lookinco

So we all know that for NA cars we need back pressure so the exhaust pipe cannot be too big.

However on FI cars, do we need back pressure? Would we gain performance if we have a high flow exhaust? for example, the exhaust manifold would go to a straight 3" pipe with no cats or muffler.

Since we have two exhaust manifold, would there be gain if we have two seperate pipe, one going to each exhaust manifold? for example, true dual straight pipe exhaust with no cats or muffler.

I know that with a exhaust like that it would be LOUD AS HELL, but this is for racing and track only.

againstallodds1

With only pushing 4 psi of boost, you still will need some back pressure.

BustedJack

running a straight pipe, you know how loud the car will be? I have a clip of a cobra running 4'' straight pipe...... you should hear it. hahahaha crazy

subinf

Will be loud as hell, sound like shit, and very hard to run true duals due to lack of space under the car. Could be done but would take some time and not worth the effort.

Black_05_TL_6SP

True duals would work, but there are several things you would need to do to make it effective. First, equal lenght, second, there would need to be a H-pipe or a X-pipe to balance pressure between the two sides of the Engine. Third, you would need to drop the size of the tubing back down to force a bit of back pressure, if not you would just burn valves.

With the low amount of pressure with the CT setup, I would just use the Procats and some 3" tubing after the J-pipe. JMO

lookinco

So do you think the stock J pipe is good enough and would actually be better since we are running low boost?

If that's the case, I would just run 3" pipe from the J pipe and exit in the back with no cats or muffler, or maybe a straight through muffler.

Black_05_TL_6SP

The J-pipe is still some what of a kink. With the way it was designed, the rear has the major bend in it and the front is almost straight. The problem with redoing the J-pipe, is keeping them equal lenght. From the previous testing I read about on a replacement J-pipe, they lost power on the all motor TL's. I am not sure if there was ever any testing on the SC TL's.

Be sure to dyno the car before and then right after with the new exhaust, this will let you know if what you did is helping. I would try to find a flange to work with, this way you are not chopping your stock exhaust to get it. Good luck!

Jason

TLdriver022

A V8 with straight pipes will be alot louder then a V6 with straight pipes

ThinJim

iTrader: (3)

You should take into consideration that if you open up your exhaust with a SC, you will lose boost. The motor will breath better and it also opens up the possibility of manipulating the pulley size to push the boost back a little.

lookinco

That is actually my next step, to have pulleys made to boost a little more and hopfully will also lean out the overly rich AF ratio under boost.

subinf

thats not saying much though. i had a 98 tt supra and for fun (bored) took off the mufflers and ran straight pipe. loud as shit, mufflers went back on