reducing induction noise ?
Discussion
was at an airfield trackday at the weekend and noticed when a pal was driving my car (R400 duratec on jenvy throttle bods foam filter with bonnet cut) it has some serious induction noise on drive by, I want to do the likes of croft which is tight on drive by noise so Im going to have to address the induction racket 
on my previous busa powered car I run a cheapie plastic box which killed the performance so ended up buying a Reverie carbon airbox with duct which killed the noise as well as the soul of the car but was very effective .
any recomendations please ?
on my previous busa powered car I run a cheapie plastic box which killed the performance so ended up buying a Reverie carbon airbox with duct which killed the noise as well as the soul of the car but was very effective .any recomendations please ?
JeffC said:
was at an airfield trackday at the weekend and noticed when a pal was driving my car (R400 duratec on jenvy throttle bods foam filter with bonnet cut) it has some serious induction noise on drive by, I want to do the likes of croft which is tight on drive by noise so Im going to have to address the induction racket on my previous busa powered car I run a cheapie plastic box which killed the performance so ended up buying a Reverie carbon airbox with duct which killed the noise as well as the soul of the car but was very effective .
any recomendations please ?
I have one of these, on my previous and current R500 duratec: on my previous busa powered car I run a cheapie plastic box which killed the performance so ended up buying a Reverie carbon airbox with duct which killed the noise as well as the soul of the car but was very effective .any recomendations please ?
http://www.caterhamparts.co.uk/product.php?id_prod...
It's pretty good at reducing induction noise, but takes away lots of throttle response sadly.
I made an airbox and cold air spliter from offcuts / scrap in the garage - it worked very well.
It was effective - no power loss and let you really enjoy the exhaust note.
If anything at higher speeds the mixture was leaner with it on (showing on the lambda readout) so I richened the mix slightly in those mapping points to compensate. There is a lot of turbulence from the wing / headlamp and that can take air away from the standard TB / ITG filter at high speeds.
Fun and games - course not tarty enough for some...
It was effective - no power loss and let you really enjoy the exhaust note.
If anything at higher speeds the mixture was leaner with it on (showing on the lambda readout) so I richened the mix slightly in those mapping points to compensate. There is a lot of turbulence from the wing / headlamp and that can take air away from the standard TB / ITG filter at high speeds.
Fun and games - course not tarty enough for some...
Jeff if you get yours noise tested at Croft (without noise reducing modification) I'd be interested to know the result. I'd like to get on there too and they've offered to noise test me at an agreed time, just haven't got round to it yet. From memory their std limit is about 88db at 3/4 revs now due to the loss of their court case so some work needed for an R400 to get down to that.
2slo said:
Jeff if you get yours noise tested at Croft (without noise reducing modification) I'd be interested to know the result. I'd like to get on there too and they've offered to noise test me at an agreed time, just haven't got round to it yet. From memory their std limit is about 88db at 3/4 revs now due to the loss of their court case so some work needed for an R400 to get down to that.
From many years expereince at croft I dont think there is a way that a Caterham would manage 88db, Pretty sure my old standard 2.0 duratec with 7" can freshly packed struggled with the old 98db static.I know they have issues and when i was there last year the council had put a driveby meter on the exit Sunny out luckily the exhaust on a duratec is on the opposite side of the car which helps but the induction side isnt, we got round it by short shifting through sunny but it wasnt the same
JeffC said:
From many years expereince at croft I dont think there is a way that a Caterham would manage 88db, Pretty sure my old standard 2.0 duratec with 7" can freshly packed struggled with the old 98db static.
I know they have issues and when i was there last year the council had put a driveby meter on the exit Sunny out luckily the exhaust on a duratec is on the opposite side of the car which helps but the induction side isnt, we got round it by short shifting through sunny but it wasnt the same
Yes, I think I'd need to lose at least about 12db which, even if possible, would drag quite a few horses down with them. The only other local venue I'm aware of is the Teeside cart track. Apparently good fun in a 7 and they weren't bothered about noise when I spoke to them recently. Failing that it's down to Donnington or up to Knockhill, neither of which are exactly on my doorstep (from Durham). We aren't exactly well served with race tracks in this part of the country. Still wouldn't move though I know they have issues and when i was there last year the council had put a driveby meter on the exit Sunny out luckily the exhaust on a duratec is on the opposite side of the car which helps but the induction side isnt, we got round it by short shifting through sunny but it wasnt the same
Donny is quite strict on noise too Ive been black flagged there the twice I've been although finding the location of the sound meter helped lol. I race karts at teesside every month and like the circuit in a kart but I'm not keen on it in a car . I was at cottesmore on Saturday and that was great quite a ballsy lay out with high speed corners and no noise restrictions it was 2 hours 40 for me I'm 13 mile south of Durham, I've also had no issues at Cadwell or oulton park,both well worth the drive !
