Race manifolds & MOTs

[Durzel]

Quick question - I was always under the assumption that de-catting cars resulted in failing MOTs on emissions, when I had the Skyline people always used to have to put their CATs back on come MOT time, etc.

Yet, I see quite a few people fitting 3-2-1 (I don't really understand that term) race manifolds like the TODA, DC Sports, etc.

What do those people do come MOT time, take the whole manifold off and replace with OEM+CAT every year?

 

[HASNIC]

4-2-1 exhausts have 4 pipes running into 2 runnning into 1 to the collector, hence the 4-2-1.

And unless you're very lucky to either have a friendly MOT tester or make it through the emissions then it'll be a case of swapping manifolds over to sort the emissions out

 

[Durzel]

Thanks, thats what I thought.

It seems to me a pretty massive inconvenience to have to change the manifold back twice (to OEM, then back to race) every time MOT comes up, but if that's what people do I guess that's my only real option if I want more power (thinking of Kpro'ing and maybe even JRSC)

Presumably people just hold onto their OEM manifold+CAT then? How big a job (i.e. expense, time) is it to change the manifolds? How much would I likely be expected to pay every year come MOT time?

 

[hovblackctr]

You would pay a lot in labour i reckon, probably 4 hours in total to swap then swap back again.

Find a friendly mot station, it's far cheaper. Or buy a manifold where the cat is seperate and use a race cat and just swap it over at mot time.

 

[Durzel]

Wouldn't know where to start trying to find a "friendly MOT station", I've always just had mine done at Honda at the same time as the servicing.

How do you even approach that sort of thing if you don't already know someone in the trade, drive up to somewhere and say "'ere mate, do us a favour yeah?"

 

[hovblackctr]

Yeah pretty much!:lol:

If you can't find one i would go with the option of buying the manifold with the cat seperate to the manifold then it would only take 10 mins to change over when its due its mot.

 

[Durzel]

lol

Well as my MOT is due end of March I might just go mental with upgrades straight away and worry about it in a years time. :lol:

 

[JonCTR]

Durzel,

Once mine started needing MOT's I got fed up with replacing the DC Sports race header each time. Occasionally I could get a mate of a mate to change it over for about 40 quid, and swap back again afterwards. The DCHR would not pass the emissions test on mine, even with full dyno k-pro tuning. The stealers charged 119.25 + VAT to remove and replace with the oe manifold and cat.

I ended up buying a 2nd hand Supersprint 4-1 race manifold and seperate sport cat. They also sell a direct replacement decat pipe section for the sport cat for easy change over. The sport cat is about the least restrictive you can get, and still passes the MOT (verified at my last MOT). Looking at Supersprint's data, the decat section in conjunction with the race manifold only gets you another 3 bhp, over the manifold + sports cat. I'm not suprised as the sports cat is about a 1/3 the size of the oem one, and you can see daylight through the metal catalyst coil inside it !

 

[Durzel]

Thanks Jon. I've gone ahead and bought a TODA 4-2-1 race manifold on impulse, I'll have to deal with the MOT issue come next year - though what you've said is useful, no doubt if I'm stuck in a position where I don't know anyone who can pass it "on the sly" then I'll end up in the same frame of mind.

 

[JonCTR]

Durzel - no worries. One of my other deciders was I was about to ship out my CTR to Oz, and in theory getting caught running without a cat here is an $8,000 fine !

The joke is though, that once's it's passed the import inspection into Western Australia, there's no annual MOT here, unless you get picked up by the cops for having a loud exhaust etc !

 

[Cosmic_Chi]

correct me if im wrong but am i right in saying that our car's dont have to have a cat fitted at anytime except come MOT time and would be deemed road legal?

this would clear things up for me and would decide on getting a race mani.

 

[Durzel]

No, that's wrong.

MOTs exist to prove a car's road worthiness (and legality), the fact they only happen once a year is technically just a flaw in the system. A car could pass an MOT and the day after develop a fault that would fail it if it took another MOT that day.

A car has to be road legal at all times - decatting is (imo) technically illegal because in so doing your car would (probably) fail emissions, and hence not be road legal. Now, the chances of actually being stopped because your car has a decat fitted is slim, but it is possible and you could legitimately be served with a Vehicle Defect Rectification Scheme notice to get it fixed.

It's all a question of risk I guess. Technically speaking it is illegal to modify a car's exhaust in such a fashion that it makes more noise than it does from the factory (Road Vehicle Construction and Use Act), and I believe strictly speaking exhausts are supposed to be BS marked to pass MOT. Neither of these things are generally flagged unless you're making a nuisance of yourself though.

 

[Earthslug]

My only option:

Change exhaust every year for MOT, no decat, no sportcat, no whatever aftermarket, >>STOCK<<


I just got word braided brake hoses are illegal as they are not safe... ??? What the...

Same for aftermarket bucketseats and 5 pin seatbelts. - Not safe...

Lowering car for lowering centre point of gravity - not safe...
Some of those office boys deciding those rules should be shot.

I think UK regulations are more relaxed and so there is not much reason to complain is there

I do understand they don't like emissions too high due to global warming ect. but I think we all have to agree, a stupid "eco" diesel pollutes way more than any gasoline engine.
Too bad autorities keep this quiet for now... Everyone takes this crap of eco-friendly-cars, and in the end, diesel will be banished due to "polluting the enviroment"...

 

[lukeykb]

i never understand how people can say its a massive inconvenience (sp) to remove and fit a mainfold/cat then reverse it just for MOT day. Say the whole process is a weeks effort. leaves you with 51 weeks of manifold goodness. ok it might be pricey if you cant do the job yourself, but get on friendly terms with a garage and either they'll put your through your MOT or they'll fit/remove cheap enough.