JPSC Forum

Hi All,

Just carried out a noise test on my car and at 4500rpm it is 103db. If this is a problem how do I get over it?

dopdog wrote:Hi All,

Just carried out a noise test on my car and at 4500rpm it is 103db. If this is a problem how do I get over it?

In competition 103db's will get you anywhere as even the harshest sound limit tracks pass you at 105db's ----- however , it won't do for trackdays as most are 98db's apart from MOTORSPORTEVENTS days at 100db's normally. If you're concentrating on sprinting this year, your funds will probably swallow up any spare for trackdays
If you really want it down to 98db's then you'll need to either repack very carefully with basalt or at the worst , fit a 7 inch silencer repackable
Mine normally comes out at 105db's right on the dot , provided I '' remember to say it only rev's to 6,500rpm ''

looks like the end of track days for me then I was going to concentrate on sprints this year so not a real loss. Its getting close and I am all ready to got. Got the car MOTed taxed and insured so should not have any issues passing the scrutineers inspection.

Mine does 96-97 on most Sprints/Trackdays. 105 is a lot !

jeffw wrote:Mine did 96-97 on most Sprints/Trackdays. 105 is a lot !

There -- fixed that for you, Jeff

hahaha

thats true you wait until its on full song then see if its under 100db

jeffw wrote:Mine does 96-97 on most Sprints/Trackdays. 105 is a lot !

True ---- however once the head was ' holed ' at Brands , the 101db's were never acheived again after the secondhand race head went on with it's silly big valves(bigger than the big ones before) . In fact on a dry day it used to be 98db's before and around 102db's if cloudy or damp. Once I've got through the static sound test , it never triggers the trackside sensors though. Simon Besant/guy with 400bhp V8 Westy , normally tests at 92db's to 98db's but then blows off all the track sensors around Goodwood so gets sent home. It's hard to compare engines test results , just doesn't seem logical

OK so I need to repack my silencer

Any help or advice with regards to material or application more than welcome.

Goggle Wunoff Exhaust Solutions in Bradford. Speak to Mark of John. Have had lots of help from them in the past with the exhaust for my Puma powered Striker and my R1 engined Riot.

These guys main business in plant and truck exhausts but they both have strong sporting backgrounds. John was an MSA noise scrute and Mark spannered his dads sprint bike. In a world of lots of promises these guys dont weave any webs. They give you the facts straight.

With the Striker I was able to make 99db before MSA asked for Cats to be fitted. Now at around 103db which is OK for Sprints and Hillclimbs. IVA required 99db at 3/4 max power which on the Riot was 9500rpm. This took some some doing with two silencing boxes and lots of sound damping around the engine bay but we got there just.

Mike S