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Running FiST with E85 Blends - Discussion Thread

JPGC

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#2
Interesting. Good read on their tuning perspective. I wonder why they pulled the hood blanket/ insulation.
 


rodmoe

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#3
I pulled mine off long time ago as it's just added fluff IMHO
 


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#5
Are the seals and gaskets safe for E85? I'm sure they're good enough for 10%, I just wouldn't be so quick to start running anything much higher without looking into seal and gasket materials used.
 


OP
koozy

koozy

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Thread Starter #8
Are the seals and gaskets safe for E85? I'm sure they're good enough for 10%, I just wouldn't be so quick to start running anything much higher without looking into seal and gasket materials used.
A number of us are running E40-E50 blends without issues. The shared knowledge consensus is that it's fine to run E85 as far as components are concerned. The article posted adds another data point to consider for those wanting to increase their blend or run straight E85. The question of whether the fuel pump can keep up with higher torque/HP tunes is still being investigated. It can be tuned to run straight E85, but at a cost of fuel efficiency. Most people are using E85 to increase power. Anything above 15% as posted on the fuel filler and stated in the owners manual is not warranty safe. Most pouring in higher levels of ethanol understand this and are willing to pay to play.
 


Sourskittle

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#9
On E45-E50, 270-285whp is about the limit. The stock turbo can not run the car out of fuel on E85 from what I've seen...

Food for thought though.... Alex of Straitfied has said that he does not really see any gains from going above E50. My personal opinion is that its more about what your tune is and what your trying to do and how close are you willing to push the car with timing boost? I don't think anyone with a stock turbo will ever have a reason to run more than E50 though...
 


DHM1

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#10
The thing with the pump limit is it also depends were you make peak power. On pump gas I am running out of pump from 3700-5800rpm at about 275hp but making around 300above that with no pump issues
 


DHM1

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#11
Are pumps are rpm based. The higher the rpm the higher the flow.
 


Sourskittle

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I saw this week that mega rich movie stars had secret tunnels leading to the playboy mansion. I didn't need to hear about that to know that all things are possible with enough money, lol.
 


Hijinx

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#15
I already respected tuners, but after reading this, I have an even higher regard.
 


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#16
All cars running E85 have lower mileage. There's less energy per unit in ethanol fuel. Are the fuel pumps not keeping up with flow, or pressure? Generally speaking, a pump will lose pressure before flow.

That said, adding a surge tank and a secondary Bosch 044 (or similar) in line is easy enough and basically would eliminate any thought of the FP being a limitation. If you're running 275-300hp anyway, the cost of adding a system like that should not be an issue, given the cost of the other supporting mods needed.

If you want to skip the surge tank, then you have to eliminate or replace the stocker pump. the surge tank allows the stock pump to feed the surge, and the 044 to supply the engine.
 


ryst

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#17
All cars running E85 have lower mileage. There's less energy per unit in ethanol fuel.
This is both true and not true. E85 is less prone to detonation because of it's effective octane (i believe 103-106), so at low load levels you can actually run it leaner than E0.

As an example I got about 28 mpg on the highway/19 mpg city (lead foot) using my E40 blend with my E40 tune, and on Cobb Stage 1 I got about 29 mpg highway and 24 city. The AFR targets on E40 at low load levels were 15.5 to 15.7, running so lean makes the overall efficiency of the engine higher. Obviously when you get into boost and higher loads on the engine, comparatively more fuel is required for ethanol blends than standard gas.

One of the problems with OEM flex fuel tunes is that they really have no incentive to get good gas mileage on E85. The EPA doesn't measure it, and it's never advertised. So likely they are spending all their time getting the absolute best MPG
on E10 and it's really a waste of resources to make their tune efficient on E85 (obviously this is just my opinion on the issue, but I imagine it's close to the truth). I have heard that brand new vehicles are actually starting to get better MPG on E85 than the older models.
 


Sourskittle

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#18
Razor said the samething, that he got reasonable fuel mileage with eth mixes because he tuned it that way. I get 21.6mpg tuning on E45-E50. But i haven't touched any of the tune that would help with that, I'm not in it for mpg. My G35 got 21mpg on E10 93oct and was driving way nicer than my fist.

Pressure is not the problem. Maybe if we upgraded the injectors it would be....
 


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#19
if you run lean on e85, you are making less power. there is less energy density in ethanol than in gasoline. that is fact, not partial truth.

to make the same power on e85 and e10, you need to inject more e85 fuel. again, fact.

your lower risk of detonation is a direct result of the lower energy density.

E85 becomes useful at extreme power and pressure levels due to its less volatile nature (less likely to detonate). At some point it becomes more beneficial to run higher boost with less volatile fuel.

It's the same theory with Top Fuel drag cars, albeit going the opposite direction; they drop the compression to 6.5-7.0:1 to combat detonation, while using a ridiculously dangerous fuel.
 


DHM1

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#20
if you run lean on e85, you are making less power. there is less energy density in ethanol than in gasoline. that is fact, not partial truth.

to make the same power on e85 and e10, you need to inject more e85 fuel. again, fact.

your lower risk of detonation is a direct result of the lower energy density.

E85 becomes useful at extreme power and pressure levels due to its less volatile nature (less likely to detonate). At some point it becomes more beneficial to run higher boost with less volatile fuel.

It's the same theory with Top Fuel drag cars, albeit going the opposite direction; they drop the compression to 6.5-7.0:1 to combat detonation, while using a ridiculously dangerous fuel.
Let me help out your on the right track but using the wrong terms. Running a lower or higher lamda (leaner/richer) on high ethanol mixes will not make it lose or gain power. Every engine has a point were it makes peak. E85 HAS to take 30-35% more fuel to reach the same lamda as a e10. That does not mean it's "richer" ethanol by nature has BSFC so there has to be more added to burn at the same air fuel ratio. That does not mean that running 12:1 afr on e85 will make less power than 11.5:1 on e10. That has to do with the engine combination. The cooling, higher octane, and increase in dynamic compression ratio is why ethanol makes more power.


Also nitro car run 13-14:1 compression ration. I have made cylinder head and pistons for nitro and alcohol teams since i was 15. Nitro wouldn't even light off if it was squeezed at 6:1. The pro mod engines I built we all 10-11:1 running on straight methanol and making over 4000hp.

Russ
 




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