Anyone make a 2.5" to 3" test pipe?

[MELLO*SOS]

s13/KA, dumb question, I'm tired of searching.... Does anyone make or sell a 2.5" inlet, [preferably resonated], 3" outlet test pipe for the s13? Looked everywhere and can't find shit. I have a junk 2.5" outlet header on my KA, mated to a 3" resonated test pipe and a 3" exhaust... Needless to say I've got a nasty exhaust leak between the header and the test pipe.... Rather than pull the header off & chop the flange, weld a 3" to 2.5" reducer & a 3" flange, I figured it would be easier to do the 2.5"->3" expansion in the test pipe.

I priced it out, to build my own 2.5 to 3" test pipe.. But for two gaskets, a 2.5" SS flange, a 3" SS flange, a SS 3" to 2.5" reducer, a foot of 3" SS piping, plus shipping and a few bucks for my welder guy, it turns out to be a pretty expensive solution to my exhaust leak. Someone has got to make a relatively cheap 2.5" inlet 3" outlet test pipe?

Open to hearing other ideas... This is a somewhat temporary solution until my motor is finished and swapped with custom DP... I can't stand listening to it idle any more!! :doh:

Thanks

Edit: I have a 2.5 in/out carsound high flow cat I can play with.. Thought about chopping both flanges to shorten it, then welding in the reducer and a 3" flange at the inlet and rewelding the 2.5" flange as close to the cat as possible... This will make it at least an inch or two longer, will that screw up the catback fitment or what? I don't mind running a cat on the KA, but I'd prefer the test pipe if possible.

[opponheimer]

Did you really just write four paragraphs concerning a test pipe?


I have a 3" test pipe going to stock exhaust, flanges match up perfect, but it restricts flow big time. Just do that, why the hell would you go through the trouble of making a 3" to 2.5" test pipe?

[ChingSR20]

Im using a apexi N1 3" with a 2.25 test pipe and its not leaking, I just used that liquid gasket stuff it works very well....

[Koopa Troopa]

The exhaust shop down the road makes one.

[MELLO*SOS]

Did you really just write four paragraphs concerning a test pipe? I have a 3" test pipe going to stock exhaust, flanges match up perfect, but it restricts flow big time. Just do that, why the hell would you go through the trouble of making a 3" to 2.5" test pipe?

Thanks for your reply.

Im using a apexi N1 3" with a 2.25 test pipe and its not leaking, I just used that liquid gasket stuff it works very well....

I used a ton of RTV on both flanges & let it cure before bolting it together with a gasket... But I knew it wouldn't do the job, it's only been a few months and it's failed completely. What specific stuff did you use? thx

The exhaust shop down the road makes one.

Thanks for your reply.

Guess I'll end up building one myself.

[axiomatik]

I'd try re-sealing it again. Right now I've got a 3" downpipe -> 2.5" cat -> 3" exhaust, with no leaks. (lame setup, I know) Don't remember what I used, high-temp RTV or something. I did it like 3 years ago and I still have no leaks.

[Skullavera]

I'm running a 2.5" header and a 3" test pipe but I did have an exhaust leak because I was using the 3" test pipe gasket on the header to test pipe side. I bought an OEM 2.5" exhaust gasket and it works fine. The leak on my exhaust was primarily because the header had oval holes on the flange where the bolts to the cat mount through. Using the 3" gasket caused the flange to have an area that was exposed and not sealed, on the inner part of the flange holes. Although it was barely visible, it was very noticeable with the engine running. Replacing the gasket with a new OEM. Gasket worked for me, maybe it can help you too.

[MELLO*SOS]

^^ EXACTLY what my problem is... iirc I just used the 3" gasket on the header->TP flange. I'll pick up a 2.5" gasket and try using a bunch of RTV in there.. Did you guys just RTV the mating surfaces, and/or RTV from the "outside"?

Thanks for your input/advice.

[opponheimer]

Oh yeah, I am using the oem exhaust gasket too, where the 3" flange meets up.. 2Bolt flanges suck ass by the way, in case you havent noticed. I like how HKS Hipower uses the 4 bolt flange.. you know those never leak.

[S14DB]

http://projectnissan.com/shopping/pc/viewPrd.asp?idproduct=591
New gasket and copper spray. Never had a problem with the stock manifold and 2.5" exhaust. Then moved to a header.

http://img.photobucket.com/albums/v108/S14DB/240sx/Exhaust/TestPipeInstalled.jpg

[MELLO*SOS]

I'll try RTV and new gaskets again since that's the cheapest, quickest solution... And seems to be working for quite a few of you.

I'm shocked that nobody makes a 2.5" inlet 3" outlet testpipe for us, I know that despite the replies so far, I'm not the only one with an exhaust leak from this... It would be so simple for someone to make! I see similar pipes for other cars, 2.25 in, 2.5 out and even 3" inlet 2.5" outlet...

Thanks for all the replies.

[S14DB]

Always replace the exhaust gaskets when you change parts. I have seen personally and from others that the exhaust gaskets on our cars seem to blow out like paper. I have a stock pile and always replace them when I take the exhaust apart.

[axiomatik]

yeah, i forgot to mention to size your gaskets according to the smaller size. I RTV'd the mating surfaces, then daubed more around the outside after clamping it all down.

[S14DB]

I find that the copper spray lasts a lot longer.

[MELLO*SOS]

Got it fixed... Just used a fresh 2.5 gasket and lots of RTV.. Seems to be holding up alright so far. Thanks for all the responses. Rep given.