Modifications To Improve Gas Mileage (1 Viewer)

Lonegrasshopper

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Joined
Sep 18, 2014
Messages
231
Location
Dallas, TX
Holy crap. This is never going to change. I was chasing this ghost about 30 years ago with my FJ60. Hate to break it you, but no matter what you do you'll never improve your gas mileage. Nothing has changed since the 2F. Our mileage sucks, accept it, we drive a Land Cruiser.
 
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flintknapper

SILVER Star
Joined
May 22, 2004
Messages
9,026
Location
Deep East Texas
Sssshhhh...no one want's to believe this. No one understands octane ratings, and if you purchase 87 at the pump you might get 92. If it's not pinging, don't worry about it. People want to believe the high performance comes from the fuel, not that their high performance engines require the fuel.


Hah!

Actually what happens is that unscrupulous station/store owners purposely 'Over Order' low octane fuel. Then when the tank won't hold it....the driver is forced to 'dump' the remaining fuel in the next octane tank up (if it will hold it). When we had vendors that would do this very often, we would cut them off and report them the Texas Railroad Commission.

So if anything....you are probably getting 'diluted' fuel.
 

MJK

Joined
Mar 14, 2020
Messages
470
Location
Tucson
I get 16ish driving in light city traffic with a stock 05 on Michelins LTXs. Synthetic diff fluids seem to help a bit.
 
Joined
Aug 17, 2020
Messages
530
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likely in the salvage yard
Hah!

Actually what happens is that unscrupulous station/store owners purposely 'Over Order' low octane fuel. Then when the tank won't hold it....the driver is forced to 'dump' the remaining fuel in the next octane tank up (if it will hold it). When we had vendors that would do this very often, we would cut them off and report them the Texas Railroad Commission.

So if anything....you are probably getting 'diluted' fuel.
Spent three years working at an oil and fuel distributor in Louisiana. Every tank we supplied fuel or oil(exxon/mobil branded) had an electronic guage connected to the internet connected to our dispatchers office. He could tell what was in their tanks before the station or oil change businesses even knew what was in their tanks and auto dispatched accordingly. This was in 2009. I imagine this technology is pretty prevalent in the country by now.
 

flintknapper

SILVER Star
Joined
May 22, 2004
Messages
9,026
Location
Deep East Texas
Spent three years working at an oil and fuel distributor in Louisiana. Every tank we supplied fuel or oil(exxon/mobil branded) had an electronic guage connected to the internet connected to our dispatchers office. He could tell what was in their tanks before the station or oil change businesses even knew what was in their tanks and auto dispatched accordingly. This was in 2009. I imagine this technology is pretty prevalent in the country by now.

No doubt. My experience dispatching goes back farther than that....so no such technology at that time, but the practice of dumping/mixing fuels is still a reality. Not a big deal in small amounts and common IF the person reading the 'stick' makes a mistake or is simply too lazy to measure the tank and just orders what they 'think' they will need. The tanker driver is not going to bring back fuel (small amounts) so they dump it into the next reservoir. I'm not saying this is a rampant problem...but it does happen. The company I worked for was quick to crack down it....since there are severe fines involved.
 
Joined
Aug 10, 2016
Messages
245
Location
Atlanta, GA
Rebuild your charcoal canister and stop all evap leaks. +2 MPG to my average since I did it in late August:

View attachment 2490481

@J1000 So did you charcoal canister give you any CEL before you redid you Charcoal can? Its not like anyone would just try to mess with this unless any CEL are thrown. Especially for the folks that live in a emissions state/city. The CEL for this is a long long list of items that if messed up is a PITA to fix.
 
Joined
Aug 14, 2018
Messages
664
Location
Morrison, CO
I only calculate my average MPG when I fill up and I do them with Fuelly, not the trip computer. I can't think of anything else that would influence the mileage that much over the SAME route/speeds/weather, etc. I always start the trip with a full tank and use 3/4 tank or more on the way to the track. Then fill up before the return trip. If I do the same trip the next week, the mileage can either stay the same or vary up to 1.5MPG, which when we are dealing with single digit numbers, is significant.
Just because you do it that way doesn't mean it's the only way. I also use Fuelly. I can fill my tank any time I want and calculate average MPG, I can fill it when it's already 3/4 full if I wanted!

Maybe experiment and you will notice things you hadn't before.

@J1000 So did you charcoal canister give you any CEL before you redid you Charcoal can? Its not like anyone would just try to mess with this unless any CEL are thrown. Especially for the folks that live in a emissions state/city. The CEL for this is a long long list of items that if messed up is a PITA to fix.
No, I didn't have any CELs. I just noticed my MPG was inconsistent one day vs. another or on long trips vs. short trips. I also noticed my truck smelled like gas fumes a lot, but now it doesn't.
 
Joined
Sep 15, 2016
Messages
697
Location
Durham, NC
Just because you do it that way doesn't mean it's the only way. I also use Fuelly. I can fill my tank any time I want and calculate average MPG, I can fill it when it's already 3/4 full if I wanted!

