i just saw this clip on youtube and was wondring how can i do the same
you know, 900hp V8, blowoff sound ??
http://www.youtube.com/watch?v=aS3jU9w4C4w

Afaik you can do such things with LFSTweak. Use searchfunction to findout more.

Alas demo users can't use it.

any possibility of getting that done in the demo version ?

Read the post right above yours?

hes S2 licensed

if you really want to use tweak, you have 2 sollutions.

1. download patch U and use it there, there is a tweak available for demo users for patch U but obviously, patch U's physics are outdated so it will be a bit crap.

2. Spend £24 and buy S2 ^^

u mean patch Q for demo users