16vsilverstreak

What are the chances of an 85 928 exhaust from the down pipes to the tailpipe bolt onto an 83 928? Both cars are US spec. Thank you.

The Forgotten On

It will bolt right in and fit. You just need a dual cat to make it work. I'm doing this to my 81 as well.

16vsilverstreak

Fantastic!

skpyle

Guys...I thought the outlet spacing of the exhaust manifolds for the 32V S3's was significantly different from the prior 16V engines?
I have read where guys have to cut/weld and/or make special spacers to fit S3 manifolds to existing 16V exhaust systems. I would think the reverse is the same...

16vsilverstreak

That does make sense. It all depends which way that extra cam and valves went.

skpyle

Silverstreak, I don't think that is as much of an issue. On my 32V S3, the cam sprockets are in the same physical location as those of a 16V engine. The extra cams are inboard of the existing cams. To my understanding, the tubular S3 exhaust manifolds are constructed to be a bit wider than the cast exhaust manifolds of the 16V engines.

Understand that I am just reciting what I have seen on my Red Witch and have learned on Rennlist. Do NOT take what I am saying as gospel. Take it as a suggestion to do more research.
Regardless, I don't think it is an insurmountable problem.

WALTSTAR

I sourced a 85 dual cat exhaust and it bolted right up on my 84 like it was original equipment. I only had to fab a bracket on the mid pipe to hang from a existing body hanger.

16vsilverstreak

I have access to a complete ‘85 exhaust. If the price is right I pull the trigger. Thank you.

hacker-pschorr

You said: "from the down pipes", the primary benefit to an 85/86 exhaust on an earlier car is the exhaust manifolds. Are you getting those too?

Mongo

There's a power gain from the S3 car's exhaust on 16v cars if I remember correctly.. You must change the manifolds too though to maximize on it.

16vsilverstreak

I was not planning on getting the manifolds but if they will benefit I will try to get those too if available. Thank you.

Mongo

Yes definitely. Do not skip out on those.

Kiln_Red

+1

I'll go a step further to say that I think it is a complete waste of effort to swap exhaust systems *without* swapping to S3 manifolds.

Wisconsin Joe

Seth - Your Red Witch is an 86.5.

Doesn't it have the S4 exhaust?
Does it have the same manifolds as an 85?

I'm not super 'up to speed' on this, so I may be way off base, but looking in the PET, there seem to be different exhausts for the S2 (84 - 86 Euro - Duals that run together), the 83 - 85 (US - single pipe) and 86.5 (S4 dual exhausts that run separate).

WALTSTAR

Have you ever done a single pipe to dual pipe swap while retaining the same manifolds? I beg to differ, but it is not a waste of effort. I can feel it in the pedal and the seat. Simply having more cross sectional area as engineered by the factory adds the benefit of more flow. The sound is much more desirable as well.