Maybe experiment and you will notice things you hadn't before.

Yes, obviously you can calculate MPG at any point..., I'm just saying for these tests that I generally am calculating at an essentially complete fill up. I don't notice any vast difference in MPG on my Scanguage between first and second half of the tank.

The point of my comment was to give the OP something else to consider, make sure PM items are up to date that may cause excess drag on the motor.
 
Joined
Apr 6, 2019
Messages
137
Location
Portland, ME
Some advice from my personal experience (2006 VVT-i 5 Spd):

Listed in order of biggest effect to smallest:

1. If your tires are large diameter than stock, you need to increase your indicated MPG by the difference in diameter from the stock tires. Also inflate to higher than the reccomended pressure for highway driving.

2. I changed my front O2's and changed the gear oil in all 3 differentials from Mobil HD 80W-90 dino to Amsoil Severe Gear 75W-90 synthetic. I noticed an improvement of around 0.33 to 0.50 MPG. Don't know which made the bigger difference, both were done on the same day. Gear oil makes a bigger difference in colder climates and shorter average trip lengths.

3. Lucas Upper Cylinder Lubricant seems to help. Buy an 8 oz bottle and a gallon at Wally World. Fill the 8-oz from the gallon and put it in with each full tank. Seems to improve around 0.1 to 0.2 MPG for minimal cost. Found out about that stuff from the head tech guru for the BMW Club of America.

4. Don't run overly thick motor oil. 5W-30 is enough for good oil pressure, and Toyota started factory filling with 5W-20 around February 2006. If you're concerned about ZDDP, buy a bottle of racing motor oil and blend a little bit in to boost the Zn-P.

5. Get a cleanable air filter. I'm running a AFE Pro Dry S. Clean once a year or no more than 20k miles.

I'm getting around 15 MPG in mostly highway driving (prob about 70% highway). I've verified this by checking trip ODO against gallons used.

I have seen (corrected for tire size) just under 17 MPG when getting on the highway just after refuelling and checking the tip computer before slowing down or stopping.
 
Joined
Sep 17, 2020
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Driving across the USA
Putting in a ScanGuage had an immediate impact on MPG. It's a bit like seeing a reminder to check your posture every 10 minutes, and makes me drive more consciously when it comes to acceleration/cruise control/etc.

A TPMS was also a quick fix, but that's more of a "I hate having to check after every swing in the temp or road trip" type of improvement.
 
Joined
Apr 28, 2020
Messages
38
Location
Orange County, CA
Like NoTempoLimit said, larger diameter tires than stock affect the odometer readings and by extension, your calculated MPG. In our case, stock LC has 31" diameter tires and I'm running 33" diameter tires. The adjustment is 33/31 = 1.06 meaning for every mile your odometer reads, you actually traveled 6% farther. You can apply the correction factor to your odometer reading OR to your MPG calculation. Either way, you'll get the same MPG result.

Ex: 250 miles on odometer / 18 gallon fill-up = 13.88 MPG. Multiply that by 1.06 correction = 14.7 MPG (corrected)
Ex: 250 miles on odometer x 1.06 correction = 265 miles driven. Divide by 18 gallon fill-up = 14.7 MPG (corrected)

BTW, the correction factor also applies to your speedometer. You're actually driving 6% faster than the speedo shows. Try comparing vehicle speedometer to a GPS based speed readout on your phone/GPS.


With bigger AT or MT tires, you can safely fill to higher pressure for pavement driving. I use 40 PSI cold for street driving with AT tires, there is significant MPG gain on the highway with higher tire pressures. City driving you won't notice it as much with all the accelerating from a stop.


Also, rehabbing your EVAP system can improve MPG if the system is not working efficiently. You often will not have any CEL codes or obvious signs of problems with the EVAP system. EVAP, in part, helps capture fuel vapors and reintroduces it into the intake stream, reducing emissions, but also improving fuel efficiency. The cheapest way is just to take 3/4" fuel line hose from the auto parts store and cut to length to replace all the sections in the EVAP system. The valves in the EVAP system and on the carbon canister are also available as spare parts either OEM or rock-auto, etc. The carbon canister itself is kind of hard to service and replacement can be expensive.

You might also want to replace PCV valve stuff. Wit's End has a kit:
 
Joined
Apr 6, 2019
Messages
137
Location
Portland, ME
Putting in a ScanGuage had an immediate impact on MPG.

I have a ScanGage. Great idea but I did not realize that it expected you to input the fuel you put in EVERY TIME you get gas. Once I got too busy to do that on the trip from L.A. to Maine, the MPG reading got super inaccurate.

I don't know if there is a fix, but once I got it displaying my transmission temperature I don't want to mess with it. So I don't display its MPG readings anymore.

Didn't know about EVAP having an influence before reading this thread. Any good links to doing a baseline on the Evap system?
 
Joined
Jul 19, 2018
Messages
549
Location
Northwest Montana
How about actually calculating gas milegae based on a full tank divided by the number of gallons put into the tank. I don't have a fancy MPG average on my dash but I would think they may not be the most accurate?
 
