Sports CAT and MoT

[blaze_away]

SPORTS CAT AND MOT EMMISSIONS COMPLIANCE ?

I am about to have a main CAT fitted (currently have straight thru custom system) to ensure I can pass an MOT in future.

Current plan is to fit a 200 cell sports CAT.

Has anyone done this before and improved their emmissions to become MOT compliant

[Andy70]

From experience with BMW's, cars will pass with 200 cell sports cats instead of the standard main 600 cell, they still have secondary cats in place. in fact the E46 CSL had them out of the factory and as far as I'm aware for any other vehicles too they are MOT compliant (i fitted them to my twin turbo 330i and passed no problem), so should it be any different with a TVR? so as long as you have secondary cats and 200 cell cats replacing the main ones shouldn't it sail through?
It was common for enthusiasts just to run on the secondary cats and cars would just scrape trough if hot enough.... that's assuming TVR's have main and secondary cats, no idea with that one???

[stevemcs]

Let them know it has a sports cat, we will ither book you in first thing in the morning or striaght after lunch - or if you wait with it, we just ask that you get it hot when it arrives and we try and test them straight away. If it fails first attempt there is an extended test they run through. Most tend to pass after a bit of time.

[sixor8]

Andy70 said:

From experience with BMW's, cars will pass with 200 cell sports cats instead of the standard main 600 cell, they still have secondary cats in place. in fact the E46 CSL had them out of the factory and as far as I'm aware for any other vehicles too they are MOT compliant (i fitted them to my twin turbo 330i and passed no problem), so should it be any different with a TVR? so as long as you have secondary cats and 200 cell cats replacing the main ones shouldn't it sail through?
It was common for enthusiasts just to run on the secondary cats and cars would just scrape trough if hot enough.... that's assuming TVR's have main and secondary cats, no idea with that one???

Chimaera and Griffs have pre cats in the exhaust manifold, no other secondary cats (if that was what you're on about?) They are only there for cold emissions. On a hot engine, the emissions should be fine with just the one main cat fitted. There is only one, your car garage suggests you have a Chimaera (?)

[Andy70]

sixor8 said:

Andy70 said:

From experience with BMW's, cars will pass with 200 cell sports cats instead of the standard main 600 cell, they still have secondary cats in place. in fact the E46 CSL had them out of the factory and as far as I'm aware for any other vehicles too they are MOT compliant (i fitted them to my twin turbo 330i and passed no problem), so should it be any different with a TVR? so as long as you have secondary cats and 200 cell cats replacing the main ones shouldn't it sail through?
It was common for enthusiasts just to run on the secondary cats and cars would just scrape trough if hot enough.... that's assuming TVR's have main and secondary cats, no idea with that one???

Chimaera and Griffs have pre cats in the exhaust manifold, no other secondary cats (if that was what you're on about?) They are only there for cold emissions. On a hot engine, the emissions should be fine with just the one main cat fitted. There is only one, your car garage suggests you have a Chimaera (?)

I see, maybe they are set up differently then, my mistake, I just know from other cars there are secondary cats and primary cats and the secondary cats can be just enough alone to scrape through emissions, which means you loose the restrictive 600 cell cats , so to replace the 600 cell cats with 200 cell and retain the secondary cats that should be more than enough, but maybe TVR's work differently then, sorry!

Edited by Andy70 on Sunday 29th September 21:56

[Belle427]

The Chim as standard has pre cats in the manifolds and the main dust bin cat.
Most remove the pre cats as they are not really required.
200 cell should pass but needs to be red hot so a friendly mot place is key here, you don't want the car sitting around cooling off waiting for the test.
My 100 cell on a Lotus just scrapes through but needs to be heated up thoroughly on the test, very tight though.

[Sardonicus]

Also take on board the distance the main cat is away from the combustion chambers so make sure tester is patient with function i.e get plenty of bloody heat into the exhaust/fast idle for a period just keep an eye on the temps and the fans are performing (a scalded tester is a pissed off tester) , its for this reason most modern stuff uses mani-cats so they light off sooner

[blaze_away]

Thank you all the replies.

My car is running really nicely plugs all good and nicely nut brownish and I have a wideband lambda that runs around 14.5.
Hopefully the 200 cell will do the job. Being fitted mid Oct and mot's in Jan. So guess we will see.

[GRC85]

I have a 200 cell sports cat on my 450 which just sailed through its MOT. It's the Clive F GT version.