Help me understand ReqFuel and VE map values

[gjestico]

I am currently tuning a turbo 6.0 LS V8 motor. 60 LB injectors on Gasoline, MS2 controller. Alternating batch fire. AFR target incorporated.

Putting those numbers into the "Engine and sequential settings" results in a Required Fuel of 7.9. As I understand it (possibly mistakenly) This is the injector pulse width for one cylinders worth of fuel at 100% volumetric efficiency at 14.7 stoich (minus any air density calcs) ; And the VE map values are a scaling of this, IE 100 on the VE means 100% of the required fuel ? Then this number is multiplied by the AFR target. ?

I ask because I am getting 23ms pulsewidth at 140 on the VE map and an AFR target of 11:1. Whereas by my rough math the PW should be around 15ms. Engine is way rich as a result. I am lowering the numbers in the VE table gradually as a result, Just want to make sure there is not something wacky with this situation.

Thanks for the help.

[whittlebeast]

Andy

[whittlebeast]

See it this helps.

http://www.nbs-stl.com/CrxTypeR/ThreeWheeling.jpg

Andy

[gjestico]

Thanks.

Ok I found this line in the end of the setting up manual :

PW = DT + (ReqFuel * MAP * Stoich/AFRtarget * VE[RPM,MAP] * AirDen * BaroCor * corrections)

I had not expected the MAP reading to be part of the equation. I thought only the Value in the VE table corresponding to the MAP value would be used. It appears both are used ? Does this explain the "Multiply Map" option in the setup window ? If so that explains a lot. Including the VE table numbers at idle.

So a 100 value in the VE table at 100kpa will be twice the PW as a 100 value at 50kpa ?

[whittlebeast]

Yep that is exactly what that option is talking about. Include MAP flattens the VE table somewhat.

Andy