Exhaust Noise

[The GMan]

If you have a sports exhaust fitted, is it usually to loud to be used on a trackday? Also what are the benefits of decatting, if you had a sports exhaust and decatted too, would this be way to loud and would you also lose some performance?

[Beano500]

In simplest terms - yes, any modified exhaust is likely to give you problems getting on the track, so check the requirementsbefore the day!

[sweeping generalisation mode]

Sports exhausts tend to be louder and reduce performance.

De-catting will be louder and potential improve performance.

You can get add on mufflers to get the dB down to track legal levels.

[/sweeping generalisation mode]

Plenty of threads which will give you much more useful detail on PH if you do some searching.

[shpub]

There is a noise FAQ on my website. Best advice is leave the thing alone especially if you want to do track days. The limits are getting tougher and tougher.

Steve
www.tvrbooks.co.uk

[2 sheds]

Many track days have limits of around 98 dba , TVRs with standard exhausts & cats are around 98 dba. if you modify or fit sports exhaust you will in most cases need extra silencing for track days, if you decat and remove silencing forget trackdays.
Tim

[CLINT887]

Not this old chestnut again! I know zilch about tuning exhausts especially TVR exhausts which to say the least are somewhat unusual. Commonsense says that you may lose a bit of back pressure hence power but I would have thought that this could be compensated for by using smaller radius tubing in the box when doing the mod. It is surprising that nobody has investigated this properly seeing how important the exhaust note is to the average tiv owner. Personally I noted a very slight loss of torque when I had the mod done but this was more than compensated for by fitting one of Tim's brilliant induction kits plus a reburned chip.
PS: Why the hell did an induction kit help with back pressure problems???

>> Edited by CLINT887 on Friday 28th February 17:53

[andy43]

I've got a griff pre-cat with a 'sports' exhaust (dont know what sports its useful for apart from car alarm baiting in multistories...) and I don't think it would pass any drive-by regs. The guy I bought it from was after a griff 500 with the idea of taking the cats off completely then refitting them for the MOT - if you get stopped on a random emissions check and you're cat-less you'll be relying on the plod being music lovers rather than jobsworths...

[2 sheds]

Thanks for the kind words clint.
to answer your question about induction mods and exhausts, i've just finished fully porting, chipping & plenum on a standard 4.0L griff, the exhaust note is now very different (exhaust standard), if you think about it, TVRs tend to have small inlets and massively oversized exhausts & manifolds, if you increase inlet ports you are going to balance things, this doesn't apply so much for 500s though.
Tim