How to quiet a 2nd gen?

[Eagle7]

86 ITS RX-7. I've got no prior experience, and haven't yet had this car out of the garage, so I have no idea how loud it really is. However, my better half is VERY nervous about what the neighbors might think about this jet that's about to leave the carrier. Also, I might want to run at Waterford Hills, which has serious noise limits. So, in order to keep the peace at home, I need an easily mounted/removed way to quiet this screamer down.

It currently has a Racing Beat header into a single 3" pipe feeding a Flowmaster muffler with a downturn outlet. How can I make it purr instead of growl while I tinker at home?

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Marty Doane
ITS RX7
CenDiv WMR

[ITSRX7]

I can see where you are coming from. Realizing it is ABSOLUTELY CRITICAL to bring the Wankel up to temp before shutting it down, it makes for intereting neigborly values.

I would build yourself a modular system. Keep what you have now and then when you need to work on it or travel to really restrictive tracks, get a SuperTrapp.

Buy some dyno time and really log what kind of power you get from the number of discs. That way you will be able to 'tune' at Waterford for max power, really cork it up while you tinker in the garage and then swap out setups at other tracks.

Have fun!

AB

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Andy Bettencourt
06 ITS RX-7
FlatOut Motorsports
New England Region
www.flatout-motorsports.com

[C. Ludwig]

I've got a Supertrapp and it does quite the car but it kills the power. With enough discs to make noise at WH the power falls off about 1000 RPMs earlier than it would uncorked. They work well for the around the house stuff though. I would not design a system to use a Supertrapp at all times. For reference, my car with a long primary setup and Dynomax muffler is right at the edge of the SCCA dB limit (101dB right?). We were 100dB at Mid-Ohio several times. So...it's LOUD.

Chris

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Chris Ludwig
08 ITS RX7 CenDiv

[Mazmarc]

Dont fool around with the Supertrapp. Go to http://www.iscracing.net/exhaust.htm. Not only did I gain @4 hp and @9 ft lbs of torque, but the db meter always reads under 97db. You can mix and match the parts. The Walker muffler is definately the way to go. I my opinion, of course.

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Marc Dana
#63 ITS Mazda Rx-7
#77 STS BMW 325I

[rx7chris]

I hate to be the one to say it, but throw the flowmaster away! Had to on my street 86, could here me comin and goin for about 3 blocks, if i took it easy. Run a single dynomax muffler, add a turn down, pointed down and away from the meter. I'd add at least 2 coat hanger wires in the tip just to make sure. The coat hangers are supposed to drop dB's by 1 each. With that setup you should not have a problem passing. you can always make the turn down removable, and clamp on a cheap econo box muffler for the garage. Just some options.

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Chris
IT7 #88
PowerTrip Racing
http://www.geocities.com/ptripracing/

[Silkworm]

I run a Magnaflow single in, single out, with 2.5" pipe from the header on back, and make 96db with a 90* elbow away from the sound meter.

At idle, it's definitely not a problem, just gurgles along. At full throttle, it's pretty loud.

I can get it under 89db with a supertrapp with all the plates, added to the end of that setup.

PaulC

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[This message has been edited by Silkworm (edited April 29, 2003).]