2.5in Downpipe Available from Vendors?

[SouthIndy_Talon]

Hello,

I am curious if anyone is aware of a vendor that sells a stainless 2.5 inch downpipe that would fit a 1990 Talon FWD? Seems like the only readily available anymore is the 3 inch downpipes. I am in the middle of acquiring everything needed to run an E316G turbo on my car. My car is currently 100% stock so I am looking to replace the entire exhaust with the new turbo. After reading about all the issues people have had with boost creep running this turbo, I am hoping that a 2.5 inch downpipe with a high flow catalytic convertor will help some in the boost control department since it may provide a little bit more backpressure when compared to a completely open 3 inch exhaust. I don't plan on going to anything crazy powerwise, so I think a 2.5 downpipe would fit my needs versus all the 3 inch downpipes out there. If I am wrong with my thought process, please feel free to provide suggestions.

I already have a slightly ported 2G O2 housing to go on the car and am planning on using the thermal catback exhaust for the rest of the system.

Thanks in advance!

 

[91talonts1]

Boost creep isn't caused by lack of turbine back pressure. It's caused by the wastegates inability to bleed off enough exhaust gas.

 

[SouthIndy_Talon]

Thanks... 91talonts1

You are right about not being able to bleed of exhaust through the wastegate. However, I was thinking that due to the design of the turbine housing itself combined with the free flowing exhausts that it allows for so much flow that it can't be "re-directed (for lack of a better term)" through the wastegate passage. If you cause a little bit more backpressure, it may help some of the exhaust to be redirected through the wastegate instead of the turbine wheel volute. I know people port the turbine housings and smooth out that area in order to help the flow through the wastegate as a cure as well. I was just thinking this might help as well or limit the amount of porting that needs to be done.

Once again, I could be wrong... just throwing my thoughts out there

 

[Vegas Smith]

You could try Facebook classifieds or just go with the 3" because not everyone has boost creep issues. I never had issues controlling mine.

 

[SouthIndy_Talon]

You could try Facebook classifieds or just go with the 3" because not everyone has boost creep issues. I never had issues controlling mine.

Do you run any type of catalytic converter or anything like like that? What is the rest of your exhaust setup?

 

[91talonts1]

I don't see any situation where running a smaller exhaust would allow you to run less boost. I see what you're getting at, but I don't think it would work that way. The exhaust is gonna try to follow the path of least resistance and the wastegate passage should always be that path since it's above the turbine.
I could be wrong, and you could be right, but I've never had any issues with downpipe size, just that tiny wastegate passage. I've ran a 16g with basically no exhaust and it didn't creep.

 

[Vegas Smith]

On my old talon I had a full 3" thermal turbo-back system with no cat and never had issues with creep. What boost are you planning to run?

 

[SouthIndy_Talon]

On my old talon I had a full 3" thermal turbo-back system with no cat and never had issues with creep. What boost are you planning to run?

I am planning on using a set of 550cc injectors from an evo 8. I think that is going to limit me slightly (I.E. wont be maxing out the 16g), but I was thinking of shooting for 18psi give or take. I don't race or anything like that, just looking to increase the fun factor a little bit when I do take it out for a drive. It is interesting that some people seem to have issues and other do not. It is hard to determine what makes you fall on either side of the line with regards to creep.

 

[1990TSIAWDTALON]

I don't know about everyone else's down pipe, but even my 3" exhaust (brand unknown, came with car) is necked down at the inlet to pretty close to 2 1/2". When I cut the head off to go with a V-band exhaust is when I noticed it, like in this picture, just for illustration purposes....
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[Justin Lauscher]

I have a full 3 inch system and a tdo5h 20g with a ported 2g housing, when I was playing with it I could hold all the way down to 7psi, they don't all boost creep!