I had a question about the timing strategies between auto and stick cars. Comparing AUJP (350/Auto), AXXD (305 5-speed), and AXCN (350, 6-speed), I can understand some of the differences, but one thing I don't understand is why the timing is so low in the stick bins for the low rpm high load areas. For example, in AUJP, in the 80-100Kpa and 400-600 rpm area, the timing is 20.04. In the AXXD and AXCN bins, the timing in those areas is 6 degrees and 10 degrees respectively. Why is that? I would think that the added timing in that area would help the motor stay alive if the clutch is let out without enough gas, no?

 

Lots of reasons. For auto's need to run the engine up against a heavy convertor before the vehicle starts to move.

Stick car, direct connection, also needs to be driveable. A lot of SA makes for a jumpy/jerky ride.

Emissions.

RBob.

 

Thanks RBob. After studying some datalogs and trying to diagnose why my car stumbled and tried to stall in an intersection with oncoming traffic at low rpm high load conditions, I bumped up timing in those areas and noticed a big improvement in driveability. Now I just need to figure out why sometimes it almost wants to stall when I push the clutch in too quickly.