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Noisy induction, failed noise test-any suggestions?


boughtoneatlast

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Hi all

I run a tweaked 1.6ss, with throttle boddies etc.......

 

I have just had car noise tested at Bedford Autodrome and on a drive by failed with 88/89 dbs.... only when passing the sensors on the induction side, the static exhaust was 97dbs well within the limit!

 

I have the standard bonnet (no hole for induction) and therefore run with the sock type filters (Piper Cross) on each trumpet.....

 

🤔 How can I bring down this noise level, has anyone else encountered this problem (silly question!!) would an air box or similar work,? and if so where could I get it and any advice on what might be needed to fit it

 

Many thanks

 

Ex 1.6 SS, now 186bhp!!, it flies

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Mark

 

Thanks for the link. Very interesting. They are using different length trumpets on the race Elise airbox. Something I advocated some months ago and that is used regularly on 4 cylinder race bikes. I'm glad somebody has finally done it and it works.

 

AMMO

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Mark thanks for this

Have you experienced it, does it make the car quieter??

I have Jenvey TB's, does this conversion work on them, it looks good, looks like it might be quieter....

 

Desperate to get the noise down for track days, to be honest, I love the way it sounds normally!!!

Gary

 

Ex 1.6 SS, now 186bhp!!, it flies

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Bernards (autoteknix) airbox is made specially for the Jenvey TBs, I've installed about 15 and they considerably reduce induction noise and help to deliver cold air to the TBs, they will just accomodate 90mm trumpets.

 

Ammo, the unequal length trumpets work a treat on Steve Butt's car bringing up the mid range torque substantially, but the cylinder may need indivudal trims to the fuelling.

 

Oily

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Oily

 

The dyno sheet is impressive. Regarding fuelling, the Jap fours have a single Uego sensor in the exhaust so the mapping is a compromise. Even though the fuelling may not be perfect on either the bikes or this particular Elise the improvement is so great, is it really that important? If money was no object then a sensor in each header and each cylinder indivdually mapped would be perfect. This is what I did on my old race Guzzi and what is still done on all race twins like Ducatis.

 

I've just got a prototype fibreglass air box from Arnie to chop about and fit to my Duratec. I may try some mega-long inlets on the dyno. It could take up to 250mm trumpets if I do away with the internal filter an fit one remotely. Hope Arnie doesn't read this 😬

 

AMMO

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Had the same problem in October at Bedford, but had done 4 other Bedford days during the year without problem. Was it a cold day? I have invested in a noise meter from Maplins, and when the salt goes (soon I hope) I am going to do some testing so I can have a few tricks up my sleeve just I case it happens again.

 

I was only just over the 87 db limit, so I am going to test

 

Tyre Pressures

Low rev limits

Throttle mods, to prevent full throttle

and air filter mods.

 

I feel its better to have 90% throttle and stay on the track, than taking an early bath.

 

If I can get that noise down, the an air box will be the next option.

 

That’s my plan anyway

 

 

 

Chris....

H15 SVN Get it !

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try www.reverie.ltd.uk

 

Mine was fitted by Caterham from new, then re-fitted by Hyperion so that the air inlet in the nose cone was re-positioned to avoid scooping up catseyes, etc. It is an expensive bit of kit and not trivial to fit soif you want to get one and you're a mechanical dunce like me *smile* it may be worth at least talking to someone like David Epstein (Hyperion 01787 478 800)

 

regards

fc

 

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Hi Gary

 

You can compare my car with yours, because my induction noise comes from a pair of 45’s. But I had no problem during the Summer, only during a cold day in October. So I now have a number of aids to reduce this, one of them is a noise meter, and a pit to car radio to tell me to keep it down. The noise meter is well worth the investment, before you spend on anything else, because it sound like you where only just over the limit like me, and a little tweek or a warmer day is all that’s needed to avoid the noise problem.

 

Either way, hope to see you soon at Bedford 😬

 

 

 

Chris....

H15 SVN Get it !

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