Backpressure

[Spikers400]

I have an HMF and at the track iv been running no quiet core. Ive heard a number of times that not having enough back pressure can have ill effects on the motor, especially the vavles. Is this true? Does the hmf provide enough back pressure? My jetting is just about perfect, and there is no popping. I doubt that they would engineer sumthing that would kill the engine but it doesnt look like the hmf gives any backpressure seeing how its just an open high flow can. Any input would be great.

[cals400ex]

you shouldn't have any problems. we are almost all running straight thru exhaust systems. :D

[Spikers400]

haha yea they are pretty nasty.

[MIKE400EX]

The valves shouldn't get hurt from low or no backpressure. Unless there is a leak near the head that is letting cold air hit the valves during the I/E overlap period (or if the exhaust system was really really short). Most of the aftermarket pipes are more or less straight through.