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172 CAT

just had a new cat put on my car, as it fell off on the way to the recent rolling road, the old one was 1 unit but the new one is a twin cat. I thought that the mk1 172 had a twin CAT and the MK2 had a single CAT. Mines a mk2 172 Oct2001. Is the twin CAT any better than the single one as Im sure i should have had a single one. just charging the camera then will post a pic of the new one

heres the old one

My mk1 has a twin cat for sure. The twin cat doesnt look like it will flow very well - in areas the piping is very narrow. I would have thought that the single cat would flow better. What factor are you concerned with when you talk about better?

Yes.....the twin cat on the MK1 flows better...or is less restrictive to be correct...and gay.


The Mk1 had a twin cat as it was less restictive to flow and they could still pass the euro 2 emissions test.

The MK2 had to comply with teh euro 3 emissions.......euro 3 are teh same emissions as euro 2 but without teh 5 min warmup time....which the MK1 had so its cats were all ncely hot and working.

what this means is that teh MK2 had no 5 mins to warmup!

so, a single cat warms easier and faster......also, it runs really rouch for teh 1st few mins (the MK2 that is) as its got to get round running low emissions with a cold cat...this is that rough running prob many complain about....its built in to pass euro 3.

Thats all.

get a MK1 twin cat and drill a 2nd boss for teh 2nd almbda sensor....job done!

thats what was fitted to my MK2 172 today (renault Leeds) there was a mk1 172 with a v6 bumper in there for service, anyone here?

h,mmmm....very strange design!!

the MK1 was s/s and shiney and had much better Y pipe joins..that looks a bit iffy....

can i get the part # off teh invoice please....i want to compare it!!

no invoice as it was a warrenty claim, i asked but there was no paper work, Ill check the sticker on it again in daylight might be able to read it off that

That looks all a bit err.... hackneyed... Im sure my cat(s) dont look like that, and Im also a little suspicious of that Y piece as I think I could weld it all up better than that!:eek: I could try sticking my camera underneath my car at the weekend and get you a few pics if youre bothered?

no sorry didnt see it, I parked very close to the door so didnt see many of the card in the car park, when it was done they brought it to the door.

whats your car in for?

i need the number that comes off the computer....could you call them up...i know its asking alot, but could you just ask them?

No probs mate, Ill take the pics over the weekend and (attempt) to post them! At the end of the day, if the car runs happily with it in place, then I wouldnt worry too much about it... It might even be an incentive to get a de-cat done! ;)

Ill try and get the No. off them. Im not sure why they fitted that twin one when it sounds like i should have 1CAT. will my car pass the emissions test with this CAT on? is it re the age of the car that the test is done with no warm up?

Yeh matt i have been looking at a magnex cat back +a decat pipe. but with me fitting the turbo soon (I hope) maybe a straight through exhaust with maybe 1 silencer will be better

no, you wont need a single cat to pass the MOT......

just the manufacturers have to have them to meet euro 3 before that can leave the will be fine.

My car is in for:

New Dash, New rear Spoiler, New interior air sensor, Front bonnet respray, O/S roof respray, New driver seat, New anti roll bar.... and a couple of other things!! :confused:

Comparing these pics to yours they look virtually the same! (except mine looks a couple of years older!) apart from the extra mount for your second lambda sensor... Didnt remember my cat looking so amateur-night welded! Oh well, maybe Ill look into a different exhaust and a de-cat? :D

thanks for the pics, been away for a bit so not had time to get back to the renault garage to ask them why they fitted a twin CAT, and like you when i have some spare cash Ill be looking at a catback system +decat pipe