'77 911 heat exchangers on '92 carerra 3.6L motor

[wanderlust]

I did an engine swap and put in a '92 C2 motor in my '77 911 and use the existing '77 heat exchangers. Would a gain alot of benefits by going with the C2 heat exchangers? Thanks...

[Steve@Rennsport]

Quite a bit, yes.

[wanderlust]

Thanks..what would my next option/upgrade be and still be in compliance with California emission law?

[Steve@Rennsport]

Given the need for smog compliance, that's your best and most durable option.

[911pcars]

Cat-back mods are unregulated, i.e. muffler options are open.

Sherwood

[wanderlust]

Thank you both! Will post the outcome. Hopefully I will notice the difference since I've been driving with the old heat exchangers for about 10k miles. Will also look into smog legal performance muffler's.

[911pcars]

Try it w/o a muffler. The catalytic converter by itself produces a louder-than-stock sound. YMMV for the desired sound.

Sherwood

[wanderlust]

OK, took the first step towards the "goal" - unfortuantely the 964 heat exchangers will require some work/mods to make it fit - the 915 tranny fork is in the way.

Exploring the 993 heat exchanger option instead. Will this 1. give me a little bit more power? l2. ess modifications 993? 3. Do I need to make my car with dual exhaust tip or can I stay with the current config..single tip.

[911pcars]

Originally Posted by wanderlust

OK, took the first step towards the "goal" - unfortuantely the 964 heat exchangers will require some work/mods to make it fit - the 915 tranny fork is in the way.

Exploring the 993 heat exchanger option instead. Will this 1. give me a little bit more power? l2. ess modifications 993? 3. Do I need to make my car with dual exhaust tip or can I stay with the current config..single tip.

I'm doing this now with a 3.2. 993 HE tubes are 1-5/8" OD (1.5" ID), borderline for 3.0 l and earlier engines, better for 3.2 and larger, but more emphasis on the top end.

For 964 and earlier engines, 993 HE inlet flanges on cylinders 4, 5, and 6 (passenger side) require flipping (rotating) to match the cylinder head exhaust port bolt pattern

There are two flavors of 993 HEs. On the outlet end, the main difference is the format and angle of the outlets. One style (Bishoff) has pentagram-shaped outlets that face approx. 45º toward the rear. The other (Gillett) has 3-bolt triangular outlets that face almost opposite each other. In both cases, neither will work w/o modifications with the factory muffler inlet locations. Both require some mods to restore the normal normal air path from engine to cabin.

As for a compatible muffler, There's not much room in pre-993 911s to fit an early factory or equivalent muffler into the available space. Many owners use a universal, 2 in/1 or 2 out or equivalent aftermarket muffler whose canister length is less than the distance between the HE outlet flanges (approx. 14-18"). Magnaflo and FloMaster mufflers are often used.

Bishoff:


Gillet, drivers sidet:
[

Gillett, pass. side


Related threads:
https://www.youtube.com/watch?v=f8TtZDRnDJU
I got crabs this weekend!

Hope this helps.
Sherwood

[wanderlust]

Any preference as far as durability? Perf? Bishoff vs. Gillett? About to search for it at my local salvage places.