Mankee Posted April 16, 2013 Share Posted April 16, 2013 I had a quick search in the archives and via Google, but couldn't find quite what I wanted. I really like Bedford Autodrome (did my first ever proper trackday there about 10 years ago) so don't really want to not go there ever again. I tripped three of the noise meters in a single lap yesterday (first semi-flying lap!) and I'm trying to work out if it's my silencer, indution noise or a bit of both. Exhaust is a 6" silencer and VHPD/SLR 4-2-1 manifold, reading 98.9db static at a bit below 5000rpm. As a comparison, it came up at 98db at Rockingham a few weekends ago, so the readings are fairly consistent. Engine is a just over 200bhp modified VVC-based lump and I set myself a limit of 7500rpm yesterday. Induction is Jenveys, Pipercross dome filter and cutout in bonnet. Driveby at Bedford is always tough at 87.5db. I only just tripped them at 87.6db, but three times in one lap is a bit silly of me really. I'm pretty sure that the ones I set off are on the exhaust side of the track when looking at the below diagram, even though I did give it welly past the meters on the north-west and east circuits: http://i401.photobucket.com/albums/pp97/shimmylasco/cars/bedford_autodrome_large.jpg So my questions are, has anyone been in a similar position and what have they done about it? I think I'm going to go to a 7" silencer first, as it's much easier to swap a silencer than mess around with bodywork, airboxes and other stuff to quieten the induction noise. Especially as my current silencer seems to read higher than what I was expecting. Noise is so subjective as always. It was quite windy yesterday too. Link to comment Share on other sites More sharing options...
Jonathan Kay Posted April 16, 2013 Share Posted April 16, 2013 Could you borrow one of those additional bolt-on cans for the exhaust and see if that solved it before replacing the silencer? Jonathan Link to comment Share on other sites More sharing options...
Mankee Posted April 16, 2013 Author Share Posted April 16, 2013 Hi Jonathan. That's a good point actually, but I'd never considered it for several reasons. I'd like a permanent, fit-and-forget solution, I've seen them strangle engines by their nature, I've had to pick a few up off live circuits when they've fallen off cars and, knowing me, I'll probably forget about it being attached and take out people's ankles/cars in the pit late! They do work though, especially on notoriously loud stuff like Cerberas and VTECs. Link to comment Share on other sites More sharing options...
Jonathan Kay Posted April 16, 2013 Share Posted April 16, 2013 You know more about them than I do! I was thinking of it as a diagnostic rather than a therapeutic intervention... Jonathan Link to comment Share on other sites More sharing options...
Jason Plato Posted April 16, 2013 Share Posted April 16, 2013 good big can and an airbox I would have thought. my air box on the 1900K reduced noise massivly and it didnt affect power. Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted April 16, 2013 Support Team Share Posted April 16, 2013 I think you are going to struggle but an airbox and a RaceCo silencer is as good as you will get. With that set-up I used to record about 96db at 5500rpm on my 226bhp K which revved to 8000rpm Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now