NCT: Emissions test for 1993 and older

Matt Simis

Been mentioned several times, but is it really true the 1993 and older emissions test can be passed without a Cat?

I know some of you work for the NCT centres, so I expect a real answer! :P

BrianD3

The advanced emissions test applies to cars registered from 1/1/94 onwards, so the answer to your question is yes. However all/most petrol cars had cats from 1/1/93 onwards which is where the confusion can arise. A 1993 car with a knackered cat should easily pass the emissions as it only has to meet the same standards as a 1986 car.

Anan1

My understanding was that the emissions standards required by the NCT are based on the emissions of the car when new?

zilog_jones

The emissions tolerances are not specific to the car, if that's what you're suggesting. Idle speed apparently is, but everything else is standard based on the date of registration. There's no lambda test for pre-'94 cars.

unkel

A link to the NCT manual is in the charter

(4) For vehicles first registered before 1st day of October, 1986, the carbon
Emission monoxide content is more than 4.5% at idling speed.
(5) For vehicles first registered on or after 1st day of October, 1986, up to
31st December, 1993, the carbon monoxide content at idling speed is
more than 3.5%.
(6) For vehicles first registered on or after 1st day of January, 1994, the
carbon monoxide content at idling speed is more than 0.5%.
(7) For vehicles first registered on or after 1st day of January, 1994, the
carbon monoxide content at 2,500 R.P.M. or at a speed specified by the
vehicle manufacturer is more than 0.3%.
(8) For vehicles first registered on or after 1st day of July 2002 the carbon
monoxide ad idling speed is more than 0.3%.
(9) For vehicles first registered on or after 1st day of July 2002 the carbon
monoxide at 2500 R.P.M. or at a speed specified by the vehicle
manufacturer is more than 0.2%.
Hydrocarbon (H.C.) (10) For vehicles first registered before 1st October, 1986, the hydrocarbon
content at idling speed is more than 1,000 P.P.M.
(11) For vehicles first registered on or after 1st day of October,1986, up to
31st December, 1993, the hydrocarbon content at idling speed is more
than 750 P.P.M.
(12) For vehicles first registered on or after 1st day of January, 1994, the
hydrocarbon content at 2,500 R.P.M. or at a speed specified by the
vehicle manufacturer is more than 200 P.P.M.
Lambda (13) For vehicles first registered on or after 1st day of January, 1994, the
lambda value at 2,500 R.P.M. or at the speed specified by the vehicle
manufacturer is not 1± .03 or within the vehicle manufacturers
recommendation.

Linky

pre EURO 93 emission norm cars (without cat) are only tested for CO and HC and only at low idle (750RPM). The limits are 4.5% and 1000ppm respectively

VolvoMan

From what I see, there are feck all pre '93 cars on the road anyway.

galwaytt

VolvoMan wrote: »

From what I see, there are feck all pre '93 cars on the road anyway.

...speak for yourself !

zilog_jones

I know at least two people with pre-'94 cars and they never have trouble with the emissions tests. I don't know if they have cats or not ('91 Corolla 1.3 and '92 EG Civic 1.5 LS), but more surprisingly they are both complete rustbuckets and still get through the NCT. I suspect they just let my grandad's car through out of pity (he's in his 80s)

Matt Simis

Well to clarify Im not talking about some 1.4litre rusty old thing. If other users reports are true, then I stand to gain about 25bhp and over 1mpg improvement on my 850CSi (5.6litre 1993) by gutting the Cats completely. They are prolly not broken (expensive at the time steel "race" cats) but they did take a massive amount of heat when my O2 sensors were broken. Hot enough to turn chrome exhaust parts golden and stainless steel pipe blue with 2days of driving..

I know our Allroad ('2000 2.7T V6) got 0.6% on 2500rpm test with no Cats but running on 100% E85.. but I cant/wont run the the 850 on that much E85. It would run mega lean. I would run it on E5 or maybe E15'ish blend though. And of course to tie in another thread, a helping of Dipetane might work too.

