Noise limits at UK tracks are becoming ever-more stringent. We're living in a noise-averse society and if you want to run your car at these tracks, you need to keep the decibels down.
I see a couple of exhaust suppliers offering a "switch" for their valved V6 exhausts to keep the valve closed and force the exhaust flow through the "quiet" baffle internally. It's not something I would recommend! A supercharged 3.5ltr V6 is pushing a serious amount of hot gas. Keeping the exhaust valve closed against that gas-pressure and the excess heat is a recipe for disaster. Their silencers have packing materials and if they cannot be replaced, how long before the silencer is burnt out under trackday abuse? Plenty of supercharged 2ZZ owners will attest to the experience of their exhaust becoming increasingly LOUDER after a few trackdays. I wonder what (if any!) warranty they promise with their "switch"?
What happens when the exhaust valve is destroyed? Even Lotus (Janspeed!) recognise the vulnerability of that valve and use an extension to remove the vacuum chamber away from the enemy - HEAT! Yet, I see exhaust valves placed hard up against one source of heat - (the silencer!) and placed high up in the exhaust bay - where the HEAT rises - not the best idea. I place the valve away from the silencer and push the vulnerable vacuum chamber to the bottom of the exhaust bay, where there is some cooling airflow.
I see some V6 owners have the Lotus Sport system fitted - the one with the 6"diameter silencer and the twin Titanium tips. When we had finished the R&D/dyno-work on the N/A Evora, the Lotus Sport system on that car had burnt/blown-out all its packing and became a droning annoyance. With no packing it wasn't doing much silencing either.
For "Track" use/abuse - you need to remove the exhaust valve from the equation. You need to remove the silencer packing so there is no danger of burnt/blown out materials. Performance is helped if you can shed some weight - you've got rid of the valve and its associated pipework, so that's a good start!
Only 2bular offer a "Track" system for these cars. I have looked at additional silencers to help meet some crazy db limits and images are alongside. These 100mm diameter Stainless tailpipe silencers help bring down db's to approx. 98dbs. I have also developed an additional silencer to fit where the old "3rd catalyser" used to be - will be testing it shortly. Being able to remove these add-ons means you can have a car which sounds like it looks most of the time - but when you want to run at a track, slip these on for better noise-control.
PRICING!: TBA - still working with suppliers to bring these in at a competitive price. The 90mm Titanium add-ons are lighter (of course!) than the 100mm Stainless add-ons but not so quiet - might be of use at non-UK tracks.