veld
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| posted on 14/1/12 at 03:44 PM |
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decrease noise hayabusa
Hello,
i am new at this Forum, i have a Westfield Megabusa witch is a fantastic car (thanks to the GB, for this car, i have also a defender V8 and a Buell
Bike) and i leave in France, so sorry for my English....
The car passed with no problems the tests of SVA in GB but it's not the same thing in France....
The tests are very difficult for the noise, 77 DB at 50 km/h in second speed....
It's difficult but not impossible, 2 or 3 Megabusa passed the tests in France.
So i have begin to try solutions to decrease the noise.
First is to fix at the tail of the car one other exhaust, for the moment i have fixed a Caterham exhaust in more of the megabusa exhaust.
After with the help of Cosmick i modify an Hayabusa air Box instead of piper cross.....
I will probably decrease the power of the engine.
I will fixed insulation under the bonnet and everywhere it's possible.
But it's probably not enough so if you have other ideas it's can very nice....
Thanks in advance and congratulations for the Forum.
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se7ensport
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| posted on 14/1/12 at 04:02 PM |
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Hi
Do you mean you are now using two silencers by this comment "for the moment i have fixed a Caterham exhaust in more of the megabusa exhaust.
"?
If not how does this work for you:
 
two silencers
pic from: http://www.wunoff.co.uk/index-2.html
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designer
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| posted on 14/1/12 at 04:15 PM |
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Are you going to re-register the car in France?
Vous re-register la voiture en France ?
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veld
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| posted on 14/1/12 at 04:17 PM |
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Yes i have two silencers but not like the picture .
one at the left (the megabusa), and one other under the car ( a big silencer of catheram 1600), for the moment i havn't test the new sound , but
it seem the more difficult is decrease the noise of "aspiration" of the motor....
Thanks
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veld
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| posted on 14/1/12 at 04:23 PM |
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For the moment i prepare the car and after i will passed the tests of UTAC....
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kjouk
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| posted on 14/1/12 at 04:54 PM |
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As the test is at fixed speed can you use large tyres to reduce rpm to minimum to achieve the test speed?
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veld
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| posted on 14/1/12 at 05:08 PM |
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I have think about this solution , but i have already 15 " on the car and the last time somebody come at the utac with big wheels (16 " ,
the inspector refused to passed the test (and you pay before), in France the Test is each times 1300 livres, so if you missed test of braking or
polution or noise you have to paid other time 1300 livres....
But for sure the solution is to decrease the RPM, maybe i can use a power commander or something to stop the acceleration, but it's necessary to
be a nice job....
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matt_gsxr
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| posted on 14/1/12 at 05:37 PM |
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If you have a sealed duct into the airbox then that can further decrease the noise.
Retarding the ignition can also decrease the exhaust noise (I believe the manufacturers have this in their maps for this reason), but I guess you
don't want to start remapping.
Where do they put the microphone/sensor when they do a 77dB test? if it is a drive-past then how far away is the microphone?
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veld
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| posted on 14/1/12 at 05:58 PM |
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there are 2 micros, one at the left and one at the right, at 6 meters of the car.
The driver pass one line at 50 km/H in second speed, he press on the accelerator at the max during 20 meters where the noise is taking.....
What is a sealed duct ?
Thanks
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MikeCapon
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| posted on 14/1/12 at 06:18 PM |
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A sealed duct is 'un tuyau d'entree de la boite a air, etanche' Et a mon avis il veit dire etanche au niveau de la jonction
tuyau/boite a air.
Sorry for the rubbish french but I can see that the OP is struggling with the mother tongue.
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veld
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| posted on 14/1/12 at 06:39 PM |
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thanks for the translation....
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MikeCapon
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| posted on 14/1/12 at 06:58 PM |
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veld, look at the top of the screen. You have a U2U message.
Mike
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ReMan
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| posted on 14/1/12 at 09:03 PM |
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A V2V non? 
www.plusnine.co.uk
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MikeCapon
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| posted on 14/1/12 at 09:07 PM |
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MDR ReMan...
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matt_gsxr
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| posted on 14/1/12 at 11:15 PM |
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If you need to push the accelerator "to the max", then you could adjust the pedal stop so it isn't full throttle for the engine.
What I mean is
accelerator == max not equal to engine throttle body butterflies == max
I can't think of a way of saying this that will translate easily.
