VersaTune User Forum

Hi to all,
I would like to ask how our cars respond by switching this table (fuel gravity)...
The stock value is 0.74 if i raise it , the idc will drop?
Also how can i calculate my fuel gravity, Europes 100unleaded (BP ultimate ) and meth mixture 60%(meth)-40%(water)

The fuel gravity parameter is actually the fuel density, 1kkg/m3 (ton/m3), or gram/ml.
You should be able to find a range of fuel density for the fuel you're using on the web site of the company selling it. By example I'm using OMV100 and the specs are 0.72 min and 0.775 max. So 0.74 is about right.

Adding meth should not affect how the injectors work because meth is not injected through the DI injectors. Changing the fuel gravity parameter will only trick the ECU and make it "think" it injects a different amount of molecules of fuel into the cylinders, and eventually the ECU will adjust the quantity by reading the AFRs. Because yes, you can make the InjDC drop with that but it will also lean the AFRs.

So if you want less InjDC then run a bit leaner. By example commanding 11.5 instead of 10.5 (it's just an example) you will gain 100*(11.5 -10.5)/10.5=~9.5% more fuel headroom. And you can go a bit leaner if you have the knock protection and cooling from meth...

mituc wrote:The fuel gravity parameter is actually the fuel density, 1kkg/m3 (ton/m3), or gram/ml.
You should be able to find a range of fuel density for the fuel you're using on the web site of the company selling it. By example I'm using OMV100 and the specs are 0.72 min and 0.775 max. So 0.74 is about right.

Adding meth should not affect how the injectors work because meth is not injected through the DI injectors. Changing the fuel gravity parameter will only trick the ECU and make it "think" it injects a different amount of molecules of fuel into the cylinders, and eventually the ECU will adjust the quantity by reading the AFRs. Because yes, you can make the InjDC drop with that but it will also lean the AFRs.

So if you want less InjDC then run a bit leaner. By example commanding 11.5 instead of 10.5 (it's just an example) you will gain 100*(11.5 -10.5)/10.5=~9.5% more fuel headroom. And you can go a bit leaner if you have the knock protection and cooling from meth...

Thanks for your info..