4.2 emissions (without cat)

[TiffsTuzzy]

Hello,
I'm just about to IVA my Tuscan Challenge car road conversion, but am a litle worried about it failing the emissions test. It currently has no catalytic converters (as they're for vegetarian tree huggers), and is running a standard 4.2 AJP8. Do any of you lucky Cerby 4.2 owners run yours without cats and sail through the MOT each year, or do you rely on bribery or refitting the cats for the big day? Where are the cats on a Cerby? If I bodged a pair of second hand ones into where the final silencer goes, is that too far away from the hot stuff for it too work properly? Do any of you get round it with an emerald ecu with an MOT friendly setting?

Any help would be appreciated..... Rich

[itiejim]

The CATs won't work properly right at the back of the exhaust system, they need to be hot to have any effect.

If you can set up a very lean map for MOT purposes you might get away with it. Rolled up £20 notes in the exhaust pipe seems to have a positive effect on emissions as well though.

[JensenA]

It won't pass the emissions test without Cats. Give Andy at APM a ring and explain your dillema

Edited by JensenA on Monday 24th October 09:44

[verminator]

Have had my 4.2 de-catted for a couple of years and it always goes straight through the MOT. You just have to find a TVR friendly station.

[brogenville]

My MOT tester used to put my cerb through as "car with engine of unknown origin", which apparently had the effect of lower the pass mark so much that even a top fuel dragster should pass.

[clive f]

I did manage to pass an mot with no cats in a 4.2, but it took some clever adjustments on the emerald whilst it was at the mot station, I think he gave me the ticket just to get rid of me to be honest

I`d seek out a tvr specialist who does mot`s.

[Mars]

Even with cats it took me over an hour to adjust my Emerald to get it through, and by then it was undriveable and the engine was so hot it was smoking.

I had to take it out for a hard run beforehand to get the cats really hot. It passed but you're supposed to hold it at that speed while the emissions testing machine makes a call to the DVLA. We relaly couldn't hold the car at it for long so, having seen all 4 indicators go green, my MoT man passed it without it making the call to the DVLA.

This was for a 4.5. Doubt if there's a world of difference.

[Mars]

By the way, leaning off the fuel map doesn't give you the desired effect. You need to advance ignition A LOT to ensure all fuel is burnt properly. A lean map will make one indicator go green as another goes red.

[scotty_d]

verminator said:

Have had my 4.2 de-catted for a couple of years and it always goes straight through the MOT. You just have to find a TVR friendly station.

This

[TiffsTuzzy]

Thanks All,
Well, it looks like I'm in deep doo-doo. Getting it through a subsequent MOT shouldn't be a big problem as I know a friendly MOT man, but I doubt the IVA man would be so easily bribed. The Tuscan racer's exhaust doesn't lend itself well to having a pair of CATs fitted up near the manifolds, so it looks like I could be in trouble. I don't like the sound of the emerald ecu fix. I thought if it got desperate, I could invest in one of those and just flick a switch to dial in the MOT friendly ECU map, but that doesn't look to be the case. My problem, but thanks for all your help. The bigger the challenge, the bigger the satisfaction when I get there!
Thanks very much..... Rich

[clive f]

YHM.

[350Matt]

hang on mo the emissons test is down to the age of the chassis OR the age of the engine, whichever is the older surely your tuscan is before 1994? so you've only got to pass 3.5% CO and no visible smoke

[Chuggaboom]

Tuscan racer chassis rarely, if ever, had any identifying numbers on them, so rather hard to prove, even if supporting paperwork was available.

Therefore I dare say the engine age would take precedence...not many AJP's in one piece around before 1994 !

[BIGMIKE1]

I think IVA rules are the same as the previous SVA, were the emissions are done on the age of the engine and you need written proof stating what year the engine was manufactured. Chassis/donor car age are only really used to decide what registration the DVLA assign it once its passed IVA. You also wont find many if any IVA examiners who will bend the rules.
If you could some how get some paperwork that stated that the engine number was a pre cat then you should be ok.

Edited by BIGMIKE1 on Wednesday 26th October 18:22

[Obiwonkeyblokey]

scotty_d said:

This

for future reference if anyone knows of one such thing within shouting distance of Bristol, could they PM me the details please. thanks ( NO Cat, sports Pipes)