From Gas to Flex?

[Tom Joad]

HI,
Since I'll have to change the fuel pump i was wondering if I should or should not start to use flex-compatible stuff in case I would like to go flex.

What do you think?
Is there any difference between gas fuel pump and flex fuel pump?

 

[rockola1971]

I think the fuel injectors are higher volume on a flex vs your current setup because using E85 requires more fuel to the cylinders than when using regular unleaded. E85 offers zero advantage when it comes to costs to drive. In fact it costs 10-20% more per mile using E85. You actually get better gas mileage using regular unleaded. So why do it?

 

[iamdub]

I believe there's a sensor module somewhere along the fuel lines that tells the PCM the percentage of ethanol in the gasoline so it can adjust for it. Between that, the pump (if it's a special pump), the tuning, wiring, etc., and no real gains, it's not worth it at all to convert your truck to be E85 compatible. Most stations currently have a maximum of 10% ethanol, which is safe for regular non-flexfuel vehicles. It could just be my area, but I have yet to see a station with any higher percentages of ethanol. It's either E10 or ethanol-free fuel around here.

 

[Tom Joad]

I think the fuel injectors are higher volume on a flex vs your current setup because using E85 requires more fuel to the cylinders than when using regular unleaded. E85 offers zero advantage when it comes to costs to drive. In fact it costs 10-20% more per mile using E85. You actually get better gas mileage using regular unleaded. So why do it?

Because I'm not american. LOL

In my f..king socialist country the gas price is up to €1.45 per liter. I let you do the math but it's circa $8 a gallon.
In the same time, the E85 is sold here half price. Almost none of the US imported vehicule here runs on gas only. Mine runs on gas and LPG (Liquid Petrol Gas) which is also half the price of the regular gas.

I believe there's a sensor module somewhere along the fuel lines that tells the PCM the percentage of ethanol in the gasoline so it can adjust for it. Between that, the pump (if it's a special pump), the tuning, wiring, etc., and no real gains, it's not worth it at all to convert your truck to be E85 compatible. Most stations currently have a maximum of 10% ethanol, which is safe for regular non-flexfuel vehicles. It could just be my area, but I have yet to see a station with any higher percentages of ethanol. It's either E10 or ethanol-free fuel around here.

I give all my cars the 98 unleaded gas (98 is the octane level. It's your "premium" gas). But the Tahoe needs a lot of gas for an daily use. That's why it runs on LPG most of the time (Premium gas is used only to start the engin and bring it to temperature before it switches to LPG).
If I can use a small percentage of E85, I'll save some money. But I'm aware some rubber and plastic doesn't like ethanol vapors. That's why, since I have to change my pump, I'd like to change it for a flex-compatible one.

I've looked on Rockauto but I'm f..ed. It seems exported truck have a different fuel pump. I'll have to remove it from the tnak to see how it looks.

 

[rockola1971]

Your PCM (engine computer) will have a different program for a flex fuel and an octane sensor in the tank too so the PCM knows which program to run off of. (E85/Regular Unleaded) Tables.
It sounds like the math adds up for you over there in France, but it sure doesnt here where E85 is about 50 cents a gallon "cheaper" than regular unleaded (87 octane). Why are you running 98 octane for? If you dont have a high compression engine then you are just wasting your money. Your owners manual should show the min octane gas your vehicle will run correctly on. Our standard 5.3L runs just fine on 87 octane.

 

[rockola1971]

I believe there's a sensor module somewhere along the fuel lines that tells the PCM the percentage of ethanol in the gasoline so it can adjust for it. Between that, the pump (if it's a special pump), the tuning, wiring, etc., and no real gains, it's not worth it at all to convert your truck to be E85 compatible. Most stations currently have a maximum of 10% ethanol, which is safe for regular non-flexfuel vehicles. It could just be my area, but I have yet to see a station with any higher percentages of ethanol. It's either E10 or ethanol-free fuel around here.

E85 which is 85% ethanol is very common around here in the midwest where all the corn is. Youd think as far left leaning California is and so full of treehuggers that theyd be screaming for more E85...even though its already fact that it takes more energy to make E85 than it saves.

 

[Tom Joad]

I believe there's a sensor module somewhere along the fuel lines that tells the PCM the percentage of ethanol in the gasoline so it can adjust for it. Between that, the pump (if it's a special pump), the tuning, wiring, etc., and no real gains, it's not worth it at all to convert your truck to be E85 compatible. Most stations currently have a maximum of 10% ethanol, which is safe for regular non-flexfuel vehicles. It could just be my area, but I have yet to see a station with any higher percentages of ethanol. It's either E10 or ethanol-free fuel around here.

