Need some help

[45es]

I recently installed a 1990 Firebird 3.1L rwd motor with manual trans into an old Jeep. The engine will be controlled with MegaSquirt II both fuel and ignition. Could someone pull a factory ignition map for this stock motor and post it. I want to use the factory ignition map as a starting point for my set up?

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[robertisaar]

want VE as well?

[Driver_10]

want VE as well?

It never ceases to amaze me how you can come up with any random piece of info on a whim.

[robertisaar]

haha, maybe that's true.... but it's what i'm good at.

[45es]

want VE as well?

Thanks for the spark map. If you have VE I'd take that as well.

Thanks again.

[robertisaar]

this should help then... the way early GM speed-density worked was there was a main table and an adder table. the main table is in effect at all times, but the adder table was only used when going above the highest RPM value in the main table. it then just added the value in it's table at the specified RPM to the proper value in the highest RPM cell in the main table that has the closest MAP value.

confused yet? LOL

[45es]

confused yet? LOL

Yup! Could you give a couple of examples say at 4400 rpm.

[robertisaar]

certainly.

let's assume WOT, so 100kPa roughly, and at 4400, the last RPM cell(4000) in the main table, so we have 67.19, plus the adder table's 4400 value, 28.13, which comes up to a VE number of 95.32. let's say you have the throttle really close to WOT, but not quite and you're seeing 90kPa at 4800RPM... then we take the 4000/90 value from the main table(66.02) and add the 4800 adder cell(25.00), and get 91.02...

kind of an odd way to go about it, but GM did it this way to increase resolution while still being able to use VE numbers above 100% without using 16-bit values to save space on the PROM.

[45es]

Now I understand.

Thanks for the help.