3 inch exhaust system on stock turbo

[91eagle_tsi_awd]

im planning on running a bigger turbo later this summer.but i just bought my apex n1.and im planning on puttin a 3inch staight pipe from turboback all the way to the muffler.if im going to run a bigger turbo later on might as well go for the 3 inch now then go for a 2 1/2 then have to spend money again for a 3 inch.my question is with a 3 inch piping will my car lose back pressure?since the turbo is stock,is this a good idea or no?

 

[nine5raptor]

lose backpressure=good thing (you have a turbo, remember?)

 

[91eagle_tsi_awd]

yes thats what i thought but some people say its a bad thing.thanks for the info.

 

[G-Ell]

I ran a 3" exhaust with the stock turbo on my 1st DSM. You'll sure notice some real nice spool-up. Nothing wrong with a "might as well". Yes, 3" is too much at this point, but the negative effects (slightly less low-end torque) are minimal.

 

[91eagle_tsi_awd]

aight thanks man

 

[Bohrn]

with a turbine wheel in the exhaust stream, you could run a 4" pipe straight up a hole in the hood and have no ill effects power wise.

the turbo will supply enough back pressure.

But explaining this to exhaust shops who mainly do v8 trucks/camaros/mustangs is a pita as they will say that you are wrong or even get mad at ya

only problem with the full 3" mandrel bent system and a stock turbo setup is the boost creep. With that kind of flow, your turbo will out flow the wastegate, and the thing will still produce boost when the wastegate is open.

To combat this, you have to port the wastegate hole, and the O2 sensor housing. I am fighting with this right now, but I cannot afford to have the porting done. Gahh.

 

[sids]

if you stick to just a cat back exhaust, then there should be no boost creep problem since the stock down pipe is still in use right?

 

[airbrat]

I have a full 3" turbo back w/ my stock T25 and have ZERO probs

 

[91eagle_tsi_awd]

thanks but i gotta wait till later to get it now,my timing belt snapped what luck i have thanks for info tho

 

[Bohrn]

oh crappy for ya on the timing belt

 

[91eagle_tsi_awd]

yea i was goin like 10-15 mph and it snapped ,i got an extra head wit all new valves do i shud be ok thanks for your info