dt7 Posted February 16, 2003 Share Posted February 16, 2003 Has anyone got any advice on how I can get my 1600x/f to 98dbs for a track day at Goodwood? (I hear they are a bit hot on noise levels). I have a standard 1600 x/f with a 2 into 1 exhaust going into a competition exhaust (5" diameter). I have no idea what the dbs level is but it sounds noisy to me and I don't want to get to Goodwood only to find I can't do the track day. Anyone got any ideas to achieve the required 98db level or tell me where I can get the Db level measured? I live in South Bucks. dt7 Link to comment Share on other sites More sharing options...
F355GTS Posted February 16, 2003 Share Posted February 16, 2003 Well aside form all the technical things you can no doubt do, make sure you lie when they ask you the redline limit, knocking a a couple of thousand revs off the top should help (the drive by meters arn;t as fussy as the static test they do) Mark Link to comment Share on other sites More sharing options...
rgrigsby Posted February 16, 2003 Share Posted February 16, 2003 As Mark says you can be judicious with your rev limit, if that doesn't help it's worth getting a bigger repackable silencer, lots of places do them. I'm fitting a 6" diameter 32" long Techcraft one to my car soon... Cheers Link to comment Share on other sites More sharing options...
Violet Elizabeth Posted February 16, 2003 Share Posted February 16, 2003 Am trying to do a similar thing dt7. I was measured at 101dB for my 1700SS. Comp. exhaust with not a lot of packing left ! Trying to get it down so I can do the 98 days. Have been talking to AMMO of Raceco exhaust (and Blatchat) fame , he has suggested that the larger Raceco exhaust may well do the trick. Will be ordering as soon as I have got the dosh together. Having done the sums, I should be able to recoup the cost in reduced fees fairly quickly. Agree with Mark though, my engine only revs to 5500, honest. Even then I wasn't even marginal. Link to comment Share on other sites More sharing options...
David Ward Posted February 16, 2003 Share Posted February 16, 2003 Has anyone got under 98dB with a side exit? My 1.6K was well under it with a rear exit (which I've still got if anyone wants it) but I've not seen another Caterham at a 98dB day. The problem is that for reasons well documented Goodwood are pretty strict. Now that I've become power crazed and afflicted by upgraditis it's all I can do to get under 105dB...... V7 HPD Link to comment Share on other sites More sharing options...
Gridgway Posted February 16, 2003 Share Posted February 16, 2003 I used my (2-7's-ago) SLR their with a brand new 7" SLR race box. The static was fine, but I got stopped by the drive-by. I put on one of their gizmos for £20 for the day and lifted a little past the meters. It was fine. Graham Link to comment Share on other sites More sharing options...
rgrigsby Posted February 16, 2003 Share Posted February 16, 2003 Pinky used to be a regular at Goodwood on 98Db days with a long 7" Techcraft silencer on his tweaked 1.6K I believe, having been out in it I was amazed at how quiet it was. I think 98Db is fairly easy achieve on a 1700SS with a decent size silencer, either 6" or 7" and 30" long regularly repacked should do the job. Link to comment Share on other sites More sharing options...
R500 CYA Posted February 17, 2003 Share Posted February 17, 2003 Hi Rob! Yes, using a 7" techcraft on my 1.6K with TB's, I got down to 96dB static with an improvement in the torque curve as well! I'm running a SLR now and the biggest problem I have had with that is induction noise. You can always lie about the red line (most 7 owners say it's about 6000 rpm) and the two drive by noise meters on the outside of the track are not a problem (one on Fordwater and one on Lavant Striaght), the big problem is the drive by after the chicane, which is on the inside of the track and therefore measuring induction: my car was doing 100.3 dB's there 😳 which can only be reduced by lifting or a new airbox config. There are of course noisy days (105 dB) but these tend to be more expensive and track time is more limited. Nick Link to comment Share on other sites More sharing options...
