Super Trap Exhaust System

[Jim Smolka]

I finished installing my dual super trapps on my 914 with a 3.2 It sounds great!

I also ran a cross-over pipe btwn the 2 headers.

[B Komar]

That looks KILLER! Wish I aad a six and that exhaust! I always thought something like that would look good. What does the crossover pipe do? Equalize pressure?

[Jim Smolka]

From what I have been told, it is to help reduce noise and increase flow. To "tune" the muffler, I am not sure how to do this with out a dyno. I know that I can add exhaust disc to increase flow, but that also increases noise. I might redo the system when I back date the rear bumper. I still have to order and install a fiberglass rear valance to give the exhaust the "Professional" look.

If I had do to it again, I would buy pre-bent 2" pipes instead of using a muffler shop type pipe bender.

The neat thing is that you don't have to have a 6 cylinder motor. This system will work on 4 cylinder motor

[This message has been edited by Jim Smolka (edited 05-20-2001).]

[Dave951M]

The crossover is to balance backpressure throughout the system. Dyno tests done in the late 70' early 80' proved the value of this arrangement and it has become a standard. Jim's setup sounds great ,especially when winding it out through the mountains while driving enthusiastically through the more twisty sections. The walls of the valleys and trees served as an echo chamber to make the effect even more intense. I hope to follow Jim thru the mountains again sometime.

Dave951M

[echocanyons]

What does a setup like that cost for a four and where do you get them?
It looks very aggressive. I bet it sounds the same.
Probably a dumb question:
Do you run headers with the supertraps?

Kelly

[7391417]

Jim,

Do you think you might be able to post some sound clips or video of your new exhaust?

It looks great, and I would love to hear how it sounds!

-Brent

[Jim Smolka]

The supertraps were purchased from racerpartswholesale.com (pelican does not sell them). They can be used with any exhaust, headers, SSI, etc. I happen to have them connect to a set of Bursh headers.

I can make a digital video with my cam corder, and then make an mpg file. However, it will take some time, since I need to update my computer. I might be able to find someone local to xfer the video to mpg.

If there is enough interest, I can start to make this as a turn key thing. However more research must be done (ie make sure HP is ok). I would eventually like the pipes to be Stainless Steel since the super traps are SS.

[jabb]

Looks good jim.... Must sound even meaner.

------------------

• Joe A.
• 84 911 Targa
• 75 914/6 3.0

[david c.]

I was just talking to my mechanic tonight about trying something like this on my 912E. Any reason why I couldn't bolt the dual Trapps with the crossover to the ends of the heat exchangers? There really aren't a lot of prefab options for 912E exhaust.

I'd like to know the approx cost also, but not if it's a touchy question. Thanks!

Dave

[Jim Smolka]

I don't see why this system would not work on a 912 w/heat exchangers. The trick would be to find plates that would mount up to the 912 exchangers. I know for early 911 and the 914/6 headers & Heat exchangers a standard 2 bolt 2" flat flange will work. You could buy a flange from Performance Engineering in CAL. They mfr the Bursche exhaust.

The cost of the 10" long supertraps are aprox $127 each from racerpartswholesale.com The cost to mount the system w/pipes, plates & crossover was $62.

You could also run the traps out the sides like a turbo. I would buy prebent pipes (30 & 45 degrees) to make this easier to mfr

[J P Stein]

A guy at the last autoX asked me what engine
I had in the car. When I told him a 2.7L
He said " humm....sure is quiet, doesn't sound like a 911 motor". I can't be having that.

I found that odd as it sounds like the hammers of hell from the drivers seat.

I love that set up.....gotta get me some...make some noise.

JPIII

[911racer]

Hi guys,
I HAVE MY DOUBTS!
While I agree that the 2 Supertrapp cans look great underneath a car, I dislike the way that they work (restrictive principle). To reduce the sound, you have to remove some plates, which reduces the amount of orifices through which the gas can escape, which reduces the flow and increases the backpressure. It will be ultimately quiet when you plug the exhaust pipe shut. A bit of common sense will tell you that it cannot be the right way to make power!!
Most other good systems uses a perforated pipe (but without internal restriction), which guarantees a free exhaust flow. The sound waves escapes through the perforations into a chamber (the silencer can), where the sound energy is partially absorbed / diffused. That is the way to make power.
But, as I have previously said, the Supertrapps look great, if that's what you're after.
Regards
Stef

[Jim Smolka]

In the above post, you are correct, if you want a really quite car, Super Traps are not the way to go. However, I wanted a muffler that would be adjustable. When I go to the track, I simply increase the number of disc. Thereby, reducing the back pressure and increasing HP.

Bottom line, they look good, sound great and can be somewhat reasonable for street use, When it is track time, they can be almost a straight pipe. Works for me!!

There maybe other mufflers out there that might help generate more HP, but IMHO, they do not offer the safe flexiblity.

[JP Noonan]

An old hotrod trick I used when I put long tube headers on my lightning was to paint the exhaust without a cross over tube. I used standard spray paint. At the point the paint stops burning off is where the gases are cooling down and a cross over helps (so I've been told).

Unfortunatly in my case that point in the exhaust was inaccesable for a crossover so I had to put it further down the line anyway. I also don't know how well it would work with a 914 exhaust because it is so short.