DECAT PIPES

[jonny tvr]

I had a Cerbera before my Griff and on this it was a straight forward installation of the decat pipes. Is the Griff just as easy and if so where do I get the decat pipes from??

[pupp]

Three cats to take care of, one primary cat in each manifold ('just' bash 'em out...easier said than done if you're not lucky and they fall out) and the main cat in the 'dustbin' collector at the front. ACT do a stainless 'Y' piece that is a straight replacement for this... enables you to refit the main cat if needed come MOT time, should pass without the primaries if the main is working ok. There is a 'knack' to fitting this

[jonny tvr]

Thanks for the info .. may go for the ACT product depending on price.

Does it make a difference to the sound and performance do you know?

[pupp]

jonny tvr said:

Thanks for the info .. may go for the ACT product depending on price.

Does it make a difference to the sound and performance do you know?

Sound is easiest to answer... mine was MUCH louder after replacement but I have got a modified back box too. The main cat appears to have a very pronounced muffling effect. I'd be cautious of decatting if you have a sports exhaust unless your neighbours are very tolerant.

Performance is much more contentious and I can't say for certain as I've no back-to-back comaprisons to base any comment on (I also made quite a few mods in a short space of time so it's difficult to attribute any specific effect to any individually). From general running behaviour, I am confident my car is quite happy to be catless and I feel it is a more responsive drive with no horrible consequences at all. Although there are those who maintain the Rv8 likes 'back pressure' (whatever that is, I always thought pulse wave reflections were the key)), I'm quite happy that all else being equal, an exhaust of adequate dimensions and configuration will work much better without being stuffed up with arbitrary honeycomb(s) that can only impede or even obstruct flow when they start to deteriorate

[jonny tvr]

Good points and thanks very much

[dnb]

The ACT performance manifolds work well.

I have run them with the decat pipes in place while I set the car up with the VEMS ECU and it's not too loud. Last year (car was standard) the exhaust was approx 96dB. This year (very modified - ACT manifolds etc, but standard back box) it made 105.7dB.

Performance increase is noticable, but I am in a position (with a fully mapable ECU and no need to play with tune resistors etc) to easily expolit changes to the engine to extract more performance.

[richb]

I run with ACT Stainless "de-pre-catted" manifolds but retain the main cat together with a "sports exhaust" - sounds great but I wouldn't want it any louder. Rich...

p.s. Topsparks has a 5.3 tuned V8 in his Griff without any cats or silencers and it sounds like race Tuscan. If you decide to go this route make sure you like noise!!!

Edited by richb on Monday 14th August 14:57

[jonny tvr]

Thanks Rich