Hi there,

I'm looking at upgrading the cats on my 2005/6 X350 Super V8. I was going to settle for the Nameless Performance Cats, however I'm now unsure if they would fit as they seem to have a bolt on flange to the exhaust system. My cats also seem to be missing the clamps at the bottom with I guess attach to the transmission?

I've attached some pictures, is this the typical configuration for connection between the cats and the exhaust on a 4.2 SC X350?

Can any one recommend a drop in replacement for mine?

 

Supercharged engines have a different manifold and a slightly diferent pipe design as a result.

There is only one flange at the top. You can see the slip join in the back in your picture.

For a replacement your bet bet is aftermarket cats with a custom pipe.
For the second sensor you will need a bung welded in the pipe behind the cat

PS the other difference is the oem cats have difernt cells stock
Supercharged has a 600cell then a 400 cell
Non supercharged has twin 400's

Both have the second sensor located between the cats
If you go for a test pipe and or a HP cat (100 or 200 cell) it would a good ides to add a minicat to the welded bung to stop any emissions errors that may come up

See here
Angled O2 Simulator, Angled O2 Simulator clears p0420 / p0430 check engine light

Cheers
34by151

 

Hi 34by151

Thanks for the advice.

I've found a place in the UK near where I live that offers a 200 cell hi flow upgrade with the post cat sensor fittings for a reasonable price. I think I'm going to get my car booked in the next few weeks to get them fitted. If I get any emission codes I'll be sure to order myself a pair of those minicats. I'll report back on how it all goes.

Matt

 

Make sure you get a dyno report before and after so you are sure the performance improves

Cheers
34by151

 

Hi wackymatt.
I had 200 cell sports cats fitted to my XJR by Tom at TL Jags last month. I have no problems with errors at all.
The sensors fit as normal too so no worries.
Les

 

Hi Les,

TL jags was the place I was looking at.

Just out of interest, what improvement to the sound, mpg and performance did the cat upgrade bring? Is the rest of your exhaust a stock system or did you upgrade that before hand?

My plan was to upgrade the cats, evaluate the sound improvements then possibly go for a mina gallery rear exhaust section then a re map.

Matt

 

Well I got the Hi Flow cats installed about 4 weeks ago along with 4 new lambda sensors. The rest of the exhaust system is stock.

The results are great!

The sound wasn't quite what I was expecting but it really is a massive improvement over the stock cats, i thought the end result would be similar to the current sound, but louder. It's difficult to describe exactly, it's very different to a Jaguar cat back / axle back exhausts I've heard in you tube. There is a slight raspy note to it which sounds fantastic and very sporty at high revs and there is a very deep V8 muscle car tone at lower to mid revs. Cruising at a constant speed there is no increase in cabin noise whatsoever.

The power is about the same at low revs, I noticed a much better throttle response however. At the mid to top end I there is a good gain in torque.

The fuel economy has improved significantly, I'm now getting about 34 mpg (UK gallons) on the motorway doing about 70-80mph, this is up from 28 mpg. The improvement could be mainly down to new o2 sensors?

I'm now contemplating a Mina Gallery axle back rear exhaust upgrade to further improve the sound and look of my car.

 

What brand and model of sport cat did TL Jags fit?

 

I'm due to replace my cat's very soon with 100cel units as im sure mine are on the way out.
I have already purchased the new units after getting good reports from others. The ones i got have a 7 year warranty as well

I'm going to fit minicats as well after the cat and use the OEM helt shield to make it look as stock as possible

Not going to bother getting a dyno test before because I think the gains will not be a fair test.

i have 140,00kms on my OEM cats and I think replacing with new OEM ones would show a gain. No if I did thet and got a dyno test then went to 100cel units and got another test done that would be fair

Bottom line, I'm going 100cel as it is close to a test pipe I can make it and still be legal.
IE "must have cats fitted", im not talking about emission here but thats not a worry as we don’t have a test for rego

Cheers
34by151