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Roller Barrell on track drive by noise restrictions


Matt230

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I appreciate this may be done to death, however I am looking for some opinions on drive by noise restrictions on track with my Caterham, particularly induction based. 

 It has a dustbin sized silencer that is repackable and very quiet, significantly quieter than my previous Caterham so no concerns on exhaust based noise.  However I have a K series with Roller Barrells, Pipercross filter but no cut out on the bonnet.  Its loud on WOT and I am concerned that this could be close to tripping the drive by limits?  Likely tracks I will be using are Snetterton, (mostly), Brands (occasionally) and Cadwell (hopefully).  Will this be an issue for the drive by? 

 I have seen airboxes such as this: http://www.emeraldm3d.com/auto-teknix-airbox-caterham-7-r500-kit.html which obviously needs a filter too.  Is this a good solution if there is a potential issue?  I’d rather not spend the money but that’s preferable than taking a day off work and being kicked off track for noisy induction.  Any other suggestions please general or other airboxes? 

 I’ve just had the car tuned on a rolling road, if this airbox is fitted does it need retuning with the airbox due to change in airflow?  I’d rather run on road without the box for the extra bark

Many thanks

Matt

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I had a 1.6K on Jenveys, no bonnet cut out, with a bespoke exhaust pushing out 155bhp & got fingered at Donington on the drive by.

Castle Combe rejected the car static @ 110dba so I repacked it & got away with 99dba. The next drive by at Donington was fine....ish! 

The Jenveys were covered by oily hands bespoke GRP intake plenum with a Pipercross filter on the end so the intake noise was reduced but the culprit was the exhaust.

 

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Hi Matt, my SLR in a previous incarnation ran Jenveys with sizeable carbon trumpets and at full tilt was bl**dy noisy.

I now have roller barrels but with the full CC R500 carbon airbox setup and this substantially reduces the intake noise - definitely an airbox is the way to go. Unfortunately the CC airbox kits are as rare as rocking horse poo and therefore command good money, the same kit can be put together from Reverie parts but I suspect it'll be upwards of £650 to do it ... the CC kit was originally £1000. They do come up second hand from time to time so it's worth putting a wanted out.

The Auto Technix airbox you've linked to is certainly a viable solution, it's not quite as tidy an install as the original R500 version but it's a fraction of the price and it's available. If you're trying to keep costs down even further there's plenty of space between the backplate and the bonnet so it wouldn't be too hard to knock up something bespoke.

Stu.

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I run an R400 with ~225BHP. I have a Raceco and a rear silencer. My exhaust static is now ridiculously low. The drive by is also pretty good. However induction drive by is still an issue and something I need to address. I starting to look into air boxes too. In addition to the options already mentioned there is a Pipercross box designed to fit the 600 back plate:

https://www.burtonpower.com/air-box-75mm-lh-no-intake-pipe-filter-c6275lh.html

The other option is knowing where the meters are and adjusting your driving by getting as far away as possible and short shifting. At the end of last year I got a couple of warnings at Bedford. It was only one of the 4 meters I was bothering, so by addressing my driving they were happy to let me continue. 

I can run all day at Snetterton and Cadwell with no drive by issues. I can tell you what Brands in like after September. Perviously I was fine there with no rear box and only ~200BHP.

 

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Thank you for the replies.

Initially i still have the question of will the roller barrels trip the drive by at Snetterton?  the car is basically an R400 k series but with a big silencer so only induction noise would be the issue.

If likely, i will invest in an airbox, looks like the Caterham one is hard to source, the Pipercross one looks like the quickest change over if required as fit on the same backplate.  I have read some concerns about this airbox strangling power?  Does anyone have any experience of this airbox?

 

Matt

 

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I bought a Pipercross box s/h but then subsequently sold it on ... they're not very big and it was coming apart along the join of the two halves, not a particularly good quality product. Also being a universal fitment it doesn't make the most of the space you have available. By comparison the CC R500 kit is massive, very well made and fits nicely into the space. It's expensive though.

Stu.

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Are RBTBs much noisier than other TBs?

I have an SLR with the older KV6 TBs fitted with a foam air filter - the exhaust is a full Powerspeed system. I too was worried about noise and had it tested last year at Abingdon - static at 4500rpm it was only 91dB. I was so surprised a that low figure that I asked to do the test again and saw the same result!

Now dynamically I'm sure it would be a different story as it sounds like an AK47 on over-run, but they only conduct static testing at Abingdon!

 

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  • 4 months later...

Thought i would give an update on this as might be of interest.

I finally purchased a Reverie Carbon airbox, had it fitted and then re rolling road to chexk that the A/F tune was ok still since fitting the box.  It was slight re-tuned to ensure the air fuel ratio was still on the safe side and i was impressed to see that it only lost 3 bhp with the Reverie box fitted.(its only a couple of months since the last tune on the same rollers)

Attended my first day at Snetterton 300 yesterday and had no issues with either the static (91dB) or drive by noise restrictions. 

Matt

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