I've only done under 200 laps at BL GP with the XF GTI and the fastest time I got was 1:40:72.
I included my replay to this to get some suggestions about what I'm doing wrong on the track.
There's also the set that I'm using in the replay which I got from Setup Field.

You can ignore the first two laps

its a long time since i drove this car / track combo so cant be too specific

firstly i didnt check your setup but try either a setup from another racer or use this set

http://www.lfsforum.net/showthread.php?t=279

bobs sets are good for beginners and fast enough

secondly your lines are a bit off, hence you are loosing a lot of time in second section

either try watching replays from other racers or do what i did and sit in spectator mode and ride with one of the faster drivers, its not always a good idea to watch a very fast driver as the difference can be too great, try watching someone whos a bit faster and consistent, if you can get their setup as well then your laughing as it lets you see the set being used

the purpose of a set (sort off)

after reviewing your mpr, i tried a few laps, first thing IMO is get rid off autoshift, do it yourself, second sharpen the brakes...
third be patient and learn other one's lines.

the force is strong with you...

Thanks for the advice for both of you! I'm doing 1:40 on average now
Got my fastest down to 1:38:74! still need for improvement.
Being a stupid newbie and not thinking about watching the
better drivers online :banghead: The thing I noticed that I was quite heavy on the brake

Worked just fine, got almost another second of my time it's 1:37:94!
One thing I usually forget to do is push the record button... Gonna try that next time I'm going for my own personal record again

i set it to record per default...

after some time when there wasn't anyting great happening i just delete them...

but this way you'll always have some evidence of things happenend to you online...