Vid of new zaust (2bular's)
Discussion
Bellow is the vid of the drive by of my Exige with 2bular's zaust and cat
Noise levels are static
94db @ 4000rpm
98db @ 6000rpm
under 98db drive by
[URL=http://s6.photobucket.com/albums/y201]
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very racy and who needs more db then that! I personaly like that one, a well done job, and still aloud on most or all tracks
Price wise best contact jim his web site is www.2bular.com/
Very pleased with the results plus its SC frienldy
Was at the Exide day at Donny and no probs with their 98db drive by - a few cars were not so lucky - stage 2s had a fair bit of bother!
[URL=http://s6.photobucket.com/albums/y201]
[/URL]
Very pleased with the results plus its SC frienldy
Was at the Exide day at Donny and no probs with their 98db drive by - a few cars were not so lucky - stage 2s had a fair bit of bother!
[URL=http://s6.photobucket.com/albums/y201]
[/URL] 
scuffham said:
Would this be the same one that got Uldis thrown off Donnington last weekend for noise? (after a 400 mile drive to get there)
I suspect the noise figures quoted are somewhat suspect....
My what a suspicious mind you have Stuffem. In case you hadn't noticed Jamie drives an Exige2, Uldis is running an S1. The exhausts are totally different.
It's been noted on SELOC that you're a born liar and brass-necked about it too. Your suspicions are wrong (as usual).
321freeflow said:
Would this be the same one that got Uldis thrown off Donnington last weekend for noise? (after a 400 mile drive to get there)
I suspect the noise figures quoted are somewhat suspect....
My what a suspicious mind you have Stuffem. In case you hadn't noticed Jamie drives an Exige2, Uldis is running an S1. The exhausts are totally different.
It's been noted on SELOC that you're a born liar and brass-necked about it too. Your suspicions are wrong (as usual).
Not at all...
just quoting your site, which shows figures that cleary are at odds with Doningtons noise testing.
400 miles is a long way to go (and then go back) to waste a day...
now, are you going to tell me you have a different way of measuring the noise level for an S2 system vs. an S1 one then?
in summary, get your ears tested.
PS. what have I lied about then? (bear in mind at this point that said engine has still not materialised several months later and that money changed hands.....)
>> Edited by scuffham on Tuesday 2nd May 13:36
Actually 440 miles, close to 1000 round trip and yes, I was the first one to be disappointed by it.
Was blackflagged about 5 times, they always let me out again after I’d done something to it, but after the fifth time they said that was it, I had my chance, but my car was simply putting out too much power for the system
Did about 60 track miles at the end so not a complete loss.
But I thought you would have noticed that Jamie drives an S2 and I drive an S1 before questioning the reading accuracy.
It turns out I have a Radio Shack analog db meter. Jim has some sort of digital one (I don’t know about Jamie as he lives down by Edinburgh, but most likely is better than mine).
Mine read 95db @ ½ m in both meters, and I took mine with me.
On the different occasions I was blackflagged I did different thing, including repacking it in a different way, spirally, as the wadding seemed to be compressing away from the perf. tube.
I always got back to the 95-96db reading and people would tell me that it didn’t really sound louder than many out there, but mine triggered the microphones and theirs didn’t
It seems it has to do with the apparent energy of the sound wave.
Find below Rox’s explanation of it:
Well I guess it was my turn, I had never been blackflagged before!
On the plus side, I really liked the power this exhaust gave, easily the best so far, miles better than the ultra bore stepped EBD I started with, and after sorting some sticking throttle bodies (kind of scary!, hint: spray WD40 into the TB link from the BOTTOM!) the engine was running like a dream!.
The conclusion I have is this system would be ideal for a racing environment, a great improvement over the EBD (more top end and lots more midrange) but with the ever decreasing noise limits, something radically quieter would be better for trackdays. Keeping the gorgeous exhaust note of course!.
I know you always said the straight through design would be too loud. And this proves you were right! But there were many people also with standard setups that were kicked off, mine was as marginal as them.
I feel that Jim has hit the sweet spot with this design, and I will soon be sporting the same but with a std layout, it’d be then ultra quiet.
Shame as I really wanted to keep the extremely light design this one had (it was ridiculously light!), but in these days I would have to trade lightness for quietness.
Was blackflagged about 5 times, they always let me out again after I’d done something to it, but after the fifth time they said that was it, I had my chance, but my car was simply putting out too much power for the system
Did about 60 track miles at the end so not a complete loss.
But I thought you would have noticed that Jamie drives an S2 and I drive an S1 before questioning the reading accuracy.
It turns out I have a Radio Shack analog db meter. Jim has some sort of digital one (I don’t know about Jamie as he lives down by Edinburgh, but most likely is better than mine).
Mine read 95db @ ½ m in both meters, and I took mine with me.
