Has anyone removed or considered removing their cats from either a V6/V8 diesel sport.
My understanding is that cats are not required by law in the UK on diesel cars.

Just wondered if the less restrictive pipes make the can more responsive / economical etc.


Daz

Hello Daz,

You are right , the MOT smoke test is a particulate one and not a gas test so removing the cat wont upset your MOT man.

Pete Bell was talking about doiing a decat system a few months ago....

You will get a better throttle response and more miles to the gallon.
The difference on a TD5 disco is very noticeable

The new front pipe will almost certainly need another silencer as the cat removes a lot of noise .

I fancy a decat pipe , if you find one let us all know.

Mart Jaguar XF 3.0D Portfolio
RRS TDV6 HSE 2006 , Zermatt , Gone

I might well look into it after Xmas, I'm lucky since my best mate owns an exhaust company called JACexhausts, I have to be careful not to advertise his services and abuse the advertising policy and get my knuckles wrapped by the moderators.

I'll get the car on the ramp and have a look one day, if we can make a pipe that replaces the cat and includes a small free flow silencer to keep noise down AND make it in such a way to make a reversable swap I might be onto a winner.

Fingers crossed

Daz

i removed a cat once was a messy experiance, blood and cuts everywhere! id recomend you dont let ya cat anywhere near your cars engine!

 RR Sport supercharged 06
strut grills, strut 22" wheels, Full Kahn Kit
Brembo big brake kit, tinted front and rear lights

CLS 63 AMG Mercedes 2008, Cayenne Turbo S 2007, C32 AMG mercedes 2004, Vito Van 111CDI 2004

Daz,

I've had the bottom engine cover off when I had my stainless exhaust fitted , to have a good look at how difficult it would be to liberate the cat.

It is very tight

You can just about get long extension sockets onto the turbo downpipe nuts.
There isnt much room at all around the pipe/cat.

Luckily there is plenty of room under the car to fit 2 silencers anyway so if push came to shove you could have a simple downpipe from the turbo.

I should have taken pics......

Mart Jaguar XF 3.0D Portfolio
RRS TDV6 HSE 2006 , Zermatt , Gone

My mate had a sport in his unit yesterday to fit HST end trims to a HSE that had been modified with a HST kit.
I would have had a good look but couldent see the point with it being petrol.

Will get min up after Xmas for a peek.

Daz 2017 4.4 Autobiography FFRR - love this car
Gone - VW T5 Transporter
Long gone - 2009 Disco
Long gone but never out of my thoughts - 2008 TDV8 HST

why not just by a full catback exhaust system....Rather than have some welds throughout your exhaust system.... 

Dont cat back systems have any welds in them.............and also dont cat back systems start and the cat and go back.....thus leaving the cat in place?????

Daz 2017 4.4 Autobiography FFRR - love this car
Gone - VW T5 Transporter
Long gone - 2009 Disco
Long gone but never out of my thoughts - 2008 TDV8 HST

id love to have a system like the ferrari F430,

where the exauust oopens up after 4000rpm! and gets alot noiser!

i have a supercharger how can i get it louder already have exaust, induction and headers! RR Sport supercharged 06
strut grills, strut 22" wheels, Full Kahn Kit
Brembo big brake kit, tinted front and rear lights

CLS 63 AMG Mercedes 2008, Cayenne Turbo S 2007, C32 AMG mercedes 2004, Vito Van 111CDI 2004

Just do it like omar had on his 355. Straight through pipes from engine iirc. Then anyone within a few miles will know your driving .

De cat sounds interesting for throttle respone and mpg. Im not into any more noise from the car.

dazsear wrote:

Dont cat back systems have any welds in them.............and also dont cat back systems start and the cat and go back.....thus leaving the cat in place?????

Daz

catbacks have no welds, they are madrel bent (if you get a good system), and then clamped on with a special adapter. If you start throwing in pieces of bent tubing thats not mandrel bent, it messes with the out flow of exhaust, which causes it too be very inefficient. If you get a catback you can easily get that section extended if you get a custom one, therefore it would connect closer to the headers and right before the cat. 

Sorry mate I was being flippent, all exhausts have weld construction somewhere if you are having silencers on the system. There is nothing wrong with a good TIG weld if it is strong and professionally done.

Without looking at the original exhaust I would have a pipe made to replace the cat section in it's whole length as a simple replacement pipe.

Quality is no issue since my mate makes exhausts for Quicksilver who sell to all sorts of specialist car people!


I will let you know how I get on, it may be possible to make more to order but I will have to talk to the site moderators before that happens to see what is required. At the end of the day I want to be help to the sponsors not a competitor which probably means going through one of them.

Daz 2017 4.4 Autobiography FFRR - love this car
Gone - VW T5 Transporter
Long gone - 2009 Disco
Long gone but never out of my thoughts - 2008 TDV8 HST

Pauly,

I'm sure you cant remove the cats on the petrol engined RRS.
You have sensors before and after the cats.
The engine management will go mental if you remove them BUT....

I'm sure Larini do hi flow cats which improves throttle response while not upsetting the ECU's.

I drove a S/C earlier this year with hi flow larini cats , they do exist.
The larini exhaust was a bit noisy for me but the sound was amazing , I felt a right hooligan

Good luck
Mart Jaguar XF 3.0D Portfolio
RRS TDV6 HSE 2006 , Zermatt , Gone

just spoke to Larini, they dont do that system anymore!

i really wana hear a larini system as i may take mine off and put one of those on! RR Sport supercharged 06
strut grills, strut 22" wheels, Full Kahn Kit
Brembo big brake kit, tinted front and rear lights

CLS 63 AMG Mercedes 2008, Cayenne Turbo S 2007, C32 AMG mercedes 2004, Vito Van 111CDI 2004