New MOT test and cats.

Post Sun Dec 04, 2011 3:43 pm

We've discussed the new regs. regarding HIDs, and it seems like there's little change relevant to the owner's of well maintained E30s, but what about Cats?
The relevant parts are:
Method of inspection:
3.On vehicles that qualify for a full cat emissions test, check the presence of the catalytic converter.
Reason for rejection:
3.A catalytic converter missing where one was fitted as standard.

Are pre September '92 E30s that were fitted with cats going to fall foul of this rule? How are testers going to know what the original spec. was? Or is the 'reason for rejection' just badly worded?
What about post August '92 E30s? Under the previous regs. they don't require cats if the engine is earlier or if they have a non standard engine, such as a M50/52, and are still tested to the earlier emissions levels (3%, 1200ppm.) under the new regs.
The cat. could be discarded under the old regs., but can it be under the new?
Can't see the reasoning behind the changes TBH! Surely all that matters is if the car passes the appropriate emissions regs. Why should HOW it does it be any concern of anyone?

Post Mon Dec 05, 2011 12:22 am

i dont think there is much of a change there, didnt spot anything significant and think the ruling is to prevent post 92 cars running catless.

a pre 92 uk e30 will not have a cat as "standard" as the katalysor delete was from factory and they were delivered standard with no cats.

Post Mon Dec 05, 2011 8:58 am

What's your take on post '92 E30s with M52s?

Post Mon Dec 05, 2011 11:43 am

It's really aimed at 2000's era cars with the cat removed, including diesels.

Anything old enough not to require a cat (pre 9/92) doesn't need one, period. Doesn't matter what engine is fitted - if the computer says it's too old, it just has to fall within the correct limits of 3.50 CO and 1200 ppm and if it doesn't pass that, there is something wrong with. Given that an M20 in decent fettle will do under 200 ppm's and under 1% CO that's not an issue. My 1989 E32 does 0.48 CO and 132 ppm's - it would almost pass a test for a cat equipped car.
Post 8/92 cars require the cat to be fitted without exceptions, and it needs to work. Really, the new regs don't affect the old stuff at all. It's business as usual.

Post Mon Dec 05, 2011 11:57 am

post 92 on the reg plate and your boned, unless you can prove the engine is pre 92,

all the testers i know work off what they can see infront of them. thus if the reg is j or later then there expecting cats.

also the computer will tell them the car should have a cat.

the tricky grey area we have is the scimitar chassied v8 ka were working on, its an m60 but the m60 iis clearly marked 92 on the back of the head...

Post Mon Dec 05, 2011 1:36 pm

It says what on the head?

What about LPG converted motors post 92? They will pass without a cat but why would they need one, and will they slip through?

Post Mon Dec 05, 2011 2:24 pm

What do you think i have been doing this port work with?

Wasnt it a specific month of 92, thus the 92 on the head may well be the proof required come mot time.....

Tbh the trick would be just get a housing that looks a bit like a cat housing and tack it around the pipe. thus looking like a cat without the expense of putting one in.
good high flow cats can be bought for later stuff and the older and more specialist stuff will carry on without and doing there insignificant milage a year.

Ethanol is another good one, as if your not burning long chain HC you wont show as having such high HC ppm, as its outside of the sensors range.
same reason the lpg will go through.

End of the day, as my regular tester said, they test what is visually presented to them and weigh that against the computer info, as long as nothing really stupid comes up then they dont care.
If it looks like there is a cat in there, and it passes emissions then as far as their concerned it has a cat.
Looks like a duck, quacks like a duck......

The more concerning one is the SRS/airbag regulation and the ABS function regulation.
As the new test requires the lights to light correctly and go out according to the expected process the computer states, this is the new extra info the computer will provide them with.
Along with this if the computer states an airbag should be there then it HAS to be there to pass.

A trick that was suggested by a tester i know was to wire everything to the oil pressure feed, thus they come on when the car is off and will go out the second the engine is fired.

Post Mon Dec 05, 2011 7:44 pm

The new manual still states that;

"Vehicles fitted with a different engine must be tested to the requirements of whichever is older, the engine or the vehicle".

The check on cats is for cars where one was fitted as standard and subject to a full cat test.

