Similar to the English, "Vrooom". The one I see often is ブロロロ but the one I'm thinking of using is ブルーン. Are there any other examples that would be better? Also, are there different ones depending on the size of the vehicle, like a motorcycle vs a car vs a semi-truck?
I think ブロロ・・ is the most common when describing a car going at a normal speed. ブルン looks like starting or stopping engine.
What I see in mangas at hand or on the web:
- ブオ(ー)ン/ブオオ is used when a car is going faster/increasing the speed. Also this may be more suitable for trucks.
- ビューン for even faster ones. This is when describing a car passing in front of you at high speed.
- キーン for very fast cars like Formua 1. This is also commonly used for airplanes flying.
For motorcycles, it depends on types of engines (which I'm not very familiar with). From here
- four-engine 「フォン、フォン、フォーン！」
- large two-engine「ズド、ズドドドドド」
- moped 「ビィィーン」