993 Trackday mufflers

[NeilMarley]

My stock 993C4 is falling foul of track-day noise regs, it just scraped by a 98dB/4750rpm limit a few years ago but this year has clocked 100dB/4000 rpm and 106dB/4750rpm.

I suspect that some of the baffles are on their way out but its not a problem for everyday driving, it doesn't sound particularly loud most of the time.

I have a 98dB trackday coming up - does anyone know if you can get the type of bolt-on mufflers you often see on TVRs etc on track-days to fit standard twin-oval rear pipes on a 993? I don't mind losing a few bhp at the top end for the day.

[david hype]

NeilMarley said:

My stock 993C4 is falling foul of track-day noise regs, it just scraped by a 98dB/4750rpm limit a few years ago but this year has clocked 100dB/4000 rpm and 106dB/4750rpm. I suspect that some of the baffles are on their way out but its not a problem for everyday driving, it doesn't sound particularly loud most of the time. I have a 98dB trackday coming up - does anyone know if you can get the type of bolt-on mufflers you often see on TVRs etc on track-days to fit standard twin-oval rear pipes on a 993? I don't mind losing a few bhp at the top end for the day.

Neil, what silencers/exhausts are you running?

[clubsport]

Why not just change the rear boxes?

last time i spoke with the guys at www.porsch-apart.co.uk

they had second hand 993 rear boxes for 100 pounds.

you can fit both sides in under an hour using new bolts, that way you will clear noise regs and hopefully not lose any bhp.

I run standard boxes on mine and never have any problem with noise restrictions at trackdays.

[cyberface]

I'm massively shocked that standard 993 silencers are falling foul of noise regs....

They're preposterously quiet as they are. If you need low noise then a healthy set of normal OEM silencers are your best bet, though they are heavy items.

You really shouldn't need additional silencers on top of a normal set of 993 back boxes. If yours are knackered, then get some more, there are *plenty* of people getting rid of OEM back boxes in order to get some characterful noise!!!

(I have the old ones off mine, but I guess given the word 'mufflers' you're in the USA, so probably not worth the shipping etc. )

[NeilMarley]

Thanks to all for the replies - concensus seems to be that standard OEM boxes shouldn't be failing and the simplest solution is to look at replacing the end boxes?

The car is standard, including the exhausts, as far as I know but has clocked >80k miles so it wouldn't be too surprising if the boxes were on their way out.
Looks like I'll need to clamber underneath and have a look over the weekend.....