Torque Application for Android - Volumetric Efficiency

[Croccy]

Now I have an Android Tablet mounted in the dash of my car (See the ICE Thread on Forum). I have started using the Torque app to display various readouts from the engine via blutooth.

One of those readout is the MPG. In the app you have to create a profile for the car and you need to enter the Volumetric Efficiency. As default it says to enter 75% if you are unsure, but at this reading the MPG is a lot lower that what I am actually getting.

Looking around the internet it seems to the K20 engine has a much higher VE rating than other engines which is why they are so efficient when it comes to the 100+bhp per litre figure.

Apparently the VE can be calculated by taking some reading etc which I may well do, but was just wondering if anyone else has already calculated this or has a figure entered into theirs that gives good MPG values?

Matt.

 

[C&S Evo7]

111 comes to mind for the k20a and 110 for the f20c but im not sure where i got it from it was years ago

why not experiment ?

 

[Croccy]

The problem is the real time values are obviously all over the shop so you need to set it, then use a full tank of petrol to check its accuracy. I don't drive the car during the week anymore so would take a couple of months to get a reasonable figure.

Would rather capture some data and work it out using maths. Sounds like a lot more fun don't you think?

I have found I can drive a lot more economically with the live readout. Am going to see if I can create my own theme and include a VTEC light, might need the devs to make a change though for it to be possible.

Matt.

 

[coyote_dc5]

Change your VE until your happy with the MPG your getting lol

 

[Croccy]

Ok, found out why the MPG was out and also fixed why the 0-60 timer and quarter mile wasn't working .

Although the dials in the car are obviously showing MPH because of whatever conversion was done, The ECU is sending out different values!

I'm still trying to get it straight in my head but here is what was happening. If I set Torque to display the Speedometer in KM/h then the reading being shown is actually the correct MPH value. (So if I do 40mph the app shows 40km/h). If I then set the app to show MPH it divides the number down so it reads too low (Doing 40mph showed around 25mph on the app).

In the Torque setting you can set an OBD Speed multiplier. So I set this to 1.609344 which will convert the value being sent by the ECU back into MPH for the app to use! Make sense???

So it seems that whatever converter was used in my car does change the value from km/h to mph but it doesn't tell the OBD port that the value is in MPH, it is still reporting it as km/h. So 40mph gets reported as 40km/h in the app.

Hope you understand that coz even after typing it I have a headache!

Anyway, long story short. Everything now works and with the default VE value of 85% the MPG doesn't seem very far off, but I will need to do some more testing the the VE should be higher in the K20 engine from what I have read. But saying that the VE changes throughout the rev range so the 85% they quote may just be the average value to base calculations on.

Matt.

 

[Croccy]

And although i've not tested it yet. This should also explain why the HP readings I was getting were so low!

 

[C&S Evo7]

have you got kpro matt?

 

[Croccy]

no :v( one day!