Fuel Consumption - What does X represent.

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JohnDee68
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Re: Fuel Consumption - What does X represent.

Post by JohnDee68 »

The1 wrote:Partially covered here already.

viewtopic.php?f=43&t=7593&p=111942#p111942
So are you saying the unit of X is then the flow rate of fuel (grams) per time (msec) ?
As the current calculated formula doesn't give anything close to the cars internal display of L/Hr. Hence why i am trying to calculate the formula correctly. But to do so, I require knowing what the unit of X actually is. Does that make sense?
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The1
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Re: Fuel Consumption - What does X represent.

Post by The1 »

It's complicated but the output is 0.02 Litres per Hour per Bit, non enhanced stock Holden bins are 0.01 as the calculations are run of the MAF.

I havn't tested it though and im not sure if enhanced or other bins are correct i havn't tested it.
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delcowizzid
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Re: Fuel Consumption - What does X represent.

Post by delcowizzid »

Reads like stock on mine on the dash just don't change the Injector size in the tune or the values will be wrong
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immortality
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Re: Fuel Consumption - What does X represent.

Post by immortality »

Fuel mileage on our VX seems accurate on the trip computer running enhanced code.
JohnDee68
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Re: Fuel Consumption - What does X represent.

Post by JohnDee68 »

Hi Guys, Coincidence or not i am unsure. But I am experiencing TunerPro RT software crashing consistently today for unknown reasons. It doesn't want to play nicely. Once i can hopefully resolve its issues, i will get back to this stuff with some further details.
Thanks again for your time and help all of you.
JohnDee68
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Re: Fuel Consumption - What does X represent.

Post by JohnDee68 »

Okay all, sorry for another long one. I don't like to do things by halves :thumbup: ,

My TunerPro RT issue is now resolved, with the aid of Mark the TunerPro developer.

Referring to my VX 2002 V6 n/a 3800. Using the Enhanced versions of the TunerPro adx, xdf.

I have been looking at the whole fuel Economy and how it is calculated in the Enhanced version of the software and I thought this might be useful to help shed some light on the situation for others as it has done recently for myself.
On my cars dash it calculates and displays fuel economy as L/Hr. In the TunerPro adx it is trying to calculate fuel economy as some usage per kmph. Two different measurements which I think are unable to be compared. Hence why the readings from the TunerPro shows "inf" when stationary, something that isn't any use to myself. I know that if I am going at 100kmph and am running at 7L/hr on the dash, I am likely to be actually using about 7 L/100km from the tank (estimated only). (Previously it was up around the 11-14L/Hr which was reflected in the economy samples and worse than a friends v8 5.7L statesman.
I was trying to get what the unit of x is so I can use it to have the fuel economy in TunerPro RT display engine fuel economy as it does display on the dash (L/hr). I am close to getting the right calculated values. If I just use x/100 it is close, but not precise enough just yet. I think that the value of x to be calculated with the 0.02 Liters per hour should be of use for me going forward to create the formula for the result I want.

As I said I would, I have also finally managed to do an actual fuel economy test since I changed the Base Injector Rate to the Bosch injector spec values using the KinjFlow calculator. Now set at 554.98 msec/gram which was best for current injectors in the car.
I ensured I did very similar driving under the almost identical locations and conditions.
I previously got up to 12.88 L/100km.
This time was calculated to 10.02 L/100km.
I am also getting around 1.3-1.5L/hr at idle where before I was getting more in the region of 2- 2.2 L/hr.

To me that calculates as almost 30% fuel saving per tank of fuel.

With the engine now nearly right with the fuel consumption, I can now start to fine tune the engine for driving conditions best suited for a balance of economy and driving performance. I understand that not a lot, if any other people want economy as a priority, but it could be useful for the few that may want to for a daily vehicle to save some fuel.
immortality
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Re: Fuel Consumption - What does X represent.

Post by immortality »

The dash should display 2 different readings. When the engine is in idle mode it will display fuel used in litres/hr, once you start driving the dash will display litres/100km.

If you wish to calculate fuel usage accurately in tunerpro you will need to reference and use distance as part of the formula to calculate actual economy.

You should also be able to tune for economy and power in the same tune as they use different parts of the fuel/ignition maps.

You can also calibrate the trip computer, there are adjustments for actual fuel used as well as distance traveled.
JohnDee68
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Re: Fuel Consumption - What does X represent.

Post by JohnDee68 »

Again, thank you for your feedback and advice. You seem to live on here. :) Which is great for us who have issues.
immortality wrote:The dash should display 2 different readings. When the engine is in idle mode it will display fuel used in litres/hr, once you start driving the dash will display litres/100km.
No the display still shows it as L/Hr when non stationary?

In TunerPro it is only non stationary that it begins to give a value. This is because it uses y which is the vehicle speed. So naturally dividing by 0 (value of y at idle is zero) will create the inf result to the formula. It isn't so much i want the L/Km, i am fine with the L/hr for my needs. As I can simply do the live math when driving. For example, if I am at 50kmph doing 3.5 L/hr, then again near 7 L/hr at 100kmph, I know I am close to the mark for ultimate fuel savings.
immortality wrote:You should also be able to tune for economy and power in the same tune as they use different parts of the fuel/ignition maps.
I am not to sure yet on the next stage I need to go for tuning. This is still newish to me. I am currently taking the approach in this order.
Fuel mixture combined with manifold airflow obviously (almost happy with it so far), then on to Ignition (spark) timing. Followed lastly by transmission gear changing for smoother ride and max economizing. What's your thoughts on that sequence?
immortality wrote:You can also calibrate the trip computer, there are adjustments for actual fuel used as well as distance traveled.
Are you referring to in TunerPro Rt or the car it self? As there isn't in my version that I know of. I only have the single display version which requires me to use non user mode access.
immortality
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Re: Fuel Consumption - What does X represent.

Post by immortality »

Do you have the single window or 3 window dash?


I'm referring to calibrating the dash for distance and fuel used. Not tunerpro.
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Re: Fuel Consumption - What does X represent.

Post by antus »

Hopefully I dont confuse the issue more, but I dont think the output has anything to do with litres. Its either open time on the injector or as the1 mentioned something to do with the MAF. I think that is why the units dont make sense. If im right about this it means tunerpro would need to be able to consider the flow rate and maybe the opening time data for the injectors in the tune, and it can not do that. You cant use data from the bin+xdf equasion in an adx equation. It needs to be direct entered the ADX. If anyone knows more maybe we can document how to update your own copy of the ADX with that information for your car and tune.
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