Which of these three exhaust set ups yield the most power?

dd74 · 09-06-2002, 12:19 AM

I've read through a lot of past posts, but can't decipher a definitive answer as to which of the three setups listed below might yield the most power.

1) Stock '74 heat exchangers with a dual-in-dual-out sport muffler (the muffler with the two center pipes).

2) SSIs with a dual-in-dual-out sport muffler.

3) Bursch headers with a dual-in-dual-out sport muffler.

Anyone have any ideas which is the most powerful of these three, or are they all pretty much even?

Thanks in advance for your help.

Chuck Moreland · 09-06-2002, 07:18 AM

SSI is the best of those choices for a 2.7 liter '74. But they are only slightly better than the early exchangers that your car should already have. Not really worth upgrading unless yours need replacing.

dd74 · 09-06-2002, 07:47 AM

that my question is in regard to a 3.0 liter, not a 2.7, if that makes any difference.

Thanks.

VincentVega · 09-06-2002, 08:07 AM

I think the Bursch headers will be the most powerful, but remember they dont have heater boxes. The SSI's are said to have a slight advantage to the stock pre-74 heat exchangers. The real sell on the SSI's though is the quality and the fact that they last a lonnggg time.

The biggest difference is the quality/longevity and the sound. Headers will be louder as will a dual out muffler.

surflvr911sc · surflvr911sc's Garage

Paul (PBS911) has the #1 setup on his car and I think he's really happy with it. I don't think you can go wrong with either #1 or #2 for an SC. It would be a win/win so the only real factor is cost. I would go with #2, it will be more expensive but it will last forever.

pbs911 · pbs911's Garage

Quote:

1) Stock '74 heat exchangers with a dual-in-dual-out sport muffler (the muffler with the two center pipes).

2) SSIs with a dual-in-dual-out sport muffler.

3) Bursch headers with a dual-in-dual-out sport muffler.

My experience with No. 1 is both the pre-74/SSI headers and Sport Muffler do something to the motor to make it rev more freely, spread out the torque curve and unlease HP on the butt dyno. The factory used this set up on their ralley cars and I think Porsche had a pretty good idea of how to get the most HP out of their motors. If the two-out the side provided more HP I think Porsche would have went with that, but they didn't. BA says the SSI combination adds about 15HP and the Sport Muffler about another 10HP. I would be interested to see dyno sheets on each of these set ups.

makaio · 09-07-2002, 12:45 PM

I'm by no means a expert, but I have heard that the Bursch headers are not as good as pre-74 H/E's or SSI's. I guess they are not tuned properly.

I read this somewhere, I just can't remeber where.

Chuck Moreland · 09-07-2002, 12:52 PM

BA's handbook says he tested a variety of headers on the dyno and found the Bursch to be the only one that didn't gain HP. I don't know the engine configuration this was tried on or the base-line exhaust that he was comparing to. Could have been early exchangers.

That says that Bursch is at the tail of the header pack. But it may still be miles ahead of the later exhaust systems.

Early_S_Man · 09-07-2002, 01:30 PM

There are a couple of negatives about the Bursch headers that nobody has mentioned ... rust and ongoing maintenance!

They are NOT covered in a high-temperature paint or coating! The black paint is only there for rust prevention during storage and shipment! The paint will burn off within an hour of running after installation. The prudent buyer will remove the paint before installation, and have them ceramic-coated, chrome-plated, or will cover them with a high-temperature paint such a Sperex. Even if properly prepped and treated with a rust conversion compound, then painted ... the Bursch need annual maintenance if rust is not to get out of hand!

dd74 · 09-07-2002, 10:54 PM

Early S Man - thanks for the information on the Bursch headers. If what you mentioned is the case, they hardly seem worth it as a "bolt on" feature that can be put in place and forgotten. For those interested (including myself) I copied this link from AJUSA:

http://www.ajusa.com/cgi-bin/inventory/view_product?prod_id=0000000416&part_number=AJR%20100%20174

In short, it details the 911 RSR-type exhaust headers - "race type." I can't tell exactly if these are like the Bursch headers, particularly when comparing the price of these headers to those on the Pelican site. Nonetheless, I thought this might be useful.

Whatever the case, if anyone has mounted these to an SC engine with a two-in-two-out-muffler, I'd like to know what your results are.

As it stands, it looks like the pre '75 HEs with the sport muffler have the good nod. I trust the P-car enthusiast opinions I've heard so far on this subject, but am open to other ideas/thoughts.

Thanks in advance.