Dinan and transmission shift points
 

My X3 has always had issue with shifting the auto transmission. For example, when simply driving down the road and with no appreciable throttle input the tranny will suddenly shift down and the engine will rev to maintain speed. It's just not "right".

I spoke to the dealer about it, and they put it off as "works as designed". One tech even said it's because the car tends to be underpowered. They did disconnect the battery to clear the transmission program so it could "re-learn" my driving style, but the "feature" remains, and I had decided to live with it.

I was thinking about it the other day and suddenly wondered if the Dinan programming might correct it. The 3.0 engine could use a little more "oomph" in any case, and the Performance Program at 299 seems reasonable, especially if I get a bit more performance from the car and get rid of the shift issue.

Anyone have any thoughts? The only other question becomes, will the software work for a 2008? They only list through 2006.

If they have a try it before you buy it policy, it might be worth looking into. The car goes in Tuesday and it might be good opportunity to load it up.

Up through 2006, the X3 used the 225 hp M54 engine. Your 2008 has the 260 hp N52 engine. Software designed for one won't work on the other. You may find software for the newer engine, but I doubt it.

The software raises the rev limit by 240 rpm, so if your shifting issues happen at redline there may have been a difference. That's a joke. I wouldn't expect any difference. The sofware claims to add 4 hp at 5700 rpm, but doesn't say how much it loses at lower rpm. In any case, 4 hp is not significant.