ECU map dealing with CAT's or No CAT's

[MarkB]

I intend to run my car with 200cpi cats when going stage3. I have toy'd with the ides of making some CAT bypass pipes for off road events.

How should I get the car mapped? Without the cats and the map will handle pulling back timing when the cats are installed? or is this unsafe and I should just get it mapped with CATs and not see such a great gain when I remove them?

Thanks

[derdle]

I've heard that you can run cars legally without cats on the road - and that the MoT station should be told in advance that the car has no cats. This from a indy Saab garage.

Paul

[jeffw]

Any new car since 1993 is required to have working catalytic converters at all times it is used on the road.

[quattronutter]

cats are required if it came from the factory with them,just leave em in the boot....

[S4]

back to the subject?

[derdle]

The reason I made my original comment as that if a car can legally run without cats on the road (I will check this tomorrow) then MarkB will be able to run de-catted and have just the one map/ECU. That could be a potential solution for him.

[MarkB]

AFAIK you have to run cats to be legal so my original question stands.

Paul, It will be interesting to hear how they think it's ok to run without them.

[derdle]

Mark, I'll get back to you as soon as I have found out. I must admit when I was told this I couldn't believe it...!

[derdle]

Hi Mark,

This is the e-mail (verbatim) that I have received from my niece and partner who run a Saab indy....

I’ve just spoken to my mot station and Ken has advised me that if you present a post 1992 car that has had the cat removed, you have to inform the mot station when you present the car that it is de-catted and then the mot tester will test the car with a non cat test (same as a pre-1992) and will advise on the mot certificate that the customer is not green. This is the procedure according to the ministry.

The regs for this have been around for years apparently!

The closing line was...if you have any problems "use our MoT station"

HTH

[MarkB]

Very interesting. I'll have to have a few words with my MOT chap.

Still not legal in my opinion though.

[jeffw]

This interesting...

One important issue must be cleared up straight away. There is no requirement for a catalytic converter to be fitted to any vehicle, regardless of its age. It is however the most popular way of ensuring engines meet the emission legislation. The MOT test is testing the emissions from the tailpipe and if those emissions meet the standard then the vehicle passes. The term 'cat' test is inappropriate, the correct term is 'advanced emission test'. Its not the 'cat' that's being tested. There are a number of vehicles which are subject to the 'advanced emission test' but are capable of meeting the requirements without the use of a catalytic converter.

and this

Advanced emission (CAT) test:

CAT test is an unfortunate term which leads many to think that the MOT is testing the Catalytic converter fitted to later vehicles but this is not so.

The MOT is testing emissions, so if the emissions from the tailpipe meet the requirements the vehicle passes. Whether a CAT is fitted is irrelevant. The deciding factor is the vehicles date of first registration. A "Cat" may be fitted to a vehicle which only needs to meet the two gas test and if the emissions are satisfactory, it passes. A "Cat" may have been removed and the vehicle is required to meet the "Cat" test standard by virtue of its first registration date. If the emissions meet the standard then it passes.

Many advanced design engines will meet the "Cat" requirements with a standard exhaust but of course may be emitting other pollutants not subject to the MOT.

Advanced emission tests must be carried out on fully warmed up engines, the oil temperature must be above 80 degrees C (some are set at 60 degrees C) and the idle speed must be within the manufacturers agreed tolerances. Both engine speed and oil temperature will be measured using equipment attached to the gas analyser.

During engine idle the engine must not be subject to electrical loading such as heated seats, heated rear windows and air conditioners. Electric cooling fans do not cause significant problems and can be active during the test.

Twin exhaust systems need to have the reading from each pipe tested and then averaged. A twin exhaust has two separate pipes from the engine manifold all the way back to the tailpipes. Systems with a balance tube between separate pipes are still considered a dual exhaust.

Multi fuel vehicles should be tested on the fuel they are running on when presented for test e.g a vehicle which runs on petrol and LPG and is running on LPG when it's presented, will be tested on LPG. The difficulty is that the hydrocarbons emitted by LPG vehicles are propane rather than hexane so the tester needs to apply a conversion known as the PEF factor, usually marked on the gas analyser, to give a sensible reading.

Where vehicles fail the advanced emission tests, remedial action should concentrate on fundamentals such as plugs, timing, air cleaners, mixture settings and the oxygen sensor before changing expensive catalytic converters. Leaks in the exhaust system are a common source of problems.

[dummi]

good info Jeff!

i think the main problem is that cats DRASTICALLY reduce co2, and if you try to reduce co2 by ignition you get nox, so this means you will have to run an cat at MOT then it becomes a legal and insurance requirement