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Pierce Przybyla Apr 8, 2022 12:17 PM

Exhaust Help
 
Here to pick somebody's brain. I have a 1985 GS that needed an exhaust so I pulled one from a 1983 GS L part car that I have unfortunately the exhaust(downpipe to Muffler) is too short. Would swapping the exhaust manifold solve this problem? Or is there another answer that I'm just not seeing?

Maxwedge Apr 13, 2022 03:54 PM

The (stock) manifolds are the same. Are you missing a CAT? Or the connecting pipe with the hangers on it?
https://cimg9.ibsrv.net/gimg/www.rx7...19d1d4c3dc.jpg

Pierce Przybyla Apr 14, 2022 09:09 AM


Originally Posted by Maxwedge (Post 12514106)
The (stock) manifolds are the same. Are you missing a CAT? Or the connecting pipe with the hangers on it?
https://cimg9.ibsrv.net/gimg/www.rx7...19d1d4c3dc.jpg

No I'm not missing anything and the exhaust fit the 83 gsl perfectly not problems. When I put the down pipe on the angle is wrong and is too short.

diabolical1 Apr 14, 2022 08:48 PM

if you think swapping the manifolds will work, then why not? you have the parts right there.

it does sound odd though. i always thought the manifolds on the '83s were the same as the S3 12A cars.

Maxwedge Apr 14, 2022 08:53 PM

Yeah, there's only 2 manifold types: The Thermal Reactor from the SA and then the Manifold on all the FB's.

https://cimg3.ibsrv.net/gimg/www.rx7...b906eb16e.jpeg


Carl Apr 15, 2022 11:07 AM

There are actually 2 different FB manifolds. The one in the picture above is more or less 84-85. The more-or-less 81-83 is similar, but the exit is longer and slightly different angle. The early one was preferred from a flow perspective for Spec7's. I have both sitting around somewhere.

Carl
https://cimg4.ibsrv.net/gimg/www.rx7...4bda838bc2.jpg
Early FB
https://cimg7.ibsrv.net/gimg/www.rx7...a2f860aa51.jpg
Late FB

Maxwedge Apr 15, 2022 11:10 AM

Thank you Carl, I never knew.

diabolical1 Apr 15, 2022 02:07 PM

i had always suspected there were two different ones, but i thought the breakdown was 1981-82, then 1983-85. so i thank you for that tidbit as well. :)

Carl Apr 15, 2022 02:42 PM

Looking at the diagrams in the parts manual, it appears that they shortened the manifold in 84 to make room for the third catalytic converter.

Carl


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