Originally Posted by Foghorn

I think that statement is only true if you put it in the proper context - less backpressure works best at WOT runs such as 1/4 mile acceleration.

Cylinder scavenging is an important component in achieving volumetric efficiency. At low rpm, or part throttle, if there is little or low backpressure, you're not going to exhaust suffiently well enough because of low volicity. By using the pulse and pressure difference of other cylinders, the velocity can be maximised therefore allowing more complete exhaust of spent gas front the cylinder and a better intake charge - this accomplishes better volumetric efficiency and gives better throttle response.

Since most of us drive our cars under a variety of load conditions, it'* neither correct to say you need a lot of backpressure nor to say backpressure is your enemy. If you want only to maximise the performance of your car for one driving conditon, like WOT, then you could optimise the exhaust for that condition only whereby you'd want little backpressure. On the other hand, if you rarely went WOT and wanted better drivability and throttle response around town, then you'll need backpressure but you'll suffer at the track.

Like many things, backpressure is a comprise condition in response to a variety of demands we put on the engine to respond under loads.

Hope this makes sense...

Cheers,

Originally Posted by DrJay

haha yeah the smaller pulley is well worth it I'd say. Between it and the filter its like I put another engine in the trunk.

Has anyone looked into the backpressure thing any? The octane thing is done (I think) so I'd like to hash this out if anyone is into it....if not oh well

Originally Posted by DrJay

I've been told I should be

My deal isn't so much with debates, which I do enjoy...If I'm right! haha
I've just been doing a lot of research and come across a few myths that I feel people should be aware of. At least I believe they are, if I'm wrong I'm wrong but with that I realize that it will take nothing less than a debate to convince people. Hell the octane thing took 6 pages to quell.