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Different VE between 2 ECUs for the same engine

Practical Dyno Tuning

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Hello mates,

I have noticed that the VE numbers put for the same car and the same engine in the Haltech elite ECU were totally different ( also we had VE numbers higher than 115% ) than the previous worked example using the AEM infinity. I am lost and confused :D

Can someone be able to explain for me ?

you have to look at all the other settings and consider things like fuel pressure.

Hi Arghx, Im talking when the fuel injectors settings are 100% correct. In both examples they were the same stock Injectors and supposedly settings.

Well, is the VE of the engine actually different? Like valve timing, intake and exhaust manifolds, air induction system, turbo, etc?

No it was the complete same stock engine. that's why i was confused.

If your dead times were out and one ecu was running semi sequential the other sequential you could see something like that. Do the MAP readings look the same under similar conditions? If one is scaled significantly off it would shift VE too.

@Slides, I am sorry dear I couldn't quite get you.

There could be other tables in the ECU that are tuned differently resulting in a different VE. For example it's clear that a different intake cam position on a variable-cam engine would change the VE. You might also find changes due to the effectiveness of injection timing or even the spark timing.

You need to keep in mind that each ECU manufacturer uses their own discretion in exactly how they apply the ideal gas law and any compensations inside of their fuel model. Beyond this there are also significant variations in how the fuel injectors are characterised and this will also affect the ultimate VE number. For this reason there will almost certainly be differences in the VE numbers between different ECUs. This also explains why you may see VE numbers that seem optimistic.

@David thanks for your input, as i mentioned previously it was the same engine and i would assume same cam timings, Andre's explanation makes sense.

@Andre Well said, thank you !