Originially Posted March 2011: Anyone running E85?? - Page 2 - Performance Forum

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Re: Anyone running E85??
Tuesday, June 28, 2011 10:54 AM
You would have to command the PCM to know what "Stoich" is... on a MegaSquirt or a Standalone like Gary's you can do that in a simple cell where you inform it what you want stoich to be. (In this case 9.8:1 for your conversion to E85)

WIth an Innovate LC-1 like mine you can plug the unit into your laptop and TELL IT what you want stoich to be, and it will recalibrate the output on the gauge for you. So if I want it to have 9.8 as stoich it will show up as stoich on my gauge. This way (coupled with a PCM where you can command stoich) you now have a guage that will "read" for E85... the voltage on the gauge also gets re-calibrated for logging. Quite useful.

Unfortunately on our PCM it's "locked" onto 14.7:1 (or close)... and there is NO way to tell it you want it to command a different value for Stoich otherwise. This means that when you are driving in closed loop the 02 sensor is reading and the PCM is trying to achieve its commanded stoich level - which is ridiculously lean for E85.

That's the hurdle you need to jump, unfortunately. Everything is just tuning. (Big injectors, lots of fuel, and remapping the timing)

-Chris-



-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...

Re: Anyone running E85??
Tuesday, June 28, 2011 10:59 AM
I'm not sure what Ryan is talking about either. Narrowbands and Widebands are lambda sensors, not true AFR sensors. Both calculate the AFR from the lambda. However, there are still plenty of issues with running close to a pure alcohol mix that make tuning difficult in changing climates without the aid of more tables. You can probably tune PE spot on, but when it comes to idle, afterstart enrichment, cranking advance, etc. etc. it can become a serious problem.
scott (section8cav) wrote:same here....i would LOVE to convert...nothing stopping me....other than the fact the capitol city of texas only has 1 e85 station....and that one is pretty far from my house...not to mention if i have to go outta town.

I'll make seperate tunes if I decide to go to E85. One for when I know I'm going to be in an area that has e85, and another for gasoline when going on road trips and such.




I have no signiture
Re: Anyone running E85??
Tuesday, June 28, 2011 10:59 AM
Leafy (Club Jeffie FEA man) wrote:I still don't know how it can tell its at 14.7 or 9.8, do we use some sort of o2 sensor that I've never heard of? All narrow bands that I've ever heard of can only tell you if the car is running at, not what the actual afr is. Hell, wide bands can't even do that, you need a 5 gas analyzer to do that.
All the O2 sensor does is read the voltage.... They all do the same thing. The PCM is what determines what the voltage value means.... And why are you bringing a 5 gas into this? Like I said earlier, you still have a lot to learn and I applaud you for wanting to learn...



P&P Tuning
420.5whp / 359.8wtq

Re: Anyone running E85??
Tuesday, June 28, 2011 11:00 AM
Ah I just re-read what you asked... "how" does it know.

It knows because that is what it's calibrated for, by reading a certain amount of gas or air it sends different voltage through the sensor. (0 - 1000 millivolts)

The PCM is told to read this voltage a certain way - hence the PCM is calibrated to the sensors readings. It knows that .7 volts (or 700 millivolts) is stoich.

Like I said, the LC-1 can be re-calibrated so that the values change, which is a really neat feature. Then you tell your custom pcm/standalone what it expects stoich to be, again - reading the voltage differently.

It's not the sensor, it's the PCM and how it is programmed to read the voltage that comes out of the sensor.

-Chris-



-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Re: Anyone running E85??
Tuesday, June 28, 2011 11:08 AM
But its trying to achieve stoich right? You see. The computer gets a voltage from the narrow band, the computer gives it a value based off a stoich value of 14.7. It then references off a take with numbers based off a stoich of 14.7 to get the fuel correction. Then it tries to achieve what it thinks is 14.7 by injecting different amounts of fuel. Now look at that. If the actual stoich value doesn't fall out of the calculations then you failed the unit conversion test in high school physics. As long as you leave your wide band to display stoich to be 14.7:1 then it all works out. If you don't tell it your wide band that you changed fuels it'll still say that you are cruising at 14.7 when you will be at 9.8.

What I'm saying is, if your sensors can only read stoich then any way the computer can give that an afr value is to assign it arbitrarily.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Anyone running E85??
Tuesday, June 28, 2011 11:23 AM
So is what yor saying is that your computer will make the correctioms needed to give you the correct fuel amount based on the oxygen seen in your exhaust regardless of the fuel you use?



