Discussion
Used a test meter on my exhaust this weekend, I knew it was loud but not this bad !
At 1.0m, 45 degree angle, and 4500 rpm it measured 119 db.
At 0.5m it measured 121 db.
Oops ! No track days for me until I sort that out !
Somehow I doubt that an exhaust "tip" will bring that down by 20 db (correct me if I'm wrong) so I guess it's new box time.
Anyone got any recommendations for a not-too-extortionate box ? (dont want to replace my down pipes as they're fine)
At 1.0m, 45 degree angle, and 4500 rpm it measured 119 db.
At 0.5m it measured 121 db.
Oops ! No track days for me until I sort that out !
Somehow I doubt that an exhaust "tip" will bring that down by 20 db (correct me if I'm wrong) so I guess it's new box time.
Anyone got any recommendations for a not-too-extortionate box ? (dont want to replace my down pipes as they're fine)
Make sure you had the weighting set correctly on the meter. 119db is mind bogglingly loud, x-flows are bloody noisy but it shouldn't be that loud.
Also, where did you test it? Where you near any walls or obsticals? Ideally you want to be in an open area that is not going to cause echo's that will give a much higher reading. Also it helps if you can angle your exhaust exit so that it's not pointing at the floor.
If all else fails then go for a re-packable silencer (£160ish).
Also, where did you test it? Where you near any walls or obsticals? Ideally you want to be in an open area that is not going to cause echo's that will give a much higher reading. Also it helps if you can angle your exhaust exit so that it's not pointing at the floor.
If all else fails then go for a re-packable silencer (£160ish).
The gauge is just a borrowed one, digital, from bookatrack. As far as I can tell, there's no calibration or setting that could be done ... ?
The car was in front of the garage on the drive, true, but the exhaust was pointing away from the garage. The pipe points out exactly parallel with the floor.
It is mind bogglingly loud ... just ask my neighbours !
Thanks juansolo, knew I could count on you replying to my postings
The car was in front of the garage on the drive, true, but the exhaust was pointing away from the garage. The pipe points out exactly parallel with the floor.
It is mind bogglingly loud ... just ask my neighbours !
Thanks juansolo, knew I could count on you replying to my postings
There is a weighting setting on a sound meter, can't remember which is the correct one, I'll have a look at mine when I get home (though mine is a old analogue one). As a goal you want to try and get your car to less than 103db which will get you onto most circuits without much trouble. Mine is under 103db on most meters (except Oultons which has me producing over twice the volume at 105db) with a packed silencer.
Okay, so here's the exhaust retest info :
Last night, middle of a field in middle of nowhere.
Meter set at weighting 'A', held at 1m from exhaust tip, at 45 degrees, level with exhaust (i.e. about 8" from floor)
Run One : gradually increase revs gently to 4500 rpm : 108.5 db
Run Two : gradually increase revs gently to 4500 rpm : 107 db
Run Three : foot slips, accidentally rev hard from 3500 to 4500 rpm : 118.6 db !!!
So, unless the meter is incorrect, if I increase revs gently then it's "quiet" ish, but if I accelerate hard (as per going round a track, for example) then nearly 120 db is easily achievable !
Ulp !
Last night, middle of a field in middle of nowhere.
Meter set at weighting 'A', held at 1m from exhaust tip, at 45 degrees, level with exhaust (i.e. about 8" from floor)
Run One : gradually increase revs gently to 4500 rpm : 108.5 db
Run Two : gradually increase revs gently to 4500 rpm : 107 db
Run Three : foot slips, accidentally rev hard from 3500 to 4500 rpm : 118.6 db !!!
So, unless the meter is incorrect, if I increase revs gently then it's "quiet" ish, but if I accelerate hard (as per going round a track, for example) then nearly 120 db is easily achievable !
Ulp !
Hi Nev,
You are having fun aren't you? If you need a new silencer try Demon Tweeks or Custom Chrome who can both probably offer a range of silencers you could fit to your existing system to replace the one you have. Think both also offer a range of bends, pipe etc for making complete custom systems. Custom Chrome certainly did.
You are having fun aren't you? If you need a new silencer try Demon Tweeks or Custom Chrome who can both probably offer a range of silencers you could fit to your existing system to replace the one you have. Think both also offer a range of bends, pipe etc for making complete custom systems. Custom Chrome certainly did.
LOUD is good.Tref, you know me too well Yeah, actually, I'm having a ball ! Okay, so it was annoying that I missed Bruntingthorpe coz of the broken stud, but I enjoyed taking the engine out, learnt a lot about the car, and fixed one or two minor problems that weren't evident until the engine was out.
Managed to find DCOE tuning info, and now she's idling a lot sweeter.
Just got to sort the exhaust (partly for trackday reasons, and partly for sanity-of-my-neighbours reasons
)
I'm waiting for a Demon Tweaks catalog to arrive (they're not exactly rushing) but I didn't know about Custom Chrome .... I'll look them up on the web, thanks
On a when-the-car-is-actually-running note, God this thing is fun !!! I'm still exploring the limits of the handling, but it completely amazes me the amount of grip this thing has got - as long as you've got the balls to keep your foot planted and keep accelerating through the corner, it's truly amazing some of the bends it'll go round ?!?
Yeah, actually, I'm having a ball ! Okay, so it was annoying that I missed Bruntingthorpe coz of the broken stud, but I enjoyed taking the engine out, learnt a lot about the car, and fixed one or two minor problems that weren't evident until the engine was out. Managed to find DCOE tuning info, and now she's idling a lot sweeter.
Just got to sort the exhaust (partly for trackday reasons, and partly for sanity-of-my-neighbours reasons
) I'm waiting for a Demon Tweaks catalog to arrive (they're not exactly rushing) but I didn't know about Custom Chrome .... I'll look them up on the web, thanks
On a when-the-car-is-actually-running note, God this thing is fun !!! I'm still exploring the limits of the handling, but it completely amazes me the amount of grip this thing has got - as long as you've got the balls to keep your foot planted and keep accelerating through the corner, it's truly amazing some of the bends it'll go round ?!?
Demon Tweeks are for the rich with an open bank balance.If you want a cheap repackable silencer,goto Autocross in Bracknell.If they havent got one,they will get one sorted.They did one for a friend and he is a tight git .Think it was about £80.Custom Chrome arent that brill for a system that you need to work on a highly modded engine.OK for a mild tune,but the have diflector plates to de-resonate the sound in the box.These reduce noise but also strangle the BHP.I bought a replacement silencer from Merlin's at Castle Coombe(100 db) and needed more packing out to get on the track.The Custom Chrome was 108db ,Merlin Unpacked 103db.Easier to repack than the CC silencer
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