TriumphZ3
Dedicated Member
- Joined
- Aug 2, 2023
- Points
- 39
My 1998 Z3 1.9 has had an amazing exhaust rattle since purchase; not the silencer as I swapped that as one of the first attempted cures. It sailed through MOT with no problems a few days after I bought it six months ago. I reckoned it was the internals of the CAT - a US recall but not UK - and on removing the CAT section found a welded plate hidden on top as if someone had already tried a fix. The exhaust is dated 1997 so presumably original. My mate - he knows these things, so he tells me - told me to remove the CAT internals completely as since these engines are so good, my car would pass MOT with nothing there at all, but he took the exhaust away to fix it and after three weeks returned it. AND it still rattled, very loudly, on startup or any kind of acceleration. However having read the threads about the after-market Euro 2 CATS failing emissions I didn't want to risk one of those and as I couldn't find a second-hand version anywhere either locally or online had to buy new and direct from BMW. Yes, it cost me almost 40% of the price of the car and they declined to take the old one as a trade-in due to the welded plate.
However: the car is now transformed and the formerly lack-lustre acceleration in first and second is vastly improved. I was never impressed with the drive experience before but now it's a real ticket-gatherer.
I suspected this was down to a blockage in the CAT - my mate (he knows things!) was going to cut open the plate and sort out the CAT internals but instead spun me a yarn about putting a device down inside the exhaust that expanded and pushed the internal material out of the way thereby stopping the rattling and removing any obstruction. b*******s; I know he never looked at it. As I had no further use for the exhaust, I decided to open it up today.
Here's the patch on top, out of sight from beneath. Under that...
Here's another!! Amazing. So: cut that one out and...
Nothing. Completely empty CAT. No internals, no trace of ever having been any, and nothing to account for the rattle. Nothing to account for the poor performance either, no blockages anywhere.
So: will anyone care to debate as to why a car with NO CAT will pass emissions, when from when I've read on here the cheap sub-£200 Euro-2 CATs won't pass UK emissions, and how the performance was inhibited very badly with the straight-through exhaust fitted but a proper BMW CAT has now transformed it? I'm stumped, but happy. And poorer.
However: the car is now transformed and the formerly lack-lustre acceleration in first and second is vastly improved. I was never impressed with the drive experience before but now it's a real ticket-gatherer.
I suspected this was down to a blockage in the CAT - my mate (he knows things!) was going to cut open the plate and sort out the CAT internals but instead spun me a yarn about putting a device down inside the exhaust that expanded and pushed the internal material out of the way thereby stopping the rattling and removing any obstruction. b*******s; I know he never looked at it. As I had no further use for the exhaust, I decided to open it up today.
Here's the patch on top, out of sight from beneath. Under that...
Here's another!! Amazing. So: cut that one out and...
Nothing. Completely empty CAT. No internals, no trace of ever having been any, and nothing to account for the rattle. Nothing to account for the poor performance either, no blockages anywhere.
So: will anyone care to debate as to why a car with NO CAT will pass emissions, when from when I've read on here the cheap sub-£200 Euro-2 CATs won't pass UK emissions, and how the performance was inhibited very badly with the straight-through exhaust fitted but a proper BMW CAT has now transformed it? I'm stumped, but happy. And poorer.