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veld
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| posted on 14/1/12 at 11:37 PM |
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Thanks for the message Mike, for sure your help can be precious....
If you put a rein to the accelerateur (i m not sure for the name), where is the best place to be discreet ?
Thanks
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bobinspain
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| posted on 15/1/12 at 01:38 PM |
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Veld,
MK export Hayabusa engined race cars to France. I'm not sure if they are road registered, but if they are, then whatever they do to get
them through your noise test would be appropriate for your car.
Spanish noise limits for ITV (MOT/SVA) are tough too. 91dB @ 50 cm and 3850 rpm.
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veld
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| posted on 15/1/12 at 02:29 PM |
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Hello bobinspain,
the indy witch are imported in France are not road registered....
It seem the road tests to spain are more easy than in France , the UTAC is realy a long way ....
Is it possible with a power commander to stop the rpm at 7000 ?
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RichardK
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| posted on 15/1/12 at 02:35 PM |
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Put a turbo on it that should quieten it down a little 
An inline catylitic converter may help too, I flanged mine so it can be removed (ah hem for trackdays)
Got mine from Here
Seller I got my flanges from arent selling anymore but guess these are similar eBay - The UK's Online Marketplace
Cheers
Rich
[Edited on 15/1/12 by RichardK]
Gallery updated 11/01/2011
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bobinspain
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| posted on 15/1/12 at 03:04 PM |
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Richard,
I'm having MK's second hand cat to keep for "trackdays" and any other time it may be required.
I can't answer veld's q. about rpm restriction via PC5, which I have fitted to my car, as it's still in UK. If you check out the MK
Indy owners f/b page you'll see it on the MK stand at the NEC Autosport Show.
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scudderfish
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| posted on 15/1/12 at 03:54 PM |
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There was a R1 Fisher Fury in one of the first issues of Practical Performance Car magazine that was well down on power. It transpired that the
engine was a restricted one for the German market and there were plastic fittings inside the throttle throats. I don't know if there are
similar restrictors for the Hyabusa.
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iiyama
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| posted on 15/1/12 at 04:14 PM |
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I have posted it up before but this is what I have done to try and reduce the noise. Induction noise from a standard suasage filter is massive! I
haven't done any test's since its been built and fitted, so have no idea at the moment if power has been affected. However the Mrs. dosent
hear me turning into the drive anymore which means that a/ my automatic garage door dosent work anymore and b/ it would appear that noise has been
reduced! (I do need to get a meter on it though). I also havent noticed any power drop but I know what the car was making before the box was fitted
and haven't managed to get it back on the rollers since fitment.
If its broke, fix it. If it aint broke, take it apart and find out how it works!
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veld
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| posted on 15/1/12 at 04:35 PM |
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Everything is very interesting,
Richard, i have already a catalyser on the exhaust of the megabusa but is possible to put one other to decrease the noise and the polution ?
The decrease of performances is not a problem because for the circuit i come back to the original megabusa.....
iiyama i have read your post witch is very interesting, it seem for noise it's the hayabusa air box ( maybe not for the performance) but is it
possible to buy a similar air box ?
bobinspain, i will read the post of the mk....
scudderfish, do you have more infomations about plastic fittings inside the throttle throats ?
THANKS AGAIN
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:{THC}:YosamiteSam
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| posted on 15/1/12 at 05:42 PM |
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what size is the exhaust silencer? you can get sometimes 7 inch diameter silencer cans and get it made as long as will fit and repackable [so if some
new product comes into the market you can change it easily]
the westfield megabusa with standard air filter runs about 105db at 3/4 full revs static
i added cosmicks airbox which has defo reduced the noise by 3-4 db with no loss of power
the standard westy silencer is 5 inch diameter so thats next on my list to change - if i can get 7 inch to fit so be it [just need to watch the weight
in case of it snapping]
i would of also thought the position of the end tail pipe will help - maybe it can be angled down?
after that im not sure - your into real techy land then!
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veld
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| posted on 15/1/12 at 06:01 PM |
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My silencers is 5 ", i will probably change after the test for a big bore titane or maybe like cosmick, rsv exhaust....
For the moment i have fixed a second silencers, your idea is probably fine, to changed the angle of the exit and maybe if it's not enough a db
killer like motorbike, but i need to keep a good polution.
With the air box of hayabusa you lose 4 DB ?
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