My dad seems to think that running 3" pipe (whether it's a single or true duals) is going to not be the correct backpressure and thus hurt engine performance.

Now he's no expert or anything, but I respect his opinions and I told him I would check with you guys... He used to be really big into cars. But got out of it after he wrecked his '71 Chevelle SS.

What do you guys think?

 

lack of back pressure hurting power is mostly BS.

3" single pipe on a bolt on lt1 or ls1 is a great setup

dual 3" would be overkill, but 2.5" would be fine...probably pick up some power in the peak.

 

It is a myth...Now exhaust velocity is a different story. The firing order of any given engine creates pressure waves in the exhaust that help evacuate exhaust gases from the cylinders. The size of the pipe also effects at what RPM these pressure waves effect engine torque the most. The faster an exhaust pulse moves, the better it can scavenge out all of the spent gasses during valve overlap...tooodahhh!

Your better exhausts for f-bodies are usually all 3" which is perfect, The only way I see justifying any bigger than 3 1/2 inch is if it's a big-block/Insane HP engine/or has more than 8cylinders...otherwise it might kill your exhaust velocity, which could make you loose some low-end torque, but probably a very small amount.

Atleast that's the way I see it...

 

You have a PM.

 

I wouldn't worry about it hurting your power numbers or performance. You may get an EGR code though as a result of the better flowing exhaust setup, which can be corrected by tuning.