Been chasing issues with a dual 4150 TB setup, sitting on top of a 12-71 blower in a Chevy Caprice SS cop car (2013) Injectors are on TOP of the rotors. It started and wants to idle at 3000-4000 rpm, timing way retarded because its above commanded idle rpm, headers glowing etc, but it didnt want to lower TPS below 26% or so to drop idle for soem reason. After asking if theyve eliminated all vac leaks for last month or so, we found brake booster wasnt on back of the manifold... so better now, will run at 1800.
Ive played around with idle scalar and not sure exactly how that should be set. Primaries open before secondaries, so 4 barrels idling. Surface area of that is slightly less than 90mm stock TB (9.62" vs 9.8" or so I think it was) Thing is how should it be set to accoutn for the other 4 barrels that open up with the progressive linkage? Want to get idle squared away first.
I wish you could log the actual math taking place, and see idle airflow being converter into blade area/tps. Why wont it chase the TPS any lower than 19% in the log? its at 1900 it knows its above commanded idle because timing is pulled to the min I set (I changed this from the - numbers allowed because it would backfire HORRIBLE) trying to get it down but it wont move blade any further shut?