Pre-cats
Author
Discussion

mrcosmos

Original Poster:

653 posts

241 months

Sunday 16th December 2007
quotequote all
HI,thinking of taking the plunge of removing the pre-cats on the Griff this winter.Just need to know for sure will the car definitely pass a MOT without them.Some say they will and others say not.Regards,Dave.

spend

12,581 posts

281 months

Sunday 16th December 2007
quotequote all
Never had a problem with mine, just warm it up before the test. There are rather a lot of us running without pre-cats for a long time now.

TBH I can only recall a single thread where it was claimed removing pre-cats would fail MOT - theres always one wink If your main cat is really foobarred it is possible I guess, but when the cat is worn I believe it is also pretty blocked & should be renewed anyway (like driving with a rag shoved up your exhaust).

Dave

mrcosmos

Original Poster:

653 posts

241 months

Sunday 16th December 2007
quotequote all
Thanks Dave.Just was'nt sure if people had a spare set of manifolds for the annual occasion.

Edited by mrcosmos on Sunday 16th December 21:17

The AJP Griff

4,360 posts

285 months

Sunday 16th December 2007
quotequote all
Hello Davewavey.I never had a problem with mine removed(done it with 2 cars),even running a H404 cam!I think as long as everything else is in good fettle you'll have no worries.
If theres something on your car thats not in good fettle i'll fall backwards!!!bow

mrcosmos

Original Poster:

653 posts

241 months

Sunday 16th December 2007
quotequote all
Cheers Mike.

spend

12,581 posts

281 months

Sunday 16th December 2007
quotequote all
Are you exempt from emissions with L110 Mike? The chassis must be pretty early - does that qualify? ie date of original build vs engine date?

Dave

Ballistic Banana

14,706 posts

297 months

Sunday 16th December 2007
quotequote all
I always understood it was the chassis...I have on the odd occasion known to be wrong though .....

ok Numerous boxedin

Oh and had my pre-cats out and been ok for Mots smile

BB

Edited by Ballistic Banana on Sunday 16th December 22:48

dnb

3,330 posts

272 months

Sunday 16th December 2007
quotequote all
Remember that you don't have to pass a standard BET emissions test, even in a late 500. smile

steve-V8s

2,924 posts

278 months

Monday 17th December 2007
quotequote all
dnb said:
Remember that you don't have to pass a standard BET emissions test, even in a late 500. smile
Why so ?

V8 GRF

7,299 posts

240 months

Monday 17th December 2007
quotequote all
Apparently the pre-cats where put in to satisfy some Euro legislation that either didn't apply or was never introduced so they're not needed.
As an aside I understand that some cars can/have passed emissions without the main cat in either.

dnb

3,330 posts

272 months

Monday 17th December 2007
quotequote all
steve-V8s said:
dnb said:
Remember that you don't have to pass a standard BET emissions test, even in a late 500. smile
Why so ?
TVR have an exemption on meeting the lambda requirement. It's listed in the MOT tester's handbook and on the MOT emissions computer system.

Johno

8,593 posts

312 months

Monday 17th December 2007
quotequote all
No problem getting through here either . . Well, the tester did have it running for quite a while, but like many I have a Stealth cam and aftermarket ECU.

When the Emerald goes in, I will be completely de-catting mine and will then have an MOT map as well as the performance map.

steve-V8s

2,924 posts

278 months

Monday 17th December 2007
quotequote all
dnb said:
steve-V8s said:
dnb said:
Remember that you don't have to pass a standard BET emissions test, even in a late 500. smile
Why so ?
TVR have an exemption on meeting the lambda requirement. It's listed in the MOT tester's handbook and on the MOT emissions computer system.
Any idea what page paragraph / section / reference etc. Is this the argument I have heard before that if it is not specifically listed it doesn’t need to comply ?

davetherave1970

2,144 posts

276 months

Monday 17th December 2007
quotequote all
This could open the flood gates biggrin
Please let us have some details!

steve-V8s

2,924 posts

278 months

Monday 17th December 2007
quotequote all
After a chat with the local MOT Man My understanding is this :-

After Aug 1992 the vehicle has to comply with the “Basic Emissions Test”, this test requires the car to be at normal operating temperature and as the pre cats deal with emissions during the warm up process they can be removed and the basic test still passed. It is unlikely however that the basic test requirements will be met with no cat fitted regardless of the fuelling. The test does not specifically require the cat to be fitted it is just unlikely that it will pass without.

However if either the chassis or the engine was first used prior to Aug 1992 the car is tested to the earlier requirements which can be met without any cats.

I have heard an argument that unless an exact match for the vehicle type is found in the database the less stringent test applies, I think however this exemption applies to a different class of vehicle.

If we do have a TVR specific loophole then please tell us, we really do need to know.

spend

12,581 posts

281 months

Monday 17th December 2007
quotequote all
I pointed out a couple of months ago that I was quite surprised when the new MOT system alerted the tester about the LSD testing.. So the MOT system does have some details on the TVR which I was sure they didn't have the year before???

Dave

mrcosmos

Original Poster:

653 posts

241 months

Monday 17th December 2007
quotequote all
Hi Steve,does this mean that the basic requirements are met with the "main" cat still in place?Regards,Dave.

The AJP Griff

4,360 posts

285 months

Monday 17th December 2007
quotequote all
spend said:
Are you exempt from emissions with L110 Mike? The chassis must be pretty early - does that qualify? ie date of original build vs engine date?

Dave
It's a 93 car,even the chassis build date.If you have a TVR registred before 1st Aug(not sure exactly)1995 then it gets tested the same as a pre-catbiggrinbiggrinbiggrin(probably just as well!hehe

spend

12,581 posts

281 months

Monday 17th December 2007
quotequote all
The AJP Griff said:
spend said:
Are you exempt from emissions with L110 Mike? The chassis must be pretty early - does that qualify? ie date of original build vs engine date?

Dave
It's a 93 car,even the chassis build date.If you have a TVR registred before 1st Aug(not sure exactly)1995 then it gets tested the same as a pre-catbiggrinbiggrinbiggrin(probably just as well!hehe
Another rarity then Mike, it has a 'hot off the press' chassis hehe

Not many folks bother to check,but I think in a thread we discussed a few years ago it seemed many chassis dates were older than the reg date. They are encoded so it is well worth knowing your chassis date for these test procedures BTW.

Dave

dnb

3,330 posts

272 months

Monday 17th December 2007
quotequote all
I can't find the document, but it does exist on the VOSA website somewhere... It's a TVR specific exemption, and I used it last year to try to get my Griff through with NO cats at all. biggrin (Passed fast idle, but failed slow idle.) All you get is a concession on the lambda parameters - a Griff is allowed between 1.1 and 0.9 IIRC. (A Cerb is basically allowed anything that is combustable wink )

Of course you can only take maximum advantage of the concession with a mappable ECU.

On a positive note, since the MOT stations all have the fancy computer system, if the car fails the BET test, the emissions machine should automatically give the tester the option to do the TVR test - no need to present any other evidence than a good V8 growl and a TVR badge. biggrin