R500 noise

[EvoDunc]

I now want to take my standard 500 to the track. Never had a noise issue with my previous ex race R400 at Brands, Snetterton or Silverstone but think Bedford might have been a problem (never tried it but understand they are strict). Would be grateful for your view.

[MikeE]

Bedford has recently got even more difficult now they've added a couple more track side microphones - I used to just short shift past the original 2 but now they have 4 it's really not worth it. I need to get an airbox sorted and I suspect an R500 would too, at Bedford anyway

 

 

 

R400 Duratec Build and Modification Pictures

here

[Gridgway]

I don't think standard R500s are any good at bedford. I did it with my old R500 with a rear-exit exhaust and the reverie air-box.

Graham

[EvoDunc]

Anyone know what the db level is of a standard R500?

[rj]

Loud

 

 

Very loud in fact!

[A10ROX]

Depends on so many things

certainly >98 maybe =101

some have failed Oulton at 105

 

Carbon airbox certainly helps

as does a 'newly' packed exhaust, remember to warm it up

what exhaust do you have? the extra large replacements also help

 

and a little on the rpm

 

then build the speed/or rpm on track till you get the warning (if there are track side meters)

The problem is not just with R500/400 but VX with big power also struggle

 

A10ROX:OK, its an R500 without the magnesium bits sump etc and only 205bhp!

 

Edited by - A10ROX on 13 May 2007 20:45:30

[Peter T]

105 db.

 

R500 260 BHP Mango Madness

[Slipper man]

As Dave says, depends on many variables. Mine, with freshly packed silencer shows 104Db at the static test. With a less fresh packing job, 108 static and 106 driveby has been registered. With the reverie and rear exit exhaust it showed 96 at Good wood on the static test. Having said all that, for Bedford, you will need some work on the car to pass the test - ideally the airbox and rear exit exhaust

[bertie]

I got chucked off Donnington at 102dB in my R400 totaly standard.

 

I've got the Caterham airbox on it now and a Raceco side exit exhaust and it's much quieter but I've not been on track with it as yet to know if it's under the 98dB.

 

What is the rear exit system mentioned?

 

I recall Caterham doinf a system in the mid 90s which had a secons silencer box under the rear but I didn't think they had anything that fitted the R300/400/500 system.

[EvoDunc]

Cheers guys. I don`t know what exhaust I have but pretty sure it`s standard stuff. Guess I may just be OK if I stick to Brands, Snett` and Silv` ......he says, hoping!!

[Graham Perry]

An airbox certainly helps but not necessarily completely, based upon our experience with a different engine.

 

Last year we experimented with a sound meter on my TB equiped crossflow. We got the MSA sound meter guy at a sprint to thoroughly and carefully measure the db on my car from two places at 5000rpm (exhaust and inlet) and made a note of the numbers. Over the winter we made our own airbox as none of the of the shelf ones would easily fit and yesterday used it in anger for the first time.

 

Yesterday we got the same MSA guy using the same meter to do the tests again, the place in paddock was the same and we even had the same awful weather ☹️. Measured near the exhaust in the standard MSA approved manner the cars noise has fallen to 101db from 103db. That is the lowest it has ever been. Its been tested many times over the years at sprints and used to show 103-105db without fail.

 

Now to the induction...............there has indeed been a massive reduction in inlet noise with the new airbox. Last year inlet noise was 104db at 5000rpm measured using the same technique and yesterday was only 94db, a whole 10 db improvement on the inlet side, which was a very satisfactory outcome. 😬 The car does seem much quieter on the road even at full chat and you don't feel the need though for earplugs any more. How this would translate to a driveby figure I am unsure but if the sound meter were on the drivers side of the track I suspect it would be much better than before.

 

It does seem though that to get my car under 100 db we will need a better exhaust system. So I guess what I am saying is that an airbox certainly helps but it may not necessarily be the whole solution if your car is being measured statically at the exhaust outlet before a trackday or other event. So a 10 db reduction at the inlet only translated to a 2 db static reduction at the exhaust on our car, which is probably about what I expected it to be.

 

 

Edited by - Graham Perry on 14 May 2007 13:12:37

[Gridgway]

Yep, I can vouch for the fact that the rear exit system does fit an R500. It has the extra box under the back which makes it a PITA to get to stuff under the back but works well for noise.

 

I did some power runs to see what effect it had on oomph and from memory I got about 223 with it on and about 229 with just the side exit. Worth the loss of power for the noise reduction!

 

Graham