Corners need to be tighter and almost without drift, quickly brake+steer and then quick nitro, to gain more nitro try to drive over signs and all what give nitro.
Before going on ramp for flats try to brake and steer and quickly press tripple nitro. That way you will get better airspeeds. If you land straight that is a bonus cause your speed when press triple nitro will short bost over max speed of car. It can be done on all 3 ramps, but practice is esential, and some luck

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My PB from before is 55.605 and if i will have enough time i will get everything i can to break it. Im not far from WR.
But first i need to remember how to exactly drive it, every detail is important.