Yet another question re exhaust for 3.6 conversion.

[pbs911]

Does anyone know about the performance of the GHL set up with the cats for a 3.6 conversion in a 78SC?

I know the GHL are not approved as being smog compliant in CA, but the last time I looked the B&B set up isn't either.

[Moses]

I bought a set for my 3.6 Beautiful work. I sent it back because it was 1.5"ID tubing. The good folks at GHL offerred to fab up a set with bigger pipes, but at that point I decided to stick with a stock 993 manifold. The GHL unit would require 180 degree rotation of the exhaust studs on the right side of a 993 (no problem, the holes are already there.) I don't believe there is a similar issue with a 964 motor.

If you order a set, get them to do a custom set with bigger pipes. (no extra charge!) If I was starting all over thats what I'd do. It may not be truly CARB certified, but it looks cleaner and closer to "stock" than anything else I've seen.

[Jack Olsen]

You can also do like I did, and start with a Carrera exhaust. It's a good way to spread your costs out, and it gives you more low-end torque (but costs you peak hp). It also has heat, a cat, and looks legal to inspectors, since it's all factory. If you're interested, shoot me an email. I'll sell you the parts I used, cheap.

[Bill Verburg]

If smog will be an issue, then the only way to go is the SC/Carrera or stock 993 exhaust w/ cat. The GHL and B&B are both available with cats but neither is CARB certified. As Jack said the B&B is better power wise than the SC/Carrera. IMO the GHL is way too expensive and has pipes that are too short for proper performance(even if they will make a set w/ larger pipes). Here is a pic of John Dunkles GHL setup for a 3.2 the workmanship is good and it is better than an SC/Carrera stock setup. the 3.6 set will be the same


The 3.6-3.8 responds well to more cam timing(longer duration) w/ 42-45mm pipes which are 24-27" long.

If you aren't doing cams then the stock 993 exhaust is the best.

If you are doing cams B&B or SSI are best in that order. Though SSI is supposed to be close to marketing a bigger set which could be an improvement on the B&B.

I will be using the B&B w/ heat from my 964 on my 993. As Moses has pointed out the exhaust studs on the right side need relocation, but the holes are already there.

Here is a pic of the B&B on my 964,

The wide spacing of the primaries facilitates plumbing the muffler, note the stock 964 heat ducts forward of the muffler.

Here is a pic of B&B on a 993 transplanted into another SC(Gary Cuozzo sp?)


Again IMO some sort of shield should be used between the exhaust and the plugs. On my 964 I retained the stock shields which work fine. However the 993 did away w/ them. Hopefully Sherwood is working on a 993 kit. Also a shield should be used between the exhaust and the "S" oil line.

and one more of Garys setup,


Gary has also done an interesting version of the heater blower. It looks like an SC blower and looks lost compared to the rather massive 964/993 blowers that do barely fit.

[AES]

Can SSI headers with heat be used?

[rfix'n]

Bill,

Did the stock 964 heater ducting have to be modified or is the spacing between the heater inlets the same for the B&B's and the stock 964 exchangers?

I've been trying to figure out how I'm going to do this, even if I have to cut and reweld the ducting this is a clean solution. (beats the duct tape and silicone hose I've been thinking about using!)

[pbs911]

Thanks for the replies. I email SSI about the new system but have not heard from them yet. It looks like it will be B&B if nothing comes of them.

Jack, as far as the Carerra exhaust it sounds like a good idea even if it means switching the system out for emissions inspection. But I already have the factory exhaust off my SC. Isn't this the same as the Carerra for purposes of the 3.6 conversion?

[Bill Verburg]

AES; the SSI will work fine and may even be better at lower revs, the heat is much more of a headache though. Here is a pic of my 964 w/ SSI

note the heat ducts to the left and right

rfix'n; the stock 964 heat ducts bolt right up to the correct B&B header. You need to order the header w/ 964 heat in and 911 heat out. It will work w/ 911 heat in and 911 heat out also but its not quite as nice. I think that Thom F. has the 911 heat in/911 heat out on his. The difference is oval vs round heat inlets. I believe that the 964 set will still work nicely any way

[Kevin Stewart]

Bill im getting lost in the exhaust thing here, I have a stock 3.6 exhaust and an sc exhaust will either work? using one of these exhaust would truely help me put funds in other places on the car, when the racing season is over in the fall I plan on putting b&b headers on, we start on the race car next week so these to projects are killing me, well any advice would be appreciated, Kevin

[pbs911]

I have a stock 3.6 exhaust and an sc exhaust will either work?

From what I have gathered, the 964 exhaust will not fit. It interfers with the clutch linkage, oil tank, etc.
The 3.2 exhaust will work, but I do not know if this is the same as the 3.0 exhaust. I am in the same boat on this issue. Anyone know if the 3.0 and 3.2 exhaust systems are interchangeable?

I believe the 3.0 exhaust will bolt on based on Steve Timmons web site where he shows a 964 motor with a SC exhaust mounted for installtion purposes, but I do not know if it will run.

[makaio]

Paul, from what I understand, the 3.2 & 3.6 have a larger bolt spacing than our 3.0l's. So no the SSI's from your SC will not work on a 3.6. You would have to get the 3.2 style ones for a 3.6.

Since I have SSI's on the CAB, I'm going to fab up a different muffler system (built with parts from ebay) to switch out every two years. It will include a CAT, so if the smog stations around here give me crap, I won't have to switch the exhaust system. It will be a 30 minute switch , instead of multiple hours.

[Bill Verburg]

The ssi's work fine on a 964 see the pic a few posts up. They will need a little persuasion and extra length on the collectors is a big plus. On a 993 the passenger side studs are rotated 90&deg but have the holes for the proper ssi pattern.

Kevin, the 964 exhaust will not work for the reasons Paul iterated. The SC exhaust has been used by several people. I know of no one that has used a 3.2 exhaust so I really don't know about that one.

964s use long studs so the thick flange manifolds are more desireable. If thin fange are used then the bolts need to be swapped out, cut off or multiple washers used.

[Jack Olsen]

I used the 3.2 exhaust without any problems. I'll sell it if anyone wants it. i've also got a test pipe to go in place of the cat.

I'll be out of town through Christmas, though.

jackolsen@attbi.com

[emcon5]

I've been told (By Dr. Steve) the SC and 3.2 Carrera HE's have different sized pipes. The SC is too small, but the 3.2 will work.

Tom

[rfix'n]

I've heard / read that somewhere as well, that the i.d. of the 3.0 is smaller than the 3.2's. Somewhat contradictory is that I think the SSI size is the same for both.