Joined
Apr 6, 2019
Messages
137
Location
Portland, ME
How about actually calculating gas milegae based on a full tank divided by the number of gallons put into the tank.

That's how I got the 15 MPG average. It's actually slightly higher than 15. I would need to check the gas receipts I calculated it on and wrote it down. I think some tanks may have averaged 15.5.
 
Joined
Sep 25, 2004
Messages
3,502
Location
Gleneagle, CO
My cruiser gets a very consistent 13 mpg.

Good Cruiser mileage is not a thing. Not really a Toyota thing. Reliability is Toyota's focus.

Fantastic fuel economy is like any other high performance goal. Diminishing returns and compromises to reliability.

If you can get the top gear in the best rpm range and stay there at 45-50 mph for a long trip then you can get much better mileage.
 
Joined
May 26, 2008
Messages
277
Location
Leduc County
Some advice from my personal experience (2006 VVT-i 5 Spd):

Listed in order of biggest effect to smallest:

1. If your tires are large diameter than stock, you need to increase your indicated MPG by the difference in diameter from the stock tires. Also inflate to higher than the reccomended pressure for highway driving.

2. I changed my front O2's and changed the gear oil in all 3 differentials from Mobil HD 80W-90 dino to Amsoil Severe Gear 75W-90 synthetic. I noticed an improvement of around 0.33 to 0.50 MPG. Don't know which made the bigger difference, both were done on the same day. Gear oil makes a bigger difference in colder climates and shorter average trip lengths.

3. Lucas Upper Cylinder Lubricant seems to help. Buy an 8 oz bottle and a gallon at Wally World. Fill the 8-oz from the gallon and put it in with each full tank. Seems to improve around 0.1 to 0.2 MPG for minimal cost. Found out about that stuff from the head tech guru for the BMW Club of America.

4. Don't run overly thick motor oil. 5W-30 is enough for good oil pressure, and Toyota started factory filling with 5W-20 around February 2006. If you're concerned about ZDDP, buy a bottle of racing motor oil and blend a little bit in to boost the Zn-P.

5. Get a cleanable air filter. I'm running a AFE Pro Dry S. Clean once a year or no more than 20k miles.

I'm getting around 15 MPG in mostly highway driving (prob about 70% highway). I've verified this by checking trip ODO against gallons used.

I have seen (corrected for tire size) just under 17 MPG when getting on the highway just after refuelling and checking the tip computer before slowing down or stopping.
Great list! Thank you. Definately going to do 2, probably 3 and maybe 4. Inflating tires in winter up here is a no-no, but for summer driving fore sure.
Regards
OP
 
Joined
May 26, 2008
Messages
277
Location
Leduc County
Like NoTempoLimit said, larger diameter tires than stock affect the odometer readings and by extension, your calculated MPG. In our case, stock LC has 31" diameter tires and I'm running 33" diameter tires. The adjustment is 33/31 = 1.06 meaning for every mile your odometer reads, you actually traveled 6% farther. You can apply the correction factor to your odometer reading OR to your MPG calculation. Either way, you'll get the same MPG result.

Ex: 250 miles on odometer / 18 gallon fill-up = 13.88 MPG. Multiply that by 1.06 correction = 14.7 MPG (corrected)
Ex: 250 miles on odometer x 1.06 correction = 265 miles driven. Divide by 18 gallon fill-up = 14.7 MPG (corrected)

BTW, the correction factor also applies to your speedometer. You're actually driving 6% faster than the speedo shows. Try comparing vehicle speedometer to a GPS based speed readout on your phone/GPS.


With bigger AT or MT tires, you can safely fill to higher pressure for pavement driving. I use 40 PSI cold for street driving with AT tires, there is significant MPG gain on the highway with higher tire pressures. City driving you won't notice it as much with all the accelerating from a stop.


Also, rehabbing your EVAP system can improve MPG if the system is not working efficiently. You often will not have any CEL codes or obvious signs of problems with the EVAP system. EVAP, in part, helps capture fuel vapors and reintroduces it into the intake stream, reducing emissions, but also improving fuel efficiency. The cheapest way is just to take 3/4" fuel line hose from the auto parts store and cut to length to replace all the sections in the EVAP system. The valves in the EVAP system and on the carbon canister are also available as spare parts either OEM or rock-auto, etc. The carbon canister itself is kind of hard to service and replacement can be expensive.

You might also want to replace PCV valve stuff. Wit's End has a kit:
Thanks for that. EVAP system seems to be something to consider but why would refreshing the hoses make a difference? Do they leak, crack, clog or plug off somehow?
 
Joined
May 26, 2008
Messages
277
Location
Leduc County
My cruiser gets a very consistent 13 mpg.

Good Cruiser mileage is not a thing. Not really a Toyota thing. Reliability is Toyota's focus.

Fantastic fuel economy is like any other high performance goal. Diminishing returns and compromises to reliability.

If you can get the top gear in the best rpm range and stay there at 45-50 mph for a long trip then you can get much better mileage.
No wonder I get better mileage in a Blizzard!
 

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