MSefi.com read only forum (Jan.15,2018)

I was curiuse as to what differet people's opinions were on these to setups for ITB's. I just adapted a toyota 4 throttle system to my brothers mazda protege and we are having some tuning issues. Currently using speed density. We can get a its just super rich like 11-1. nice full throttle run and tune. But our map range is so close togeather that we can't seem to get a nice highway cruise. Anything above 60 MPH puts us right up in 90-100 kPa range even though it is less than 1/4 throttle. Is this typical of ITB's? The ITB's have a common plenum for vacuum ports and such so our map sensor should be pulling from all 4 runners. We allready had to put a check valve for the powerbrakes to work for left foot braking. Thanks for any insight.

scott

Check a datalog and see how stable your MAP signal is. Have you checked for a vacuum leak using a propane torch, (unlit of course)?

I could only get down to 60kpa with my ITB set up on a 2.1l Pinto motor.

Had to go Alpha-n as even a 10% throttle opening would push it up to 90kpa.