Why not speak to Over Finch and ask for their advice? Tim
RRS sold and replaced with a Skoda Kodiaq after appalling RR Dealer experience and LR inability to supply new cars in any sort of reasonable time frame..

I’m actually awaiting their reply to another question I have, so will put it to them when I hear from them. Thanks Tim.

ok, so on further investigating, the system is completely standard apart from the downpipes having been removed and the shady welding which was done for some unknown reason. The 2 centre boxes and 2 backbones have not been touched. All welding is to OE spec.

Would a sport cat downpipes make much more noise than a stock one?

Yes, they flow a lot more. OEM cats are between 400 to 700 cells (the higher the EU-norm, the more cells, obviously) which block between 35 and 50% of the cat diameter. Sport cats are mostly 200 cells which block 15 to 25% of the diameter. Since the cat is wider than the adjacent elements of the exhaust system, it pronounces the bass rumble created by the sudden expansion of the exhaust gases in the increased volume. Additionally, this increased volume allows for the pulses to overlap, creating even more noise. Regards etc.,

Wojtek

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WAS: 2006 RRS Supercharged
IS: 2010 RRS TDV8 HSE

I've got you, thanks for explaining.

What's your thoughts in regards to the universal 400 CPI cats I see dotted around? While it's not a sports cat, if I can't find stock DP's and the Mrs wouldn't drive the car if it's too smelly and noisy...it may be my only option...

I don't have the specs of the stock cats available so can not really compare yet endorse any particular product. I believe if the cell number checks out, they'd be good to go. I would check, however, if your RR had a remap to suit the high-flow cats, as it would be not compatible with the stock...ish units. Regards etc.,

Wojtek

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WAS: 2006 RRS Supercharged
IS: 2010 RRS TDV8 HSE

Yes, that would certainly be an issue. I’ve considered the idea of requiring a remap after fitting different cat’s. It could come down to doing this, or my wife may refuse to drive it. lol

Looking further afield, I’ve found a Canadian company which makes their own cat’d DP. The website doesn’t mention CPI, but I’ve emailed them to confirm. Could be a happy medium.

https://excelexhaust.com/products/catalyti...over-sport

If keeping to the U.K., Gravity Performance offer a high flow sports cat DP that is 200 CPI. I’ve spoken to them and they’ve stated while it won’t be as smell and noise free as my wife would probably like, it’ll definitely be better than it currently is. At under £500 delivered(10% off with code), it’s a reasonable price, but money wasted should it simply not be good enough for my other half.

https://www.gravityperformance.co.uk/produ...SwQAvD_BwE


Lots to think about. I mean I’d rather keep what performance has been gained, but need my wife to be happy with it…I realise that’s an impossible task, but we have to try don’t we?