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anybody failed sva on induction noise?
NS Dev - 13/9/06 at 11:34 AM

getting worried about induction noise for sva test.

I have a plan of action to quieten the exhaust note for the test, (it is no doubt too loud) but sat in the car I can't even hear the exhaust over the induction noise!!!!

Has anybody failed on induction noise.

If only the exhaust side of the car is tested I should be ok as the induction noise is obviously worse the other side.

Hellfire - 13/9/06 at 11:43 AM

They don't test induction noise at SVA as such. It's only the exhaust noise, although any external noise coming from anything other than the exhaust may have a small affect on the overall reading.

Phil

Schrodinger - 13/9/06 at 11:46 AM

I havn't got a copy of the SVA manual close to hand but it is measured fairly close to the exhaust so it will soon drown out any noise from the induction

Hellfire - 13/9/06 at 12:01 PM

500mm from the exhaust outlet and at 45 degrees.

You'd be surprised how much influence the induction noise has on the test.

Phil

shortie - 13/9/06 at 12:04 PM

You could try lagging the underside of the bonnett with fireproff matting to cut down the induction noise, SVA just measure noise per say so any noise will get picked up.

Rich.

Peteff - 13/9/06 at 12:05 PM

Are you in an enclosed space Nat, the test is done in the open at Derby and the noise is dispersed a lot more, not echoing off of next door's fence, garage wall etc.

Schrodinger - 13/9/06 at 01:16 PM

IIRC it has to be done outside in the open

NS Dev - 15/9/06 at 08:37 AM

quote:
Originally posted by Schrodinger
I havn't got a copy of the SVA manual close to hand but it is measured fairly close to the exhaust so it will soon drown out any noise from the induction


Unfortunately not so!!

Need to verify it with the sound meter but my mate confirmed last night that standing 1m from the exhaust, the induction noise from the other side of the car drowned out the exhaust noise completely!!!

Air filter pokes out of the bonnet, lengths are much too long to get a decent filter under the bonnet, so bonnet lagging will make no difference.

What I don't know is revs at which the noise is worst, will connect a revcounter and have a look, because what feels like 4500 revs (what i hope I can wrangle the test at!) sounds a bit quieter!

NS Dev - 15/9/06 at 08:38 AM

other thing is the throttles are not balanced yet (need to borrow your synchrometer Mike!) and that may be making them bark worse.

Haven't got an up to date pic but this gives the idea!:


progress1
progress1

[Edited on 15/9/06 by NS Dev]

chriscook - 20/9/06 at 09:09 AM

Is this something XE's are known for? My XE on dellortos (45s) and a friends Caterham HPC on throttle bodies both make a lot of induction noise. Mine isquiteneed down by the bonnet though.

02GF74 - 20/9/06 at 11:10 AM

quote:
Originally posted by NS Dev

Air filter pokes out of the bonnet,


what is wrong with that - both of mine do and SVA man said nowt about it.

Mark Allanson - 20/9/06 at 07:35 PM

Put a temporary throttle stop on it

russbost - 20/9/06 at 09:48 PM

Don't fit a rev counter till after the sva test - they don't usuallyhave any means of checking revs so your judgement needs to be suitably low.