So I thought my car had cats, as all the E34 M5's have.:deal:
I mean these look like cats dont they?
My car being a 1991 would have been run for a time on leaded fuel, so I was convinced the cats would be well and truly contaminated, possibly slightly blocked. So today, I had them cut off. To my surprise this is what I found inside the units:oohhh:
No catalytic material, no, these are mechanical type silencers, they have all the BMW part numbers and stamps on them. Even made of stainless steel while the rest of the system is mild steel as you guys know.
Then I looked for the O2 sensors on the exhaust pipe. Also none to be found on this SA built car. :cool2:So I dont know how the car's closed loop ECU controls itself, maybe sensors further up on the branches themselves. If so, they are not visible from beneath the vehicle
IIRC these were manufactured by Boysen (same company Alpina uses) for BMW, for countries that had limited availability of unleaded feul or no legislation requiring cats. There's a non-adaptive software program from BMW designed to work without O2 sensor and cats. Member BillieS38's car used to have this setup, and was quite surprised to find these under his car after repeatedly failing the annual emission test.
You might want to try if your top-speed limiter is programmed, because is it is missing that answers a long standing question. Serge's car had no limiter when running the non-cat program, while being limited when on the cat program.