din....

[seawise]

whats the approx dB that a '00 superlight r (sans catalyst) should be producing for trackday compliance (noise test in paddock)?

anyone got an idea ?

tnks

[sfaulds]

Anything from 98 upwards in my experience.

[fergus]

I've got a '99 SLR with a brand new 7" powerspeed silencer, which recorded 97dB at Cadwell (4.5k rpm). The main problem with them tends to be the induction noise on any drive by test......

It gets booted out of Bedford though....

PS make sure your silencer is packed to the gunnels with decent (new) wadding.

Edited by fergus on Thursday 27th March 16:40

[Piers917]

I measured my de-cat '00 1.6 Superlight recently and that was 94-95dB at 4.5k revs.

Edited by Piers917 on Thursday 27th March 17:26

[rubystone]

SLR on TBS - at least 100dbs and probably nearer to 102....esp if you don't have anything on the induction side and a standard exhaust. A Cat would help, Oliver, as would a decent aftermarket exhaust.

Let's put it this way, don't bother turning up to Bedford in it...

[seawise]

ah, right, tnks all - thats good advice. perhaps i'll refit the cat and be sure to check the static noise before towing it all the way to the 'ring. i doubt my Discovery3 would be much fun on the nordschleife....

[jeremyc]

My '99 SLR is decatted with the biggest Raceco silencer available and easily passes 98dB static tests.

As mentioned above, it is often the induction noise that gets you on driveby.

[fergus]

seawise said:

ah, right, tnks all - thats good advice. perhaps i'll refit the cat and be sure to check the static noise before towing it all the way to the 'ring. i doubt my Discovery3 would be much fun on the nordschleife....

I think you'll be OK at the Ring as long as you are sensible on the approach to the barrier. Rumour has it that there are also a few noise meters out on the circuit though...

In extremis, it may be worth also considering an airbox/plenum, which will knock a few dBs off the total noise contribution from the airbox (may also knock off a few hp, but then again, there's no point in having a car you can't use on track).

If you have an Emerald ECU, you could be very sneaky and use their switchable map facility to run a very retarded ign curve, which would let the car run, but *really* restrict the power. This would probably also kill the noise, even when reveed to XXX rpm!

I'd speak to Dave Walker at Emerald before trying this though!

[Piers917]

When are you going to The 'Ring Seawise? I'm off there in May so i'll report back afterwards re the supposed stricter noise testing.

[seawise]

Piers, yes def be interested to hear how u get on - my trip will have to be on the spur of the moment due to work/family commitments, probably i shall time it for august when the mother-in-law comes to stay.....

[Piers917]

Sounds like a good time to get away Seawise

[Dale@RSRNurburg]

No noise meters on circuit. Not yet. But it's all down to perception. Keep her on tickover all the way through the barriers and if you see a marshall attending to a crash knock it into top quick smart... perception is reality here...