"Cant" run E85 on stock PCM? OK.. why cant we run this? - Page 4 - Tuning Forum
Forum Post / Reply
You must log in before you can post or reply to messages.
I think he was trying to save you time and money Brad, but like every other conversation I've seen between you and him, its you that always has to be right, even when you are blatantly wrong.
I really wouldnt mind seeing a jbody file. Thanks md for somewhat agreeing with me. The funny thing is even though gtp's have more tuning parameters most all dont use them all. They only change their ifr tables and add timing. Thats it and through research the others who dont have ifr tables used injector constant which is what you have. Even ls1 guys that start out dont use all their parameters cuz quite frankly its over their head to make completely new tables. The tuning gods of the ls tell beginners the same thing. Dont mess with all your tables just change your ifr's and it'll be fine.
Edited 1 time(s). Last edited Wednesday, April 17, 2013 11:12 AM
FU Tuning
Reverant GTP wrote:I really wouldnt mind seeing a jbody file. Thanks md for somewhat agreeing with me. The funny thing is even though gtp's have more tuning parameters most all dont use them all. They only change their ifr tables and add timing. Thats it and through research the others who dont have ifr tables used injector constant which is what you have. Even ls1 guys that start out dont use all their parameters cuz quite frankly its over their head to make completely new tables. The tuning gods of the ls tell beginners the same thing. Dont mess with all your tables just change your ifr's and it'll be fine.
I have uploaded a bunch to HPTuner's repository, they are under -MD- HHR or -MD- Enforcer.
I'm not arguing that is you add enough fuel you can get it to run well, but as soon as the ethanol content changes are PCMs and cars will freak the @!#$ out. I think what you can not understand really is our PCMs are not like anything else. Hell not even other GMs. I mean all principles for tuning are the same, but J-bodies do not respond the same way to doing "normal tuning practices" that other cars do. The best example I can think of is 2nd Gen non-SRT4 neon's. Their PCMs are probably worse than ours.
Edited 1 time(s). Last edited Wednesday, April 17, 2013 9:55 AM
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Ok well either way you only need to change injector constant.. thats it. Regardless what the pcm is working toward for afr... it is trying to acheive stoich... is it not?
I have never seen a thread blow up in the tuning forum like this - it's a shame that it was for all the wrong reasons.
Brad, I'm glad you aren't going to go with this "solution"... genuinely. Now you say you are going to have your tuner do the tune for E85... do you mean on a stock GMSC pcm? I know somebody in the boost forum was talking about somebody that had a friend with a J running E85 on the stock PCM dynoing some good #'s... we all agreed the car is a time bomb BUT it apparently has been running for a year so far.
I also know that "Old Man" Gary has been running E85 but I'm fairly sure he went standalone. He would be a good source to ask about what he needed to do that was Jbody specific.
I can understand that you like to do things properly, and I can understand the temptation to cut a corner here and there esp when $$$ is involved. I too, like to do things properly but have been forced to cut the odd corner here and there due to the limitations of the Jbody PCM and the platform in general.
With that said, I fear your limitation with the JBODY PCM will be two fold... 1 will be the injector offset (you will max it out quickly I believe) and the other will be the inability to change the value of stoich for the PCM in closed loop. You cold force it to open loop all the time and tune it for that at the loss of gas mileage, I think... not ideal but do-able.
I know that my Innovate LC-1 allows me to change the value of stoich which would be helpful in your situation for tuning, I don't believe the AEM lets you do that but I could be wrong.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
what is stoich you ask? stoichiometric is a mixture that has just enough air to completely burn the available fuel. It is a mathematical formula of part fuel to 1 part oxygen to produce stoich.
Regardless of fuel used it is a formula to acheive stoich.
The air to fuel ratio is the property of fuel and chemical composition of the fuel that defines the value for this ratio. Most of the fuels we use in internal combustion engines are hydrocarbons, and their burning will obviously result in the release of hydrogen and carbon as residuals, along with heat and pressure. Let us have a look at the oxidation reaction of methane (natural gas) as a fuel.
