Marc '99T/A

iTrader: (22)

H/C car with about 430 rwhp. The exhaust is pacesetters & 2.5" TD's with Spiral Flo's. (The cam is a 223/227.) I'm curious if I would gain anything by going to a 3" setup; the only thing is I'm also worried about ground clearance. What's the verdict?

Marc '99T/A

iTrader: (22)

Bueller...........Bueller.............?

dpw41285

iTrader: (26)

i doubt your hurting anything...there probably other things robbing u of power then exhaust size. plenty guys make big power with ory and single 3 in

02TransAm/Batmobile

iTrader: (32)

True. To adress this issue, you would also have to adress any other power-robbing parts you have, such as: Flywheel, Driveshaft, Rear-end, Mufflers, Clutch, HVMC equipped longtubes and etc, etc. I've heard of people losing around 20 horses by switching to Torq Thrust II's because of their 27 lbs of rotating mass!

bsf

iTrader: (7)

Assuming the mufflers do are not a flow bottleneck, a properly bent 2.5” dual system should support ~510hp loss free. So I would say the answer is no.

rayray979

iTrader: (1)

Taken from td sticky

Q. What size piping should I go with?
A. The most common sizes for duals are 2.5” and 3”. The general rule is that if plan on lowering your ride, go with 2.5”, if you are going to stay at stock height go with 3”. Anymore than 500HP and you will probably want to go with 3", unless lowering takes priority. There are lowered cars that run 3” with no problems. Both sizes will support plenty of power, more than almost all of us will likely make.

junior28570

iTrader: (22)

When I called SLP for a true dual set-up to replace the LM1 I run now, they told me their LM1 will support >700rwhp "and that's dyno proven. So why bother replacing it?". IF what SLP told me is remotely true ..since the LM1 is single 2.5" (2.25 merge @ the Y) that goes to two 2.5" over the axle, and a single 2.5" will support >700rhp, dual 2.5's should be plenty.

IDK. I will eventually get to a true dual set-up and find out for myself one day.

orangeapeel

iTrader: (18)

I love my 2.5 duals. I think scavenging is helped in this case. I would vote no, you are not robbing yourself of power. I make almost 430 as well with a poor choice of cam.