E85 and Ethanol/Methanol. The ins & outs of AFR's

MDCmotorsports · Mar 19, 2008

Ok, time to do some big home work.

Im lost to begin with.

I was reading through Dok33's post on his E85 build, and he states that the AFR will be 14:7, the same as gasolene.

I have a problem with this.

http://www.ext.colostate.edu/pubs/farmmgt/05010.html
http://www.knfilters.com/airfuelmonitors.htm
http://www.experiencefestival.com/a...r_burning_E85_gasoline_and_ethanol/id/1345236

Now, for you lazy -

E85 stoich is recorded by the above posts as 9.7
E100 stoich is recorded by the above posts as 9.0

Is this is true, can the conclusion be made that the stock ECU will be in a mass confused state because of the oxygen value being way off?

Or am I missing something here?

Input please!

*NEWBS STAY OUT*

figgie · Mar 20, 2008

MDC

you are right but the thing is......

Widebands ALWAYS read LAMBDA. Lambda is then converted to the fuel of choice AFR by dividing the lambda reading by it's stoich level.

for instance

In gasoline, stoich = 14.7

If you have a lambda of 1.18 that means the AFR scale for gasoline shows....12.37 Gasoline AFR.

The thing is that regardlesss of fuel. At stoich, Lambda will ALWAYS = 1.

IE

Methanol, stoich is Lambda = 1 = 6.4 Methanol AFR
NitroMethane, stoich is Lambda = 1 = 1.7 NitroMethane AFR
Gasoline, stoich is Lambda = 1 = 14.7 Gasoline AFR.

What this means is that you can use gasoline AFR scale to tune to stoich on WHICH ever fuel you want

MDCmotorsports · Mar 20, 2008

Ok, so what about OUR stock ECU? Is it going to freak out?

figgie · Mar 21, 2008

That I can not answer as I just know the widebands.

But my educated guess. If it is reading o2, then it is more than likely calibrated using lambda so the same principle applies.

Using the Gasoline AFR scale you should get a good idea of fueling but you know how great the stock narrow sensor is in our cars!

buldozr · Mar 21, 2008

If you run e85, factory computer will freak out. If you plan to run e85, a standalone would be a good idea.

figgie · Mar 21, 2008

buldozr;964882 said:
If you run e85, factory computer will freak out. If you plan to run e85, a standalone would be a good idea.

well you want to know something funny?

If you upgrade from 440cc/min injectors to 550cc/min injectors and not change the AFM to the bigger Lexus one. You will be spot on. Unfortunatly pig rich if running gasoline.

buldozr · Mar 21, 2008

o2 sensor will not like it. Thats what was previously asked, the o2 sensor readings will be off for e85. Your injector math may be spot on, but the computer will still show to be off and try to compensate. Standalone would be a good option.

Edit: Also, personal note, using e85 for power, using 550's would be like pissing on a house fire, you will probably start with atleast 1000cc's injectors for E85.

figgie · Mar 21, 2008

buldozr;964934 said:
o2 sensor will not like it. Thats what was previously asked, the o2 sensor readings will be off for e85. Your injector math may be spot on, but the computer will still show to be off and try to compensate. Standalone would be a good option.

Edit: Also, personal note, using e85 for power, using 550's would be like pissing on a house fire, you will probably start with atleast 1000cc's injectors for E85.

no.

again o2 value are the same at stioch regardless of fuel.

Lambda = 1 @ stioch regardless if it is gasoline or a piece of paper.

MDCmotorsports · Mar 21, 2008

See, at the start of this whole road, I was thinking 1000cc injectors too.

It takes roughly twice the amount of ethanol as it does gas. 550's = 1000's.

But, in Dok's build, he's running 670's or something like that.

So WHICH IS IT?

Also, do you think there could be a way to input a resistor into the signal of the o2 sensor to fool the computer????

CALLING IJ & JJ....

figgie · Mar 21, 2008

MDCmotorsports;965180 said:
See, at the start of this whole road, I was thinking 1000cc injectors too.

It takes roughly twice the amount of ethanol as it does gas. 550's = 1000's.

But, in Dok's build, he's running 670's or something like that.

So WHICH IS IT?

Also, do you think there could be a way to input a resistor into the signal of the o2 sensor to fool the computer????

CALLING IJ & JJ....

Guess I am clear as mud, lol

MDC

Methanol is 100% more (Double). Ethanol is only 40% more than gasoline. E85 is only 30% more hence the 440 to 550 working fine.

The 1000 cc/min injector are fine if you plan on producing high power but be mindful of the fuel pumps. You will also need twin walbro's for that and you will more than likely run out of injector before you run out of pump in that case.

O2 on the resistor?

there is ZERO need. o2 content is the same after ANY combustion process regardless of the combustible.

see the AFR........... Lambda = 1 @ stioch (thrid time now) whether it be

Methanol
Gasoline
Diesel
LPG
Natural Gas
Paper
cardboard
human body
garbage etc

Lambda is a constant regardless of fuel. That is why it is always a good idea to understand lambda instead of AFR as lambda does not change due to caloric content per gallon etc.

MDCmotorsports · Mar 21, 2008

Thank you.

Very very much. Soon to be another e85/e100 car on the road!

You think 700's would be fine?

figgie · Mar 22, 2008

MDCmotorsports;965261 said:
Thank you. Very very much. Soon to be another e85/e100 car on the road!

You think 700's would be fine?

what power levels are you going for?

MDCmotorsports · Mar 22, 2008

Im working with a holset hy35. If Ive done my math right, Im hoping to be in the 475ish range.

figgie · Mar 23, 2008

well 425 rwhp = about 500 bhp.

Those injectors should take you there but you will be cutting it thin on the fuel injectors PW.

Doward · Mar 23, 2008

Get a set of 850s at least, imho.

figgie's got the lambda calculations dead on the money.

blake · Mar 24, 2008

I keep stumbling upon Figgie's posts about running E85 (and Motecs) on various forums and he keeps being right.

There's a great deal of confusion about E85 out there, but thanks to people like Figgie the situation is finally getting somewhat coherent. =)

Red7m · Mar 24, 2008

For ppl that know would it be okay to run e85 with my fcon/vpc/gcc combo? Or should I just wait untill I go standalone before I worry about running e85.

buldozr · Mar 24, 2008

Figgies right, lambda lambda lambda, even though gasoline and e85 when tuned correctly will have different AFR's, lambda will still be 1 when both are stoich(not sure if I said that right). I stand corrected but in my quest for more info, found a great site of info.

http://forums.turbobricks.com/showthread.php?t=73061

Good read.

Mr.PFloyd · Mar 24, 2008

So stock cars can run e85 basically??? i am too confused...

jetjock · Mar 24, 2008

buldozr;964882 said:
If you run e85, factory computer will freak out. If you plan to run e85, a standalone would be a good idea.

buldozr;964934 said:
o2 sensor will not like it. Thats what was previously asked, the o2 sensor readings will be off for e85. Your injector math may be spot on, but the computer will still show to be off and try to compensate. Standalone would be a good option.

buldozr;967592 said:
Figgies right, lambda lambda lambda, even though gasoline and e85 when tuned correctly will have different AFR's, lambda will still be 1 when both are stoich(not sure if I said that right).

Now you know why I stay out of threads like these....

E85 and Ethanol/Methanol. The ins & outs of AFR's

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