3.0 SC vs 3.2 Carrera: Exhaust Differences
 

I'm working with a good manufacturer to get another exhaust system on the market for us, and had a few questions for you guys. They already have a system for the 3.0 fully developed, but lack a 3.2 to prototype. My questions are:

-Do the two cars share indentical mounting points?
-What is the stock pipe diameter difference?
-Anything else I should be aware of?

The 3.2 uses a different forced hot air (to the cabin). If you plan on offering this (heat), take a close look at all the ducts and plumbing from the top side down.
Also, the mufflers will not swap as the 3.2 has an indent formed into the top rear to accomodate hot air the crossover pipe.
Bill K

I guess my question at that point is why companies like M&K offer the same muffler for both cars?

yes

same size for SC and 3.2 Carrera, 964 is the same design but w/ bigger pipes, the hot air transfer air inlets are in the same position as the 3.2 Carrera and use similar under engine transfer pipe but the 964 inlets are oval and the 3.2 round

The air path for heat is different, you need to look at the inlets to see if they are different

SC has transfer air tubes that run on top of the engine, 3.2 Carrera has the transfer tube under the engine, the heat exchange inlets are in the same position but may be angled differently, w/o having both in front of me I can't say

Here is a 964 layout, the 3.2 is the same but w/ round air inlets, also the exhaust crossover from the right side header is flattened on the 964 round on earlier versions, also note the air out lets which are shorter than on earlier versions
http://forums.pelicanparts.com/uploa...1400074500.jpg

here is an SC exhaust(w/ some extraneous parts), note the angle of the air inlets
http://forums.pelicanparts.com/uploa...1400074764.jpg

1983 SC
http://forums.pelicanparts.com/uploa...1400075263.jpg
1986 Carrera
http://forums.pelicanparts.com/uploa...1400075294.jpg

So a 3.2 cat bypass could mount up to a SC muffler?

The cat bypass is the same for both cars, other than some of the early or RoW SCs not having an O2 sensor bung.

The stock mufflers are essentially the same, except the 3.2 muffler has an indent on the back to clear the heater tube. So (if I understand correctly) a 3.2 stock muffler should fit an SC, but not the other way around.

Some manufacturers make aftermarket mufflers that fit either. If the muffler has clearance for the air tube (either by smaller size or indented) it should fit either car.

This is excellent gents. :D

Does anyone have a photo of the indent on the 3.2?

That picture is a little fuzzy, but I assume we are talking about that continuous compression across the engine side of the muffler?

Yup, that's the one.

Port sizes??
 

Aren't the port sizes different between the 3.0 and 3.2? Early SC has flat thin flanges. Late SC have thick flanges with the stub that inserts into the exhaust port. Carreras have the same thick flange and stub insert. I thought I picked up somewhere when searching for a replacement heat exchanger that the 3.2 port is a few mm larger such that the 3.2 stub insert won't fit inside a 3.0 SC port. I know the exchangers and gaskets carry different part numbers. -J

ETA - I searched. 35mm vs. 38mm ports. More info in links below.

http://forums.pelicanparts.com/porsche-911-technical-forum/478506-sc-heat-exchangers-v-3-2-hes-cheep-upgrade.html

http://forums.pelicanparts.com/porsche-911-technical-forum/692157-difference-heat-exchangers-sc-vs-3-2-a.html

Does anyone have a higher res photo of the stock muffler? Preferably from a few angles. It apparently is a hard term to Google. : /

Yes, there are differences in the heat exchangers. But I'm gathering that the OP is talking about the muffler and cat bypass only, not the HEs.

Correct.

Also note that the 3.2 chain cover on the right side comes down lower on the 3.2 than on the 964 on account of the 3.2's sprocket style tensioners. I have run into an interference problem trying to fit a set of 964 B&B headers w/heat onto my 3.2 because of where the air inlets are for the 964 in relation to the 3.2.

Excellent!