Re: Anyone running E85??
Tuesday, June 28, 2011 11:48 AM
Leafy (Club Jeffie FEA man) wrote:But its trying to achieve stoich right? You see. The computer gets a voltage from the narrow band, the computer gives it a value based off a stoich value of 14.7. It then references off a take with numbers based off a stoich of 14.7 to get the fuel correction. Then it tries to achieve what it thinks is 14.7 by injecting different amounts of fuel. Now look at that. If the actual stoich value doesn't fall out of the calculations then you failed the unit conversion test in high school physics. As long as you leave your wide band to display stoich to be 14.7:1 then it all works out. If you don't tell it your wide band that you changed fuels it'll still say that you are cruising at 14.7 when you will be at 9.8.

What I'm saying is, if your sensors can only read stoich then any way the computer can give that an afr value is to assign it arbitrarily.
Your sensor does NOT read Stoich... It read 0 to X(whatever voltage/depends on NB or WB).... That is all it knows... The PCM is what determines what that voltages meaning is. If you can not command what Stoich should be, you are just introducing more headaches. The PCM we have has none of this, therefore its going to just keep throwing fuel trims out of whack trying to control it back to Stoich.... Throw your BS unit conversions out and think Lambda.... Lambda is always 1. On the LNF, It understands that Lambda is 1. Now 1st, people were raping their MAFs to adjust for the fuel. Doing this caused some other issues because the LNF PCM is completely LOAD based. By skewing the MAF, the Load calculations were off and MAF readings were off, and that was causing incorrect data for the PCM to interpolate. Once we got the fuel tables, we are now able to change more than just the "constant", but actually when the injection window is. This plays a big part also, and with the other fueling tables, and the fact the PE command is in LAMBDA (remember, value of 1), we are able to not RAPE the MAF and skew the load values and still achieve the E85 values because we are not using 14.7 as a Stoich, but Lambda which is always 1.





Edited 1 time(s). Last edited Tuesday, June 28, 2011 11:49 AM


P&P Tuning
420.5whp / 359.8wtq

Re: Anyone running E85??
Tuesday, June 28, 2011 11:53 AM
Yes exactly. You hit it on the head. Lambda 1 is always lambda 1 no matter whatever arbitrary value the computer assigns to it while it stores it in memory for its own calculations. @!#$ you could take and lsj and tell it stoich was 4 and as long as you adjusted global trims to compensate it would run 93 octane perfectly fine. Our global trim is the injector constant, so is the lnf's, the lsj has a table for injectors so I guess you could do it there too but you have to change more than 1 number.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Anyone running E85??
Tuesday, June 28, 2011 11:54 AM
brodycog wrote:So is what yor saying is that your computer will make the correctioms needed to give you the correct fuel amount based on the oxygen seen in your exhaust regardless of the fuel you use?


If he thinks the j computer can do that then he needs to quit tuning asap. To sum this entire post up so everyone can understand it...... In order to run E85 safely you need a stand alone..... Point blank...... The j ecm cannot accomplish it safely.



Re: Anyone running E85??
Tuesday, June 28, 2011 11:55 AM
Leafy (Club Jeffie FEA man) wrote:Yes exactly. You hit it on the head. Lambda 1 is always lambda 1 no matter whatever arbitrary value the computer assigns to it while it stores it in memory for its own calculations. @!#$ you could take and lsj and tell it stoich was 4 and as long as you adjusted global trims to compensate it would run 93 octane perfectly fine. Our global trim is the injector constant, so is the lnf's, the lsj has a table for injectors so I guess you could do it there too but you have to change more than 1 number.
WRONG!



P&P Tuning
420.5whp / 359.8wtq

Re: Anyone running E85??
Tuesday, June 28, 2011 11:56 AM
Leafy - the sensor doesn't read stoich. It reads volts... that's it.

The PCM takes that voltage and from its programming decides what stoich is, and what corrections to make.

Like any other sensor on the engine... all the 02 sensor does is provide voltage to the PCM. The rest is up to the PCM.

Since you cannot recalibrate the PCMs values for what "stoich" is... it won't work. Same reason you can slap a 2 bar sensor on a 1 bar setup, and why you cant plug a 5 volt o2 sensor into our setup and expect the PCM to read it right.

Make sense?

-Chris-


-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...

Re: Anyone running E85??
Tuesday, June 28, 2011 11:59 AM
SweetnessGT wrote:Leafy - the sensor doesn't read stoich. It reads volts... that's it.

The PCM takes that voltage and from its programming decides what stoich is, and what corrections to make.

Like any other sensor on the engine... all the 02 sensor does is provide voltage to the PCM. The rest is up to the PCM.

Since you cannot recalibrate the PCMs values for what "stoich" is... it won't work. Same reason you can slap a 2 bar sensor on a 1 bar setup, and why you cant plug a 5 volt o2 sensor into our setup and expect the PCM to read it right.

Make sense?

-Chris-


Bingo!



