I have a 87 S-10 pickup with a Tuned Port Injected 350 in it. It is a speed density setup and I want to boost it but I have never worked with a speed density system that was boosted. Vortec has a supercharger for the application but how does the computer know that it is under boost if the map is pegged at 1-2psi? How do you get the extra fuel accuratly?

 

Not 100% sure on your setup, but I had to get a 2 bar map sensor, and reprogram the computer's operating system to a 2 bar speed density system by using HP Tuners.

There are ways to "trick" the pcm...just set your fuel curve to add enough fuel at your highest boost level, but that's not nearly as accurate.