rickc

Has anybody installed a late model C2 exhaust on an SC chassis/engine? I am converting to a Carrera induction with electromotive TECII ignition system. <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

Clark Griswald

I have no experience with that one. But I can't imagine why you would want to do this. These are equally poor systems, not really an upgrade.

rickc

Thank you fro your response. I am looking for an improvement over the SC exhaust , knowing that the stock systems do not flow like headers would. If I could find an aftermarket system that included Cats,and that could be bolted up without chassis modifications, I would be a proud owner. I am not aware of any legal aftermarket systems that flow as well as the stock Porsche late model exhaust systems. All advice is appreciated.

Bill Gregory

There are two header systems incorporating cat's that come to mind, one, by a Rennlist sponsor, is GHL (http://www.ghlmotorsports.com/) and the other is FVD (http://www.fvd-usa.com/). GHL just came out with a 964 header/cat system, don't know if they have one for a pre-964.

The stock 964 header system is not very good. The 993 has a revised system which picked up a bunch of HP. As I recall, most, if not all, of the model-to-model increase (17-20hp?) was due to the exhaust system. If you want to try and adapt a 993 system to an earlier model, one gotcha is that Porsche moved the head studs on the 993, so you need to either move the head studs or cut and weld the header exhaust connectors to line up with the non-993 head studs.

Randall G.

I can add a little more to what Bill has written about the GHL system. Last I checked with GHL (about 2 months ago), they were still waiting for C.A.R.B. certification before shipping to California. They are already shipping to other states, and they do make the system for pre-964 cars.

Some pics of the system, taken at the German Autofest last September. GHL is also featuring the system in their Excellence magazine adds:





The FVD system looks nice, but at close to $6k with cats and heat, is nearly twice as expensive as (the already pricey) GHL system . Also, it seems unlikely FVD is looking for C.A.R.B. cert. of their system--important to us Californians.

rickc

the 993 or 964 system has to be an improvement over the stock SC exhaust. For nearly 6K I ought to be able to hire someone for a month to modify the 993 system to fit.Granted the GHL system looks neat and probably works very good. I just dont think that the cost to benefit is warranted, at least in my personal financial situation. I would rather spend the money elswhere in the engine compartment. The long and short of what I am hearing is that, yes the later sytems are marginally better but will not be a direct bolt-in.

Randall G.

Hey Rickc,

I'm not really an expert on exhaust systems, but I believe the pipes on the 993 system have too large an I.D. to be effective on your 3.0L engine (Bill V., someone else?, please confirm). And, as others have written, the 964 system would not be an improvement over your existing system (even if the pipe size was correct).

If you don't know already, the GHL system costs just under $3k--10% off that, if you're a rennlist member. As you may know, there are less expensive options (e.g., B&B, SSI), but they do not necessarily incorporate cats. I say not necessarily, because B&B sells cat. "tips" that fit between the final muffler and tail-pipe. Would help pass emissions, but may fail a visual inspection.

Yeah, I agree that these aftermarket exhaust systems seem to be pretty pricey, considering the benefit yielded. As you suggest, I suppose their ultimate value depends on each person's unique situation, wants and/or needs.

Another option some people take is to install a cat-less system (e.g., SSI), and reinstall the smog-legal system whenever a smog check comes due. Too much hassle for me personally, but some people don't mind the bother.

rickc

I am planning to bump up the displacement to 3.4 and finish the installation of the knoxville supercharger. With the carrera induction system and TECII engine management, I am in the 300+ hp territory. That would necessitate the 3" I.D. The later model CATS flow better from my understanding of their construction. The emissions guys are also less likely to flag a stock looking 964/993 exhaust than the stainless header systems. That was my plan.

Randall G.

Hey Rickc,

Yeah, good point about not wanting to arouse the smog-police. What state do you live in? When my hybrid 964/993 went for its first smog check, the waiting was less stressful, knowing that I had a (mainly) stock 964 exhaust system under the car. On the other hand, the fact that I still have this system is what makes the GHL system (or a 993 conversion) so compelling.

I just read (see below link) that the 964's exhaust system uses a relatively small 1 5/8" O.D. pipe (same as a Carrera), so it might make an okay match for your modified 3.0L--except for the interference with the 915 throw-out arm, as discussed here:

<a href="http://instant-g.com/Products/36Conversion/FAQs.html" target="_blank">Dr. Timmons 3.6L Transplant Page</a>

I'm not sure how familiar you are with what must be done to stuff the 993's exhaust into an earlier model car. Obviously, the left-rear valence panel must support the second exhaust tip. On a 964, this requires a cut in the existing panel or a new panel w/cut-out. More problematic is making room inside the fenders for the 993 mufflers. Also, as Bill has mentioned, you need to modify the right side heat exhanger flanges. Kevin in the NW has converted the 993 exhaust system to fit
a 964--not sure what would be different for a 911SC:

<a href="http://forums.rennlist.com/scripts/rennforums/ultimatebb.cgi?ubb=get_topic&f=4&t=000493" target="_blank">993 Exhaust System in 964</a>

Well, I've about exhausted my knowledge of 911 exhaust systems. Hopefully, someone else will step up soon.

Best of luck!

Bill Verburg

rickc, given your goals and legal environment, the best bet is to try to adapt some 993 headers and cats to your application. While I have never tried the 964 exhaust with a 3 or 3.2 and 915 I know for a fact that it will not fit on the 3.6 with 915 combination(the clutch actuation arm interferes). If you are using a G50 with hydraulic clutch then no problem)

The left side header will bolt on to any 3-3.6 head, the right side flanges will need to be cut off and rewelded after a 90 rotation. The 993 cat otlets will need to be modified to accept some sort of muffler(there is almost no room for the mufflers, someone on the 964 list has done it and posted some pics so a search there may be productive)

Randall G.

Hey Bill V. .... curious .... do you know the pipe size for the 993? Same as the 964, 1.625"?

Bill Verburg

Randal, not off the top of my head, Robin S. may know though.

Here is a pic of the 993 header and one from a 3.2. Either will fit with a 915, the heat plumbing on the 993 is the other problem that I neglected to mention.

Randall G.

[quote]Originally posted by Bill Verburg:
<strong>***snip***

the heat plumbing on the 993 is the other problem that I neglected to mention.

***snip***</strong><hr></blockquote>

Oh yeah, I forgot about that, too.

Randall G.

Okay, one more thing. Here's an interesting "bird's-eye view" photo of the 964/993 systems. In this photo, you can see that the right-side heat exchanger flanges are oriented differently, and the heat goes-in/goes-out are in completely different locations. Finally, notice how much wider the 993 system is ....

Bill Verburg

Randall-thats the picture i've been looking for(what is the source?). It clearly shows why the 993 mufflers cannot be used on the SC/Carrera chasis, and will be tough to use in a 964, there just isn't room in the quarters.