Well iv been hearing that if you run open headers you will warp valves. Is this true? Thanks!

 

i think the general idea is that open exhaust causes the exhaust valve to heat up and warp.

im not really sure how true it is but i think on a street engine running open headers wont kill the motor but its probably not the best thing to do

 

http://www.uucmotorwerks.com/html_pr...torquemyth.htm

Read that. Backpressure used to be an issue with old carb engines, but there are no worries on newer fuel injected motors. The idea that a certain amount of backpressure is needed for your engine is a myth.

 

Very interesting read, sending it to all the backpressure believers.

 

I thought the concern with open headers was not backpressure, but that oustide air might reach the valves?

 

On our cars, the only concern you need to have about running open headers is that more air gets to the O2 sensors, causing the PCM to think the car is running lean, so it adds more fuel, and you burn super rich.

 

Ahhh sounds reasonable.

 

Back pressure is a myth, scavenging is not. The reduction of size than adition of size when it enters the Y pipe and exhaust creates a venturi effect. Thus pulling exhaust out. We have seen it with our own eyes on a chassis dyno that a good long tube header with a good exhaust makes more power than open headers. In some extreem cases the exhaust might be a restriction. So I think the question isnt will it hurt my motor, but more along the lines of will it help my performance? Just my .02.........prorac1