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Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: StavFC on August 06, 2009, 11:00:56 AM

Title: Single turbo people- How do you get on regarding track noise regs?
Post by: StavFC on August 06, 2009, 11:00:56 AM
As title really. My FC currently runs a unsilenced screamer and a ERC exhaust system with a large single rear box. Obviously the car is mentally loud, far too loud for the track, so I was thinking of shutting it up a little (even though I love the noise and REALLY dont want to get rid of it :() just so I can use it more often, as at mo its restricted to (most!) drift days and the road.
 
I was thinking adding a large middle box and also a large/long silencer to the screamer pipe, and I know on friends 600bhp piston engine cars this is usually enough, but you know what rotaries are like :Hammer
 
So... Any of you guys who still manage to pass track noise regs on big single turbo converted RX7s, could you please describe your exhaust system so I could get a rough guide on what will be enough silencing?
 
Cheers
Title: Single turbo people- How do you get on regarding track noise regs?
Post by: rx jamie on August 06, 2009, 12:05:59 PM
plumb you screamer into the down pipe that will massively reduce noise anyway. my super dragger system has a bung that i can put in the silencer and that helps loads aswell.
Title: Single turbo people- How do you get on regarding track noise regs?
Post by: StavFC on August 06, 2009, 12:30:36 PM
I dont want to plumb it in or run a bung, both will be restrictive to exhaust flow, which is the last thing I want to do.
Title: Single turbo people- How do you get on regarding track noise regs?
Post by: mx1311 on August 06, 2009, 02:46:42 PM
pluming it in will loose you 20-50hp, run a seperate silencer

ive got a hbp gt42 with 4" exhaust front to back and have a 15" long 4" midbox and another mid box as a backbox with a dolphin tail welded to it

102.7 db static

have not got round to making the seperate system for the wastegate yet
Title: Single turbo people- How do you get on regarding track noise regs?
Post by: StavFC on August 06, 2009, 03:04:50 PM
102 static still! Jesus! Makes wonder if its worth even trying, lol
Title: Single turbo people- How do you get on regarding track noise regs?
Post by: Initial-D on August 06, 2009, 03:13:44 PM
Got a link for said silencer?
I currently run the Greddy/Trust silenced midpipe with 94mm piping its quiet ish but obviously you may get better flow through through your midbox? I get 102 also.
Title: Single turbo people- How do you get on regarding track noise regs?
Post by: mx1311 on August 06, 2009, 03:20:50 PM
got them both from reworx mate. one left over from max\'s nippon build, one off phil g\'s car ;)


http://www.burnsstainless.com/UltraliteMuffler/ultralitemuffler.html
Title: Single turbo people- How do you get on regarding track noise regs?
Post by: suba on August 24, 2009, 02:02:32 PM
This also depends on the track - Bedford autodrome has an 87db drive by test with sensors on the track, and a static 101 test.  I doubt any car with a screamer pipe would meet this, likewise if you are running a 4 inch exhaust.....
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