I think we have a small turbo boost issue on my wifes 35d - help required

[The Doc]

Hi all,

My wife's X5 35d is feeling a little sluggish these days from the lights and I've recorded an average of 3 0-60 runs of around 8 seconds using a racelogic V-box and have also noticed the MPG around town has suffered going from around 23mpg to around 20mpg, although on a run it's still doing 25mpg at 85 mph, following this I've just done some boost logging by driving on a nice flat road in top gear (manually selected) at approx 1200 RPM and flooring the throttle (not to kick down) it's producing the following Average PSIg at given RPM:

1200 RPM 1.74 PSIg (held not "on boost")
1420 RPM 11.46 PSIg
1590 RPM 19.00 PSIg
2000 RPM 22.34 PSIg (Max boost sown on my scan tool)

So in essence your having to be at 1800 rpm to reach full boost making me think that the little turbo isn't doing much at all. Once you have hit 1700-1800 rpm up its a nice solid 22.34 PSIg

Does anybody have any ideas on standard boost PSIg at low revs on the 35d please or can anyone log their boost and let me know?

And I've also logged mine in the 40d (variable nozzle turbo's etc but still...)

1200 RPM 1.74 PSIg (held not "on boost")
1240 RPM 18.27 PSIg
1290 RPM 22.34 PSIg
1450 RPM 22.34 PSIg
1620 RPM 22.34 PSIg

What experiences have you guys had with BMW detecting problems like this before I send it in?

Thanks in advance.

[The Doc]

Got the requested boost figures for the standard map in the 35d if it helps anyone in the future:

1000rpm - 11.76psi
1250rpm – 21.17psi
1500rpm – 24.99psi
1750rpm – 26.02psi
2000rpm – 26.46psi

It's off to BMW on Tuesday