R.B Posted September 13, 2003 Share Posted September 13, 2003 Looking at most of the trackdays they seem to have alot of NOISE limits so i need to change my exhaust to a quieter one. Any ideas please Cheers R.B Quote Link to comment Share on other sites More sharing options...
steve_m Posted September 14, 2003 Share Posted September 14, 2003 I got mine from Powerspeed. Stainless steel, repackable, very quiet although not measured yet. The induction noise seems louder than the exhaust now. Steve Quote Link to comment Share on other sites More sharing options...
Bazzer Posted September 14, 2003 Share Posted September 14, 2003 I bought a 7" x 30" can from Techcraft. I had to chop 1.5" off its length to make it fit. This was measured at Goodwood at 98/99db As Steve said, induction noise and rattling panels can make a big difference. Me Blondie on the Bec list has noise proofed his engine bay and uses a second exhaust box under the rear of the car. This has brought his noise levels way down. Cheers Bazzer Quote Link to comment Share on other sites More sharing options...
jasonlycett Posted September 15, 2003 Share Posted September 15, 2003 Predator exhausts have told me they can supply a 98db silencer for £175 complete with fitting. They said it has a small baffle, but that shouldnt affect the power too much. Do a search for 'Predator' they have a website. I have also bought some sound proofing for under the bonnet, as drive by noise will still be a problem i think. Quote Link to comment Share on other sites More sharing options...
busapower2001 Posted September 15, 2003 Share Posted September 15, 2003 The factory do one now at 98/99 dB :-) Quote Link to comment Share on other sites More sharing options...
R.B Posted September 15, 2003 Author Share Posted September 15, 2003 Ive spoke to westfield today and they dont do one. Quote Link to comment Share on other sites More sharing options...
busapower2001 Posted September 16, 2003 Share Posted September 16, 2003 Ah ok could be oversight on my part. How is the test done? What is the 98db reading at? Is it a drive by (full throttle) test rather than static test? The 98/99db I was referrring too was for sva at approx 6500rpm short distance away (<1ft) from tail pipe. So if it isn't akin to the sva test then I guess they don't do one... but if it is ala sva then speak with Mark Walker. Quote Link to comment Share on other sites More sharing options...
Tony B Posted September 16, 2003 Share Posted September 16, 2003 If its track noise youre looking at its generally at 1-1.5m away from the exhaust at 45degs and 3/4 max rpm... this can vary between tracks and organisers.. some are more forgiving Theres also the driveby which again can vary, this could be 10m from side of track, trick is to take a nice gentle lap and suss out all the sensors, when you know where they are back off slightly going past them I'm in a similar position, my car has a very loud Titanium system fitted, I need to either get a new track day system fitted or hack the current one and put a larger box on it.. Anyone had a Bike zorst bult who can give a rough estimate as to cost... Had one bult for the car on the left but this obviously didnt have the bike sensor bits in the zorst (new to the bike engined car game so not got all the techie stuff sorted yet ) Quote Link to comment Share on other sites More sharing options...
R.B Posted September 19, 2003 Author Share Posted September 19, 2003 Thanks chaps i dont get some of this db thingy ? I didnt want to buy an exhaust to find that its still to late. Cheers R.B Quote Link to comment Share on other sites More sharing options...
peterg Posted September 19, 2003 Share Posted September 19, 2003 I know of several people who needed 'quiet' exhausts for trackdays and these were built by (in no particular order) Techcraft, Raceline, BTB Exhausts and Raceco (AMMO who posts on Blatchat does these with great success for previously very noisy C*terhams and I believe resonable cost) edited to include.... Goodwood is probably the most stringent circuit for noise and they measure 98db static but have a 92db drive by limit (IIRC). An increase of 3db is a doubling of the actual noise so if you want to do Goodwood and currently have a car that makes 101db then you'll have to halve the noise output Oh and after you silenced the exhaust, you might then find the induction noise is loud enough to cause a problem with the drive by limit Quote Link to comment Share on other sites More sharing options...
Tony B Posted September 19, 2003 Share Posted September 19, 2003 You can also buy Supertrap type additional silencing, I got one from Castle Combe for the Lotus, I stick the pipe in one of the exit pipes of the zorst, this takes 5 db off the static, looks a bit daft but hey you dont lose your track day... Im contemplating using this for the westie, by getting a bit of flexi pipe, fatening it to the end of the zorst, and routing it up to the Supertrap somewhere behind the passenger seat, may have to make a bracket but thats what owning a kits all about isnt it Forgot to mention, Demon Thieves sell an assortment of these and IIRC have some that are adjustable to add/remove silencing. Quote Link to comment Share on other sites More sharing options...
peterg Posted September 19, 2003 Share Posted September 19, 2003 word of warning, DON'T use a Supertrapp on a bike engined car ....it can cause horrible things like overheating etc and knocks the top end of your performance Quote Link to comment Share on other sites More sharing options...
Tony B Posted September 19, 2003 Share Posted September 19, 2003 word of warning, DON'T use a Supertrapp on a bike engined car ....it can cause horrible things like overheating etc and knocks the top end of your performance Peter, Mines more of an additional silencer, its about a foot long with a 2.5" straight through pipe, I have used it on my 200BHP Elise on several occasions (Goodwood a couple of times) it doesnt cut power at all, all it does is cut down on the resonant noise coming out of the end.. As long as the pipework from the zorst exit to the end of the additional silencer is the same then there should in theory be no loss of power at all. Bought it from Merlin Motorsport for about £45, got me onto a few quiet days at Combe and Goodwood. Quote Link to comment Share on other sites More sharing options...
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