Warren& the Gang, Exhaust help please!!

Confirmation please:
Are the stock heat exchanges(SSI's?) off a '71 911S, the same ones that come so highly reccomended for HP upgrade on SC's, along with the muffler as well. More feedback on why this is so effectice is also much appreciated.Thank you guys!!!

I'll take a stab at this one since I have been doing a lot of research on this lately. The stock heat exchangers are not SSI's. I talked to the owner of SSI when I bought mine a couple of weeks ago and he showed me around the plant and how they make them. The headers underneath the shrouds are more equal in length than factory original (a good thing). A company called Dansk is making heat exchangers now, with all the original factory tooling. As far as the muffler goes, the muffler that comes highly recommended is the sport muffler. The body of which looks a lot like a stock muffler but the exhaust outlets are more towards the center of the muffler instead of at the ends. The combination SSI heat exchangers and Sport Muffler are suppose to be good for around 15hp. I think this is accurate info. If not I'm sure some of the more experienced Porsche folk here will provide more assistance.

Mark
'74 911S Coupe

[This message has been edited by GruvSyco (edited 02-04-2000).]

If your 71"S" is stock with the original MFI, you will want to get the SSI for the MFI specific cars. The reason for this, is that there is an extension on the driver's side heat exchange that allows heated air up to the thermostat (if I remember correctly). This is very important for correct running during the colder months.

SSI is a brand name for an aftermarket stainless steel exhaust, which is in design very similar to the pre-75 911 exhaust (two inlets to the muffler).

Yes, the stock '71 exhaust is the TYPE of exhaust people mean when they talk about backdating an SC exhaust, although I'm not sure that a'71 exhaust would work that well on an SC, since there is such a big difference in displacement (2.2 v 3.0). The aftermarket SSI's for the SC look very similar to the '71 exhaust, but I'd imagine have a little bit of a bigger bore.

It is an effective update for a couple of reasons. First, the early exhaust is a "tuned" exhaust, with equal length runners for each cylinder. The SC exhaust is far from that, it is really a tangled mess b/c all of the exhaust gases had to be forced through one pipe for the cat. converter. Second, the early exhaust is probably more freeflowing, for the same reason.

Brian

[This message has been edited by Brian Kumamoto (edited 02-05-2000).]