7 replies to this topic

[WillMini]

so i was just wondering what fitting a catalytic converter to a mini would do to its performance? I just feel guilty driving around all the time without one. So I have a few questions; one would be would it be pointless? has anyone done this before? would it make my already slow 998 be noticeably slower?

thanks

[mini93]

so i was just wondering what fitting a catalytic converter to a mini would do to its performance? I just feel guilty driving around all the time without one. So I have a few questions; one would be would it be pointless? has anyone done this before? would it make my already slow 998 be noticeably slower?

thanks

guilty?? what for?? dont worry about it...if you fit one to a carburettor car as soon as you over fuel you kill the cat' and thus voiding its use...and shortening your engine life!

[Asphalt]

Quite common mod here, due to the growing population of city-zones you are only allowed to enter if your car has a closed loop cat-system and at least runs with EURO1 emission standards (oh, and has a silly green, yellow or red badge sticking on the front window )

It's more the lambda sensor which is prone to bad maintainance, thought.

Performance-wise it's not that great.
I talked to several people runing the system and they agreed it's like putting a cork into the exhaust...
On the other hand that applied to a system using both the Rover cat and an additional one.
For a 998 it's one cat and therefore propably not as bad (at least I didn't hear much complaining from 998 drivers).

There's a new kit which just hit the market (for above reasons) which uses only one cat.
I'm propably going to use it next year, as I mybe have to move house to such an area...

But - and that's true - the system needs a constantly well maintained engine.
On the other hand - and that's propably just MY opinion - some electronic aid to fueling can't be wrong!

The biggest advantage in D is the reduced taxes. On a 1275 with EURO1 (which is achivable with a cat-system) taxes drop from 329€/year to 196€/year.
This starts to pay out after 4-5 years (now you can estimate how expensive those kits are ).

So unless you can save a considerable amount of taxes or you are forced to have a car with controlled emissions - I'd leave it.

[Bungle]

i gained a small bit in performance when i removed the cat from my exhaust

i found the engine reved a bit more freely but what i really noticed was a big chunk more MPG

so go green leave the cat off and use less fuel

[m1n1]

late 90-95 minis had carbs engines with cats. I think if you fit the inlet/exhaust manifold from one of them then you can fit the complete exhaust system with cat without any problem.

is your car not exempt due to its age?
why do you feel guilty just because you have a classic car?

[Rosslin Racing]

with this type of cat the exhaust is measured from a pipe take of in front of the cat and then again at the end of the exhaust. not for much but you do not need the lamda.

[Asphalt]

Yeah, Rover carb engines with cat were open-loop cats, resp. without lambda-control.

Injection engines (that's one reason they switched to injection as it allows better control of the air-fuel ratio) have a closed-loop cat with lambda-controled fual-mixture.

You could either convert to an open-loop cat or to an closed-loop cat on a carb engine.
Closed-loop works by - verry basicly - having a too rich mixture set up on the carb and blowing, controlled by a ECU, in additional air after the mixture has been build (resp. behind the throttle plate). Anyhow - in my eyes it's only worth having an closed-loop catalytic converter (the actual cat sitting in the exhaust pipe is almost the same! It's just about controlled mixture/lambda giving the cat a better 'basis' for doing it's job)...

Thats why - if the lambda sensor or ECU is shot - those engines can consume more fuel...
And they are harder to tune due to the requirements of the system.
I watched the process in a local garage - they gave up, put back the stock needle and unhooked the system

There are two kits around (of which I know). One needs a different needle and stock manifold,
the other is more of a universal fit weld-in item:
http://img246.images...pboard01eg3.jpg

Cheers,
Jan

PS: Gimme a hint if that's too much of blablabla

Edited by Asphalt, 13 December 2008 - 09:12 PM.

[WillMini]

wow, thanks for the replies. I thought maybe you could just weld in a universal catalytic converter and it would help filter emissions. i didn't know they were so complicated. I just saw them at car shows and stuff for a reasonable price and thought sticking one in the system might decrease my cars emissions. But i guess that would be pointless. I guess its not that bad. There were no reasons for doing it in terms of government emission regulations, since my cars over 20 years old im exempt from those here in ontario. but thanks agan for your info, i guess ill just make sure my carb is set up properly.