I also had an extra rear silencer box - it was a struggle with the 2.5" bore pipe from the side silencer but doable.
the rear box was from a Saab9000 I think it was. It was fitted by removing the silencer rear cap / side pipe and fitting a new cap with under car tube that hook hooked up to the under the tank rear box.
The whole thing weighed a bit and did sap a little peak power.
My VX was always 105dB static at 3/4 revs (ok a little less perhaps) without either the induction box or the extra silencer - not a problem for normal for race days (back then). With the rear box on it was very quiet indeed but I never measured it.
There are various solutions - then only way to get really quiet is a 2 box system.
the rear box was from a Saab9000 I think it was. It was fitted by removing the silencer rear cap / side pipe and fitting a new cap with under car tube that hook hooked up to the under the tank rear box.
The whole thing weighed a bit and did sap a little peak power.
My VX was always 105dB static at 3/4 revs (ok a little less perhaps) without either the induction box or the extra silencer - not a problem for normal for race days (back then). With the rear box on it was very quiet indeed but I never measured it.
There are various solutions - then only way to get really quiet is a 2 box system.
JeffC said:
From many years expereince at croft I dont think there is a way that a Caterham would manage 88db, Pretty sure my old standard 2.0 duratec with 7" can freshly packed struggled with the old 98db static.
I know they have issues and when i was there last year the council had put a driveby meter on the exit Sunny out luckily the exhaust on a duratec is on the opposite side of the car which helps but the induction side isnt, we got round it by short shifting through sunny but it wasnt the same
I know they have issues and when i was there last year the council had put a driveby meter on the exit Sunny out luckily the exhaust on a duratec is on the opposite side of the car which helps but the induction side isnt, we got round it by short shifting through sunny but it wasnt the same
Edited by Yellow 7 on Wednesday 2nd November 11:57
Ive got an airbox that i never fitted its can be adapted for rollers/ jenveys etc, a guy on ebay used to advertise them. If you look at some Pics of Cameron Purdie in his westfeild SMRC, DDMC he has one fitted...cant find a photo just now as am at work (loose term). I can send a photo when i get back.
AutoTeknix make an airbox for K series cars running Jenveys - maybe this could be adapted to fit. I have used one on my K-series with both 42mm Jenveys and now with 45 mm Jenveys and 90mm trumpets. I guess it depends on what backplate you have, what size throttle bodies, what length trumpets and also how close the Duratec port spacing is to the K series.
Jenvey themselves make some airboxes but I'm not sure if they will fit under a Caterham bonnet.
I want to have an interchangeable system where I can swap between filter and airbox using the same backplate but I haven't found a suitable solution yet. Jenvey make a moulded deep backplate which looks hopeful and I will be trying that over the winter.
Jenvey themselves make some airboxes but I'm not sure if they will fit under a Caterham bonnet.
I want to have an interchangeable system where I can swap between filter and airbox using the same backplate but I haven't found a suitable solution yet. Jenvey make a moulded deep backplate which looks hopeful and I will be trying that over the winter.
JeffC said:
spot on sam if you can that would be great
Knew there was a picture somewhere:http://www.smrc-uk.com/media/photos/2011_april/S&a...
Back on the 15th so will get one across then.
the air box that Nigel links to is crap and draws hot air from under the bonnet , this has been seen to reduce the r500 power down from circa 260bhp to as low as 225bhp.
try a search for the c400 airbox that has the intake ouside of the bonnet, This doesn't reduce power by much and when fitted onto my duratec has reduced drive by considerably .
the c400 box is available from Caterham cars.
dj
try a search for the c400 airbox that has the intake ouside of the bonnet, This doesn't reduce power by much and when fitted onto my duratec has reduced drive by considerably .
the c400 box is available from Caterham cars.
dj
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