NOCONES

Hello, i'm thinkin of running MegaSquirt, or a modified GM TBI unit on my 12a. Does anyone know of a good way to start out a VE table. The GM unit might not work because i don't know if it's VE table has modifyable RPM ranges. The rotary revs a little higher than any of the other engines GM has (like 4K higher), so i'm going to pull the prom on my computer to see if it's adjustable. Either way i will need some type of VE table to use as a starting point. Has anyone done something like this before and therefore has a VE table that they used, or have any good ideas for one.
The megasquirt uses a 8 X 8 VE table, and for now i will be operating NA with stock RPM constraints. Thanks for any help with this matter.

Daniel

REVHED

What do you mean by VE table? The only VE I know of is volumetric efficiency which has nothing to do with EFI fuel mapping. Please explain.

NOCONES

I mean this thing here. The VE table. And VE is EFI. I believe newer systems don't require this as they rely solely on a Air flow sensor to aquire this data, but older sytsems use this VE table as a base at any Engine pressure/speed, multiply it by a BPC (Base Pulse Constant), a BLM (Block Learn Multiplier, calculated by the O2 sensor when it's in Closed loop), and determine the BPW (Base Pulse Width). In reality it isn't quite this simple as theres other things such as Engine temp and quite a few others that come into play but this is the bare bones of how most early (pre 1995ish GM) EFI systems work. Megasquirt uses This logic as it's an offshoot from a project to create a kindof all inclusive Clone of GM EFI. Check out www.diy-efi.org It will tell you everything you need to know.. except the basis for a rotary VE table which actualy might be in there somewhere, but i figured some one on here has to have tried this before so i choose to find it here, and maybe introduce some of you to the idea of CHEAP efi. My whole system is going onto a GRM $2004 challenge Midget, and should cost around $200 total, with parts sourced from the GM 2.5L series of engines, which are widely available. It Will be able to easily Self correct for up to 21PSI of boost, once i get it up and running with a proper VE table.

Thanks again,

Daniel