Run a lap or two and see how fast it will go, adjusting the "wide" slider until the car tops out just below redline (not the rev limiter, the redline) when it's limited by drag. Leave yourself enough extra revs before the limiter so that you won't get the power cut off when you're drafting faster than the car will go by itself.
Also, if you can't just stay ahead permanently under your own power, stay behind the #1 car until about 2/3 of the way through the last turn of the last lap, when you should be 4 or 5 carlengths back. Starting at that point, floor it and run up right behind him, but step out to pass before you get to him. Your momentum should carry you past him and over the finish line before he can catch back up.
That's called a slingshot pass, and on several occasions I've won 30-minute races by less than 0.300 seconds using that method.
Hoep this helps.