Hi,
My 318is went in for an MOT yesterday, and the mechanic told me that there is a CAT fitted to my exhaust. I didn't think that cars before 1993 had CATs fitted?
If it does have one...
1. Would removing it give much of a power increase?
2. If I fitted a bypass pipe, what else would I have to do (i.e. remap the ECU, or do something to trick the relevant sensor?)
Cheers...
Removing a CAT
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Brianmoooore
- E30 Zone Team Member
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BMW handbook figures give a 2 bhp drop on a 318i fitted with a cat, but no drop at all for the iS.
Does show a 5% increase in fuel consumption though for the iS,
Does show a 5% increase in fuel consumption though for the iS,
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Brianmoooore
- E30 Zone Team Member
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- Joined: Mon Jan 10, 2005 11:00 pm
Leave it in place.oze30 wrote:what do you dio with the lambda sensors?
Hmm.. Might have to do this. make up a section of pipe the same length as the cats, flange it and unbolt the buggars. (I need them when it goes back to Oz)
So there's no problems with the sensors like that? I'd have thought that they would change the fueling abit to compensate? Or do they really have nowt to do with cats?
So there's no problems with the sensors like that? I'd have thought that they would change the fueling abit to compensate? Or do they really have nowt to do with cats?
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Brianmoooore
- E30 Zone Team Member
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- Joined: Mon Jan 10, 2005 11:00 pm
Cat isn't needed on post '92 LPG powered vehicles, as they easily meet emissions requirements without one, so they are often removed.
Usual method of dealing with it is to remove it and destroy the ceramic innards of the thing with a steel rod up the outlet pipe. Shake all the bits out, and refit the casing.
Usual method of dealing with it is to remove it and destroy the ceramic innards of the thing with a steel rod up the outlet pipe. Shake all the bits out, and refit the casing.
Thanks for the advice...
Just to make sure I understand...
If my 318is does have a CAT, removing it won't increase the power. If I do remove it, I don't need to do anything to the chip as the existing lambda sensor (which is there to protect the CAT) will take care of everything?
Just to make sure I understand...
If my 318is does have a CAT, removing it won't increase the power. If I do remove it, I don't need to do anything to the chip as the existing lambda sensor (which is there to protect the CAT) will take care of everything?
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dannyboy759
- E30 Zone Camper
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- Location: Hampshire
You can remove it, It will increase torque a little.
And as long as the car is pre Jan 1992 the car does not have to have one.
As for the Lamda sensor, if its in the manifold like an M3(cant remember with the is) then great
If its in the exhaust like the other e30´s then you can either drill a hole in the exhaust and weld a nut on it to attach it or just leave it off.
If you do the later the ECU will go into a default mode which will not affect anything else but it will go to a different type of fueling.
I cant explain it all on here but it was explained to me by one of the technicians in MÃanich, but anyway the car will run fine and still pass and MOT.
And as long as the car is pre Jan 1992 the car does not have to have one.
As for the Lamda sensor, if its in the manifold like an M3(cant remember with the is) then great
If its in the exhaust like the other e30´s then you can either drill a hole in the exhaust and weld a nut on it to attach it or just leave it off.
If you do the later the ECU will go into a default mode which will not affect anything else but it will go to a different type of fueling.
I cant explain it all on here but it was explained to me by one of the technicians in MÃanich, but anyway the car will run fine and still pass and MOT.
did it pass?
Yep =)
I had the rear discs stripped down and the handbrake adjusted...still not great, but a lot better. Also had to replace the rubber fuel pipes under the inlet manifold due to a leak, and replaced the rubber boot (AFM to Inlet Manifold) as it was torn. That plus an MOT, oil change, air filter cleaner & injector cleaner, and i'm just about at my original budget, so it's all good. Seems to be running v. nicely now...
How's the E36
Yep =)
I had the rear discs stripped down and the handbrake adjusted...still not great, but a lot better. Also had to replace the rubber fuel pipes under the inlet manifold due to a leak, and replaced the rubber boot (AFM to Inlet Manifold) as it was torn. That plus an MOT, oil change, air filter cleaner & injector cleaner, and i'm just about at my original budget, so it's all good. Seems to be running v. nicely now...
How's the E36
Just to clarify - any car of any age does NOT need a CAT to pass the MOT, so long as it can meet the emission limits for its age.
I had an old 525e in the early '90s with over 170k on it and it would pass a CAT test, even though the only cat it knew was the one it ran over on the way to the MOT!
I had an old 525e in the early '90s with over 170k on it and it would pass a CAT test, even though the only cat it knew was the one it ran over on the way to the MOT!