Fabio421

Will the 85-86 manifolds fit a 16v car?

Is it possible to "flip" the manifolds around so that the outlet flange is in the front instead of the rear? Basicly you would put the left manifold on the right side and vice versa. This question goes for both the 16v and early 32v manifolds.

danglerb

Yes thats pretty much what I plan to do, and no clue on the second, but isn't stuff in the way on the front?

John V

Yes, they "will fit" but they don't just "bolt on". You have to enlarge some holes, remove some heat sheilds, and extend the Y pipe on the right side (for use in the conventional orientation). On my car ('81), the right side motor mount support bracket had to be modified as it was rubbing on the manifold bellows.

As far as reversing... I have no idea.

byrdman454

They bolted on fine on my '84 Euro. I was also using a 32V Ott X so the RH pipe of the Ott had to be extended to reach the 85-86 manifold.

Fabio421

Is the bolt pattern symetrical? I am mainly interested in flipping them to the front. Maybe an way to ask this is:

Does this photograph depict an early 32v exhaust manifold or a purpose built manifold.

Thanks.

byrdman454

That looks like the early cast design manifold to me, but there is something funky going on at the bottom where it would hook to the cat. The webs between the downtubes is a sign to me that it is the older cast design and not the early 32v tubular.

Fabio421

Thanks Byrdman.

OK. I found a pic of the 85-86 manifold. Can anyone confirm that the pic shown attached to the engine is indeed a 16v manifold and whether or not it has been modified?

This picture is provided courtesy of www.928intl.com

byrdman454

Here is a pic from ebay. I think they are definitely early cast manifolds, but the bottom portion has been modified so that it turns straight down instead of angled.

hacker-pschorr

IIRC those who have flipped them around melted the timing belt.

marton

I believe the best solution is to install the S4 fabricated manifolds; at least 10 HP more. Maybe some issues versus 2 bolt & 3 bolt fittings.

Marton

Fabio421

The reason I am asking this is that I am trying to figure out what I will need to get started on a twin turbo project. I have seen a home made twin turbo 928 recently and I have also been doing alot of research as to what is involved in making this happen. Top that off with aquiring an 8.5:1 compression ratio 4.5L and I now am more eager than ever to try it. I believe it can be done at a reasonable cost with minimal plumbing. I was hoping that I may be able to mount the exhaust manifolds backwards and build from there. I plan on mounting the turbo's low and forward. I have two plans for intercoolers. Both involve air/air I/C's the only difference is location and quantity.

hacker-pschorr

Look up John Kuhn - he has an awesome manifold setup. The forward idea is a good one, not so sure on a 928 though. Think about it, the turbo would be in inch away from the power steering pump and other accessories. That much heat there? I'd aim for the other direction - John proved this can and does work out.

I hope John is progressing along with his S4 project.

toofast928

Ok I give up. Why flip the exhaust manifold and have it exit the front of the engine.
Marine application?

Fabio421

Please scroll up and read my last post. (hint-twin turbo) If you mount the turbo's low and up front you eliminate a heck of alot of volume (plumbing). Thats volume that doesn't have to be filled in order to gain boost. You also loose less exhaust heat and velocity when mounting the turbo's at the manifold. Once the turbo's are mounted here you can pretty much run the exhaust plumbing in its stock locations and routing. The compressor inlet is now facing forward where you have access to cool charge air ( even ram air if you wanna get fancy, but I really don't think you would gain much). That leaves the compressor outlet plumbing. And like I said, theres a couple of ways to do that.

The 16v manifolds look to be cast and the 85-86 32v manifolds appear to be fabricated. Is this correct? If so I may have to use the 85-86 manifolds for durability. I'm not sure how well I could get the cast manifolds to hold together at the welded joint, even using a hi Ni content filler. It looks like both styles of manifold will have to be modified to get a vertical orientation (<30 degrees) of the turbo's. This should also allow the turbo's to be mounted slightly above sump level and therefore eliminate the need for an oil scavenge pump.

ROG100

85/86 are fabricated and the pre 85 are cast as the eBay pic shows.
IIRC the 85/86 fit on the 16v cars but not the post 86 ones allthough they look similar.
Roger