldn't that mean they designed it to get all the power out of it at the 9,500 rpm point or very close to it.

As for my predator a rev box wouldn't help me any because I never hit the rev limiter. My power band is gone long before I hit the rev limiter. Just some stuff to think about.

[MRPoopie]

well if you had two of the same motors same hp and everything but one reved higher than the other by a 1000 rpms which do you think would be faster top end


Clayton

[smokinwrench]

well if you had two of the same motors same hp and everything but one reved higher than the other by a 1000 rpms which do you think would be faster top end


Clayton

I think the one with the higher rpm would win in a top speed race. I also think that in a 300 foot drag strip they would be tied. Once you run out of power in your rpm range, it doesn't help to keep revving your engine higher.

[MRPoopie]

well the rev box changes you power curve and shift points and add some hp making your top end better

[smokinwrench]

well the rev box changes you power curve and shift points and add some hp making your top end better


I have heard that also but I also know that my cousin with a higly modded yfz was on the dyno for about 30 runs one afternoon changing everything. His high dollar aftermarket cdi done nothing for his dyno run. Power was the exact same everytime on every setting.

Buddy of mine put a aftermarket cdi on his predator. He couldn't keep ti running after that. Cdi caused it to start hard and die when hot and not restart.

After being around both of them, you won't see me buying an aftermarket cdi. My troy lee predator could use one because of the huge gap between 4th and 5th. I installed a full exhaust sytem and aftermarket intake that took care of the problem.

It might be a good investment on a Z400 but I have not seen any proof for me to spend that kind of coin on an aftermarket cdi. I would do some research before I bought one. I work way to hard for my money for a product not to work.

[willcamach]

the brp ds650 absolutely needs a rev box its sucks ass without one. so i would say they are worth it for certain engines.