B]EDIT: And then I re-read:[/B

unkel wrote: »

A link to the NCT manual is in the charter
pre EURO 93 emission norm cars (without cat) are only tested for CO and HC and only at low idle (750RPM). The limits are 4.5% and 1000ppm respectively

Thanks for the link. So you are saying that my car with Cat would be tested in a test that cars with no Cat are meant to pass? I should have no worries about passing it with the Cat removed then!?

VolvoMan

galwaytt wrote: »

...speak for yourself !

zilog_jones wrote: »

I know at least two people with pre-'94 cars and they never have trouble with the emissions tests. I don't know if they have cats or not ('91 Corolla 1.3 and '92 EG Civic 1.5 LS), but more surprisingly they are both complete rustbuckets and still get through the NCT. I suspect they just let my grandad's car through out of pity (he's in his 80s)

I'd actually love to see more old cars on the road. I think it's a shame that most of them end their life prematurely in Ireland due to our overall neglect for cars as a nation and our registration system.

unkel

Matt Simis wrote: »

So you are saying that my car with Cat would be tested in a test that cars with no Cat are meant to pass? I should have no worries about passing it with the Cat removed then!?

It should think so. Unless there is a requirement that if the car originally came with the cat, it should be tested with it. You look it up

My '86 4.7l V8 Porsche (no cat) passed well within the limits twice in the past 2 years.

Cosmo K

BrianD3 wrote: »

The advanced emissions test applies to cars registered from 1/1/94 onwards, so the answer to your question is yes. However all/most petrol cars had cats from 1/1/93 onwards which is where the confusion can arise. A 1993 car with a knackered cat should easily pass the emissions as it only has to meet the same standards as a 1986 car.

Brian is a 100% right! Even if you take the cat, the car should still pass.

Matt Simis

Ill go book the test now. Just got the Cats out, only drove the 15min back from the garage so far. But man, I swear its quieter than before, no droning at very low RPM any more and raspy up top like a V12 should be, sounds excellent. Huge improvement all round. Will check motorway type speeds tomorrow.
Definitely seems more lively too.

rebel.ranter

What did you replace the CATs with? Did you get someone to fabricate straight through pipes?

Matt Simis

Yes, Souhans in Trim. They make custom exhausts, fabricated a Y Piece from the each of the 2 sets of manifold downpipes per side into a single 3" (IRC) pipe inplace of the Cats (1 either side/bank).

They had previously made up some custom pipe-age to fit the 2 Magnaflow backboxes. They even put in custom heatshields at my request last time to protect some rear rubber pipes.

JoeySully

Pre 93 cars are only tested at idle. They do not rev the engine and take the high level reading. This is why its so easy to pass the test.

This is true for petrol only - All diesels are revved for the high level reading

unkel

JoeySully wrote: »

Pre 93 cars are only tested at idle. They do not rev the engine and take the high level reading. This is why its so easy to pass the test.

This is true for petrol only - All diesels are revved for the high level reading

Incorrect. See my linky. Makes no difference if the car is petrol or diesel...

JoeySully

unkel wrote: »

Incorrect. See my linky. Makes no difference if the car is petrol or diesel...

Im reading the same manual as you Unkel

NCT Manual - Page 3 wrote:

