Rear Axel

[soc45cer1]

I was wondering how would i go about making both of the rear wheels spin for lets say a burnout comp?

[Injuneer]

You need a "limited slip differential", also called "positraction". That's an option on many cars, which involves replacing the "open differential" (allows one wheel to spin while the other wheel just sits there) with a carrier that contains a system of clutches or conical surfaces that lock the two axles together when one wheel starts to slip. A "posi" unit is generally standard equipment on high HP cars like the 4th Gen V8 models.

There are also other ways to achieve a two wheel burnout, including "lockers" that use a ratchet mechanism, with a more notchy "on-off" action, or even a "spool", which eliminates all differential functions of the rear end, and splines the two axles together as a single unit. Lockers can be too harsh for a street driven car, and spools are almost impossible to live with, causing one wheel to have to slip in turns.

What year/model/engine is your car? We could give you some idea of how to make the change and what it would cost.