Fuel Mileage Expectations
#1
Instructor
Thread Starter
Fuel Mileage Expectations
I'm wondering what gas mileage I should be getting in my 3.2 A/T? On a road trip, my economy meter says I'm getting between 7-8 L/100km, when in fact I averaged around 9.5-10. I was averaging around 110kmh on 2 lane highway for about 90 minutes and 130kmh on 4 lane freeway for 30 minutes. It was 0 Celsius outside. Am I getting pretty normal gas mileage? What speeds would I have to do to get closer to 7.5-8 average?
#2
Latent car nut
iTrader: (2)
Most likely your economy meter is more accurate than your calculations. Keep in mind, unless you average at least three full tanks (five would be better), of fuel together, your hand calculations for fuel economy will almost always be incorrect.
For my car I typically see about 6.75-7.00 liters per 100km when doing steady state cruising on the highway and more like 9.00 liters per 100km during my day-to-day driving. That said, my car has a manual transmission, so it will most likely be a bit better than what you can expect with an automatic transmission.
For my car I typically see about 6.75-7.00 liters per 100km when doing steady state cruising on the highway and more like 9.00 liters per 100km during my day-to-day driving. That said, my car has a manual transmission, so it will most likely be a bit better than what you can expect with an automatic transmission.
#3
Instructor
Thread Starter
Most likely your economy meter is more accurate than your calculations. Keep in mind, unless you average at least three full tanks (five would be better), of fuel together, your hand calculations for fuel economy will almost always be incorrect.
For my car I typically see about 6.75-7.00 liters per 100km when doing steady state cruising on the highway and more like 9.00 liters per 100km during my day-to-day driving. That said, my car has a manual transmission, so it will most likely be a bit better than what you can expect with an automatic transmission.
For my car I typically see about 6.75-7.00 liters per 100km when doing steady state cruising on the highway and more like 9.00 liters per 100km during my day-to-day driving. That said, my car has a manual transmission, so it will most likely be a bit better than what you can expect with an automatic transmission.
#4
Latent car nut
iTrader: (2)
A few comments:
- My best fuel economy runs were done at about 120 kph, my single best tank of fuel yielded 855.69km on 56.34 liters, which works out to 6.58 liters per 100km; the OAT was about 4°C.
- Anecdotal reports consistently indicate our cars run best with the OEM NGK plugs; your Denso plugs might be the issue.
- As a general rule, coils either work or they don't, there really isn't a situation where they will work under normal circumstances and then not work at high RPMs.
- Lucas injector cleaner is an absolute waste of money.
- Seafoam is another absolute waste of money.
#5
Instructor
Thread Starter
A few comments:
- My best fuel economy runs were done at about 120 kph, my single best tank of fuel yielded 855.69km on 56.34 liters, which works out to 6.58 liters per 100km; the OAT was about 4°C.
- Anecdotal reports consistently indicate our cars run best with the OEM NGK plugs; your Denso plugs might be the issue.
- As a general rule, coils either work or they don't, there really isn't a situation where they will work under normal circumstances and then not work at high RPMs.
- Lucas injector cleaner is an absolute waste of money.
- Seafoam is another absolute waste of money.
#6
Latent car nut
iTrader: (2)
I do not believe our cars have a MAF sensor, instead they use a MAP, and quite honestly, I've never seen actual evidence a dirty MAP will cause such issues.
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#8
Instructor
Thread Starter
Well, I sure hope it's not a problem related to the spark plugs I just changed, but I'm sure the ngks might help a little. the car has a slightly rough idle that's consistent. Like I said, there was one time that I floored it to pass someone and the check engine light flashed when I hit red line, and eventually shut back off, I checked for engine codes and it had a cylinder 1&5 misfire. I used my blue driver to read o2 and map sensor data, they seem to be within spec. Maybe I ought to start with changing the coils on those cylinders
#9
What plugs did you use? Hopefully not some cheap ones from ebay or autolite.
#10
Instructor
Thread Starter
#12
Instructor
Thread Starter
It's the only thing my local Canadian Tire stocked other than champion copper plugs, I also figured since it was still a platinum plug and gapped at .040" I didn't think it would be an issue, surely it would run better than what was in there. At the time I didn't know running OEM Ngk's was so crucial at the time. I'm not quite convinced my plugs are causing this. The car has 360,000 kms on it and I think a lot of stuff is original, including coils, I noticed cylinder 2 coil has been replaced at some time. I've watched videos by MODSFOREVER, when he replaced coils and cleaned throttle body it made a huge difference. I'm thinking I will try throttle body cleaning, and looking into carbon buildup in the egr system, and potentially replacing coils.
#13
It's the only thing my local Canadian Tire stocked other than champion copper plugs, I also figured since it was still a platinum plug and gapped at .040" I didn't think it would be an issue, surely it would run better than what was in there. At the time I didn't know running OEM Ngk's was so crucial at the time. I'm not quite convinced my plugs are causing this. The car has 360,000 kms on it and I think a lot of stuff is original, including coils, I noticed cylinder 2 coil has been replaced at some time. I've watched videos by MODSFOREVER, when he replaced coils and cleaned throttle body it made a huge difference. I'm thinking I will try throttle body cleaning, and looking into carbon buildup in the egr system, and potentially replacing coils.
what tires are you running?
#14
Instructor
Thread Starter
Yea, I also don't think plugs are your mileage problem. Just curious as Rockauto has NGK and I am also from Canada. On my 3.5, I have to drive conservatively at 100-110 km/h to get 7-7.5L/100km on my touring MXM4 tires. Winters get me 8.5-9L/100km on my very new and sticky Xi3.
what tires are you running?
what tires are you running?
#15
Instructor
Thread Starter
Well tonight I did a Seafoam treatment by spraying the aerosol version on the throttle plate and following up with throttle body cleaner once the motor was hot soaking. There was quite a bit of carbon in the intake and the car definitely runs better and idles smoother. It's not perfect but a big improvement, I'll monitor my gas mileage for a bit and see if there's some improvement
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