Two Supertrapps - good or bad?

[Scott S]

Hi All (and Happy Holidays)
I am doing some touch up work on my car - namely the 916 rear bumper. I am pretty sure it has a Sebring exhaust (4 into 1 header with a seperate bolt on muffler). The car was running fat and discolored the paint on the bumper. When I buffed it off I burned through some of the clear. Since I will be repainting the bumper, I thought about moving the existing tail pipe hole to line up with the heat exchanger, cutting an additional hole on the passenger side to match and installing a supertrapp on each side. I used to run one on my street preparred GTI and loved it, both for adjustability and sound. Is this a good idea? If it matters, the car is a 2.0 with cam, 44's, MSD, compufire, and stainless heat exchangers.
Thanks for any insight, and again, my best Holiday wishes to you and yours.
Scott S

[Brant]

Hi Scott,

Hope you are doing well.....
Ok here is my take on your supertrapp question. When I get done rambling I'm going to sound like a hypocrit and tell you to do what you like.

I run a single supertrapp, and for 10 years have always been told that the double works on a -6, but not a four. Knowledgeable persons have led me to believe that you would need a cross in the exhaust lines to take advantage of the 4 banger torque. Locally, Alen Johnsen and the talkented people don't do it.

Having said all of that, last September the fastest 914 in production at the club race ran twin supertraps. He is Brian Bohannen from Colorado, and this was on an injected (pretty stock) motor. I would still stand behind my theory of SINGLE = MORE POWER, but just believe that Brian out drove everyone.....

take care and Merry Christmas to you and your family.
brant

[Jim Smolka]

Though I am not sure what would work best for a 4 cyl car, I like the looks of the dual supertraps.

[maf 914]

I think the idea of attaching a separate muffler to each heat exchanger may not work well. The T-4 firing order is 1-4-3-2. If you look at a Bursch header (4,2,1 collector arrangement) you will see that they take the four pipes and first combine the pipes from cylinders 1 & 3 and 2 & 4, then they connect the resulting two pipes. They do this to balance the exhaust pulses and take advantage of the scavenging effect. The heat exchangers connect to cylinders 1 & 2 and 3 & 4. Note where these pairs are in the firing order. Both of these pairs fire consecutively followed by a delay as the other pair fire. If these pairs are connected and exhausted by individual pipes I suspect this imbalance will result in a loss of scavenging. I also suspect you may end up with one wierd exhaust note, although that may be a bonus, depending on personnal taste! Let us know how it works out.

Mike

[Pillow]

It has been proven time and time again that on ANY engine there need to be some sort of "X" pipe or merger of all the exhaust pipes for the best performance. Even V-8s do much better with an "X" pipe, like about 10-15 HP.

You could still fabricate some sort of "X" in there and end up running two Supertrapps though.

I think the dual look is awesome!

[Jim Smolka]

Pillow,

I wish their was room for an "X Pattern". All I could realistically install was the cross-over pipe since I did not want to alter the headers. The cross-over pipe is somewhat visible in the picture.