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914World.com _ 914World Garage _ Exhasut Choice - H/e's --Supertrapp

Posted by: kenpolives May 4 2004, 08:17 AM

I have a 74 1.7L with a bigbore kit. The prior owner autocrossed the car and had a nice supertrapp muffler header setup that worked well for him. I don't race the car and it is quite loud for a daily drives. I have the S/S heat echangers and a 4 tip monza muffler in good shape. I know the vehicle will be quieter with the muffler on but I am concered about the following.
I do not plan on hooking up the heat, will the heat exchangers vent more hot air into my engine compartment then the headers? Should I hook up all the ducts and j pipes or just leave them off?

Thanks

Posted by: Jake Raby May 4 2004, 08:49 AM

I'm not fond of supertrapps at all..... too restrictive when toned down to any reasonable level.

As long as the heat exchangers are connected to the blower hpusing and cool air passes through them, the engine should not run hotter.

Posted by: Brett W May 4 2004, 08:57 AM

I agree with Jake. Supercraps suck. Look at the Dynomax Superflow series mounted on the header or run a Bursch. If you aren't going to run heat then leave the header on it will make more power than the HE. What header do you have? Does it exit on the right or left?

Posted by: Scott Schroeder May 4 2004, 09:38 AM

I have used supertrapps on every car I have built - love them. I currently use stainless HE through an old sebring 4 into 1 exhaust. I cut out and replaced the cherry bomb type muffler with a straight pipe, exiting through a 10" stainless trapp. On my carbed mildly built 2.0, I need to run fewer discs than I ever had to on the gti's to get it to run right in terms of mixture. So the car is quiter than a monza (and most bursch's I have heard) but has that cool super trapp buzz - and once in a while I uncork the thing and go scare people on the freeway underpasses........

Posted by: Brett W May 4 2004, 09:52 AM

That "Supercrap buzz" is what kills me. It sounds like something is wrong with your car. I ran a three chamber flowmaster on the end of a Bursch that I removed the stock muffler. Sounded awesome. Under overpasses I could drowned out anything, but the 44idfs and the straight cut cam gear really sounded cool. THey were louder than the exhaust. I can't wait to build my custom exhaust.

Posted by: ! May 4 2004, 09:55 AM

If you get a big enuff "diameter" Supertrapp they are fine. Most people get the smaller sized ones designed for motorcycles.....

I run two on 3.6 and they are fine......

Posted by: lapuwali May 4 2004, 10:49 AM

People who like Supertrapps seem to think noise = power. Or they just like noise. Whatever floats your boat. In every objective test I've seen done, Supertrapps are just about the worst flowing "mufflers" for a given level of noise. As Jake said, once you get them quiet, they don't flow.

Posted by: Jake Raby May 4 2004, 10:57 AM

I have seen exhaust ports with cracks clear through them- from supertrapps...

They are only good for spark arresters for quads and off road buggies IMHO

Posted by: Scott Schroeder May 4 2004, 02:32 PM

Interesting. So the adjustability I used all the time depending on the track was just noise? On the GTI we would run all or none of the discs on an open track or autocross course. With the techtonics head we could move the power band much higher up in the revs. For a tight parking lot auto cross we would install a few discs and move the power band way low in the rev range. Seemed to work fine then.

So, Carbs suck. Supertrapps Suck. All is left is to put the car up on ebay.

Posted by: lapuwali May 4 2004, 02:42 PM

No one is saying the discs do NOTHING. However, there are mufflers out there that flow more and make less noise than the Supertrapp does. A few dyno tests on bikes have shown that the Supertrapp, with fewer discs, didn't "move the power down low", it just reduced power everywhere. I know from my own experience that this can sometimes FEEL like the powerband has been moved down, but the dyno says otherwise.

The Supertrapp was orginally designed to take the harsh raspy edge off the exhaust note of a rotary for aerospace uses (which didn't pan out). The company then sold them into the bike arena, then into motorsports, to earn some cash. Subsequent testing by a number of places with dynos, flowbenches, and the ability to use them and analyze the results, have shown that, for most engines, they're very much sub-optimal.

btw, you'd never get Jake to say carbs suck.

Posted by: kenpolives May 4 2004, 07:08 PM

Thanks for the feedback, looks like the supertrap is moving out. By the way Jake I just watched your engine video and that really helped me out. I picked up a 75 2.0 motor (cheap) and am taking it apart as a learning experience. I got stuck and sure enough you gave the info I needed.

The supertrapp exits the car on the drivers side. I think the header is a kelly(?) 4 into 1. Part of my problem in putting the heating ducts back into the car is due to the fact I have a fuel line going through the engine sheetmetal where the j-tube would come up through. I know, move the line...... but the set up is real nice with the 44 webers.... (opps.... not F/I) don't hold it against me....

Posted by: TimT May 4 2004, 07:17 PM

Didnt mikez post some before and after dyno pulls with supertrapps with varying amount of discs?

Posted by: seanery May 4 2004, 07:56 PM

I think it was drew wasn't it?

Posted by: TimT May 4 2004, 08:00 PM

I just remember some one posting some before and after supertrapp info.. It kinda vindicated the suprertrap bashing