Tundra 5.7, Flex Fuel engine vs. non Flex Fuel
- Thread starter Clutch
- Start date
tacoma_AL
Adventurer
I don't have any hands on experience with the 5.7 Tundra with Flex, however, some of the trucks we use at work are flex fuel and some of guys use it. I have noticed worse gas mileage with E85 vs Regular 87 here. It equals out in the long run, but I would just stick with 87 or what the Tundra calls for. I rather run diesel than E85 though if an option (I know it's not with the Tundra)
I'll add that I know a few of the guys I hang around use E85 flex kits in their cars to boost the power on turbo/blower additions. It actually does a good job, how it works though I couldn't really tell you.
I'll add that I know a few of the guys I hang around use E85 flex kits in their cars to boost the power on turbo/blower additions. It actually does a good job, how it works though I couldn't really tell you.
bkg
Explorer
Hmm. Fantastic question. I dropped my 2011 tundra because I was averaging about 14.... On a good day. It was an FFV. the other truck I test drove was a non FFV and was registering almost 20 on the digital readout, vs 14-15 on the FFV during test.
I do know the FGV "can't" suppert the supercharger.
Makes me wish I had more experience with the noN-FFV... May have been what I was missing on my crewmax
Edit. The best mileage I ever saw on my 2011 was 16 and change at 65mph while pissing off a lot of folks between Memphis and Nashville.
I do know the FGV "can't" suppert the supercharger.
Makes me wish I had more experience with the noN-FFV... May have been what I was missing on my crewmax
Edit. The best mileage I ever saw on my 2011 was 16 and change at 65mph while pissing off a lot of folks between Memphis and Nashville.
Abe Froman
Adventurer
Old POS tundra DC 4x4 stock with the non FF 5.7 never saw 15MPG.
I drive like an old man.
I got rid of it because of all the warranty issues, leaks, and transmission problems, but the mileage was horrible.
That isn't a great engine by any means, IMHO.
Happy day when I sold that truck with only 36k miles on it.
I drive like an old man.
I got rid of it because of all the warranty issues, leaks, and transmission problems, but the mileage was horrible.
That isn't a great engine by any means, IMHO.
Happy day when I sold that truck with only 36k miles on it.
Myfirsttruck
New member
I have 2014 crewmax flex fuel and average 17mpg mixed driving. I fill up with 87 ethanol free gas...
I don't know how some folks claim/achieve such terrible mileage with their Tundra.
My Tundra has a small lift and 275/70/18 BFG ATs--2008, DC, 4x4, 5.7L
My most recent longish trip was to Pagosa Springs, CO. I got something like 17.5 going up and 19.5 coming back. On a 3000 mile trip through the Rockies, loaded with a truck camper and sitting at 8000lbs GVW, I averaged 13.5 MPG. I have gotten 14 MGP towing a light race car on an open trailer throughout my state. I don't typically daily drive my Tundra, but when used as such, it averages around 15-16 MPG. BTW, mine is a non-FFV.
My Tundra has a small lift and 275/70/18 BFG ATs--2008, DC, 4x4, 5.7L
My most recent longish trip was to Pagosa Springs, CO. I got something like 17.5 going up and 19.5 coming back. On a 3000 mile trip through the Rockies, loaded with a truck camper and sitting at 8000lbs GVW, I averaged 13.5 MPG. I have gotten 14 MGP towing a light race car on an open trailer throughout my state. I don't typically daily drive my Tundra, but when used as such, it averages around 15-16 MPG. BTW, mine is a non-FFV.
Last edited:
amo292
Adventurer
Flex Fuel Vehicles get worse mileage when running E85 because the E85 has a higher combustion temp and is not as efficient as regular gasoline. My only explanation for lower fuel milage while running regular is that maybe they have the engine tuned for the less efficient fuel? I really have no prof its just a theory.
As for varying fuel milages between trucks there are so many variables that play a role there is really no saying whats causing a six mpg difference. Everything from elevation to temp can make a major difference. I live in an area where my over all average speed is never really more than 25 mph dropping my mpg to 13-12. If I go on trips or I am staying on the highway I can average 16-17 mpg no problem. Temp also plays a role in my mpg. Once there is a foot of snow on the ground and its below 20 degrees my milage is shot.
2008 TOYOTA TUNDRA DBL CAB 4X4 5.7
I run:
285/70R17 Cooper ST Maxx
are cold air intake
corsa exhaust
tracr rac in summer
cap in winter
As for varying fuel milages between trucks there are so many variables that play a role there is really no saying whats causing a six mpg difference. Everything from elevation to temp can make a major difference. I live in an area where my over all average speed is never really more than 25 mph dropping my mpg to 13-12. If I go on trips or I am staying on the highway I can average 16-17 mpg no problem. Temp also plays a role in my mpg. Once there is a foot of snow on the ground and its below 20 degrees my milage is shot.
2008 TOYOTA TUNDRA DBL CAB 4X4 5.7
I run:
285/70R17 Cooper ST Maxx
are cold air intake
corsa exhaust
tracr rac in summer
cap in winter
tacoma_AL
Adventurer
If they are both running 87 there should be no difference, once the E85 is run out of the system given they are under the same conditions
That's interesting about your Tacoma. When mine was running, 3.4, I didn't notice any major difference between the two; maybe the ethanol free has something to do with it, not sold around here. Mine got around 19 on the highway at 60-65 cruise control 14/15 city.
That's interesting about your Tacoma. When mine was running, 3.4, I didn't notice any major difference between the two; maybe the ethanol free has something to do with it, not sold around here. Mine got around 19 on the highway at 60-65 cruise control 14/15 city.
Clutch
<---Pass
Found the issue from the owner, apparently the fuel sensor on the Flex Fuel truck has a tendency to malfunction, when non-E85 is used the computer thinks it still is E85, thus causing a richer mix.
He had to take it to the dealer to reset it.
It has been like that since I bought it, it does not like low octane fuel. I know it is not supposed to make a difference, but it does in mine...it runs quite poorly too.
He had to take it to the dealer to reset it.
It has been like that since I bought it, it does not like low octane fuel. I know it is not supposed to make a difference, but it does in mine...it runs quite poorly too.