R500 CYA Posted February 17, 2003 Share Posted February 17, 2003 Forgot to mention, I have bought a 7" techcraft for the SLR and will let you all know how much difference it makes Link to comment Share on other sites More sharing options...
bstark Posted February 17, 2003 Share Posted February 17, 2003 I've been ignoring the 98db days for the same reason, but I have just been making an assumption about my exhaust noise (it's a standard rear exit on a 1700SS, but again it sounds bloody noisy to me). How easy is it to tweak a rear exit pipe for the day? Bob Stark Supersprinter Link to comment Share on other sites More sharing options...
peterg Posted February 17, 2003 Share Posted February 17, 2003 and don't forget you can turn up at Goodwood circuit on virtually anyday and get your car tested by the marshals in the paddock so you know how loud it is/will be and therefore IF you need to do anything about it..... 😬 Link to comment Share on other sites More sharing options...
Jaseb Posted February 17, 2003 Share Posted February 17, 2003 I got my Supersprint down from 104db to 98/99 db with a techcraft fitted by Chris Wheeler at the 7 workshop, I say 98/99 cos I think I blew some of the stuffing out of it fairly quickly but it definitely got 98 before my first track day with it fitted. I too have a 4-2-1 manifold. I didn't think it sounded any quieter myself but I think all I can hear is inlet roar anyway... Would give him a bell tho Teaching you all how to do it properly, flares and a crossflow... Edited by - jaseb on 18 Feb 2003 08:41:48 Link to comment Share on other sites More sharing options...
jerrypike Posted February 17, 2003 Share Posted February 17, 2003 pinky very interested to know how you get on with slr & side exit for goodwood peterg they're very helpful checking with a static meter, but varies quite a lot: i've scored 102 & 105.5 on different days, same car/revs 105 days mean a lot of queuing jerry Link to comment Share on other sites More sharing options...
Sheds Moderator Posted February 19, 2003 Share Posted February 19, 2003 A pal of mine used to get has rallycross Mini past scrutineering only with his coat over the inlet trumpets (in the cabin...). I don't know if induction roar is contributing to your noise level or how you could practically reduce it for testing, but it might help. Link to comment Share on other sites More sharing options...
STEVE GILBERT Posted February 19, 2003 Share Posted February 19, 2003 Guys How much does one of the 7 inch Techcraft Silencers weigh? I might try for sub 98 myself and am looking at options Steve See My Zetec Power 7 Here Link to comment Share on other sites More sharing options...
Eric McLoughlin Posted February 24, 2003 Share Posted February 24, 2003 Back in 2000 I failed the Goodwood noise test with my 1600 Crossflow Classic. At the time it was fitted with a rear exiting 4 inch exhaust and registered 103 db. The lollowing year I had the car fitted with a 6 inch non-repackable side exiting exhaust (by Redline in Caterham) and it has now passed noise tests at Goodwood and Hullavington. I seem to get readings in the order of 96 db now. The chances of pulling the wool over the eyes of the marshalls at Goodwood are slim. They've had years of experience of Crossflows and they always insist on you taking the revs to 4,500 rpm. They are very helpful, however, and do what they can to help you get past the test. Link to comment Share on other sites More sharing options...
RiF Posted February 24, 2003 Share Posted February 24, 2003 Try Raceline. I was there last Friday and with the exhaust they are selling they have got down to 94 😳 Worth a ring. Richard in France Build is just starting of my Duratec 7, painting this week 😬 😬 😬 Link to comment Share on other sites More sharing options...
Phil R Posted February 25, 2003 Share Posted February 25, 2003 I was at Goodwood yesterday with my 1.8 Vauxhall 8 valve. 95 dB with a brand new techcraft 6"x30" silencer from the 7 Workshop. Previously had about 101dB (with the standard 5" Caterham job) which makes sense as that's the SVA limit and the car's only been on the road 9 months. /Phil. Link to comment Share on other sites More sharing options...
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