911 2.0L Competition Headers

[eronbo]

Any advice on the best builder of competition headers for my 1967 911S 2.0L? I am building up a new twin-plug engine and am looking for recommendations. Thanks.

[Mr9146]

Any advice on the best builder of competition headers for my 1967 911S 2.0L? I am building up a new twin-plug engine and am looking for recommendations. Thanks.

There are guys who've already done the R&D on this stuff ... I've heard the 901 shop get tossed around in conersation regarding 2.0L arms race motors/exhaust. I think they get about $3-4Gs for a complete system.

I also happen to know Paul Kramer at the Autokennel has a set of headers with a stinger straight pipe for sale that came off a 2.0L racecar. Not sure who made them, but theyre good pieces.

[smedley]

Allen Johnson won the 1967 SCCA C Production Championship with a 2 litre 911S. The car is detailed in a four page pictorial article in Road & Track, I believe, an early '68 issue. The car was sponsored by Roger Bursch.....BUT! He ran stripped heater boxes as headers with megaphones!

Many engine builders still swear by the original factory configuration. SSI will sell just the header tubes without the boxes. They're gorgeous.

With many tracks requiring sound supression the parameters may have changed. If you go with a modern fabricator, ask for the dyno data.

[RennTyp]

Duel have a trick system they designed and use with great effect. See http://www.duel.nl/specializations. Know a few people who have found useful power and torque gains from using this system in historic Motorsport.

[jeff eelkema]

The Duel system looks and sounds great (follow the media links for some great in-car footage). In theory this design should work well, particularly to boost mid-range. I would love to see some dyno results if anyone has done any back to back tests with a traditional style system.

Cox Motorsport also a do similar design but I don't know if theirs has any sort of muffler. The Cox system would probably have been developed with larger engines and I don't know if they have worked on smaller 2L versions.

Given the level of competition in 2L FIA spec cars in Europe, competitive cars need to squeeze every last bit of performance so the Duel system seems to work from this perspective. I understand the Duel system is around 2200Euro.

[RennTyp]

I've heard first hand reports of the Duel exhaust being worth 5 - 10hp over the factory road set up when tested on a rolling road. More impressive is the gain in mid range torque which can be as much as 20% up. The manifold diameter is smaller than stock which must have something to do with this. On the negative side they are quite noisy and struggle to get under the UK circuits' 105dB noise limits. The faster SWB cars in European historic racing all seem to run them - which must mean something.

[eronbo]

Thanks for the advice. I appreciate it.

[Steve@Rennsport]

Hi,

The choice of header design and configuration really depends on several variables that include: camshaft profile, need for a muffler system, and type of use.

There are several good choices however one would need more detailed information to offer anything constructive.

[eronbo]

Steve, good counsel! I want my engine builder to try various headers on the dyno.