Lpfp e85 limit

[Dubesa05]

As I just ordered my PI and intake mani, I see a lot of stuff saying stock LPFP will run 700-750hp. Is that full e-85 or a blended mix? Do we know what it will run full e-85? I have a gas station down the road selling e90, would be nice if I don’t have to mix.

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[DVMKV]

I made it to e55 and began to see pressure drops. Had to back it off to e50, which I think most would agree is the limit.

 

[razorlab]

It depends more so on demands than actual E%. Stating a certain E% is the limit without also stating what type of turbo/airflow, boost levels and state of tune isn't telling the whole story.

99% of people on this forum stated you couldn't run any decent boost on an upgraded turbo on an E-blend with the factory fuel system and here I am running 28-29psi on E40.

These things are not absolute. Many factors are at play.

 

[Thraxbert]

As Bryan said, it's not the ethanol percentage that matters. It's the amount of fuel flow required.

Less boost can use more E.

More boost can use less E.

Bigger turbo can use less E.

Stock turbo can use more E.

Why the differences? Because more boost and bigger turbos produce more airflow, which requires more fuel. Eventually the fuel pump cannot move any more fuel to keep up with the air. For a given volume of air, ethanol requires 30% more fuel than gasoline. So it becomes a balancing act between turbo, tune, boost, and fuel to find the right mix.

Whatever ethanol you can run depends on your setup. In general, the stock fuel system is good for around 600WHP. Even that number is a generalization with a lot of asterisks, but it's a reasonable guide post. You can reach that number in many ways.

 

[Dubesa05]

As Bryan said, it's not the ethanol percentage that matters. It's the amount of fuel flow required.

Less boost can use more E.

More boost can use less E.

Bigger turbo can use less E.

Stock turbo can use more E.

Why the differences? Because more boost and bigger turbos produce more airflow, which requires more fuel. Eventually the fuel pump cannot move any more fuel to keep up with the air. For a given volume of air, ethanol requires 30% more fuel than gasoline. So it becomes a balancing act between turbo, tune, boost, and fuel to find the right mix.

Whatever ethanol you can run depends on your setup. In general, the stock fuel system is good for around 600WHP. Even that number is a generalization with a lot of asterisks, but it's a reasonable guide post. You can reach that number in many ways.

Yea understand the variables there, more wondering what people are seeing on full e85 stock LPFP with PI. Trying to gauge the need for a LPFP now or later.

If people are only seeing 600-700 on e40 with fuel pressure drop past e40 on stock lpfp and PI. Then I know I’ll need to do a second pump.

 

[razorlab]

Yea understand the variables there, more wondering what people are seeing on full e85 stock LPFP with PI. Trying to gauge the need for a LPFP now or later.

If people are only seeing 600-700 on e40 with fuel pressure drop past e40 on stock lpfp and PI. Then I know I’ll need to do a second pump.

Yea PI adds more demand because the pump is feeding basically two systems at that point.

 

[jacobwbonilla]

I would just get the lpfp. It’ll help you squeeze out the extra hp with no problems as the stock one will give out earlier than you think

 

[kern417]

full e85 can support around 550-600whp.

ethanol mix (e30-e50) can support around 650-700whp.

depends on AFRs as well. some tuners are more comfortable leaning out a bit on ethanol since it burns cooler.

 

[zrk]

It depends more so on demands than actual E%. Stating a certain E% is the limit without also stating what type of turbo/airflow, boost levels and state of tune isn't telling the whole story.

99% of people on this forum stated you couldn't run any decent boost on an upgraded turbo on an E-blend with the factory fuel system and here I am running 28-29psi on E40.

These things are not absolute. Many factors are at play.

As Bryan said, it's not the ethanol percentage that matters. It's the amount of fuel flow required.

Less boost can use more E.

More boost can use less E.

Bigger turbo can use less E.

Stock turbo can use more E.

Why the differences? Because more boost and bigger turbos produce more airflow, which requires more fuel. Eventually the fuel pump cannot move any more fuel to keep up with the air. For a given volume of air, ethanol requires 30% more fuel than gasoline. So it becomes a balancing act between turbo, tune, boost, and fuel to find the right mix.

Whatever ethanol you can run depends on your setup. In general, the stock fuel system is good for around 600WHP. Even that number is a generalization with a lot of asterisks, but it's a reasonable guide post. You can reach that number in many ways.

eeehhh...

As Bryan said, it depends more so on demands than actual E%. Stating a certain E% is the limit without also stating what type of turbo/airflow, boost levels, and state of tune isn't telling the whole story. 99% of people on this forum stated you couldn't run any decent boost on an upgraded turbo on an E-blend with the factory fuel system, and here Bryan is running 28-29 psi on E40. These things are not absolute. Many factors are at play.

However, I have to disagree slightly. As Robert said, it's not the ethanol percentage that matters. It's the amount of fuel flow required.

Less boost can use more E.

More boost can use less E.

Bigger turbo can use less E.

Stock turbo can use more E.

Why the differences? Because more boost and bigger turbos produce more airflow, which requires more fuel. Eventually, the fuel pump cannot move any more fuel to keep up with the air. For a given volume of air, ethanol requires 30% more fuel than gasoline. So, it becomes a balancing act between turbo, tune, boost, and fuel to find the right mix. Whatever ethanol you can run depends on your setup. In general, the stock fuel system is good for around 600WHP. Even that number is a generalization with a lot of asterisks, but it's a reasonable guidepost. You can reach that number in many ways.

 

[razorlab]

ZRK has been assimilated by AI.

 

[zrk]

ZRK has been assimilated by AI.

yes

 

[Dubesa05]

Thanks guys, LPFP in bound filling anywhere between 91 and e90 without having to worry is best case.

 

[kern417]

Thanks guys, LPFP in bound filling anywhere between 91 and e90 without having to worry is best case.

add flex fuel and watch your life change

 

[Dubesa05]

add flex fuel and watch your life change

Yea I have flex fuel, but not having to mix gas is what I’m here for. In a few mile radius of my house I have a e50 station and a station that sell e90.

 

[Dubesa05]

LPFP is in, just waiting for my PI and intake, my house smell like gas and my fiancé is pisssed.... is there any benefit to upgrading the main fuel line to a bit bigger line? Where do we see fuel limitations due to total flow through that line?

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