[Ryan4544]

To anyone who is interested in the FJ cruiser's engine performance and how I was able through testing to improve gas mileage....

I purchased one of those Scangauge's that monitor mpg,horsepower,temperatures, etc... because I felt that I had horrible gas mileage I estimated to be around 14-15mpg.

After driving to work and back without changing my driving style I was averaging 14-16mpg. Being able to see the mpg change in realtime on the gauge I was able to adjust my driving to increase mpg and I was amazed at the differences acheived.

I have compiled a list of data that some may find interesting:

2007 FJ Cruiser 4x2 32" all-terrain tires w/3in lift, AT ****All data is taken from a flat surface @ 87-92F Intake air temp in high humidity(not sure of exact figure)... Shreveport, LA*****

0-25mph------14-21hp @ 0-6mpg!!!!!!!
25mph non-cruise --------17-19hp @ 28-35mpg
25mph cruise-------17-19hp @ 30- 35mpg
60mph non-cruise------ [email protected] 28-33mpg
60mph cruise [email protected] 28-35mpg
70mph cruise --------47-74hp @ 21-26mpg
70mph non-cruise----47-74hp @ 19-25mpg @ 3.45GPH!!!!!

By using cruise every chance I get I was able on one 20 mile trip home from work by way of downtown interstate driving to highway and then through suburban stop and go traffic I acheived a 24.1mpg avg

Additional information that some may find amusing....

AT ENGINE IDLE: .33gph @ 5.5hp with a/c compressor on .45gph @ 7.5hp

On regular unleaded gas I acheived 243hp by flooring it from 0 mph at a stop sign.

Without cruise engaged.... coasting down hills and slight slopes on the interstate registered 60-90mpg @ 10-14hp.

And as figured disengaging the engine from the transmission produces 60-90mpg at speeds above 20mph.

Next I'm going to see how much of a difference it makes while drafting behind an 18 wheeler:thinkerg:

Anyways... hope this was helpful to someone.

 

[tgormtx]

I need to get one of those installed. I regularly avg 17-18, but it could always be better.

Thanks for the detailed write up

 

[Ryan4544]

Yes It's a great tool. After a few fill ups with improved gas mileage it will pay for itself.

 

[Ivan70]

great info Ryan, SG2 is fantastic, probably paid for itself on my truck already. It really really taught me how to drive FJ and get the best out of it. I assume your data is for AT? Not 6MT.

 

[syncitizen]

I use the heck out of my SGII also. def payed for itself in saved gas through altered driving habits.

 

[Ryan4544]

Yes it's an AT.

 

[Layonnn]

I wouldn't trust the scangauges accuracy of MPG very well. I just use it as a ball park figure and use the pump and miles driven technique.

For instance, have you verified that your speed is exactly correct on the scangauge using a GPS? Every single FJ from the factory with factory sized tires shows it is going faster than it actually is. At 70 with factory tires, you are actually going about 68-69. With 285s, your speedometer is more accurate than with factory tires.

I use the heck out of my SGII also. def payed for itself in saved gas through altered driving habits.

This is the best way to use it to save gas. Monitoring your driving habits in real time will let you adjust accordingly.

 

[1911]

I wouldn't trust the scangauges accuracy of MPG very well. I just use it as a ball park figure and use the pump and miles driven technique.

+1

Those devices just use engine vacuum to estimate instantaneous mpg and are not accurate for actual mpg. No doubt that they can teach you to have better driving habits, but the mpg from them is all relative, not absolute at all.

 

[Lucario Runner]

To gain the most MPG you need to keep engine load down to a minimum, ie low revs. Other thing of course are tires, aerodynamics, weight, etc but those really aren't in favor of the fj so it really comes down how you drive it and maintain it. Wanna see the most mpg, drive like grandma.

 

[Ivan70]

To gain the most MPG you need to keep engine load down to a minimum, ie low revs.

