Join Date: Dec 2004
Location: Fishers, Indiana
The pipe size is a reflection of the engine power so the more power then the bigger those pipes need to be. Most stuff you see at the drag strip is 600HP or less and a 2 1/2 to 3" pipe is right for that.
A longer pipe also helps your low end torque as compared to an open header. What NAB said is correct and most drag cars vent the exhaust before the axle or out the sides so they don't face the restriction of the bends needed to go over the axle. Those bends add a lot of restriction over the normal straight pipes or open headers.
I bet I'm the only fast car that runs a full exhaust over the axle to the back bumper with mufflers on every pass, no open pipes or headers. I have blown pieces out the 4" dual exhaust so that tells you how much pressure is there and why no one does this in drag racing. I only do it because it's one more thing that makes this car different than what you are going to normally see but it's not the best way to do things.
So a smaller right size pipe will make you faster than a pipe too large as that will push your power band way up or beyond your RPM range. 2 1/2 or 3" is right for most cars and why you see it so much.
LTX Aluminum LT1 block engine
Most HP from an OBD1, 1900 plus horse power
Only TH400 with lockup and shifts from factory GM computer
Fastest Impala with everything still in it, 4520 pounds no weight taken out. ? in the ? MPH