4" Exhaust!?
Saying its not worth it does not answer the question. He has a 3inch tbe. He does not car about money. What gains would he see with 3.5 tbe and 4tbe. Here is a example
3tbe made 400hp
3.5tbe made 402hp
4tbe made 410hp.
See what he is asking. He does not care about price. He just wants to know if it will make a difference and if so what kind of difference.
Weather its worth it or not is your opinion. Not his.
3tbe made 400hp
3.5tbe made 402hp
4tbe made 410hp.
See what he is asking. He does not care about price. He just wants to know if it will make a difference and if so what kind of difference.
Weather its worth it or not is your opinion. Not his.
The opening at the bottom of your 02 housing is between 2.5 and 3" I believe. Even with a full 4" this will still be your greatest restriction. Do you have a way of creating a 4" outlet on an 02 housing?
The only people I have ever heard of running greater than a 3" exhaust had VERY large turbos with outlets that were also 4"
With the size of the outlet on the stock or green turbo, I just dont think a 4" exhaust will do much.
The only people I have ever heard of running greater than a 3" exhaust had VERY large turbos with outlets that were also 4"
With the size of the outlet on the stock or green turbo, I just dont think a 4" exhaust will do much.
Heres a link to my thread about 3.0 vs 3.5.. pretty much the same thing as 4.0.. its a debate about bigger being better
https://www.evolutionm.net/forums/sh...d.php?t=246180
https://www.evolutionm.net/forums/sh...d.php?t=246180
I'll let you know how it works out, as I've got a 3" turboback now and will change over to a 4" in the near future. Although I'm just rocking the stock turbo for now. I bought everything for a tubular manifold and 4" exhaust with the purchase of a GT3582R...that ended up as an internet fraud dispute that I never got the turbo from. I decided to use all the materials to make a stock turbo setup anyway. 3" IC piping with a 26x12x4 intercooler, 4" turboback, tubular manifold, 280+ cams, 1000cc injectors, blah blah blah...
Problem with 4" is it is HEAVY...
Unless you use aluminum...which seems to work well on drag cars, I'm betting it doesn't work so well on a street car, but I'll let you know on that as well.
Problem with 4" is it is HEAVY...
Unless you use aluminum...which seems to work well on drag cars, I'm betting it doesn't work so well on a street car, but I'll let you know on that as well.
Even if cost is not a factor, a 4" is not worth the hassle.
4" is pretty hard to fit and very bulky. I'm not sure what the roads are like around you're area but a good flowing 3" will be just fine.
On the IS300, 3" exhaust have made over 900rwhp.
I opted for a 3" going into dual 2.5" and am looking for 500-600 on pump 18psi and i believe it's very doable. Just giving you an example of what a 3" is capable of.
On the EVO, I would never go 4".
There are plenty of other things you could do that would make much more of a difference. Put your time into that instead.
4" is pretty hard to fit and very bulky. I'm not sure what the roads are like around you're area but a good flowing 3" will be just fine.
On the IS300, 3" exhaust have made over 900rwhp.
I opted for a 3" going into dual 2.5" and am looking for 500-600 on pump 18psi and i believe it's very doable. Just giving you an example of what a 3" is capable of.
On the EVO, I would never go 4".
There are plenty of other things you could do that would make much more of a difference. Put your time into that instead.
4" is useless. A 4" might be beneficial if you were running a twin turbo (sequential) set up using a small turbo to push a larger turbo. I bet you'll see a decrease in performance as turbo's utilize some backpressure to build boost. Zero backpressure = longer lag.
I know the best exhaust for a turbo car is no exhaust at all BUT, if you have to run piping there is such thing as to big. If there isn't enough gases to fill the piping your going to lose power. The reason is, all the gases are just tumbling around in the pipe trying to get out. Theres just not enough to fill the pipe to push it out. A Supra generates enough gases to uitilize a HUGE exhaust. Ours just needs 3" unless its gonna make 800whp then just dump it out the front bumper. then the piping is only 3' max and you can use 4" then.
I know the best exhaust for a turbo car is no exhaust at all BUT, if you have to run piping there is such thing as to big. If there isn't enough gases to fill the piping your going to lose power. The reason is, all the gases are just tumbling around in the pipe trying to get out. Theres just not enough to fill the pipe to push it out. A Supra generates enough gases to uitilize a HUGE exhaust. Ours just needs 3" unless its gonna make 800whp then just dump it out the front bumper. then the piping is only 3' max and you can use 4" then.
on a forced induction car (turbocharged) the less back pressure the better.
for example. look at the buschur or ams drag car and look at there exhaust.
Last edited by deadbeatrec; Jun 13, 2007 at 11:15 AM.
APS makes a 3.5'' TBE which would be more than plenty for your setup. You'll definitely feel the power gains, and you won't lose as much torque as you would with a 4". Check out the piece, APS quality is awesome
Most of the responses are somewhat misleading...
For his power level, of course he dont need a 4" exhaust. But with a 4" exhaust, whether its a stock turbo or not, he will gain some spool and possibly a couple horses. Remember, no exhaust, is the best exhaust, for turbo applications.
With that said, take into consideration the difficulty of installing such a large exhaust and the noise.
For his power level, of course he dont need a 4" exhaust. But with a 4" exhaust, whether its a stock turbo or not, he will gain some spool and possibly a couple horses. Remember, no exhaust, is the best exhaust, for turbo applications.
With that said, take into consideration the difficulty of installing such a large exhaust and the noise.
Most of the responses are somewhat misleading...
For his power level, of course he dont need a 4" exhaust. But with a 4" exhaust, whether its a stock turbo or not, he will gain some spool and possibly a couple horses. Remember, no exhaust, is the best exhaust, for turbo applications.
With that said, take into consideration the difficulty of installing such a large exhaust and the noise.
For his power level, of course he dont need a 4" exhaust. But with a 4" exhaust, whether its a stock turbo or not, he will gain some spool and possibly a couple horses. Remember, no exhaust, is the best exhaust, for turbo applications.
With that said, take into consideration the difficulty of installing such a large exhaust and the noise.
Buschur did a test on his own car about this. He took off his exhaust (his 3") and gained 0 power.