Picked this up off another forum after having alot of trouble with one or 2 of the detonator events and it shaved a few seconds off my time, 
Basically a bad game mechanic , when turning instead of just holding turn it works alot better just to repeatedly flick the stick to turn instead of holding it in, Bug whatever you want to call it but its as if the game was built for a dpad the way this works. 
Trust me if still racing correctly you will get better times in the detonator events.

Another Forum?  But...there are no other forums...

its a big one called google

I don't remember the race but there is one where you have to use a bigger truck for a time trial race. If you just back up it will start you down the lane a bit and you will be going fill speed. Makes the run very easy. 
 
I got all gold and it wasn't too bad after this tip I read somewhere else.