That might work for AT, amazingly 6MT likes RPM, if you keep it down to minimum it eats gas like there is no tomorrow. SG2 told me that :lol:

As said above, tracking MPG with SG2 is nowhere near as accurate as "ball park figure and use the pump and miles driven technique" but it sure helps to figure out optimal driving style.

 

[Woodsman]

To gain the most MPG you need to keep engine load down to a minimum, ie low revs. Other thing of course are tires, aerodynamics, weight, etc but those really aren't in favor of the fj so it really comes down how you drive it and maintain it. Wanna see the most mpg, drive like grandma.

Yup. I have a Scanguage but it hasn't taught me anything I didn't already know: careful driving at or below the speed limit (when on the interstate) will give the best results. Local mileage will always suck.

On my trip back from Cruise Moab, I nailed down tanks of 18mpg, 20.4 mpg and 19 mpg getting me from Moab to central Kansas. After that, nasty winds put the kibosh on good mileage. Considering my weight and setup, those numbers are about as good as it gets ... short of driving home at 45-50 mph and that isn't going to happen.

 

[BoneheadNW]

That might work for AT, amazingly 6MT likes RPM, if you keep it down to minimum it eats gas like there is no tomorrow. SG2 told me that :lol:

Ditto here. Driving my 4.5 mile commute where the speed limit varies from 25-40 mph has taught me that keeping the revs around 2500 is the best. Unfortunately, with this type of driving, 15 mpg is considered good with my 6MT.
Bonehead

 

[Ivan70]

I wish i had to drive 4.5 miles to work 60 miles round trip for me.

 

[combatbevo]

My Nuvi has a Eco feature on it where you enter gas prices, mpg, etc; And it gives you a number based on your driving habits, 0-99, and then everytime you shut off your engine it tells you how much fuel you've used, mpg, etc. I've found this alot more useful, along with the dividing miles driven by gallons pumped=ball park mpg.

 

[JPR]

I need to get one of those to see if I can better my driving habbits. I try to keep my 6MT when commuting to work around 1500 rpms but I really dont see that much diffrence. I used to get 280 miles per tank and now i am just getting 240 - 250 max.

I just changed my plugs back from the E3 to Denso IKH20 recommended by URD and a few other people. Also cleaned my air filter and sensor. lets see if that helps out a bit.

 

[Ivan70]

I need to get one of those to see if I can better my driving habbits. I try to keep my 6MT when commuting to work around 1500 rpms but I really dont see that much diffrence. I used to get 280 miles per tank and now i am just getting 240 - 250 max.

6MT hates 1500 rpm and burns whole at lot more gas then on 2000-2200. :cheers:

 

[JPR]

6MT hates 1500 rpm and burns whole at lot more gas then on 2000-2200. :cheers:

good to know!!! i'll experiment and increase my rpms to 2000 -2200 and see how it goes.

Thanks

 

[Pappylaz]

+1

Those devices just use engine vacuum to estimate instantaneous mpg and are not accurate for actual mpg. No doubt that they can teach you to have better driving habits, but the mpg from them is all relative, not absolute at all.

Mine plugs into the OBDII connector and reads codes from the system and computer, it will read engine temp, fuel flow rate, GPH consumption, vehicle speed, etc. and not by vaccum.

 

[SWITAWI]

Mine plugs into the OBDII connector and reads codes from the system and computer, it will read engine temp, fuel flow rate, GPH consumption, vehicle speed, etc. and not by vaccum.

And it is entirely probable that the ECU is using vacuum pressure along with other sensor readings to produce those displayed values. I would think that vacuum and RPM would be the primary indicators for rate increase/decrease in an ECU. :cheers:

 

[1911]

Mine plugs into the OBDII connector and reads codes from the system and computer, it will read engine temp, fuel flow rate, GPH consumption, vehicle speed, etc. and not by vaccum.

How does it know how much gas you put in the tank and at what miles? As has been said, that is the only accurate way to know your mpg.

... the ECU is using vacuum pressure along with other sensor readings to produce those displayed values.

Bingo.