Re: Anyone running E85??
Tuesday, June 28, 2011 12:12 PM
No the sensor reads stoich and outputs volts to the PCM. If the sensor read volts we'd call it a volt meter. The PCM gets that voltage, and I trust ryan to be correct in saying that the computer then converts that voltage into an afr value scaled off of a stoich value of 14.7:1. Since this is the case it must then use that scaled value on a look up table to decide what the difference is between what the engine is doing and what it wants the engine to be doing (a table that is also scaled off of a lambda 1 = 14.7 afr), then another table based off of that reading to decide what the fuel trim is and then to change how much fuel its injecting. The stoich value in the computer is solely for the computer's own record keeping. If the computer worked the way you guys act like it does our cars would struggle to run on modern day e10 gas since the stoich value is different (~14.2:1 irrc). You still tune a car as if its running on e0 dont you?

And ryan I should have worded that better; the injector constant can be used as the global trim even though that is not its purpose and does effect other things.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Anyone running E85??
Tuesday, June 28, 2011 12:17 PM
Leafy.... ALL of the sensors on the engine are volt meters. All of them.

Thats all they are - they just get fancy names due to their function.

TPS reads volts. IAT reads volts. O2 reads volts. CPS reads volts. CKS reads volts.

That's all they do, read volts. The PCM translates those volts into the values it needs.

Since we cannot tell the stock J PCM to change ANY of the values for ANY of those sensors... we are stuck working within their parameters... including the PCM's recognition of "stoich".

I can't explain it any better than that, man!

-Chris-


-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Re: Anyone running E85??
Tuesday, June 28, 2011 12:24 PM
SweetnessGT wrote:Leafy.... ALL of the sensors on the engine are volt meters. All of them.

Thats all they are - they just get fancy names due to their function.

TPS reads volts. IAT reads volts. O2 reads volts. CPS reads volts. CKS reads volts.

That's all they do, read volts. The PCM translates those volts into the values it needs.

Since we cannot tell the stock J PCM to change ANY of the values for ANY of those sensors... we are stuck working within their parameters... including the PCM's recognition of "stoich".

I can't explain it any better than that, man!

-Chris-
Exactly!



P&P Tuning
420.5whp / 359.8wtq

Re: Anyone running E85??
Tuesday, June 28, 2011 12:28 PM
Ok its like we are saying the same thing but I see it a bit differently. Yes we cant tell the PCM to change any of those values and frankly we dont need to (or even want to really). The PCM recognizes stoich as 14.7:1, that's all good for it in its happy little world.

Let me put it this way. If you emptied your tank and put e85 in there right now, here is what would happen. Your car would start and I bet would stall, you may have to right to keep it running a bit for a few minutes. During those few minutes your car is going to be furiously maxing out the fuel trims to achieve what it believes to be 14.7:1 (which if you had a 5 gas analyzer on the tail pipe it would rear an air to fuel ratio of 9.8:1 ish). Ok understand now? That is what happens. Of course you shouldnt driver like that because more likely than not you will pop a bank 1 lean code for maxing out the fuel trims and just barely making it to stoich. Now if the computer thought your injectors were 30% smaller than they actually were...

The computer lives in its own reality with its own set of rules, which dont always have to mesh with whats happening in the real world.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Anyone running E85??
Tuesday, June 28, 2011 12:33 PM
Leafy (Club Jeffie FEA man) wrote:Ok its like we are saying the same thing but I see it a bit differently. Yes we cant tell the PCM to change any of those values and frankly we dont need to (or even want to really). The PCM recognizes stoich as 14.7:1, that's all good for it in its happy little world.

Let me put it this way. If you emptied your tank and put e85 in there right now, here is what would happen. Your car would start and I bet would stall, you may have to right to keep it running a bit for a few minutes. During those few minutes your car is going to be furiously maxing out the fuel trims to achieve what it believes to be 14.7:1 (which if you had a 5 gas analyzer on the tail pipe it would rear an air to fuel ratio of 9.8:1 ish). Ok understand now? That is what happens. Of course you shouldnt driver like that because more likely than not you will pop a bank 1 lean code for maxing out the fuel trims and just barely making it to stoich. Now if the computer thought your injectors were 30% smaller than they actually were...

The computer lives in its own reality with its own set of rules, which dont always have to mesh with whats happening in the real world.
You still don't get it... I'm starting to feel like I'm talking to a brick wall.......





