dB for standard cerb 4.5 with ACT exhaust
Discussion
i'm thinking of going to an airfield to have some 1-2-1 tuition on driving my cerb and me to the limit and the airfield has a dB limit of 100dB. My cerb a late 4.5 is standard except for a decatted ACT exhaust.
Will it be way off the 100dB? If so, where can i get something to reduce the noise?
Cheers for your help
Steve
Will it be way off the 100dB? If so, where can i get something to reduce the noise?
Cheers for your help
Steve
Alistair H. said:
2 choices....
ACT do bolt on tail silencers.
or ACT do cat replacement sections which have exhaust cherry bomb sections in.
Take a look at the site. Either way...As it is you will be way over 100db.
With both of these options fitted I can get mine down to 104dB for trackday use.ACT do bolt on tail silencers.
or ACT do cat replacement sections which have exhaust cherry bomb sections in.
Take a look at the site. Either way...As it is you will be way over 100db.
I'm running the full ACT system now with silenced decat pipes, its great at cruising speeds but still makes some serious noise when the loud peddle is pushed. I've got a track day in may at Silverstone and need to get mine sound checked before I go.
My guess is your way over 100 at the min !
My guess is your way over 100 at the min !
You will not get thru sound testing if its 100bd. Even with track day cans from ACT you will need to baffle the output from the exhaust. Its a real pain in the arse and I don't think if its CATTED or DE-CATTED makes much difference. I'm just about to test a new "quiet" exhaust from ACT on my car so I will post up the results.
a1rak said:
You will not get thru sound testing if its 100bd. Even with track day cans from ACT you will need to baffle the output from the exhaust. Its a real pain in the arse and I don't think if its CATTED or DE-CATTED makes much difference. I'm just about to test a new "quiet" exhaust from ACT on my car so I will post up the results.
Please do!I am catted and have just fitted the new big bore ACT system. I have the removeable tail sections, so I have the option of changing these for something quieter. I do Zolder every year and they are brutal at 95db drive by. I was previosly 98 db static with the std system, so I am keen to see what difference the ACT system makes.I wont hear it run till next week though.
gruffalo said:
I have a 4.5 decatted large bore sports system from ACT, mine is 116dB.
OMG is that at 4500 revs or full chat?My 4.5 is decatted and although not ACT looks to be similar bore. I am booked on a trackday on Anglesey next Sunday and have purchased 2 Decibel Devils, but i reckin they will only knock 5 or 6 db off, so may be a long way to go to watch other people enjoying their track-day
Gazzab said:
There aren't many late cerbs but suspect the 4.5 whether 2004 or 1997 is going to be over 100db unless cats in and standard rear system. Maybe some track cans will help.
Sorry wasn't very clear by saying late, I meant mk2. I wasn't sure if that made a difference.So reading through, sounds like I'm knackered! Lol
Cheers Steve
firewallguy said:
OMG is that at 4500 revs or full chat?
My 4.5 is decatted and although not ACT looks to be similar bore. I am booked on a trackday on Anglesey next Sunday and have purchased 2 Decibel Devils, but i reckin they will only knock 5 or 6 db off, so may be a long way to go to watch other people enjoying their track-day
You should be absolutely fine at Anglesey. Although I was warned that I was getting close to the 105dB drive by, I didn't start short shifting, and I didn't get black flagged. When I was there last year there was no static test.My 4.5 is decatted and although not ACT looks to be similar bore. I am booked on a trackday on Anglesey next Sunday and have purchased 2 Decibel Devils, but i reckin they will only knock 5 or 6 db off, so may be a long way to go to watch other people enjoying their track-day
Last week in Spa I tested at 110dB @4500 with Cats and Sports tails, to get down to 105dB I had to put the track cans on, it seemed to me that their meter was reading a little high.
firewallguy said:
gruffalo said:
I have a 4.5 decatted large bore sports system from ACT, mine is 116dB.
OMG is that at 4500 revs or full chat?My 4.5 is decatted and although not ACT looks to be similar bore. I am booked on a trackday on Anglesey next Sunday and have purchased 2 Decibel Devils, but i reckin they will only knock 5 or 6 db off, so may be a long way to go to watch other people enjoying their track-day
In spa last week I tested at 116dB with the track cans on but their sound meter seemed to be over reading by quite a bit.
Cerb's do not like a static noise test due to the crackle and pops from the exhaust giving an artificially high reading, I have never failed a drive by but static testing is a challenge unless you pack a load of exhaust wadding down the exhaust for the static test and then remove this for when you are actually running on the track and under load when the car will actually be fuelling correctly for the revs you are doing rather that the frankly pointless static test that most tracks use.
Rufus Roughcut said:
I've done a test this morning using an industrial "Casella CEL" brand dB meter, calibrated with its own calibrator. Only interested as I want to do the Nurburgring later this year, looks like I'll need to manufacture a bit of extra pipe work.
Except that says 0.5m 45deg, typically track day sound test is 1.0m 45deg (although there's no static sound test at the 'Ring).Yep get some cherry bomb silencers put in place of the cats and get some track day silencers put on the back.
That would give you six silencers in total you must be able to get below 100 db with that lot.
FYI mine has a standard Tvr sports exhaust (two boxes at the back) and with the cats in and track day cans on the back it is just below 105db.
That would give you six silencers in total you must be able to get below 100 db with that lot.
FYI mine has a standard Tvr sports exhaust (two boxes at the back) and with the cats in and track day cans on the back it is just below 105db.
ukkid35 said:
Except that says 0.5m 45deg, typically track day sound test is 1.0m 45deg (although there's no static sound test at the 'Ring).
Hadn't realised there was a difference between testing bikes and cars, 100% sure when running in a Straightliners event on my bike it's taken at 500mm and 45deg.Rufus Roughcut said:
Hadn't realised there was a difference between testing bikes and cars, 100% sure when running in a Straightliners event on my bike it's taken at 500mm and 45deg.
Should be half a meter at 45 degreeshttp://www.msauk.org/uploadedfiles/msa_forms/blueb...
I knew I wasn't imagining it, here's what the MLR day at Spa says
MLR said:
The Spa sound limit is 107dB static measured 1m from exhaust, 45 degrees and ¾ RPM AND 103dB drive-by measured 15m from the track centre axis.
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