9 replies to this topic

[almarsh132]

As I understand, it is illegal to use a decat pipe on a mini after 1992 injection model. I have a 1992 carb (last of the carbed engines), so I could use a decat pipe?

[Tommyboy12]

I believe the cut off is if it is registered before 1st August 1992. Any time before then and you are free to remove your cat without any MOT difficulties.

Edited by Tommyboy12, 23 June 2011 - 09:07 AM.

[Liam Mini 35]

I have a 94 mini 35 Which has a carb engine and i removed the cat. Went through the mot fone when they finally tested it on the correct test. So yes you should be fine

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As Liam says, cars fitted with the Open Loop Cat (Carb cars) aren't able to be tested, so any original carb cars can have the cat removed, the Injection cars must retain it

[bunch1980]

Soo, that means my 1275cc 93' sprite on a HIF 38 will be ok to remove cat? and put in a de-cat pipe?

I have a play mini single rear back box now and its sounds nice not to loud or quiet, will putting in a de-cat pipe make it
a bit much on single box system?
Also will I need to have fuelling adjusted after?

[bobs]

As you know Lee I have the same model.

Removed Cat, but have a twin box maniflow, which give a nice grumble... Single might be loud.

I added a LCB, and inlet, and had to change the carb needle to a richer profile, and make mixture adjustments for tickover, so yeah.

[bunch1980]

As you know Lee I have the same model.

Removed Cat, but have a twin box maniflow, which give a nice grumble... Single might be loud.

I added a LCB, and inlet, and had to change the carb needle to a richer profile, and make mixture adjustments for tickover, so yeah.

Yes you do!
Thats my worry dont want it silly loud, i think i can get a pipe with a with mid silencer in to replace current pipe to back box then add a de-cat pipe or maybe even one long pipe that goes from manifold to back box with a silencer some where along it to!

Would think it be wise to change needle as might run to lean, as can imagine the cat is quite block on the exhaust normally.

[Spud_133]

No car needs a cat as long as it passes the emissions test, but it is extremely unlikely to pass without one as the regulations are so strict.

[SurreySprite]

My '94 Sprite which was one of the last ones with a carb is de-catted and has no problems with the MOT.

I believe the open loop catalyst is quite restrictive on these engines.

[bobs]

I believe the open loop catalyst is quite restrictive on these engines.

Nah not really, look through one, it's not restrictive at all, just a square mesh of coated metal.

It does however baffle the noise a bit, not much, just a bit, and yes having a twin box system is more agreeable for the neighbours...

In terms of power restriction, again, not noticeable, you can however get it through the MOT emissions test much easier with the cat fitted as you don't have to lean the naff out of the carb to meet the strict requirements...

I'm lucky to have a gas testing machine knocking about;
Mine without cat and richer needle will average 18% and run sweet as a nut, a tad on the rich side which is what I like.
With cat on and rich needle about 5-10% so you can see it does do something.
With cat on and lean needle anything from 0.3-4% depending on how bad you want it to pick up revs and drive!

I believe that these models need to reach <3.5% to pass the MOT emissions test?

This is just what I have experienced and not in anyway a scientific study into open loop cats!