butane has been proven to yield the same power increases as nitrous oxide in nitro-powered rc cars. i had a HPI-nitro car and i rigged up butane injection. It started out with a top speed of ~80mph after the butane, it hit about ~105mph. and we did use my friends dads radar gun (his dad is a cop)

2 weeks later i used a little bit more butane, lost control, and it shattered against a brick wall. that was the end of that hobby