How much muffler is generally needed?

[mtgmanracing]

I am planning on going straight from the header about 4 feet then a 45 degree bend and having a supertrapp exiting behind the passenger area in front of the rear fender...

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Would this be enough sound deadening, or do most you run glasspacks in addition to a regular muffler?

[Knestis]

I am NOT a supertrapp fan for a lot of reasons. The only thing they have on their side is light weight and easy installation. I don't know how many disks you'd need to run to get a VW legal now but I'd go with a good quality baffled box muffler instead (like a Walker or something).

K

[racer_tim]

I run a cherry bomb glass pack, attached to about 12" of flex pipe, and a 45 degree down pipe that exits right in front of the rear axle.

It's worked for me, and we have VERY restrictive sound requirements for Laguna Seca.



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html

[joeg]

I used supertrapp end plate only for years. K is right--quite the royal pain chasing the correct number of plates and unless you take them apart and clean them (yes clean them)regularly, you'll have lots of back pressure.

They are good as flame suppressors.

[Rex B]

Try it first without a muffler.
I ran a 2300 Pinto with a straight pipe ending in a downturn in front of the rear axle. I think it ran about 98db.
I intend to do the same thing on the Jetta

[m glassburner]

Make sure it goes past the driver....I got a lecture about my previous system.. http://Forum.ImprovedTouring.com/it/smile.gif mike g.

[Dick Elliott]

REX!
Still have that pipe on my new Pinto! 98 db inside the car, thats for sure. Has your welding improved? Jetta? Tell me more. What happen to the RX-7? DICK
mjelliott@cox-internet. com



Originally posted by Rex B:
Try it first without a muffler.
I ran a 2300 Pinto with a straight pipe ending in a downturn in front of the rear axle. I think it ran about 98db.
I intend to do the same thing on the Jetta

[Dick Elliott]

If you must run a muffler, get a Lowback spiral muffler from Moroso. Use a 3" in and out reguardless of your down pipe size. Just expand the pipe at the muffler to fit. This way it will be low back pressure and quiet too. These mufflers will out last the car and are cheap too. Muffler should be the last item in the exhaust system. Back by the back bumper is the best place. If you place the muffler under the car, with a long tail pipe, the exhaust has time to speed back up and get loud again. Total length is found by where you want the power to come in at. Short for top end / long for low end.

[Mark LaBarre]

about 3' of pipe and a 12" glass pack with turndown under my car gets me to about 92 db on an 86 Scirocco. No muffler was 99 to 102 db.

[Bill Miller]

I ran a straight pipe on my old ITB car, and run one on my HP Rabbit. I'm usually 99-100db w/ the Prod car, and was pretty much the same w/ the ITB car.

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

[JohnRW]

Straight pipe, following the original path, exiting in the stock location in the rear thru a 'turn-down'. No muffler, no resonator. Never ever had a sound problem, and when I've checked, it's always been under 100dB...probably closer to 97-98dB.

If it exits in the rear, the driver doesn't need ear plugs, and won't get a headache.