V6 fuel mileage

[mikeinaus]

i started logging my milage with an app (fuellog) for the past month since i got my new phone.

my last 3 fill ups with chevron 94 ive gotten exactly 9.85L/100km, 10.46L/100km and 9.95L/100km. my current tank ive been babying (shifting at 2.5k-3k rpm) to see if it nets a significant change in milage. im planning on running different octanes for a month at a time and see what impact it has on my milage. most of my driving is city and i am usually fairly heavy on the gas so im not expecting much changes.

farthest ive gotten with this car on a tank was 415km with mostly highway, and i was driving fairly hard in high altitude. i also fill up as soon as my light comes on...

94 mx3 with klze/probinator , short ram intake, 2.5" catback, 205/40/17 falken azenis tires, and new wheel bearings, and live at sea level if that makes any difference.

[wytbishop]

It's funny but this time of year when the weather starts to cool down sharply my mileage takes a significant downturn. I can already see it in the tank of fuel I bought late last week. I'll be lucky to get 400 km from this one.

I'm going to start a separate log in my iphone app for winter and see exactly what the difference is from my summer mileage.

[mitmaks]

You will be more precise if you hand calculate your mpg, not using your apps or in-dash monitors, etc.

[mikeinaus]

how exactly? i imput my odometer reading, price per liter, and total liters in fill up and the program does the math as well as logging it for me. ive always kept a rough estimate in my head and i average around 10L/100km which is exactly what the app is telling me... the program will also track maintenance costs and give me multiple breakdowns on cost per day-week-month-year. its a good way to keep track of the cost of your car vs buying a newer one with better milage/less maintenance. not that i plan on getting rid of my car anytime soon...

[wytbishop]

The iPhone app does exactly what and paper logbook or one of those gas station fuel log things does...it's just faster.

[_-Night-Shade-_]

It's funny but this time of year when the weather starts to cool down sharply my mileage takes a significant downturn. I can already see it in the tank of fuel I bought late last week. I'll be lucky to get 400 km from this one.

I'm going to start a separate log in my iphone app for winter and see exactly what the difference is from my summer mileage.

How's your thermostat? Does your car take a while to warm up? It might never be fully closing and the effect is more noticeable with colder temperatures a.k.a. winter.

[Daninski]

I never let my car idle to warm up. Right after start up I hammer the gas pedal to the floor and look out schools kids cuz I'm bring that motor up to operating temp mach shnell. Takes about 1.5 minutes and I'm at 190deg with the idle at 700rpm. Mileage is great but the cost is kinda off set buy spun crank bearings.

[_-Night-Shade-_]

Yes, I'm sure everyone knows your driving habits Mr. 8,000RPM

[wytbishop]

cooling system works great. I have had other non-related troubles with it in the past so I keep a close eye on it. And it's not cold enough yet to consider extended warm up times...though like you Dan I don't idle in the cold any more than I have to.

No this has happened every spring and fall since I got the car. My thoughts have always been that the colder air is triggering a fueling change in the ECU and just the fact that the air is a little denser which may also trigger heavier fueling, though I'm not convinced of that one.

[_-Night-Shade-_]

I never bought that theory. I would imagine if the air is denser and therefore more fuel is being dumped, there would be more power produced and you'd be on the throttle less as a result. Everything evens itself out.

[Ryan]

They actually do change the fuel composition in fall/winter. I read why a little while ago... something to do with vapour pressure.

[mikeinaus]

whats everyones city mileage? ive been babying my last 2 tanks and they had the worst mileage ive gotten since i started keeping track. both were however the only tanks ive used completely in the city. first tank was 12.13L/100km and the one i just filled up with was 12.42l/100km. all my other tanks were city/highway blend and i averaged about 10l/100km of spirited driving.

for city driving ive been shifting between 2.5k-3krpm.

[MrMazda92]

Best was about 32.2 MPG, or roughly 13.6 K/L, average is closer to 30.

[mikeinaus]

Wow was that a k8 or kl? Was that city driving? I can't even get close to that even on the highway.

[MrMazda92]

Wow was that a k8 or kl? Was that city driving? I can't even get close to that even on the highway.

It's with a K8, I can't top 28 highway. Never could, no matter how hard I try. I shift at 2-2.2k around town, and run HIGH psi on my tires.