Engine VE Percent

[bubba2533]

So I'm trying to determine how to convert the .Bin values into a standard VE Percent (%) from the units "gm * K / kPa".

Based on what I know the Engine Size is used, but other than that I'm not sure. I would like to put out an .xdf for my LS1 Boost OS that uses the more standard VE % rather than the "gm * K / kPa".

If you know anything about how to convert please post and I would be very happy to add it to my xdf. If I'm able to figure it out on my own I will post it up for others to use.

So far I know that to convert to "gm * K / kPa" the formula "X / 5120" is used.

[kur4o]

This will get you almost the same numbers as efi live got for the percentage. I am really unsure where the *0.4069 comes from. It can be derived from cyl volume which means it wont work for other volumes than 5.7. I will look for some other dependancies.

(X*0.0195312500)*0.4069

[kur4o]

(X*0.0195312500)*0.38832

This is what it comes for 6.0

If you find the relation between multiplier and engine volume, a better formula can be made.

[kur4o]

0.2896402

Looks like this is the scalar for engine volume to get you the multiplier

0.7458801[litres]*0.38832=0.2896402

X*0.000030517578=cyl volume

0.2896402/cyl volume= ve multiplier

(X*0.0195312500)*(0.2896402/(A*0.000030517578))=ve %

x= raw ve value
A=raw cyl volume value

[bubba2533]

That is extremely close to the gas constant of air (28.9647 g/mol) Source

Thanks for the quick help!!! Now I just need to put it into the xdf and make sure it's working.

[bubba2533]

Ok so here is what I have.

VE (%) = (X / 5120) * (28.96 / A)

X = Raw VE Value
5120 = Scaler to "gm * K / kPa"
A = Cylinder Volume (liters)
28.96 = Gas Constant for Air (g/mol)

Cylinder Volume (liters) = Y / 32768

Y = Raw Cylinder Volume
32768 = Scaler to "liters"

It seems to look like it is giving pretty reasonable values. Hopefully others can confirm.