EXHAUST SMOKE (DIESEL)
Method of Testing
(A metered smoke test does not apply to vehicles registered before 1st January, 1980)
NOTES: (Vehicles registered on or after 1st January, 1980)
(a) No smoke test should be carried out without having done the pre test check detailed on page 5.
(b) It is absolutely essential that the engine is at normal operating temperature before carrying out a
smoke test. Testers should ensure that engines are not warmed up by being left idling or at half
throttle. They should be warmed up by normal driving.
(c) Engines left idling for any length of time will show a high smoke opacity reading.
(d) When carrying out this test the throttle must not be “blipped”.
Vehicles registered on or after 1st January, 1980
1. Check visually that the emission control system is complete and properly connected and that there are no leaks
in the exhaust system.
2. With the engine at normal operating temperature, raise the engine speed slowly to 2,500 r.p.m. or half the engine
manufacturer’s recommended governed speed whichever is less and hold for 20 seconds in order to purge the
exhaust system. If the engine emits any unusual noises the test should be abandoned. Slowly raise the engine
speed to its maximum r.p.m. and note if the governor operates within the vehicle manufacturers’ recommended
R.P.M. setting. If not the test should be discontinued. Do not hold the engine at maximum r.p.m. for any
length of time.
3. Connect the diesel smoke meter to the vehicle following the smoke meter manufacturers’ instructions. Depress
the accelerator pedal firmly from the idling position to the maximum fuel delivery position following the prompts
of the smoke meter. The smoke meter is programmed to ignore the first reading. The operation is repeated and
if the reading on this occasion is less than 60% of the acceptable limit the test is ended. If the reading is not less
than 60% of the acceptable limit, the operation is repeated. If the average of this and the previous reading is
within the acceptable limit the test is ended. If the average readings are not within the limits the operation is
repeated up to a maximum of 3 more times taking the average of the last 2 readings after which the test is ended.

Matt Simis

Definitely quieter. A lot quieter. The booming at very low RPM is gone (at idle and driving). I put it in 6th and rolled through a village at 25mph, no boom, very little noise. I had theorised before getting it done the exhaust gases were passing too slow at these RPMs to get properly cancelled by the crossover piping, looks like something along those lines was happening indeed.

Its now so quiet its disconcerting! :eek:

jimjims64

Hi I brought my 1988 Volvo 340 1.4 Petrol in to the nct last week for the test and it failed for emmisions.. he said im allowed 3.5% for Co2 but my reading was 6.59%!:eek:

I only bought the car 2 months ago and it was in a shed for almost 8 years being drivin very little by previous owner...it only has 60,000 miles and is very well minded so im surprised it failed..

If anyone has any ideas on how to lower the emmisons, it would be really helpfull! I dont know if my car has a Cat but it is a carburettor engine..

Thanks alot!!!!:D

kasper

i would say jim a service and tune the carb

zilog_jones

jimjims64 wrote: »

I dont know if my car has a Cat but it is a carburettor engine..

IIRC Volvo didn't make cats standard until around 1990-1 and models that had them had a big "Catalyser" badge on the back.

kasper

the 1.4 engine in the 340 is a renault unit ,same as the renault 18 i have seen them with almost 500 thousand miles and still servicable not burning oil and still economical

jimjims64

I wonder if I lower the idle speed would it help decrease the emmisions? its currently idleing at 1,250rpm and the hyanes manual states it should idel at 900rpm?
Also it was suggested to me that i can buy a bottle of octane boost in a motorfactors which might help with the emmisions?

And its not burning a drop of oil and running perfect so i cant understand where all this Co2 is coming from!?

kasper

it could be running rich and just need a tune up

JHMEG

It's not whether a car requires a cat (there is no legal requirement), but it must pass the emissions standards of the day, which are the Euro standards, and that's what the NCT tests against.

http://en.wikipedia.org/wiki/European_emission_standards

A car which is physically on fire will probably pass the Euro I requirements.

johnplayerblue

VolvoMan wrote: »

From what I see, there are feck all pre '93 cars on the road anyway.

well la di da.....:)

Matt Simis

I dont think I actually updated this thread with the Cat-less test results:

Low Idle (2980rpm)
CO: 0.53% Max Allowed 3.5%
HC 144 ppm Max Allowed 750

Easily passed. jimjims64 youre car must be running extremely bad to get those results, considering my 5.6litre has 4 times the CC yet 13times lower CO output... :eek:

kasper

jim what sort of mpg are you getting ?