Exhausting Questions, Down with Downpipes...

Joe Rainville

New Member
Hey Guys,
Another 'dumb' question...I am currently undoing a few decades of neglect, lame 'repairs' and hack 'fixes' on my basically stock 87 T-top GN. The exhaust rattles, vibrates and sounds like an exhaling hippo. The cat back part is an "OK looking" dual set up. But what it between the turbo bell and the that is a mess. Some clown stuffed in a 3" down pipe and then "welded" in a "test pipe" where the cat should be, but it looks like he used a coat hanger and a car battery for welding equipment.

While the motor is actually all stock (even the stock pressure fuel pressure regulator and turbo), it somehow has this hack exhaust system on it. So I have been looking at all the nice new down pipes, and I like the ones that remove the restrictive 90 deg turbo exhaust elbow, they all seem to be 3" diameter.

Question: Does anyone sell a downpipe around 2.5" anymore? 3" seems a but much on a stocker...



Wrinkled Member
Question: Does anyone sell a downpipe around 2.5" anymore? 3" seems a but much on a stocker...

I don't think so. Look at Kirban's. Think they had a few offerings.


Texas, Where are you from
I kinda don't remember a 2.5" downpipe. Just the stock ones . You could probably score a stock one and go that way but then you are using the elbow. Get a rotary tool and do some clean up on that elbow and it will do some good.
Exhaust isn't the be all, end all. Can it help? Sure, but not like more boost and the mods that allow more boost.


Active Member
Experts say that a stock downpipe will do the job deep into the 10's, and they never get stuck and cause motors to blow up. Try and get a good stocker and use a test pipe and you'll be good to go.


Well-Known Member
Unless your in California no need for stock appearing down pipe.
Could be some stock pipes around, I’m a pack rat and keeping mine for my son to chuck after I’m dead.
I see no disadvantage to a 3 in. If your tired of the Clown work time to just move up to a new down pipe.
It will come with every thing you need to get you to you 4 bolt cat back.
Can’t place the hippo sound unless it’s some exhaust leak after turbo. The rattle will turn into KR and that can make a man go MAD. How is the exhaust hanger at the transmission mount? And motor mounts? All mounts?