Few driveability q's (long)

[S351 R]

Few driveability q's (long) edited

Looking for some driveability guidance.

Currently working in Open loop below 2500rpms for tuning.

EDIT]
Things are smoother with reducing AE MAP from 2040 to 540, bringing AE TPS to 0 for first increment, and richening bottom light load cells.

Still get "trailer hitching" when holding 2K in 2nd gear- real touchy for on/off throttle

- How much fluction should there be in Open Loop if MAP/TPS are real steady?
- Holding a neutral 2K rpm in OL shows a full 1pt AFR steady fluctuation between 14-15 - normal?


- What are the rules of thumb to maintain idle with higher accessory drag ie supercharger, Amp draw, AC - car doesn't like to idle with AC.

Any $.02 is appreciated

 

[Craig Smith]

In theory, the AFR should be perfectly steady with no input conditions changing. I suspect most of the fluctuation you are seeing is due to a lack of good airflow across the O2 sensor at low engine speed/load conditions. With a good sized exhaust and any cam at all, this can be a problem.

It sounds like adding a little fuel has fixed a bunch of stuff, and this is what I would expect in a stick car with a blower. My experience here has been that the off-idle stuff takes more fuel to work properly in these setups.

I think you are on the right track. I would be tuning by feel here as much as I would be tuning by O2 reading.