Removal of catalic converter

[Guest]

Sorry if this has been covered before.....

I have a german import LHD 1989 Carrera 3.2 fitted with a catalic converter. As the Cat & back box are getting tired it is my intention to remove the Cat and use a by-pass pipe. My question is will this upset the ECU in my car?
I don't know whether the ECU is the same as in a UK car?

Regards Alex

 

[Simon Davidson]

I am not an out and out engineering expert but I know some of my customers have removed the cats and replaced with std exhaust parts so I dont think you have any problems with the ecu.

should see/feel a power gain according to the feedback I have recieved.

Best Regards, Simon
www.essentialstyling.comyou

 

[Guest]

I am thinking of doing this to my car to also a german import I was told that I would need an O2 sensor mounted on to the bypass tube hope that may be a help

 

[plhorner]

Paul,
What you say would make sense, the Lamda sensor (o2 sensor) is linked directly to the ECU and provides an input for the fueling / ignition advance. Without it fitted, I reckon you'd have serious problems in getting the car to run correctly. Then there'd be the MOT test to deal with aswell, you'd have serious exhaust emissions problems.

I think Colin Belton would be able to give the definitive answer on this one.

 

[Guest]

My understanding is that if the O2 sensor is disconnected the Motronic runs in 'open loop' mode in which the various signals from the sensors around the engine dictate what the timing and fuel values are. When the O2 sensor is connected the system runs in 'closed loop' mode and the mixture is continually adjusted to keep it at an optimum level. This optimum is not optimum for perfomance but optimum for emissions.

I think if you have a cat then you should have a functioning O2 sensor connected or the cat may be damaged by richer fuel mixtures. If you have no cat then you can run open loop and should get some improvement in performance.

Some other points...

When you are full throttle the 02 sensor is ignored anyway.
On 88/89 the chip in the Motronic DME contains the same code anyway.
If you have a high compression motor (ie not US) and no cat or O2 sensor then its the same as a UK delivered car anyway.
The car will run without the O2 sensor and you will not necessarily have emissions problems.

I would also suggest you search the Pelican forums (lots of talk on there about this) and even more important drop Steve Wong at 911Chips a line. He knows tons about this stuff and is very helpful.

Note that I am not an expert and all the above is my understanding arrived at by reading forums like this etc..

Cheers

Andy