Paid £1000 for turbo back 3'' Millteck with sports cat (3 months old)
on my 06 WRX 2.5
just had first MOT and it failed on c0

Just spoken to Milltek
They were great about it
Explained all about car re-map ect
They say it needs to be hot to pass MOT

If it dose not pass they will sort

Can’t fault that
Email must have got lost?

 

Heat the cat up by revving the engine for a bit just before & while checking emmissions. May work.

 

Failed on CO2 ? Thats weird as that has nothing to do with the cat's effectiveness.

Think you mean CO (as in carbon MONoxide, as thats strict and very dependant on the engine being in a good state of tune and fully up to temperature).

Car needs to be driven and given a good thrash immediately before the emmssions test to get everything propery up to temperature. Just letting it fast idle to reach operating temp won't cut it on some cars.

 

where are you based?

 

sorry me and my keyboard not best of freinds

But still you pay lots of £££ you expect it to pass without having to do a dance with the MOT guy
i would expect Milltek to give info on how to pass MOT

 

sometimes it helps WHO you take it to, i take it you are in a club?

 

see what you are saying
but its a sport cat so it should pass?
if not i should have saved ££ and gone cat less

 

You should. £25 to fit your cats at MOT time and all the BHP released for the other 364 days of the year..........

 

They do suggest heat wrapping the sports cats, and most sites have a bit of a disclaimer about maybe not passing a mot,
Milltek are normally pretty good, I got a lot of info on noise etc and they had a lot of time for my questions so try giving them a bell.

 

addison,

You may find the exhaust is not at fault. I had a 1999MY Turbo back in 2002 and it could only just pass its CO test at its first MOT on the OEM exhaust by making sure the engine was fully wramed up with a blat down the private roads before the test.

Yet my current classic passes all tests with a Nur Spec R on i.e. no centre cat at all.

You may want to look at the engine tuning as well as the exhaust.

 

I passed the MOT with a Prodrive sports cat. Took the car in for the MOT straight after work (17 mile journey) so nice and hot, the tester still had to rev it for about 5 minutes to get it up to temp because it failed the first test.

 

My car with ppp sportcat passed easily 0% CO on both tickover and fast idle. I should say you need it looking into as £1000 is a lot of money if it don't do what it is supposed to.

 

as said, run the car on boost for a while before test- same thing happened to mine and the run before got it through

 

all this warm your car up is great if you take your car right before it's due in, what if like me you drop it off and pick it up later? I have a Prodrive sports cat and have never had a problem, if you pay that sort of money you expect it to work.

I would keep trying Miltek as they wouldn't want people going round telling people on public forums that their sports cats are worthless if you know what i mean

Aaron

 

Its all well and good blaming the catalytic converter. But the catalyst is a passive device; it only cleans up so much "pollution" the engine produces. If the engine is not running properly, be it from a fault, being used for short journeys of recent, or just not properly warmed up. The catalyst will be overwhelmed and the car will fail emissions.

Could be just a case of fouled spark plugs from excessive idling from cold, an old and tired engine, a slighty clogged fuel injector or a slow switching oxygen sensor. In these cases an "Italian tune up" immediately prior to a test does help (most good and helpful MOT testers know this).

Sensor issues also being a problem. You cannot exepect the cat to do its job properly if the oxygen or MAF sensor is shot; as they directly control fuel mixture. Same if there is a vacuum leak or dodgy coil pack. Incorrect fuel mixture = bad emissions.

This would be more apparant by the car producing high HC emissions (even if it passes the HC - the limit is not very strict), HCs should be below 100ppm, ideally 50ppm at the most, anything nearing the 200ppm maximum limit indicates the engine is not running properly (HC=unburnt fuel in the exhaust, or oil). A knock-on effect is high CO - which is what it usually fails on.

Put it this way, my old MY97 Impreza would only "just" fail the CO limit of the MOTtest WITHOUT any cats fitted at all! 0.38% CO with no cats. Refitted a catalyst (downpipe) and that went to 0.00% CO. HC remained below 50ppm throughout.

 

Got to agree with Ali-B, kind of what I was getting at in my post. I have a feeling the cat is not your problem.

 

The car is spot on, the only things it can be is A-needs to be hot when tested and B- cat no good
will phone milltek monday but they have not replyed to my e-mails
If it needs to be hot when tested why don't Milltek tell you this before you buy

 

As the cat is in the centre section (as opposed to the downpipe) it will cool down quite quickly if left to idle while all the other items that need the engine running, are checked eg steering, brake master cyl. etc.
My emissions were poor with my Milltek but a quick blat up the road (brakes need to be tested on the road as it's 4wd) lit the cat back up and the test done immediately on return produced totally different results (.02% Co, 12ppm) Revving the engine in neutral will not always produce enough exhaust gas temp. to re-light the cat.
JohnD

 

cat is in down pipe
i will run some tests with it hot

 

If it's a 3" miltek and 3 months old, the car is in the centre. It's a silencer in the downpipe.

Cat needs to be hot, my local MOT places need no special instructions and have between them passed a dozen or so cars with the same exhaust.

 

FULL SYSTEM (INCLUDING HI-FLOW SPORTS CAT) - 3" system

Consists of: Tailpipe Style

Downpipe and Hi-Flow Cat Assembly
Centre Link Pipe
Rear Silencer Single 100mm Special

 

Same here I took my sports cat out went catless car had its first MOT at the begining of the year and flew through....3" Miltek still had the cat which as Paul says in the centre section at hand if it didnt pass ready to put on ...but didnt need it.

 

Is or has the CEL Light been on...this sounds like the car is guess mode...i.e. the CO2 sensors are not giving the data so the ECU is guessing the values and they always go on the rich side hence the CO2 figure.

Other slim chance is that the Cat is faulty

 

Just spoken to Milltek
They were great about it
Explained all about car re-map ect
They say it needs to be hot to pass MOT

If it dose not pass they will sort

Can’t fault that
Emails must have got lost?

 

What looks like a silencer, is in fact, the cat. There are two resonators, one in the downpipe the other adjacent to the cat.

JohnD

 

like I said always found them pretty good.

 

Like you bu my Miltek is 3 years old and didn't pass MOT, gave Litcho a ring he said make sure it HOT and all will be well

Sure enough, gave instructions to MOT guy and it flew passed the MOT

Tony

 

My first MOT was the other day. It was supposed to be at the end of May, but I didn't realise...

3" Milltek (the sort with the cat in the middle) on an 06 Forester STi mapped by Jolly Green Monster to 343 bhp and 370 ft lbs

Fast idle:
CO 0.06 % (max is 0.20 %)
HC 14 ppm (max is 200)
Lambda 1.016

Natural idle:
CO 0.05 % (max is 0.30 %)

I dropped the car off at the local non-franchise garage on the way to work and they did the test at lunchtime, so no special warming-up.

 

You're sure of that? Don't forget, as it's 4wd, they have to take it out on the road to test the brakes.

JohnD

 

Is this a new thing? When I had an MOT in April the tester took my car out on the road to do this, previously they just used the rollers.