Your PCM (engine computer) will have a different program for a flex fuel and an octane sensor in the tank too so the PCM knows which program to run off of. (E85/Regular Unleaded) Tables.
It sounds like the math adds up for you over there in France, but it sure doesnt here where E85 is about 50 cents a gallon "cheaper" than regular unleaded (87 octane). Why are you running 98 octane for? If you dont have a high compression engine then you are just wasting your money. Your owners manual should show the min octane gas your vehicle will run correctly on. Our standard 5.3L runs just fine on 87 octane.

Why E85? Because it's cheaper and it could help me reduce costs.
Why "98" gas? Because the "95" is less energetic and, despite "95" is cheaper at the pump, you gotta go to the station more often. All savings are lost. That's reason one.
Reason two is I tried once E10 (which is now replacing the regular "95". After checking my sparkplugs they were all covered in red. Never saw that color in the Hanes manuals.
After using 98 again, Plugs get their normal color back. It teaches me a lesson : never use a gas that your engine is not made for.
That's why I'm planning to swap as much parts as I can to close match the Tahoe "Z" although mine is a "T".

E85 which is 85% ethanol is very common around here in the midwest where all the corn is. Youd think as far left leaning California is and so full of treehuggers that theyd be screaming for more E85...even though its already fact that it takes more energy to make E85 than it saves.

Sorry i didn't get the meaning of your phrase and the online translator neither. Are you running your truck on E85? IS it a "Z", flex-compatible?

 

[rockola1971]

Why E85? Because it's cheaper and it could help me reduce costs.
Why "98" gas? Because the "95" is less energetic and, despite "95" is cheaper at the pump, you gotta go to the station more often. All savings are lost. That's reason one.
Reason two is I tried once E10 (which is now replacing the regular "95". After checking my sparkplugs they were all covered in red. Never saw that color in the Hanes manuals.
After using 98 again, Plugs get their normal color back. It teaches me a lesson : never use a gas that your engine is not made for.
That's why I'm planning to swap as much parts as I can to close match the Tahoe "Z" although mine is a "T".


Sorry i didn't get the meaning of your phrase and the online translator neither. Are you running your truck on E85? IS it a "Z", flex-compatible?

I have (2) 03 Tahoes that are vin z flex fuel. I rarely run E85 in them . Only to clean injectors. Octane rating has nothing to do with "power" in a standard low compression engine. You will not make more horsepower using 98 versus 95 octane. The octane rating is a calculated number used to represent resistance to detonation (Preignition/Spark knock). It sounds as E85 would be cheaper to run where you are. It just isnt mathematically here. Although you would have to go fill up more often using E85 because it takes more of it to go the same distance as it would with regular unleaded.
To give you an example. If you would use 20 gals of regular unleaded (liters where you are) a week to drive back and forth to work, you would use approximately 22-25 gals (Liters) running on E85 to drive the same distance.
Dont forget to convert yours to a vin z (flex fuel) you will have to change the PCM program (possibly the whole PCM), fuel injectors, rewiring of the harness going to the PCM and the fuel system mods like the fuel pump, fuel lines, most likely all seals too.

 

[M1Gunner]

HI,
Since I'll have to change the fuel pump i was wondering if I should or should not start to use flex-compatible stuff in case I would like to go flex.

What do you think?
Is there any difference between gas fuel pump and flex fuel pump?

Running e85 may be cheaper in price per gallon where you are BUT your gas mileage is going to plummet!

I own a vin Z and run nothing but mid grade in it. Yes the fuel sending unit is completely different! Size and pressure. It is cheaper to purchase than the non flex sending units though.

 

[Tom Joad]

Running e85 may be cheaper in price per gallon where you are BUT your gas mileage is going to plummet!

I own a vin Z and run nothing but mid grade in it. Yes the fuel sending unit is completely different! Size and pressure. It is cheaper to purchase than the non flex sending units though.

I know that ! It's the same for the LPG. Even with a lower MPG I'm still saving money !
Since I won't be able to find a "Z" truck, let's come back to the subject of the thread : what's the difference between "Z" and "T" fuel pumps? Just a ethanol-resistant gasket?