On the different occasions I was blackflagged I did different thing, including repacking it in a different way, spirally, as the wadding seemed to be compressing away from the perf. tube.
I always got back to the 95-96db reading and people would tell me that it didn’t really sound louder than many out there, but mine triggered the microphones and theirs didn’t
It seems it has to do with the apparent energy of the sound wave.
Find below Rox’s explanation of it:
Rox said:
From reports by peeps watching from pit wall, Uldis exhaust didn't sound as loud as some of the others that managed to stay on track... and at static test it seemed to pass.
However, the meters read dBA - which you prolly know is a weighted reading in attempt at simulating the response of the human ear (biased in the 500Hz-10000Hz range) and its most accurate for sounds around the 40 dB area (i.e. pretty quiet) so its perfectly plausible that the 'pitch' (wrong word but its what Uldis used to try and explain so I’ve used it as well)..... of his exhaust under engine load and at high(ish) revs generates higher intensity (watts/m2) inside the weighted dBA contour. This won't necessarily mean its actually 'louder' but it will mean he'll get black flagged.
this is because two different 90 dB sounds won't have the same 'loudness'. On the dB scale 40dB at 1000Hz sounds about as loud as 30dB at around 4000Hz to the human ear (that's technically around 6 times quieter in absolute terms). So to the dBA meter if Uldis zorst had lots of mid-range (1kHz-5KHz) at higher intensity then I can see the possibility of him getting a big score on the meter however, the next guy with an exhaust full of <1Khz and >10KHz which is actually LOUDER might well escape.
Ohh and another thing.... when things get louder the human ear starts to respond 'flatter' (that's why Bass disappears first when you turn the volume down on your car stereo)... so the discrimination applied by a dBA meter becomes more important..... and more of a disadvantage in overall 'loud' environments.
Well I guess it was my turn, I had never been blackflagged before!
On the plus side, I really liked the power this exhaust gave, easily the best so far, miles better than the ultra bore stepped EBD I started with, and after sorting some sticking throttle bodies (kind of scary!, hint: spray WD40 into the TB link from the BOTTOM!) the engine was running like a dream!.
The conclusion I have is this system would be ideal for a racing environment, a great improvement over the EBD (more top end and lots more midrange) but with the ever decreasing noise limits, something radically quieter would be better for trackdays. Keeping the gorgeous exhaust note of course!.
I know you always said the straight through design would be too loud. And this proves you were right! But there were many people also with standard setups that were kicked off, mine was as marginal as them.
I feel that Jim has hit the sweet spot with this design, and I will soon be sporting the same but with a std layout, it’d be then ultra quiet.
Shame as I really wanted to keep the extremely light design this one had (it was ridiculously light!), but in these days I would have to trade lightness for quietness.
it's an expencive and painfull learning curve this noise one...
I hate it as much as everybody else, but in this new world of ninby power, we are just stuck with it.
problem really is that no amount of static testing is any use, engines vary massively on what noise the produce at what RPM and load, this is made much worse with iVTeC and VVTi engines where they don't have max cam lift and overlap until they are running under load, something you just can't do with a static test.
Bedford is probably the tightest run cct, and are very helpfull for testing out stuff if you need to make it very quiet, although it's still a fair treck to keep goign there. That said, if you can pass Bedford, then nowhere else will be an issue.
I hate it as much as everybody else, but in this new world of ninby power, we are just stuck with it.
problem really is that no amount of static testing is any use, engines vary massively on what noise the produce at what RPM and load, this is made much worse with iVTeC and VVTi engines where they don't have max cam lift and overlap until they are running under load, something you just can't do with a static test.
Bedford is probably the tightest run cct, and are very helpfull for testing out stuff if you need to make it very quiet, although it's still a fair treck to keep goign there. That said, if you can pass Bedford, then nowhere else will be an issue.
scuffham said:
it's an expencive and painfull learning curve this noise one...
I hate it as much as everybody else, but in this new world of ninby power, we are just stuck with it.
problem really is that no amount of static testing is any use, engines vary massively on what noise the produce at what RPM and load, this is made much worse with iVTeC and VVTi engines where they don't have max cam lift and overlap until they are running under load, something you just can't do with a static test.
Bedford is probably the tightest run cct, and are very helpfull for testing out stuff if you need to make it very quiet, although it's still a fair treck to keep goign there. That said, if you can pass Bedford, then nowhere else will be an issue.
My transverse (std) layout on an S2 has already been run at Bedford, several times, with no problems.
The Straight-Back system can be quiet one time and noisy the next. A round silencer being the most efficient at noise-control (all else being equal) the fact I have to run a fat, flat oval probably explains these variations. The packing is being compressed awkwardly and whilst it stays in the box, it needs a "re-shuffle" before it works properly again. This just doesn't happen with the round silencers.
I like the layout of the Straight-Back; it's light, efficient and easy to re-pack. Unfortunately, it may be for "Race Only".
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