Matt Sullivan Posted July 11, 2001 Share Posted July 11, 2001 Trawling through the Blatchat archives, and some of the more recent postings, I'm trying to find a definitive answer to my problem.... 1991 Vx 2.0 HPC Swindon tuned to 235BHP with 4 into 1 Comp side exit exhaust is giving me 107.3 db at 4500 revs and 45 deg and 0.5m. This is too loud to get me onto the Wheeltorque Silverstone noisy day at the end of July :-( Is this the noise level I should expect, or is my exhaust shot? I've been reading about guys installing these Techcraft 7 inchers, but I'm loathe to spend a couple of hundred quid if all I'm doing is lowering to 106db. I want to retain the power as well. I've also read Roger King's warning on the SuperTrapp - a mate has one for his 911 with no probs, but that doesn't have Carbs. I know this is old ground, but can anyone help in the context of my spec. cheers, Matt. Matt Vx Swindon 235 'Power Is Nothing Without Control' Link to comment Share on other sites More sharing options...
Mike Bees Posted July 11, 2001 Share Posted July 11, 2001 I'd say your silencer is shot to bits! You should be able to get it down to at least (or do I mean at most) 100db with a decent can. Mike Link to comment Share on other sites More sharing options...
Matt Sullivan Posted July 12, 2001 Author Share Posted July 12, 2001 Does a new standard Caterham side exit can count as a decent pipe, or am I better going for one of the larger Techcraft units? Are they a simple DIY job to fit? Link to comment Share on other sites More sharing options...
Mike Bees Posted July 12, 2001 Share Posted July 12, 2001 The Caterham ones aren't repackable but are just as effective (when new) as any other s/s can. They're all basically the same, a perforated pipe through the middle with wadding between the pipe and the can. The Techcraft ones as supplied by Techcraft aren't a simple DIY fit 'cos they're not tailor made for a 7 - they come with in input stub and an output stub and that's it. And they tend to come apart at the front end if unsupported. The Seven Workshop (where's Roger?) advertise Techcraft silencers, maybe they can supply them read-to-fit to a 7? There are quite a few people who will custom build cans at reasonable cost (e.g. www.play-skool.co.uk). Try searching the se7ens list archives (http://www.se7ens.net/cgi-bin/wilma/sevens) for 'repackable'. I'd recommend going for at least 6" diameter, and if the can is being custom-made then get it as long as possible given the space available. I use an aluminium repackable can made by Custom Fabrication Engineering (http://www.forceracingcars.co.uk/) - not cheap (circa 300ukp) but very effective. The aluminium can seems to help keep the noise down compared to a stainless one. Mike Link to comment Share on other sites More sharing options...
FH Posted July 12, 2001 Share Posted July 12, 2001 Chris Wheeler at Seven Workshop fitted a Techcraft to our R500 in less than half an hour - he's on 01992 470480 .... Top Man, Chris thumbsup.gif Being re-packable seems to make an awful lot of sense and we went from 101dB to 97dB on static smile.gif I don't know a widget from a grommet, so I don't know how long it would take in DIY terms blush.gif FH Link to comment Share on other sites More sharing options...
Matt Sullivan Posted July 12, 2001 Author Share Posted July 12, 2001 Thanks for this. I'll give the 7 Workshop a bell about fitting a Techcraft unit. I'm also getting carried away with all this talk of aeroscreens, so I may fit one of these first before the exhaust. Though having said that, I was thinking of joining RMA next year, so the exhaust needs to be sorted. cheers Matt. Matt Vx Swindon 235 'Power Is Nothing Without Control' Link to comment Share on other sites More sharing options...
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