How do flex fuel vehicles sense E85?
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I was told that my 09 F150 5.4L simply relies on the 4 oxygen sensors to adjust the "offset" for the fueling tables. And, once it's in the E-85 range, more advanced ignition timing is allowed.
Interestingly, when transitioning from regular gasoline to E-85, the truck runs a bit oddly. And certainly is down on power. After a few miles (maybe 20) , the truck picks up a good bit of mid range torque on E-85.
I prefer E-85 in the Florida summers. It really "wakes up" my truck. And it's use more than offsets the power loss that comes with 100 degree days.
Interestingly, when transitioning from regular gasoline to E-85, the truck runs a bit oddly. And certainly is down on power. After a few miles (maybe 20) , the truck picks up a good bit of mid range torque on E-85.
I prefer E-85 in the Florida summers. It really "wakes up" my truck. And it's use more than offsets the power loss that comes with 100 degree days.
The system I've read up on measures the index of refraction (how much it bends a light beam) of the fuel passing through the fuel rail and adjusts in real-time.
My Ram 1500 with the flex-fuel 4.7 (don't know what system it actually uses) doesn't flinch or change a lick when you switch to E-85 or back to regular. No hard starting, no change in idle... just more power after its fully on E-85 because the octane is so high that the timing can be advanced all the way to the engine's optimum limit.
Of course mileage drops by about 3-4 mpg, and that's starting at about 16 in the city and dropping to 12.5-13. I did the math a few months ago, and despite E85 being 30 cents a gallon cheaper than regular unleaded it still cost about 3 cents a mile more to run E-85.
My Ram 1500 with the flex-fuel 4.7 (don't know what system it actually uses) doesn't flinch or change a lick when you switch to E-85 or back to regular. No hard starting, no change in idle... just more power after its fully on E-85 because the octane is so high that the timing can be advanced all the way to the engine's optimum limit.
Of course mileage drops by about 3-4 mpg, and that's starting at about 16 in the city and dropping to 12.5-13. I did the math a few months ago, and despite E85 being 30 cents a gallon cheaper than regular unleaded it still cost about 3 cents a mile more to run E-85.
Interesting. I've read a few complaints about low mpg's on Tundras, and I know mine seems a bit lower than I expected, thus I'm curious. [I'm 99% sure mine is flex fuel, need to double check it.] I'd think it'd flag something for something amiss, but one never knows.
Thanks.
Thanks.
how long before the hot rodders figure out how to hop it up?
Supton: lower mileage with E85 is expected and perfectly normal. Something would be wrong if it WEREN'T lower, because E85 has less energy per gallon than gasoline, and the injectors have to spray more E85 per cylinder stroke to get the air/fuel ratio correct.
Morris: there's already an E85 community among hotrodders and weekend racers. Companies like Edelbrock, Barry Grant, and others already have high performance carburetors set up and jetted for E-85. The equivalent octane rating is well over 100 for E85 which lets you run huge compression ratios without detonation.
Morris: there's already an E85 community among hotrodders and weekend racers. Companies like Edelbrock, Barry Grant, and others already have high performance carburetors set up and jetted for E-85. The equivalent octane rating is well over 100 for E85 which lets you run huge compression ratios without detonation.
Older Flex Fuel Fords used an actual standalone part called a flex fuel senor or ethanol sensor, but I don't know how it worked.
Mine is a flex fuel vehicle, but does not have the sensor, so it must be going off the O2 sensors. It seems to adjust pretty quickly and there is a noticeable improvement in power, but also a big decrease in fuel economy, usually around 5 MPG below regular gas.
Mine is a flex fuel vehicle, but does not have the sensor, so it must be going off the O2 sensors. It seems to adjust pretty quickly and there is a noticeable improvement in power, but also a big decrease in fuel economy, usually around 5 MPG below regular gas.
Sometimes the sensors are built into the pump. I have seen a same vehicle have a regular pump around $500 and the Flex Fuel one be $800-1200.
Originally Posted By: bdcardinal
Sometimes the sensors are built into the pump. I have seen a same vehicle have a regular pump around $500 and the Flex Fuel one be $800-1200.
Yeah, mine is $600, non-FFV ones are $450-$480.
Sometimes the sensors are built into the pump. I have seen a same vehicle have a regular pump around $500 and the Flex Fuel one be $800-1200.
Yeah, mine is $600, non-FFV ones are $450-$480.
Originally Posted By: 440Magnum
Supton: lower mileage with E85 is expected and perfectly normal. Something would be wrong if it WEREN'T lower, because E85 has less energy per gallon than gasoline, and the injectors have to spray more E85 per cylinder stroke to get the air/fuel ratio correct.
Oh, I know. However, there's been an issue on the Tundra's, maybe not widespread, where people are getting E85 mpg's while running E10. I feel my truck is getting low mpg's too, just not that low. So I'm trying to understand a bit how the system senses ethanol.
[Actually, I'm now 99% sure I don't have a FFV engine, so that's a dead end.]
Supton: lower mileage with E85 is expected and perfectly normal. Something would be wrong if it WEREN'T lower, because E85 has less energy per gallon than gasoline, and the injectors have to spray more E85 per cylinder stroke to get the air/fuel ratio correct.
Oh, I know. However, there's been an issue on the Tundra's, maybe not widespread, where people are getting E85 mpg's while running E10. I feel my truck is getting low mpg's too, just not that low. So I'm trying to understand a bit how the system senses ethanol.
[Actually, I'm now 99% sure I don't have a FFV engine, so that's a dead end.]
Originally Posted By: morris
how long before the hot rodders figure out how to hop it up?
Actually, there are tunes out there for the Audi 2.7t that can then run E-85. It is all predicated on the 4 O2 sensors reading the exhaust and upgrading the fuel injectors and FPR to handle the increased volume of fuel. That, and the turbos are turned up to their maximum efficiency.
It puts the stock 250hp V6 into the upper end of 300hp for <$800.
how long before the hot rodders figure out how to hop it up?
Actually, there are tunes out there for the Audi 2.7t that can then run E-85. It is all predicated on the 4 O2 sensors reading the exhaust and upgrading the fuel injectors and FPR to handle the increased volume of fuel. That, and the turbos are turned up to their maximum efficiency.
It puts the stock 250hp V6 into the upper end of 300hp for <$800.
Originally Posted By: morris
how long before the hot rodders figure out how to hop it up?
As you know, E85 fuel injection adjusts all by itself.
But E85 carburetors have been on the market for quite some time. Of course, high compression pistons have been on the market for decades. Put them together and it's just a matter of fine tuning.
how long before the hot rodders figure out how to hop it up?
As you know, E85 fuel injection adjusts all by itself.
But E85 carburetors have been on the market for quite some time. Of course, high compression pistons have been on the market for decades. Put them together and it's just a matter of fine tuning.
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