Exhaust questions

gatorm

New Member
Jul 12, 2011
42
0
0
Centerville, Tn
Ok, I've read and read about this and Im still a bit confused about what i need and how Im gonna make it all work. I just purchased a '87 Turbo and the exhaust on it is just the downpipe (nothing else). I have a HKS Turbo exhaust I got from a guy not long ago to put on it but Im not clear as to what I need as far as a downpipe/converter to make it all hook together. I think if I remember correctly the HKS is 60mm pipe which is like 2.9 inches in diameter. Do I need to buy a 3" downpipe? Do I need a converter to connect the downpipe to the exhaust I bought? HELP! Not real concerned with what I should have bought etc etc...just want to know what I need to make it all work
 

WI88Supra

WI Supra Fan
If you have a downpipe (stock I assume) and a catback, then the part you are missing is the cat itself. Get yourself a testpipe like this http://www.protuninglab.com/tepico86tosu.html that will replace the cat. I'm sure you can find one cheaper than that on ebay and it will work fine, remember its just a stupid piece of pipe.

If you need to pass an emissions test then you'll need an actual catalytic converter.

Some downpipes have this section of pipe already accounted for so you don't need any test pipe at all, so are we talking stock downpipe? Any pictures?
 

gatorm

New Member
Jul 12, 2011
42
0
0
Centerville, Tn
That is what I thought was needed. The pipe appears to be a stock pipe but not sure, it does have a flange on the end. Hmmm, cant remember if I saw a precat or not.
So my HKS Sport will be flanged to hook to a stock size cat, correct? And that is what 2.5"? Im asking because I dont have it here at the moment. I do indeed have to pass emissions so yes, I will need a converter. Any ideas on a brand?
 

mecevans

Supramania Contributor
Jan 18, 2009
1,295
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M-bay, cali
Driftmotion sells a 3" downpipe for $200. Raptor racing sells high flow 3" cats that are 49 state legal. Both of them are vendors here.
 

WI88Supra

WI Supra Fan
You can definitely look at the high flow cats, they should get you through inspection.

If I were you, I would put up a wanted to buy add and try to get a used cat from someone here to use for your emissions test and then take it off and put a test pipe on it for better sound and performance. But that's cheating.