Noise / Decibel question - R500 Duratec with Carbon Airbox and Cat

[Guest]

Off on a holiday at the end of the week and the car is being serviced whilst I'm away (collection booked for this Thursday).

 

I'm going to try and get booked up for a few track days for when I come back, but does anyone know what sort of db their exhausts are outputting with this configuration:-

 

R500 Duratec

Carbon Airbox

Cat in place

Std Exhaust

 

No worries if no one has the info - I'll just go to Maplin and get a db monitor, but wanted to save myself a couple of quid 😬

[Jonathan Kay]

Do you have a smart 'phone... lots of apps available. But I don't think that anyone has shared a good test of them yet.

 

Jonathan

[Guest]

Quoting Jonathan Kay: 

Do you have a smart 'phone... lots of apps available. But I don't think that anyone has shared a good test of them yet.

Yes I do, but I don't trust them enough to warrant a drive to Cadwell or somewhere far afield, only to be turned away due to noise...

 

Once I've got a bypass pipe (that fits!) I'll probably do a video of the different output of all the possible configurations (if I can be bothered!!)

 

Edited by - Roadracer1977 on 7 Jul 2014 11:32:40

[Jonathan Kay]

A couple of comparative tests, from the occupational noise angle:

1

2

 

For some reason both tests found that performance of iOS apps was better than that of Android apps.

 

Jonathan

[Dr Slotter]

Phone Bedford and ask them if they can test it.

[Mark w]

My guess is that you will have issues on driveby at MSV circuits unless it's a " noisy day " as they seem to be working to 92 db driveby these days .

 

All the 500 s and a couple of 400s got thrown off at Brands the last time I was there due to exceeding drive by limits ( but passing the static tests ) .

 

Unfortunately a static test won't tell you if this is going to be an issue

 

The 620 rear silencer will help but unfortunately means replacing the whole system due to the way it fixes to the side can ( which also holds the cat )

 

 

 

 

[LazerBrain]

Quoting Jonathan Kay: 

For some reason both tests found that performance of iOS apps was better than that of Android apps.

Possibly due to the small variation in hardware of iOS devices compared to Android. The Android app I used was fine on my Samsung Ace 2, useless on the Ace 3. The app author said he didn't have calibration data for either, so the Ace 2 must have been lucky! I bought a sound level meter from eBay for just under £20 instead.

[Mankee]

Quoting Dr Slotter: 

Phone Bedford and ask them if they can test it.

This is exactly what I was going to suggest, as Bedford is probably the closest track to you, but don't worry about phoning in advance. Just turn up on a day when you know there is a trackday on, e.g. 21st or 26th July, and ask for a noise test when you see the MSV staff as you are a prospective Bedford trackdayer.

 

There are usually 3 or 4 guys doing the noise tests at Bedford due to the especially tight regulations, and they are always more than happy to help out before you trigger the meters, but will send you home if you ever breach the 87.5dB drive-by. Be humble and they will respect you.

 

As pointed out in this thread a static test doesn't directly correlate to whether you will be fine on drive-by with the engine fully loaded, but it will give you (and circuit staff) an idea of what level of noise pollution you car will emit.

[Pendennis]

Those air boxes reduce induction noise considerably, I reckon your be fine

 

Whenever I get black flagged I cover up the induction then I am fine again, never been thrown off due to exhaust noise. I would imagine your static noise be fine.

[chris956]

I got black flagged at Brands last time out. The noise limit on the day was 102 static and 91 or 92 driveby.

Mine is a standard R400D. They throw you out on the strength of a driveby infringement but do not test this prior to entering the track hence you have no idea how it will go once induction , wind direction and nearby traffic will effect it. Bare in mind that most of the circuits are right handed and the microphones are on the infield i.e. your exhaust is pointing straight at them !!

I used a bent piece of metal jubilee clipped the end of the exhaust to direct the gases and noise at the back wheel rather than out sideways and it made a 2 decibel difference on the static test.

To be on the safe side , I stick to noisy 105 decibel days as its too much to risk and hassle trying to be quiet.

[Pendennis]

Chris, reference Brands:- Are you sure the microphones are on the inside?

[Guest]

cheers for the responses guys

 

So next question... Exhaust options? What to buy? ...and who / where from???

The aim is to keep maximum power, but reduce the noise output (I know both go hand in hand) to something that'll definitely get me onto bedford whilst running the carbon track day air box

 

Edited by - Roadracer1977 on 7 Jul 2014 19:29:00

[Mankee]

Without doubt, a Raceco will be at the top of your list:

 

http://www.raceco.com/silencers.html

 

Ammo has recently left/fled the country for pastures new and has handed over production who made the silencers for him. Not sure if Metal Mickey is still on Blatchat?

