Originally Posted by PhilipA
The engine is a 3.9 running 14CUX but with new style Bosch 4 hole injectors.
Vacuum advance is controlled by the unichip to give a rudimentary electroic control..
Cam is standard 3.9.
I feel a lot of the gain is from
1 throttle openings less due to Thor long runners giving better charge at lower revs so that the injection is at a leaner position on the curve.
2 less changing down by auto on long hills.
3 Unichip providing much more advance at small throttle openings.
I still think I can get a lot more from the engine so next step is to map the
mixtures with a wide band O2 sensor.
4.6 using gems or motronic constantly try for 14.9 stoicometric fuel air ratio at cruise and advance to knock then back off, so they are very difficult to improve.
Regards Philip A