Here is the offical download page:
Yes, I know. It says it's for ZTE Turies Series, but check it out. This source contains not only the code for Turies, but also many other devices, including our Racer!
Have a look at the my screenshot of it: QQ截图20121207024935.png 18.33KB 14 downloads
It have mooncake configs, by which you can see the difference between Racers from diff regions(mainly are wifi and camera).
actually I tried this almost a year ago, I complied the kernel( use one of the mooncake configs) without any changes to the source and got a zImage which can use in official rom.
Some may already know about this, but since no record here, I think maybe someone still need it.
Tips: You may need 7-zip to decompress the files.