Therefore whichever is older, then the appropriate emission test applies. If the test required is a full cat test then a catalyst will be checked for.
So, for vehicles registered Aug 92 - Jul 95 where there is not an exact match in the database (e.g. an E30 with a newer none standard engine) then it goes to a none cat default test ie no cat required. (Sect 7.3 page 9 flow chart).

Cars Aug 95 on with a newer engine will default to a cat test using default limits and therefore will need a cat.

BTW diesel cats are not part of the new MOT requirements as the vehicles are not subject to full cat emission testing.

HTH

Post Mon Dec 05, 2011 8:18 pm

HairyScreech wrote:post 92 on the reg plate and your boned, unless you can prove the engine is pre 92,

all the testers i know work off what they can see infront of them. thus if the reg is j or later then there expecting cats.

the changeover date was 1st august 1992, which was the date the 'K' plate was released.

Post Mon Dec 05, 2011 8:36 pm

nice to know, sounds like our 92 casting v8 will be katalysor delete.
tbh i have no real problem with fitting one (or two) if it wasnt for the cost, you try getting a SH one as well, scrap yards wont let those out of there clutches.

Post Mon Dec 05, 2011 8:45 pm

I have a 1991 325i with a factory cat on, hopefully I'm not affected with this.

Post Mon Dec 05, 2011 9:42 pm

hennabm wrote: So, for vehicles registered Aug 92 - Jul 95 where there is not an exact match in the database (e.g. an E30 with a newer none standard engine) then it goes to a none cat default test ie no cat required.

This is how it has always been, and still is as far as the test results are concerned, but the exact wording of the new regs. is "3.A catalytic converter missing where one was fitted as standard.", and I will be presenting a post '92 touring, fitted with a M50 engine with no cat.

Post Mon Dec 05, 2011 9:53 pm

HairyScreech wrote:
Ethanol is another good one, as if your not burning long chain HC you wont show as having such high HC ppm, as its outside of the sensors range.
same reason the lpg will go through.

Testers are supposed to switch the emissions tester from hexane to propane when testing LPG vehicles under the old regime, which more than doubles the reading, although I've never seen a tester switch it yet! Even so, a properly set up LPG powered car should meet the regs without a cat., even with the correction.

Post Mon Dec 05, 2011 10:10 pm

Brianmoooore wrote:
hennabm wrote: So, for vehicles registered Aug 92 - Jul 95 where there is not an exact match in the database (e.g. an E30 with a newer none standard engine) then it goes to a none cat default test ie no cat required.
This is how it has always been, and still is as far as the test results are concerned, but the exact wording of the new regs. is "3.A catalytic converter missing where one was fitted as standard.", and I will be presenting a post '92 touring, fitted with a M50 engine with no cat.

So long as it is not post 95 then because an exact match cannot be found in the emissions database then it goes to none cat default.

The way it has been interpreted is if the car is subject to a full cat test then it will need a cat on it. Clearly as yours isn't an exact match as it has a none std engine and will go to none cat default limits because of its age and engine configuration, it won't need a cat.

Post Mon Dec 05, 2011 10:30 pm

It doesn't need a cat. to meet the limits ( twice over, since it's LPG as well), but it's on a 'L' plate, so has "a catalytic converter missing where one was fitted as standard.".
IMO, the wording is flawed, as it says you would still need cat. on the electric powered E30 in another thread on here at the moment, if it were built into a later shell.

Post Mon Dec 05, 2011 11:36 pm

Brianmoooore wrote:
HairyScreech wrote:
Ethanol is another good one, as if your not burning long chain HC you wont show as having such high HC ppm, as its outside of the sensors range.
same reason the lpg will go through.
Testers are supposed to switch the emissions tester from hexane to propane when testing LPG vehicles under the old regime, which more than doubles the reading, although I've never seen a tester switch it yet! Even so, a properly set up LPG powered car should meet the regs without a cat., even with the correction.

didnt know they were supposed to switch it, infact i have neaver heard it mentioned before at all, which i guess is why the above is true.
I assume there is no realistic way they could know what fuel the vehicle was burning at the time so they just dont bother to look or switch it.

The higher vaporization of the lpg helps as well, it prevents buildup in the cavities in the combustion chamber like the top ring land and the squish band and plug bore, all of which can create dead spots in the chamber.