IVA Noise Test

Simeon · Post by **Simeon** » Mon Mar 15, 2010 12:53 pm

I'm buliding a Westie S8 with a standard RV8 3.5. I have seen some photos of a car where the side exhausts came straight out of the engine bay and swept down the side similar to the Cobra look which looks absolutely awesome. If I did the same would I have any problems with IVA with regards to noise? Any other issues you can think of?

Simeon

JJMclure · Post by **JJMclure** » Mon Mar 15, 2010 12:56 pm

apart from buring your leg when you get out and setting off car alarms none here!

Simeon · Post by **Simeon** » Mon Mar 15, 2010 12:58 pm

Third degree burns is a small price to pay for that kindney stone shattering sound!!

Ian Anderson · Post by **Ian Anderson** » Mon Mar 15, 2010 1:02 pm

It might actually also help

By having 1 pipe either side of the car they can only "hear" the note from one pipe at a time

Don't forget though you need good silencers as the 99db they testt o now is damn quiet!

Ian

Simeon · Post by **Simeon** » Mon Mar 15, 2010 1:35 pm

I was thinking Wunuff cans, would you agree?

Stu E · Post by **Stu E** » Mon Mar 15, 2010 5:48 pm

We SVA'd a Cobra just before the switch to IVA. It had straight through sidepipes, which were painfully load

. We ended up making a baffle to fit inside the pipes. You have to make sure the tester can still put the emission tester in the pipe, and it doesn't appear to be a temporary fix.
Seemed strange they worried about the radius on the outlet, but not the fact you can leave half your leg on it.
HTH Stu

badger · Post by **badger** » Mon Mar 15, 2010 5:59 pm

99db isn't that quiet really, rally cars have to pass noise scrutineering at 100db........

Ian Anderson · Post by **Ian Anderson** » Mon Mar 15, 2010 8:15 pm

1st test the GT40 was 106 by 2000 rpm

Needed a lot of work to get it through

Ian

seight · Post by **seight** » Tue Mar 16, 2010 10:12 am

I've seen a video of one on youtube, it did sound good. Not sure they are my cup of tea on a Westfield but it would be boring if we were all the same. As mentioned I think it would take some work to get them down to 99.

When I SVA'd my first Westfield the tester left half his trousers on my side exit exhaust. I thought it was quite funny and so did his mate - he didn't!

Mike

Ian Anderson · Post by **Ian Anderson** » Tue Mar 16, 2010 10:55 am

Yes GT40 note is different to most V8

Because the exhaust crosses over the 2 and 3 from each side into the other collector it means it pulses alternatively down each pipe.

So it is like 2 - 4 cylinder engines running the same at exactly the same revs

And the tail pipes are about 6 inches apart so "cannot hide half the noise"

I'll advise how noisy it is in a couple of days time as I'm off to Cadwell Park tomorrow and they insist on noise checks!

Ian

SuperV8 · Post by **SuperV8** » Wed Mar 17, 2010 1:38 pm

I have a rush with standard ish 3.5 and side pipes.

I passed the SVA which I seem to remember was 103dB (don't quote me, I'll check) but I only just scraped under.

Tom.