I have M52B28 engine with Simota CAI.
I did a "before" dyno on Friday, car was running ok, everything looked fine. From Monday till Wednesday bmw authorised service installed S52 cams and Alpina manifold from B3 3.3. They told me, that they reseted adaptations, engine is running smoothly, but pre-car oxygen sensor for bank 2 (cylinders 3,5,6) is not heating and should be changed. It wasn't available, needs to be ordered and delivery might take a week or more.
So I was driving hard for 2 days for the engine to adapt around 500km total, but I wasn't impressed very much with the results and on Friday went to "after" dyno without changing the oxygen sensor (and I thought, that most probably it was dead before "before" dyno, so I wanted to check the gains from cams and manifold).
"Before" run is dashed. As you can see, I lost lots of torque, and only on the high revs above 5500 there is some gain. Not very usable on the street. Everyone tells me, that it shouldn't look so bad. We did around 4 runs on the dyno, the curves were the same, but on the first run results were better, probably when engine or coolant wasn't very hot, but still loosing torque. Values are on the wheels in 4th gear and on very pessimistic dyno.
Any ideas what could be wrong? Just the O2 sensor? Cams timing? Leaks? Etc?
I did a "before" dyno on Friday, car was running ok, everything looked fine. From Monday till Wednesday bmw authorised service installed S52 cams and Alpina manifold from B3 3.3. They told me, that they reseted adaptations, engine is running smoothly, but pre-car oxygen sensor for bank 2 (cylinders 3,5,6) is not heating and should be changed. It wasn't available, needs to be ordered and delivery might take a week or more.
So I was driving hard for 2 days for the engine to adapt around 500km total, but I wasn't impressed very much with the results and on Friday went to "after" dyno without changing the oxygen sensor (and I thought, that most probably it was dead before "before" dyno, so I wanted to check the gains from cams and manifold).
"Before" run is dashed. As you can see, I lost lots of torque, and only on the high revs above 5500 there is some gain. Not very usable on the street. Everyone tells me, that it shouldn't look so bad. We did around 4 runs on the dyno, the curves were the same, but on the first run results were better, probably when engine or coolant wasn't very hot, but still loosing torque. Values are on the wheels in 4th gear and on very pessimistic dyno.
Any ideas what could be wrong? Just the O2 sensor? Cams timing? Leaks? Etc?
Torque lost after installing S52 cams and Alpina manifold on M52
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