[chris956]

Quoting Pendennis: 

Chris, reference Brands:- Are you sure the microphones are on the inside?

 

100% yes..... On the start finish gantry and at the marshals post as you rise up from paddock hill on the right ..... But shhhhhh.... Its a big secret !!!!

[Pendennis]

Blimey I am surprised, both those positions are arguably at points you lift. I was told there was three and after where you apply the power, I also believed there be one at a position you not mentioned 😬

[Delbert]

Forget putting an R500 on Bedford

If your set up is similar to my R530 then you are looking at 101 / 102

 

Better heading to Cadwell where drive by is helpped by your zorst being on " wrong" side

Or Mallory or Rockingham

 

However forget Bedford ( just in case you missed the clue at the start

[Mankee]

Snetterton is in the middle of nowhere and not too strict for driveby on daytime sessions.

[Pete - W.Sussex]

Don't even think about it - get a Raceco. My R400D struggled everywhere on static but never a drive by problem (but never dared Bedford) except Silverstone (where in two visits I have never had a static test). When I had RBTB fitted I decided to go Raceco (no cat) and the R500 race airbox and deep joy. Low to mid 90s static and I don't need the earplugs!

[Silverback]

Daniel - I am heading to Bedford soon to be tested if only to get an idea of noise. We were going to test it with Andy's noise meter at North Weald but in all the excitement of the day I forgot

 

You are welcome to join for the blat there and back (is likely to be a weekday though).

 

Does anyone know if they do both the static and drive by tests on a turn up - I remember having my Impreza tested up there (years ago now) and one of the instructors took it out on track so that static and drive by could be checked.

[chris956]

Quoting Pendennis: 

Blimey I am surprised, both those positions are arguably at points you lift. I was told there was three and after where you apply the power, I also believed there be one at a position you not mentioned 😬

 

Don't lift at these points or you want make Paddock Hill entry or once through there you won't make it up the hill to Druids. Both places are flat out 😬

You can short shift or back off but that ruins an already short lap IMHO

[Pendennis]

Thanks for the advice Chris

 

I was looking at my last race there, I still have my foot in going past start finish and the marshal post before Druids bridge, but seeing as light moves faster than sound I am surprised at their locations

[chris956]

Quoting Pendennis: 

Thanks for the advice Chris

 

I was looking at my last race there, I still have my foot in going past start finish and the marshal post before Druids bridge, but seeing as light moves faster than sound I am surprised at their locations

Haha. . I suppose technically the one situated on the rise up to Druids may get you on the way back down the other side too

[Guest]

So an update...

As Bedford is my closest circuit (and quite possibly the strictest in the UK in terms of noise) I thought it a good idea to speak to them. I've spoken with Andrew Gardener (at Bedford Autodrome) this morning.

 

He confirmed their noise limits as follows:

101db static

87.5db drive by

If you exceed the drive by you are excluded for the rest of the day without warning - based on that I asked how do you know if you're going to trip the drive by? He suggested that if you're under 96db on the static there's practically no chance of you exceeding the drive by.

 

They test the db at 2/3rds of your maximum rev limit.

 

He said so long as he's there I can run the car up there to get it noise tested for free and we can take it from there.

[Mankee]

Quoting Roadracer1977: 

He suggested that if you're under 96db on the static there's practically no chance of you exceeding the drive by.

This is generally true for most cars with rear exhausts, but we (as in Caterham drivers) can get in a pickle because of our side exit exhausts. You will have to slowly build up the revs when on-track at Bedford and, once you get shown the NOISE board at the start of the main straight, then you know you've nearly overstepped the mark. The NOISE board means you are within 1dB of the 87.5dB sending home limit.

 

I have a self-imposed rev ceiling of around 7200rpm there, which gives me a few hundred rpm leeway in case I mis-shift, forget to change gear or am following a pack of loud cars. But mine is a K-series with no CAT, bodies and an open filter through the bonnet to atmosphere, so you might have a different experience.

[Guest]

Quoting Mankee: 

But mine is a K-series with no CAT, bodies and an open filter through the bonnet to atmosphere, so you might have a different experience.

OK cheers buddy - I'm going super careful with carbon airbox, no cat and probably a 750mm raceco exhaust...

 

Hopefully that'll keep me safe??