De catting 318is

Thu Feb 12, 2009 9:51 am

Hi Guys, does anyone know what i need to do to de-cat my 1990 318 is. Its a euro car so has the cat and ideally I'd like to keep it for test purposes visually at least

The cat is already empty, but makes a noise like a moped LOL Does anyone know If i can weld a pipe into the cat, or do I have to remove it completely and put either a flexi joint/pipe or straight piece of pipe on. I have no idea, so if anyone can help that would be great, thanks chaps

Thu Feb 12, 2009 9:59 am

Would be easiest to remove it and weld in a bit of pipe instead

Thu Feb 12, 2009 10:22 am

Thought that might be the case, thanks

Wed Feb 18, 2009 5:08 pm

By Euro do you mean UK or mainland Europe? Cos i have a 91 iS but was sure it didn't have a cat!

Wed Feb 18, 2009 5:19 pm

before fitting my stainless steel exhaust i may decat mine, is it acutally worth it ??????

Wed Feb 18, 2009 5:29 pm

i think you might get a few more horses alex
you dont need a cat for mot if the car is pre 1992 .

Wed Feb 18, 2009 5:31 pm

m666w wrote:i think you might get a few more horses alex
you dont need a cat for mot if the car is pre 1992 .

i thought it was 1991, i might just smash the internals out, same sort of thing, what happens with the lambda sensor or does that just stay as is

Wed Feb 18, 2009 5:32 pm

Alex wrote:before fitting my stainless steel exhaust i may decat mine, is it acutally worth it ??????

Are you sure it has one? There is a silencer that looks like a catalyst but there is no lambda sensor.

Wed Feb 18, 2009 5:34 pm

DHFiS wrote:
Alex wrote:before fitting my stainless steel exhaust i may decat mine, is it acutally worth it ??????

Are you sure it has one? There is a silencer that looks like a catalyst but there is no lambda sensor.

positive, ive checked the vin on that vin decoder thing on the net and it says its fitted with one, it also looks like it has one underneith, there is two boxes one must be the box you are on about and the other must be the cat

Wed Feb 18, 2009 5:38 pm

Alex wrote:
DHFiS wrote:
Alex wrote:before fitting my stainless steel exhaust i may decat mine, is it acutally worth it ??????

Are you sure it has one? There is a silencer that looks like a catalyst but there is no lambda sensor.
positive, ive checked the vin on that vin decoder thing on the net and it says its fitted with one, it also looks like it has one underneith, there is two boxes one must be the box you are on about and the other must be the cat

Fair enough. I'd remove it then, the ECU will still work without the input from the lambda.

Wed Feb 18, 2009 5:46 pm

DHFiS wrote:
Alex wrote:
DHFiS wrote: Are you sure it has one? There is a silencer that looks like a catalyst but there is no lambda sensor.
positive, ive checked the vin on that vin decoder thing on the net and it says its fitted with one, it also looks like it has one underneith, there is two boxes one must be the box you are on about and the other must be the cat

Fair enough. I'd remove it then, the ECU will still work without the input from the lambda.

thanks

Thu Feb 19, 2009 5:55 pm

am I right in thinking that a CAT was an option on the iS?

Thu Feb 19, 2009 6:05 pm

Must have been an option...

The spec sheet for my 318iS I got from Cotswold BMW shows that it was bought without a CAT. It has one now though. If a car that old doesn't require one by law why would it have been fitted?

Thu Feb 19, 2009 6:08 pm

MrWhite wrote:Must have been an option...

The spec sheet for my 318iS I got from Cotswold BMW shows that it was bought without a CAT. It has one now though. If a car that old doesn't require one by law why would it have been fitted?

i got the spec sheet for mine and its a bum basic IS and never said it had a cat although it does

prehaps it could depend on the dealer or whoever was on the production line that day

Thu Feb 19, 2009 6:18 pm

Check that you've got a lambda sensor. An easy way it to look for a 4pin round connector under the battery tray. If that's got a blanking plug then it's got no lambda sensor, no lambda sensor == no cat. As said above the stock non-cat system has two boxes in the centre leading people to believe they have a cat when they don't.

Thu Feb 19, 2009 6:21 pm

http://www.bmw-z1.com/VIN/VINdecode-e.cgi

that tells you weather you have a cat via the vin

mine does

Chassis number EE47738
Vehicle code AF92
Series E30
Model 318is
Body type coupe
Catalog model ECE
Production date 1990 / 09
Engine M42
Transmission Manual
Steering Right
Catalyzer YES

Thu Feb 19, 2009 6:23 pm

so that's what that plug thing is.
cheers

Thu Feb 19, 2009 6:25 pm

hoshy wrote:Check that you've got a lambda sensor. An easy way it to look for a 4pin round connector under the battery tray. If that's got a blanking plug then it's got no lambda sensor, no lambda sensor == no cat. As said above the stock non-cat system has two boxes in the centre leading people to believe they have a cat when they don't.

There is now a massive hole under my battery tray where I attacked it with an air saw, don't remember seeing any connector. However, I put my VIN into the site mentioned above and it says it does have a CAT. (?)

Thu Feb 19, 2009 8:19 pm

Alex wrote:http://www.bmw-z1.com/VIN/VINdecode-e.cgi

that tells you weather you have a cat via the vin

mine does

Chassis number EE47738
Vehicle code AF92
Series E30
Model 318is
Body type coupe
Catalog model ECE
Production date 1990 / 09
Engine M42
Transmission Manual
Steering Right
Catalyzer YES

Just checked mine and this website says catalyzerYES as well. Defo no lambda on mine though.