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E85 Guys.


thorne

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You can tell how much knock you have from logging the KNOCK SENSOR.

 

If you are not tuning for E85 other than injector scaling you are wasting your time.

 

KNOCK SENSOR??? how could I forget. How many people actually do this? I have a hard time believing E30 won't cause an engine to knock on an E0 calibration.

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KNOCK SENSOR??? how could I forget. How many people actually do this? I have a hard time believing E30 won't cause an engine to knock on an E0 calibration.

 

 

I <3 knock sensor. For now until I can learn more I'm not fucking with it. I assumed it was like race gas. I know in the past I've mixed in racegas and when racing it worked out better.

 

For Daily and some racing 93 octane works more then efficent. But I was thinking of more of a buffer. I did not relize there was so many changes to switch fuel types. If I do anythng I will go 100% e85.

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You won't need to adjust the display unless you want to read something different. I have the AEM UEGO that reads AFR by default, but I switch it to display lambda on the gauge just to learn it. It still outputs 0 - 5V to my ECU. When I first switched over the car was really lean, but I just bumped up my required fuel value until I got stoich back to 14.7.
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KNOCK SENSOR??? how could I forget. How many people actually do this? I have a hard time believing E30 won't cause an engine to knock on an E0 calibration.

 

Anybody that doesn't log knock, is not tuning. They are throwing shit at the car and praying it works.

 

E30 is more knock resistant. Ofcoarse it won't knock. Assuming you scale the injectors so you have enough fuel to not lean out.

 

What so many people fail to understand is that race fuel, E85, E90, or any knock resistant fuel is LESS combustible. Thats why it lessens the chances for pre-detonation. On a correctly tuned car, with no knock adding a fuel that doesn't burn as well can only hinder performance unless you are going to adjust the tune accordingly.

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If you are adding boost or timing ABSOLUTELY use a more knock resistant fuel. I was only talking about the people that get tuned for 93, then put race gas in the car at the track on the same exact tune. <--That is useless
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If you are adding boost or timing ABSOLUTELY use a more knock resistant fuel. I was only talking about the people that get tuned for 93, then put race gas in the car at the track on the same exact tune. <--That is useless

 

You are 100% correct.

 

Ethanol sucks for cold start in low temp applications. It does not like to atomize and tends to puddle.

 

However, E85 is like cheap race gas, and if the car you use is not your DD, then E85 is certainly the way to go. Lower intake temps (most likely wouldn't even need an intercooler), high octane rating, and about 1/2 price when compared to race gas, you end up on top. My next big project is going to be an E85 conversion and recalibration.

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Quick & Dirty way of calculating stoich: (amount F1 (%) * stoichF1) + ( amount F2(%) * stoichF2)

 

e.g. E85 = 85% Ethanol * 9 stoich (industry standard blend) + 15% gasoline * 14.7 stoich = 9.855~

 

What so many people fail to understand is that race fuel, E85, E90, or any knock resistant fuel is LESS combustible.

I think you understand the concept, but the resistance to knock and how readily any fuel combusts are two different things. Petroleum based: it gets down to building stable chains of HC, Alcohol based: centers on control of hydrogen oxide formation in the chamber. Again, you have the idea, but the wording invites an egotistic engineer to unload. :)

 

E85 is very tolerant of being pushed lean, and pushed hard. You have a variety of things working for you: better positioning of peak pressure point (mass fraction burned is improved depending on cylinder condition), higher octane rating, and higher mean pressure throughout the cycle with lower peak pressure.

 

It really is the poor man's race fuel these days...

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I think you understand the concept, but the resistance to knock and how readily any fuel combusts are two different things. Petroleum based: it gets down to building stable chains of HC, Alcohol based: centers on control of hydrogen oxide formation in the chamber. Again, you have the idea, but the wording invites an egotistic engineer to unload. :)

 

 

I am always down to learn something. Is my thinking wrong? I was not looking at it from a scientific point of view, because I have seen time and time again that numbers on paper don't equal real world results. Is E85 not less combustible than 93 octane gasoline? If it is less combustible why would taking a tune that is OPTIMIZED for combustion at X parameters be better when with the less combustible fuel.

 

Aside from having an improper tune in the first place I don't get how it could make improvement.

 

Again, I know that E85 is great stuff. When you turn up the boost, and add timing ofcoarse it will make better power. I was only referring to the tons of people I hear about now just adding stuff like this to a car tuned for 93 expecting gains.

 

If I am wrong in my thinking, so be it. I just want to know why and see a real world example of a PROPER, non knocking 93 oct tune gaining power from less combustible fuel.

 

btw, not trying to argue... just discuss, otherwise I wouldnt learn anything

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WOW I didnt read all that crap it started to give me a headache.

I have ran 1/3 E-85 for over a year. All I did was scale my injectors aprrox 10%

If you know what the l trims are right know with gas, add the 30% E-85 and scale the injectors 10%. At that point watch the Ltrims and fine tune if needed logging them. When there the same the WOT (open loop) will be spot on. It was a really simple 20 min tuning job.

Dont even worry about the stoich, lambda or anything else, your O2 sensors read free oxygen and burn whatever it takes to make the oxygen go away.

