Hello Megasquirt gods! I bow before your ultimate knowledge.

First off- thanks for all of the prior help. My little 94 is running great and the idle is killer.

I now have a Japanese VVT engine and 6 speed in the garage to replace my somewhat tired engine.

Anyway- different question here.

My car will see 12.5 KPA or so on max deceleration, however my VE table starts at 20. It would seem that I should adjust my bottom row to 10 to accurately measure and tune.

Additionally, if not running boost- is it worthwhile to set the top row to 110 versus the current 210?

Lastly, doing this would require a full rebuild of the table, right??

Thank you for the advice.

 

For reference.

 

If you have no plans to go forced induction I would definitely rescale the map to give you more resolution. You just click on each cell along the Y-axis and change it to what you want. Just make sure you're changing the values in the table along with the pressures so it doesn't throw your tune off.

As for vacuum on deceleration most people have over-run fuel cut enabled so it cuts fuel anyway. Otherwise it'll just supply the fuel in the 20kpa row. Since you're going to be picking up some considerable resolution by eliminating the boost rows you could easily add a 10kpa row, but it's not really necessary.

 

I wouldn't bother with the low end. When you're sucking a huge vacuum on decel, you should be in overrun fuel cut anyway.

Worth it on the high end for resolution. You don't really "rebuild" the table, rather just shift the cell values so they line up with your new row definitions (interpolating as required for row values that didn't exist before). Then head out and autotune.

"Sucking a huge vacuum" just seemed like the right thing to say.

 

If you click the two arrows in the bottom left corner of the VE table, any table in Megasquirt, you can rescale both axies and it will automatically interpolate all the table values it can to fit.

Less autotune that way.