joels2k

hi guys,

i recently got my turbo kit (pfab twin scroll/ gt35r divided)now im deciding between the dual 70mm invidia q300 or single berks 3" exhaust.
whats you guys opinion the best choice between the 2. pros and cons would help.

cheers..

S2-Kai

The 3" Berk, it's quiet and it'll make the power you want

joels2k

thanks for the input. i wonder how much hp gain and lost difference between dual 70 mm q300 and single 3" berks.

s2klariat

I dont personally have the q300 but I've read several complaints that it is extremely raspy with a test pipe instead of a cat. I'm assuming you'll be running a testpipe, so something to keep in mind.

benes2k

Just go with whichever you prefer for sound.

the best exhaust for a turbo is the least restrictive exhaust, so the 3" would yield higher gains.

depending how much CFMs your moving will tell us if your exhaust will be restrictive at 2.75 inches, whats your turbo specs?

joels2k

I have a garrett gt35r T4 1.06 divided, .70 a/r housing. turbine wheel . 68mm w/ 84 trim, compressor wheel 82mm w/ 56 trim . dual bb. Not installed yet so i dont have an exact numbers yet. But hoping to get more or less 500hp. So is dual 70mm 2.75" exhaust good enough.?

benes2k

no you will need a 3" minimum for anything over 400 hp.

riceball777

Turbo 4 cylinders should always have a full single 3 inch straight through turbo back exhaust with no cat for optimal power.

illestrolla

So much mis-information here. You absolutely, 100% do NOT need a 3" pipe to facilitate 400whp, or even 600 for that matter. I had some of the same concerns when I was working through my build, Jeff @ Evans tuning said he's seen well over 500whp on a true 70MM pipe, and as long as there is 0 loss.

The problem with most of the available 70MM systems on the market, is the fact that they feature restrictive muffler designs, and has little to do with the pipe diameter. A straight 2.75" pipe is more than sufficient for your goals.

For example, I'm running the T1R 70EM duals. Made 475whp on 13psi, but my exhaust ended up holding back some power due to how restrictive the mufflers are. Remember most of those exhausts out there are designed for an N/A application, with much lower requirements for flow. They are baffling for noise/rasp ect ect.

baZurk

Illest is right, however if you want to be sure that you make 500hp, a less restrictive "straight through" exhaust will make more power then a smaller diameter dual exhaust.

Muffler design and the bends on the exhaust play a bigger roll than just piping diameter.