MOT - Emissions

[David H]

I've always taken my Griff to a very friendly local MOT station that I've used all my life, and since the installation of a H404 cam a few years ago emissions testing has been a problem. The garage has now closed down forcing me to seek out a new (perhaps not so friendly) test centre so I'd like to do all I can to prep the car before the test

Spec:
H404 cam
Pre-cats removed
Main cat remains
Engine rebuilt a few years ago

I always drive the car hard enough to get some heat in to the cat prior to testing but is there anything else I can do?

I've read on Blitzracing's web site that idle (up to 2500rpm) mixture adjustment of the AFM is only applicable to non-cat ecu setup. I guess I could switch in to this mode and tune for the test but would this help?

Other peoples MOT test experiences with a H404 equipped car would be good to hear

Help appreciated

[Del 203]

Take a few extra ££ with you ......

[blitzracing]

You can put a switchable resistor to switch between the cat and non cat map on demand. The ECU is quite happy with this, but you do need to cycle the ignition off when you do switch maps. At least this way you could mess around with the CO trim on the side of the AFM whilst its on the gas analyser in non cat mode if it wont pass in cat mode. Don't however run the car permanently on the non cat map, it will be a Range Rover map. Unfortunately a long duration cam, an AFM a 14CUX and low emissions are a hard balancing act. It would be worth putting some really good catalysts cleaner in the fuel tank before hand. I tried some that was about £15 and claimed it could drop the emissions by 30% (on a MOT failing Fiat), but I did not believe it would work this well, but the gas results showed otherwise.

[dnb]

Passed 3 times with H404 and no cats. Oh and no bribery either...

[pk500]

first a cat test is done if it fails and there is no information on emmisions which im sure there not! up to 1994 you then carry out a normal test which is up to 3.5% most cars usually pass this !good luck

[dnb]

There is TVR emissions data. There is a concession that can be useful to those of us with aftermarket ECUs.

[steve-V8s]

dnb said:

There is a concession that can be useful to those of us with aftermarket ECUs.

Would you care to expand on that ? I suspect that may be of interest to a fair few people.

[dnb]

I've posted it many times, so if search works, it should be easy to find the details. The Cerbera AJP8 also has concessions too.

[Pasco]

dnb said:

I've posted it many times, so if search works, it should be easy to find the details. The Cerbera AJP8 also has concessions too.

The search is Cac as usual

[dnb]

Found by Googling "dnb Griffith emissions".

If any mods are watching, this should be added to a sticky thread because I seem to be the only person that knows about it outside of the MOT tester community.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

MOT tester chap said:

the TVR range with cats get less stringent requirements; late 'S' models, Chims and Griffs; less than 0.3 CO% less 200 HC and 0.9 to 1.1 lambda reading. Speed 6 and AJP engined cars less than 0.3 CO%, less than 200 HC and 0.9 to 1.2 lambda all at 2500 - 3000rpm for min 30secs and 0.5 CO at idle.

[Pasco]

Thanks Dave