555 replies to this topic

[Winstar]

Was that one of Chris' 3" systems?

Nope it was my 2.5" system.

Readings taken @4500rpm static but it was a windy day so don't know if that would have any effect

edited

[Muncher]

Just a reminder of the figures we got on the initial test of the 3" system: 3,000 rpm = 89dB 3,500 rpm = 91dB 4,000 rpm = 91dB 4,500 rpm = 92.4dB 5,000 rpm = 95.5dB 5,250rpm = 96dB Still waiting for Jon @ Courtenay's readings.

[PiperRS]

We tested a few cars with the sound meter, the one thing i noticed was that with the supercharged cars there was a pronounced spike in the reading when lifting off

Piper 2.5" - steady 90 db, going to 100 on lift off (wind blowing away from meter)
Tullet 2.5" - steady 92 db, 101 on lift off (wind blowing towards from meter)
N17VES- low cam 94db, high cam 101db
DucanVXR - 94db

So were not to bad after all.

Would be good to get another comparison done on a still day as that should make for a quieter reading we have found.

Garry

[The Batman]

shame bedford got a 101db though....

[PiperRS]

shame bedford got a 101db though....

Thats the problem, different meters, different days, different weather conditions all play large parts in the readings.

When you do the test, if you lift your foot off the throttle as gently as you push it down when doing the test you should not get any pops, or decel noises.

Garry

[Winstar]

shame bedford got a 101db though....

Thats the problem, different meters, different days, different weather conditions all play large parts in the readings.

When you do the test, if you lift your foot off the throttle as gently as you push it down when doing the test you should not get any pops, or decel noises.

Garry

Different days, conditions, etc will always give different results the meter we had was a properly calibrated one . But by far the biggest thing with the SC cars was that the spike in the readings on lift off that didn't happen with the VXT or Nicks Exige. so maybe the key is to ramp the revs down slowly

[PiperRS]

shame bedford got a 101db though....

Thats the problem, different meters, different days, different weather conditions all play large parts in the readings.

When you do the test, if you lift your foot off the throttle as gently as you push it down when doing the test you should not get any pops, or decel noises.

Garry

Different days, conditions, etc will always give different results the meter we had was a properly calibrated one . But by far the biggest thing with the SC cars was that the spike in the readings on lift off that didn't happen with the VXT or Nicks Exige. so maybe the key is to ramp the revs down slowly

I agree 100% with you

Garry

[The Batman]

so whats happening with the box then? if you are happy with it? now do remember that Matt's (techieboy) system has the smaller 6" silencer straight after the cat

[PiperRS]

so whats happening with the box then? if you are happy with it?

now do remember that Matt's (techieboy) system has the smaller 6" silencer straight after the cat

Well its a bit tough really. Im happy enough the product is as good as we can get it now with the supercharger but i was really wanting Matt to get a confirmed reading of 98 or lower.

All new sales of this system will be sold under the proviso that we cannot offer any guarantee with regards to hitting a set DB limit. You can all see that we have done all we can to make it as quiet as possible.

Im aware Matt has the smaller pre silencer in his system and this will be offered as an extra to people that want to try everything possible to keep the DB limit down.

Joe, have you had a DB reading from your car recently. Your running the 29" silencer alone so would be good to get a comparison.

Kind Regards

Garry

[The Batman]

Im aware Matt has the smaller pre silencer in his system and this will be offered as an extra to people that want to try everything possible to keep the DB limit down.

Joe, have you had a DB reading from your car recently. Your running the 29" silencer alone so would be good to get a comparison.

so am i right in thinking i am going to have to pay more?

i am running the standard backbox with material that seems to stay in. the last test i got was 101 static.

[techieboy]

Am waiting for a call back from the guy at Bedford Autodrome who does the sound testing. I'm working from home all week, so am hoping they can get me in this week and also do the drive-by this time. Really couldn't believe the numbers we got on Saturday - nor the effect of an un-damped lift-off on the noise readings. Really hope it wasn't too affected by the quite strong wind.

[The Batman]

give me a shout when you do go, as i will come aswell and blag a sound test off aswell.... getting bored of having to drive million miles away to get on track

[PaulCP]

Am waiting for a call back from the guy at Bedford Autodrome who does the sound testing. I'm working from home all week, so am hoping they can get me in this week and also do the drive-by this time. Really couldn't believe the numbers we got on Saturday - nor the effect of an un-damped lift-off on the noise readings. Really hope it wasn't too affected by the quite strong wind.

Would be nice to get the comparisons on this sort of test

[NickB787]

Am waiting for a call back from the guy at Bedford Autodrome who does the sound testing. I'm working from home all week, so am hoping they can get me in this week and also do the drive-by this time. Really couldn't believe the numbers we got on Saturday - nor the effect of an un-damped lift-off on the noise readings. Really hope it wasn't too affected by the quite strong wind.

Can you give me a call when you do Matt could do with one myself

[techieboy]

Finally managed to get booked in for a soundtest at Bedford. But, they can't do it until next Thursday (30th). Described the car mods and told him about the low Anglesey readings which surprised him. But, they're putting the car on the South and West circuits so they get a full beans measurement in top gear and also a 2nd to 3rd gear change . Will report back with their measurements......

[PiperRS]

Finally managed to get booked in for a soundtest at Bedford. But, they can't do it until next Thursday (30th). Described the car mods and told him about the low Anglesey readings which surprised him. But, they're putting the car on the South and West circuits so they get a full beans measurement in top gear and also a 2nd to 3rd gear change .

Will report back with their measurements......

Matt

Thanks again mate.

Kind Regards

Garry

[techieboy]

No worries. I'm even more keen to resolve it than you are. He did say that there was a PalmerSport day on that day and even if I registered a bit over on the static this time (as long as it wasn't stupidly over), they'd put it round the track.

[Muncher]

Just got back from Snetterton with my 3" system. @ 5,250 rpm I was 96-97dB with a lot of background noise and to be honest I wasn't doing my best at keeping the revs constant. The chap said I'd have no problems at Snetterton at all.

[AMOSS]

How is the cheap 4 into 1 manifold going... I have the money waiting

[vxr36]

Over promised, under delivered. No change there then!