I'd edit your post, and add 'anese' after 'jap'wickedgreyzx3 said:they did this in the neon's forever, and finally the japanese
lol honda's 90ftlbos of torque is now 60ftlbs
aero_student said:Backpressure has nothing to do with torque, I'm sick of that myth and all the idiots that perpetuate it.
The intake in front exhaust in back is the most logical orientation.
Originally posted @ FJ
What about backpressure if i put a 3" exhaust on my car?
This is the question I pretty much hear from everyone. The truth is, backpressure is NOT what you need to worry about. Backpressure is only the measure of restriction in the exhaust. You need to worry about EXHAUST GAS VELOCITY the most. You also need to worry about SCAVENGING, which has a direct relation to the velocity of the exhaust gases. Let me explain a little bit better. While your car is running, there are exhaust gases constantly moving thru the exhaust tubing. These gases moving out of your exhaust tubing can also be used to "pull" exhaust gases out of your cylinders. This situation is called scavenging. Typically, the faster the gases are moving, the more benefits you get from scavenging. Keep in mind that your exhaust header/manifolds affect the scanvenging a lot also, but I will not go into that right now. Heres where it gets a little tricky.
The larger the tubing, the SLOWER the exhaust gases are flowing. This will cause LESS scavenging, but will flow MORE than a smaller tube.
The smaller the tubing, the FASTER the exhaust gases are flowing. This will cause MORE of a scavenging effect, but will flow LESS than the larger tube. If you reduce your tubing size too much, the benefits of scavenging will quickly go away and you will be stuck with tubing that is too small for your motor...period.
People always claim they lose low end TQ because of the "backpressure" they lost with a larger exhaust. What they are really losing is the scavenging effect.