I have a 1985 rx7 with a ported 13b. It has the racingbeat 650 holley double pump. I've been looking around for a decent turbo for it when my friend told me he had a turbo out of a volvo sitting around. Heck i dunno what size or nothing. Guessing aroud 30mm or so?

Would this turbo even work if i tried???

 

Turbos used on small piston engines (I'm guessing it's from a 4cyl volvo) are too small to be used on rotaries. Rotary engines require a large turbine.

Besides that, it seems like you're unfamiliar with just how much work goes into converting an NA engine to turbo. First of all, you're probably not going to want to run a carb with a turbo. EFI is far better, and if your car is a GSL-SE, it at least had it at one time. This guide will give you a better idea: http://www.aaroncake.net/RX-7/naturbo.htm. It's made for series 4 NA engines, which are very similar to the EFI 13b found in the GSL-SE.

If you're set on going turbo, consider swapping in an entire turbo engine/drivetrain from a 2nd gen TII. In many ways, this is simpler.