Quieter engine

[Tony Bird]

Hi,
Can anyone suggest a simple way to tone down the noise level on my 350 small block for the SVA?
They now want this 5000rpm figure as a baseline for noise testing which i@m sure is going to make it awkward to pass.
Thanks

[cliffords]

What car are you building ?

[lutman]

Originally Posted by Tony Bird

Hi,
Can anyone suggest a simple way to tone down the noise level on my 350 small block for the SVA?
They now want this 5000rpm figure as a baseline for noise testing which i@m sure is going to make it awkward to pass.
Thanks

Did SVA state why they want 5000rpm as baseline ? Whilst that figure is probably about right the SVA manual states that the noise is tested at 75% of maximum power, has the car been on a dyno yet ? If so the max power setting would be indicated on the print out and SVA should test at 3/4 of that.
Or where no max power figure is available then at 66% (two thirds) of engine max design speed. So if the rev counter has a red line then 2/3 of that.
At these figures it must be less than 101db for SVA.

HAs anyone tried the route of a rev limiter set to say 4500rpm and using that as the engine max power figure, can be seen by SVA that the engine cuts out at 4500rpm and then tests at 2/3 of that - so noise tested at 3000rpm ?? - perhaps a bit naive and symplistic but perhaps acceptable to SVA ??

[JonnyT]

Not tried the rev limiter trick but they are really tightening up on the max power setting. We put down 4500 rpm (which for a small block ford is probably not a million miles out). After we got the form we got a phonecall saying that we were taking the p*** and in the event that we didn't let him amend it upwards, he'd refuse to book it in for a test.
He accepted 5000rpm in the end.

Anyway, it was too loud by about 4db. Two s/s brillo pads shoved up the 2" baffles reduced it nicely though to 96db - held in by two split pins through the holes in the baffles. Get the ones without the soap otherwise it might be interesting!! Btw - don't use normal wire wool as it burns. Be careful not to restrict air flow too much or run it for long periods as it may give you problems with overheating, but seemed to be fine for the test.

You may find that the brillo pads fall out very shortly after the test on the way back from the station

Jon

[Sidecarbod]

Originally Posted by JonnyT

Not tried the rev limiter trick but they are really tightening up on the max power setting. We put down 4500 rpm (which for a small block ford is probably not a million miles out). After we got the form we got a phonecall saying that we were taking the p*** and in the event that we didn't let him amend it upwards, he'd refuse to book it in for a test.
He accepted 5000rpm in the end.

Anyway, it was too loud by about 4db. Two s/s brillo pads shoved up the 2" baffles reduced it nicely though to 96db - held in by two split pins through the holes in the baffles. Get the ones without the soap otherwise it might be interesting!! Btw - don't use normal wire wool as it burns. Be careful not to restrict air flow too much or run it for long periods as it may give you problems with overheating, but seemed to be fine for the test.

You may find that the brillo pads fall out very shortly after the test on the way back from the station

Jon

All good stuff but you maybe better off with those scrubber things that look like swarf from a lathe. (Or even use swarf from a lathe!)

Try putting a brillo pad across a 9v battery if you want to see it burn like Nov 5th (it stinks)

Pete

[JonnyT]

Those are the ones I meant Pete - I'm sure they were called brillo pads on the packet. Still - not overly acquainted with the kitchen department so I bow to your superior knowledge on the domestic cleaning product front

[Sidecarbod]

Originally Posted by JonnyT

Those are the ones I meant Pete - I'm sure they were called brillo pads on the packet. Still - not overly acquainted with the kitchen department so I bow to your superior knowledge on the domestic cleaning product front

I'm sure that there's a dig at me somewhere in that post but I'm too daft to understand it!

[JonnyT]

No digs - you've given me too much help for that with my carbs for me to have a dig at you!

[Sidecarbod]

Originally Posted by JonnyT

No digs - you've given me too much help for that with my carbs for me to have a dig at you!

No problem mate!