The car has crappy brakes.
I had good results using early braking and a bit of coasting.
On the opening straightaway, from the right, brake at the end (laps 2 and 3 brake at the beginning) of the crosshatched striping, down to 2nd (50mph) and coast/turn into the left hander until the car is pointed at the apex and accelerate to the right hander, brake to 45mph, then even throttle ½way around the carousel and accelerate out. Make your way to the left side and brake at the last shadow (on the right), down to 2nd, turning in (45-50mph) and coast until the car points to the apex (38-40mph), accelerate, turn left, quick lift, accelerate, turn right, quick lift, accelerate around both right handers and down the next street, braking at the end of the guardrail (or a bit past) on the right, down to 2nd 48-50mph, turn left and full throttle over the sidewalk. Over to the left and brake at the 2nd crosswalk (maybe a little past) to 50mph, turn right, coast to 45mph and accelerate over the apex and down the street. Move to the right, brake at the beginning of the rumbles (maybe a car length before) while turning left, down to 2nd around 45mph, full throttle over the curb and you should be on the bumper of 5th place. Down the back straight, up to (110-112mph), after the kink, in the last shadow, start braking just past the 2nd set of stripes, down to 2nd, turn right while braking around 60mph until 33-35mph, then accelerate around and down the main straight.
Or something like that.
Managed a 6:43.4