Like above poster said, you will have to stay drifting for quite a long time to get Level 3 Boost, like more than 10 seconds. Also, switch from side to the side didn't help as it stuttered the hissing sound.
So instead of relying just on Level 3 Boost, you should put some items in uses, as they can help you speed up the race or wrecking the opponents out of ways easily. Also, just don't focus on using the main road, try seeking out the shortcut and you can get ahead of your opponent quicker that way. Tightly turns, hidden road, etc.
I used to be hearing person like you, until I took the fever in my ears. ~FredCat