Not Ranked
I run the Speed Pro unit on my SPF. I also run it on a 69 big-block Camaro. The Accel DFI isn't a bad unit but it's slow to program, wants to be re-programmed if the weather (humidity) changes, doesn't have altitude compensation, and doesn't use a wide-band O2 which gives you full-throttle closed-loop operation.
I've seen both units tuned on a chassis dyno many times. The Speed Pro is dialed in with two or three pulls. The Accel takes 6-10 pulls. Also the tables load VERY slow. Now they have a new computer coming out and it is probably much improved.
The closed-loop operation will give you better driveability and mileage in my opinion. With the wide-band you can keep the closed-loop on even with full throttle which if your tuning is a little lean the computer will add the fuel you need to prevent running too lean and possible engine damage. The wide-band can accurately rear a wide range of A/F ratios which you'll be in between full-throttle and cruising. The standard O2 can't read well away from 14.7-1. That's why the factory computers without wide-band go to open loop under full-throttle.
My small-block (Chevy) in the Cobra runs Hilborn port injectors. It makes almost 600 h.p. and is EXTREMELY smooth even with a solid-roller cam with 264 duration at .050. This car would run COMPLETELY different with a carb.
Jody
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