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No, you're correct in what you have said, just the word 'combustable' can take on different meanings. If you look at combustion as soley the amount of energy to start a reaction between fuel and the oxidizer with respects to quanity of heat energy to start the inital process, you could get away with using the word without anyone trying to correct you. Again, you have the point from what I've read - more energy (heat) is requierd for the catalyst to take place and combustion to begin.

 

Think of things as moving around the amount of fuel mass burned in relation to crank angle, and (re)centering the position where max cylinder pressure is acheived.

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WOW I didnt read all that crap it started to give me a headache.

I have ran 1/3 E-85 for over a year. All I did was scale my injectors aprrox 10%

If you know what the l trims are right know with gas, add the 30% E-85 and scale the injectors 10%. At that point watch the Ltrims and fine tune if needed logging them. When there the same the WOT (open loop) will be spot on. It was a really simple 20 min tuning job.

Dont even worry about the stoich, lambda or anything else, your O2 sensors read free oxygen and burn whatever it takes to make the oxygen go away.

 

In 99% of engine control strategy this works, and works great. Why? Because Ray is the man, that's why.

 

Really though, it's because injectors operate at a global level, and are not apart of any load calculation/torque estimation,etc. If you dive in and do it the 'correct' way - you may not have access to redundant tables (limp home), and if triggered for whatever reason, could leave you stranded.

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don't forget that it not only changes the stoich but the max power lean and the max power rich are going to be different and ratio is not a constant.

 

 

 

fuel AFRst equivalence ratio lambda

gas stoich 14.7 1 1

gas max power rich 12.5 1.176 0.8503

gas max power lean 13.23 1.111 0.9

e85 stoich 9.765 1 1

e85 max power rich 6.975 1.4 0.7143

e85 max power lean 8.4687 1.153 0.8673

e100 stoich 9.00078 1 1

e100 max power rich 6.429 1.4 0.714

e100 max power lean 7.8 1.15 0.87

 

 

for e30 i estimate stoich will be around 12.94

max power rich will be around 10.67

max power lean will be around 11.60

 

and from my experimenting with it in the vette i was breaking even as far as Dollar per mile, my MPG went from 28-30 with 94 sunoco to 22-25 with e85.

 

so it was costing me 15.45 to drive 100 miles on e85 @ 3.40 a gallon

and 15.35 to drive 100 miles on gas @ 4.30 a gallon

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Rob,

 

I didn't see much of a power difference outside of what my car ran best at (.82 lambda) on the dyno, swinging from .78 to .86 lambda. Most likely it differs per setup, but the important thing is that you won't be worse off then you were on gasoline (equivilent oxygen ratio)

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why does it always do that when you try and make a list?

maybe this is better.

 

 

fuel AFR

gas stoich 14.7

gas max power rich 12.5

gas max power lean 13.23

e85 stoich 9.765

e85 max power rich 6.975

e85 max power lean 8.4687

e100 stoich 9.00078

e100 max power rich 6.429

e100 max power lean 7.8

 

 

Equivalence ratio

gas stoich 1

gas max power rich 1.176

gas max power lean 1.111

e85 stoich 1

e85 max power rich 1.4

e85 max power lean 1.153

e100 stoich 1

e100 max power rich 1.4

e100 max power lean 1.15

 

Lambda

gas stoich 1

gas max power rich 0.8503

gas max power lean 0.9

e85 stoich 1

e85 max power rich 0.7143

e85 max power lean 0.8673

e100 stoich 1

e100 max power rich 0.714

e100 max power lean 0.87

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Rob,

 

I didn't see much of a power difference outside of what my car ran best at (.82 lambda) on the dyno, swinging from .78 to .86 lambda. Most likely it differs per setup, but the important thing is that you won't be worse off then you were on gasoline (equivilent oxygen ratio)

 

what type of car?

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Guest coreymdean

"Anybody that doesn't log knock, is not tuning. They are throwing shit at the car and praying it works."

 

 

That is one of the biggest bull shit quotes i have heard. Do you know how many hondas get tuned everyday on a hondata and a p28, which does not accept knock input. Or pre knock how many engines get tuned and never even considered using a knock sensor. How many small block chevys have you seen that have a knock sensor on them.... I though with proper air fuels, and a dyno to tune your timing with is the way to go. A knock sensor is a nice idiot light to have but seriously it is not needed. Ever tune an engine without a 02.... its not the easiest but it can be done as well....

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"Anybody that doesn't log knock, is not tuning. They are throwing shit at the car and praying it works."

 

 

That is one of the biggest bull shit quotes i have heard. Do you know how many hondas get tuned everyday on a hondata and a p28, which does not accept knock input. Or pre knock how many engines get tuned and never even considered using a knock sensor. How many small block chevys have you seen that have a knock sensor on them.... I though with proper air fuels, and a dyno to tune your timing with is the way to go. A knock sensor is a nice idiot light to have but seriously it is not needed. Ever tune an engine without a 02.... its not the easiest but it can be done as well....

 

I wasn't even going to reply to this fucking fail of a post, but since it got bumped I will. 1st of all no shit older engines didn't have knock sensors. Tuning is not "one method fits all". Different engines, control systems etc. obviously play a part in that. Thorne's WRX DOES have a knock sensor and I will say again, that anyone that tunes a WRX and doesn't pay attention to the knock sensor is insane. Just because people tune piece of shit honda's without one doesn't mean the rest of the world can ignore them.

 

/end of rant

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