Cal Club Autocross Forums

... can you recommend something else for a quick tone down to get to events ... and possibly for running at Qualcomm.

http://www.supertrapp.com/product_secti ... p?CatID=27

Right now our exhaust ends with this 2.345" tail pipe ... which will need to be replaced by a 2.5" tail pipe.

3" or 4" Disc Only SuperTrapp tail pipe ?

Racing Beat exhaust header plus high flo CAT going in next week.

Love that exhaust hanging hardware :heyes: :heyes: :gpower: :gpower:

You seem to have lots of room there. What about a muffler made for some big V8 application? That should tone down the noise and provide little backpressure to a little 1.8's exhaust output.

There's the Apex'i Exhaust Control Valve:
http://www.frsport.com/Apexi-APEX-i-155 ... _9083.html



They make different sizes too, so 2.5" shouldn't be a big issue. Not sure if you will lose too much power from having a butterfly valve in your exhaust system, but it's a neat toy!

I had a similar control valve when my car was too loud n/a (still on the car, but just left open all the time). At "fully closed" position (still allows air through), the car was as quiet, if not quieter than my car when it was stock.

Another simple solution would be to get a universal 2.5" silencer on eBay & just drilling a hole in the 2.5" pipe exhaust tipe - slap it on before the drive & take it off after you arrive & the exhaust has cooled down. Of course, from a quick search on eBay, smallest diameter tip of the universal silencers is 3.5"...

You could also rig up multiple exhaust tips & do the same thing, essentially. If you want to save on gaskets & be a lil fancy, use vband flanges. My current exhaust tip is actually setup w/ vband flanges so I can swap tips out for fun in the future. It seals great & very easy to change out.

Mako Koiwai wrote:... can you recommend something else for a quick tone down to get to events ... and possibly for running at Qualcomm.



Right now our exhaust ends with this 2.345" tail pipe ... which will need to be replaced by a 2.5" tail pipe.

3" or 4" Disc Only SuperTrapp tail pipe ?

Racing Beat exhaust header plus high flo CAT going in next week.

Got money for a set of Penske shocks, but can't get a proper exhaust hanger.

http://www.supertrapp.com/product_secti ... D=456-2508" onclick="window.open(this.href);return false;

? ... but it's ... Lite Weight!

The SuperTrapp discs ARE the muffler. Easily added on if you have the right hardware on the tip. Take plates out to make it quiet, add them back if you're under the SD limit.

Is that exhaust hanger 14 or 12 gauge wire?

I tried a SuperTrapp on a Z car once. Worked OK with a lot of disks and was reasonable on the street, but trying to get quiet enough for something, don't remember if it was SD, I had to take out so many disks the car would barely run.

Still have it somewhere if you want to try it, not sure off the top of my head what the inlet size is, but I can check.

Looks something like this one: http://www.supertrapp.com/product_secti ... p?CatID=29

You could always take the turn down off and add one of these and put the turn down on the end of that:

http://www.coastfab.com/ultralightweight_mufflers.html" onclick="window.open(this.href);return false;

Coast Fab makes the ones Burns sells.

Bob Beamesderfer wrote:Is that exhaust hanger 14 or 12 gauge wire?

Coat hanger

The best answer to your Supertrapp question is... don't.

1) you have to run it out from under the car to keep from cooking your bumper skin.

2) running a disc-only setup, if you take out enough discs to make it quiet enough to run in SD, it won't make any power.

A small muffler/resonator with a turn-down tip is all you need. Or, you could run a bottle-type muffler under the car in the stock resonator location and keep the tip in the same place.

Take a look under the back of my car at this next event: I have a similar setup that makes the same power as an open pipe and is quiet enough to run on the street (91 db in my initial tests.)

A tail pipe all the way out past the bumper will help with on-road noise. A clamp on 90 will help with the SD sound meter.

Don't know what you run but maybe a quieter muffler is in order. I've had success with quite inexpensive DynoMax "Welded Series" straight thru mufflers (14" x 9"x 4.5") as long as you get opposite-offset input and output for a diagonal flow thru the muffler. My 500hp CP car has never hit even the SD warning level using these.

See the photo in the first message ... what muffler? (It's only a Miata) That big empty space is usually filled with the oem muffler.

Bob Beamesderfer wrote:Is that exhaust hanger 14 or 12 gauge wire?

Whitehead has a pissed off neighbor who had a wire that was holding up a tree in his front yard "stolen by some kids". This wire was the exhaust hanger for the Supertrapp on the ST Civic...

Curt Luther wrote:

Bob Beamesderfer wrote:Is that exhaust hanger 14 or 12 gauge wire?

Whitehead has a pissed off neighbor who had a wire that was holding up a tree in his front yard "stolen by some kids". This wire was the exhaust hanger for the Supertrapp on the ST Civic...

That wire has been replaced by a proper hanger now. It even has a new pipe from the cat to the supertrapp!

Curt Luther wrote:

Bob Beamesderfer wrote:Is that exhaust hanger 14 or 12 gauge wire?

Whitehead has a pissed off neighbor who had a wire that was holding up a tree in his front yard "stolen by some kids". This wire was the exhaust hanger for the Supertrapp on the ST Civic...

Whitehead has only *A* pissed-off neighbor?

I agree with the "don't" comment. All the dyno tests I've seen show that system way, way down on power compared to almost anything else. I like Magnaflow myself and have seen good dyno charts on them... My old 2276 Bug motor really liked it FWIW.

Aaron McKinnon wrote:I agree with the "don't" comment. All the dyno tests I've seen show that system way, way down on power compared to almost anything else. I like Magnaflow myself and have seen good dyno charts on them... My old 2276 Bug motor really liked it FWIW.

Not defending Supertrapp here, but if weight is a concern, Magnaflow, Borla, Thermal, etc. will all add weight. You can light or you can have cheap.

Bob Beamesderfer wrote:

Aaron McKinnon wrote:I agree with the "don't" comment. All the dyno tests I've seen show that system way, way down on power compared to almost anything else. I like Magnaflow myself and have seen good dyno charts on them... My old 2276 Bug motor really liked it FWIW.

Not defending Supertrapp here, but if weight is a concern, Magnaflow, Borla, Thermal, etc. will all add weight. You can light or you can have cheap.

Eat one less burger. There's not much weight I can take out of my car... so I added 5 pounds with my exhaust system, but have lost 18 so far by changing my diet.