3" exhaust flange to 2.5" (3 bolt)

[rocky.ca]

I haven't been able to find a clear answer.

Simple question, will a 3" 3 bolt flange mate up to the stock a4 downpipe flange? Or better yet, will it mate up to an AWE 2.5" flange (should be the same as stock I believe)?

I am thinking of trying to modify a T25 downpipe that I have laying around this weekend to see if I can get it to work with my PSI concepts manifold.

Thanks guys!

[Audiguy1234]

Stock pipe is like 2.25 or 2.5 I forget. Either way it is possible just get a reducer from 3 to whatever. I think they go for 20 bucks max.

Sent from my SGH-I317 using Tapatalk 2

[victimdumper]

are you talking about a 3in test pipe matching up to the rest of the stock downpipe?
in that case, usually yes it will fit fine as the flange is the same size and the pipe is just bigger

FWIW i have a 3in RAI test pipe that matches right up to the stock exhaust downpipe flange no problems.

[EErie B6]

Stock pipe is like 2.25 or 2.5 I forget. Either way it is possible just get a reducer from 3 to whatever. I think they go for 20 bucks max.

Sent from my SGH-I317 using Tapatalk 2

55mm... which works out to like 2.17" (a hair bigger than 2 1/8")

[Audiguy1234]

Wow I thought stock pipe would be at least 2.25 inch. But I guess it is pretty close give or take.

Sent from my SGH-I317 using Tapatalk 2

[texasboy21]

I haven't been able to find a clear answer.

Simple question, will a 3" 3 bolt flange mate up to the stock a4 downpipe flange? Or better yet, will it mate up to an AWE 2.5" flange (should be the same as stock I believe)?

I am thinking of trying to modify a T25 downpipe that I have laying around this weekend to see if I can get it to work with my PSI concepts manifold.

Thanks guys!

As long as both pieces bolt in the stock location the two sizes should fit. However a step down that abrupt can disrupt the exhaust flow, but if the stock turbo than I wouldnt worry about it too much.

[MikTip]

The 3" 034 HFC and test pipe all bolt up to the OE 2.5" exhaust down pipe.....

[texasboy21]

The 3" 034 HFC and test pipe all bolt up to the OE 2.5" exhaust down pipe.....

OE downpipe is barely 2" inside diameter - literally just measured.

[MikTip]

OE downpipe is barely 2" inside diameter - literally just measured.

Details....

The flange where the down pipe and HFC/cat bolt is considered a 2.5" flange, or its metric equivalent...

My custom exhaust is 2.5"ID.....bolts up fine to my 3" 034 HFC.

[rocky.ca]

OE downpipe is barely 2" inside diameter - literally just measured.

would you be able to measure the distance between bolt holes center to center? thanks a bunch!

[texasboy21]

Details....

The flange where the down pipe and HFC/cat bolt is considered a 2.5" flange, or its metric equivalent...

My custom exhaust is 2.5"ID.....bolts up fine to my 3" 034 HFC.

You are correct. My TP is 3" and DP is 2.5".