P&P Tuning
420.5whp / 359.8wtq

Re: Anyone running E85??
Tuesday, June 28, 2011 12:36 PM
I think the difference just is: I'm willing to basically ghettoerize a tune to do something "impossible" because I know it will "work" and you have a reputation and integrity and stuff.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Anyone running E85??
Tuesday, June 28, 2011 12:46 PM
Leafy (Club Jeffie FEA man) wrote:I think the difference just is: I'm willing to basically ghettoerize a tune to do something "impossible" because I know it will "work" and you have a reputation and integrity and stuff.
You are right, I do have a reputation and integrity. And to be honest, without integrity, you have nothing. How many vehicles have you actually tuned? Real world full out tuned? I can't even count how many as its a sh!tload..... Ask any of my customers also, I am a straight shooter, and I have no problem showing them what I am doing and explaining to them why I am doing it..... The reason why I jump your @ss in your posts so much is because you do NOT know 100% what you are doing, and I don't want somebody (with even less knowledge than you) taking your inaccurate advice and fu(king their sh!t up!





P&P Tuning
420.5whp / 359.8wtq

Re: Anyone running E85??
Tuesday, June 28, 2011 12:53 PM
Full out tuned? 4, 3 with hpt and 1 with a haltech s2000 which I started from nothing, not even a base map. I had to create the base VE maps by hand from pure math. And they just happened to end up being within 10% or better once I got it on the dyno. I'm a straight shooter too man, but my reputation is that such that I'm expected to just make @!#$ work. I get handed something and my boss just says, make this work, I don't care how. I guess I put too much stock in other people's competence to do their own research and not take my word as law/jesus/perfect. Which is why I've been trying lately to make posts that blatantly lack information that's easy to find through google which will inevitably make that person read more on the subject.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Anyone running E85??
Tuesday, June 28, 2011 12:56 PM
I'm with Ryan... you cannot give advice unless you totally know what you are talking about - in this case unfortunately my friend, you don't... so it's best to not dispense incorrect information.

This forum was overrun with that kind of thing a few years ago and most of the "experts" gave up....

Ghetto-izing a tune costs engines. If you want to do that quietly in your own garage on your own car - go to town! But don't tell people it "works"... because it doesn't. That's irresponsible - unless you want to start paying for people's engines?

I have no problem putting my name on anything I touch or any information I give... Neither does Ryan. Im sure if he blew up an engine tuning it on the dyno he'd do all he could to fix his mistakes...

The bottom line is - no standalone or custom PCM... no E85. The ONE guy who's done it and posted in this thread told you so... take it for what it's worth.

-Chris-


-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...

Re: Anyone running E85??
Tuesday, June 28, 2011 1:07 PM
I had a nasty response about how turbo's on alpha-n a ghettoize tunes so dont be a hypocrite but I deleted it because it was not in the best interest of the j-body community to continue this stupid fight. Lets just leave it this way. If you want to run e85 on a j-body you better have someone who knows what they @!#$ they're doing and be willing to risk mistakes happening, whether it be with a stand alone or otherwise.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Re: Anyone running E85??
Tuesday, June 28, 2011 1:10 PM
Oh and Leafy... just to clarify...

You think that by changing the injector constant you move stoich on the PCM? Not at all... you tell it the injectors are smaller when you put in bigger injectors - that's fine... but the PCM is programmed to run stoich for GASOLINE.

You can change ANYTHING you want in the PCM... VE tables, timing tables, injector constant... but NOTHING will convince it to stop trying to achieve stoich for gasoline... nothing. (Other than shutting off closed loop but that car will run like a bag of donkeys as soon as the weather or altitude changes...)

Im sorry - there is just no way to reliably do it on a Jbody PCM. There is no hack, no workaround, and no ghetto way to make it happen. Why else would Gary have gone to a standalone? Because he likes to make custom wiring harnesses and spend big bucks on standalones and tuning from 100% scratch with no base maps?

(Hey maybe he loved every second of it... but 99% of the people won't.)

If you want to give it a shot - go for it! But I guarantee you'll end up frustrated and with a car that runs like a bag of monkey poo.

Take it from a guy who ran 21 psi on a 1 bar setup, 18 psi on a faked 2 bar, and has tuned over 16 J-bodies. The stock PCM is just too limited to do it safely, let alone do it right.

-Chris-


-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Re: Anyone running E85??
Tuesday, June 28, 2011 1:14 PM
A turbo setup on an Alpha-N setup can be a bit ghetto at low boost, and very unreliable. On moderate boost it's a total hackjob. On a Supercharger - its fine since it won't get over 10 psi and is linear.

The stock PCM is just too limited, and it's truly unfortunate. I'm not trying to attack you, just provide sound information.

Definitely no need to get nasty, this is a civil forum and a civil discussion amongst friends. *thumbsup*

-Chris-




-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Re: Anyone running E85??
Tuesday, June 28, 2011 1:14 PM
SweetnessGT wrote:O but NOTHING will convince it to stop trying to achieve stoich for gasoline... nothing.


Take out the words "for gasoline" and that is a correct statement.

Put it this way. I could light farts on fire in front of a narrow band and if I happened to have the perfect stoichometic ratio the narrow band would output 451mV.


1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by: Kronos Performance

WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
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