Think I already know the answer to this one but I’ll ask anyway (!) does anyone here get away with running a 2bular decat and GT3 backbox on track days or is it too loud?
I’ve got a cheapo decibel reader ap on my iphone and it was reading 97 - 98 db at 5k revs static (read at 500cm away and 45 degree angle), however I doubt thats very accurate and i still have no way of knowing what my driveby reading would be - flippin loud I’d guess.
Static you will be fine, however drive by you will have no chance 
Yup…me
2bular 4into1 manifold, GT3 and silenced decat (also from Jim)
last time out at Castle Combe 87 static. Also short shift and Bedford just OK but very very near the mark
driveby reading would be - flippin loud I’d guess.
Driveby is effected by many things so is never constant
Cheers chaps, just what I thought. Booked the car in at track club for amongst other things my decat to be removed and sent to Jim for a silenced one to be fitted. Hopefully i’ll be fine then.
Once other thing…My exhaust seems a bit louder recently, spoke to Jim and he doesnt seem to think my silencer packaging is shot and said it might be my cam change point has shifted (?) anyone heard of this?
not heard anything…exhaust is too loud…can’t hear a thing…gone deaf : )
My std 2bular was 97db when new and 3 months later was 101.5db at Donny and getting louder 
Re-packable is the way forward.
Can’t wait for mine to arrive (Tullett)
[quote=chrisexigegt]My std 2bular was 97db when new and 3 months later was 101.5db at Donny and getting louder
[/quote]
To be fair the weather was causing most of the cars to read high that day, the wind was blowing in a very odd direction
[quote=ade][quote=chrisexigegt]My std 2bular was 97db when new and 3 months later was 101.5db at Donny and getting louder
[/quote]
To be fair the weather was causing most of the cars to read high that day, the wind was blowing in a very odd direction [/quote]
[font:Comic Sans MS][color:#CC33CC]Toto, it’s a twister, it’s a twister[/color][/font] 
[size:20pt] [/size]
Ive said it 500 times and i will say it again, repackable, repackable, repackable!!!
We have some lovely ones made, call John!
You can hire BaT’s official noise tester for �9 including P&P?
[quote=SeanB]Ive said it 500 times and i will say it again, repackable, repackable, repackable!!!
We have some lovely ones made, call John! [/quote]
I wont need it repackable as a silenced decat will do the job. In fairness Jim did tell me at the time when i ordered my current system it will be loud and as usual he was right (!)
Anyway I couldnt leave 2bular, I’m sure other brands are nice but my manifold is a total work of art and I was one of Jims early exige customers on my 1st car 5 yrs ago. That exhaust is still going strong so ive got no complaints and it says everything about Jims build quality. As an aside he’s also a top bloke to deal with 
a top bloke to deal with
I have similar set up but main problem is induction noise and not exhaust noise.
It will fail at most circuits.
Ex77
+1 F*****g great guy 
you will stll struggle with a sienced decat, I have one as well and still can’t pass the drive by at Donny
[quote=Whiteysback]Think I already know the answer to this one but I’ll ask anyway (!) does anyone here get away with running a 2bular decat and GT3 backbox on track days or is it too loud?
I’ve got a cheapo decibel reader ap on my iphone and it was reading 97 - 98 db at 5k revs static (read at 500cm away and 45 degree angle), however I doubt thats very accurate and i still have no way of knowing what my driveby reading would be - flippin loud I’d guess. [/quote]
Meh, there’s no way you’re getting on a track with that exhaust dude - sorry.
Looking back at your e-mails/build-sheet, your target was +300bhp and the lightest exhaust possible. So that meant the 70mm 4-1/de-cat/system. Now there’s no way I was giving you the little 6x18 GT3 - it’s light but on this install it would be unbearably LOUD. So I made you a 7x24 GT3.
I also noted that you that you were never going to do Trackdays! I tested my new 2.5" SDCP + Trackday system/4-1 recently at a US track with an 84db drive-by limit - it passed. You guys with the bigger bore 4-1’s/de-cats/systems are always going to struggle with the limits now imposed.
Yep totally right there I did say I’d never track it and you made a wonderful sounding exhaust for me, in fact I’ll be slightly gutted when I do manage to make it quiet.
I guess I’ll be needing a whole new back box (8x24?) as well as the silenced decat now Jim? Or would it be possible for my current back box to be modified in some way (more packaging or smaller exit pipe)?
Any suggestions much appreciated Jim.
Also If need be I won’t be tracking it at the ultra quiet circuits (donny, Bedford,etc), I spend a lot of time in France and plan to do most of my track days there. If memory serves me right they aren’t so keen on making sports cars sound like family cars over there.
[quote=Whiteysback]Yep totally right there I did say I’d never track it and you made a wonderful sounding exhaust for me, in fact I’ll be slightly gutted when I do manage to make it quiet.
I guess I’ll be needing a whole new back box (8x24?) as well as the silenced decat now Jim? Or would it be possible for my current back box to be modified in some way (more packaging or smaller exit pipe)?
Any suggestions much appreciated Jim.
Also If need be I won’t be tracking it at the ultra quiet circuits (donny, Bedford,etc), I spend a lot of time in France and plan to do most of my track days there. If memory serves me right they aren’t so keen on making sports cars sound like family cars over there. [/quote]
Yup, we can mostly agree on what an exciting exhaust note sounds like - well that note won’t get you on a track almost anywhere now - very frustrating. More power = more NOISE. I need to hear from Ade about Donington - might have to make a larger SDCP - you definitely need two silencers with 300bhp/de-cat. Tailpipe dampner? Every design I’ve seen has a restrictive effect on gas-flow - not recommended on an SC install. Deflectors - I have tried these with some success.
I sell a LOT of exhausts to French owners, the new Trackday system is very popular over there with race teams. You’ll need a variation of it - 70mm though - hmm.