I am just wondering which would be the most effective on a stock MAP 305 that is going to be turbo'd.
Would both be best? I'll probably be running 24 lb SVO injectors.

 

Both. You'll need to lower your fuel pressure from the stock 45ish to about 38ish if you run 24 lb injectors on a 305. And you'll still need the FMU unless you burn a custom prom.

Jon

 

Yep. Both. The FMU does a very different job than an AFPR.

The AFPR is just a fine tuning aid to get your fuel injectors calibrated correctly to the programming in the chip. It's effect is going to be at part throttle and up to regular atmospheric pressure. Above that (boost) is the job of the FMU.

The FMU bumps up fuel pressure in relation to boost at a ratio of about 6 PSI of fuel pressure per PSI of boost. Your computer has no way of knowing when the engine goes into boost- above regular atmosperic pressure, so it won't/can't provide the added fuel to match the added air being forced into the motor by the blower. The FMU is a mechanical/analog device that adds this needed extra fuel by increasing fuel pressure.

I've glossed over some details to keep it brief, but that's pretty much how it works.