CH4 + 2(O2) → CO2 + 2(H20)
If we look up the atomic weights of the atoms that make up octane and oxygen, we get the following numbers:
Carbon (C) = 12.01
Oxygen (O) = 16
Hydrogen (H) = 1.008
So 1 molecule of methane has a molecular weight of: 1 * 12.01 + 4 * 1.008 = 16.042
One oxygen molecule weighs: 2 * 16 = 32
The oxygen-fuel mass ratio is then: 2 * 32 / 1 * 16.042 = 64 / 16.042
So we need 3.99 kg of oxygen for every 1 kg of fuel
Since 23.2 mass-percent of air is actually oxygen, we need : 3.99 * 100/23.2 = 17.2 kg air for every 1 kg of methane.
So the stoichiometric air-fuel ratio of methane is 17.2.
When the composition of a fuel is known, this method can be used to derive the stoichiometric air-fuel ratio. For the most common fuels, this, however, is not necessary because the ratios are known:
Natural gas: 17.2
Gasoline: 14.7
Propane: 15.5
Ethanol: 9
Methanol: 6.4
Hydrogen: 34
So now knowing this... the pcm is trying to achieve stoich... which is a ratio to produce a certain number of byproduct to produce the what the oxygen sensor wants to see which in turn outputs a voltage to the pcm to let the pcm know we achieved this. Not many tune in lambda or e85 afr's... they use standard gas afr's because all the gauge is showing you is a formula based off lambda, volts, whatever you want to call it... it doesnt matter. Its all formulas and math... no voodoo, magic or anything like that. Just simple math.
SweetnessGT wrote:I have never seen a thread blow up in the tuning forum like this - it's a shame that it was for all the wrong reasons.
Brad, I'm glad you aren't going to go with this "solution"... genuinely. Now you say you are going to have your tuner do the tune for E85... do you mean on a stock GMSC pcm? I know somebody in the boost forum was talking about somebody that had a friend with a J running E85 on the stock PCM dynoing some good #'s... we all agreed the car is a time bomb BUT it apparently has been running for a year so far.
I also know that "Old Man" Gary has been running E85 but I'm fairly sure he went standalone. He would be a good source to ask about what he needed to do that was Jbody specific.
I can understand that you like to do things properly, and I can understand the temptation to cut a corner here and there esp when $$$ is involved. I too, like to do things properly but have been forced to cut the odd corner here and there due to the limitations of the Jbody PCM and the platform in general.
With that said, I fear your limitation with the JBODY PCM will be two fold... 1 will be the injector offset (you will max it out quickly I believe) and the other will be the inability to change the value of stoich for the PCM in closed loop. You cold force it to open loop all the time and tune it for that at the loss of gas mileage, I think... not ideal but do-able.
I know that my Innovate LC-1 allows me to change the value of stoich which would be helpful in your situation for tuning, I don't believe the AEM lets you do that but I could be wrong.
-Chris-
Chris, Gary is running a Tec-3 and is on E70 last I heard. I believe almost all the newer wide bands can be changed. I know my MTX-L and DB both can.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
AEM uego has a port on the back of the gauge with five different settings you can choose from to read different fuels. its all in the instructions plus the instructions also give you formulas to figure out different fuel afrs based off normal gas afrs.
Carry on.....
P&P Tuning
420.5whp / 359.8wtq
QWK LN2 (P&P Tuning) wrote: Carry on.....
Shut up Ryan, it's not like you know anything anyway! 
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
OK fine... lets try this... i looked at the repository and saw stock, m45 with gmpcm upgrade to read map.... and i saw turbo... and stock the only difference through a very quick skim was the injector constant, ve, and pe being changed. I saw different injector sizes, i saw different power adders yet only these things changed. They obviously ran and worked and as we all know alot can go wrong with boost. Yet there are numerous tunes in the repository varying in different approaches however the changes remained the same. All using regular gas... now to use e85 all you must do is increase how much fuel is being used. Thats it... nothing else "NEEDS" done... fuel, spark, and boost. Are there other possibly better ways... yeah obviously. You can completely rip a tune apart and create everything new... but you dont need to. You can just get a whole new car like an LS with more maps and a better all around platform... but why you guys have ran turbo, s/c, n/a and changed injectors and everything with your very limited tuning parameters. All you need to do is add more fuel and adjust timing. No different than you all have obviously already done. You arent building nascar or formula one cars or running endurance that have to extract every last ounce of power at every single rpm in every single situation in every singe altitude in every single terrain etc, etc, etc... as the old saying goes keep it simple stupid or "Hows a rainbow made? whys the sky blue? how does a posi track rear end on a plymouth work? It just does." Let the pcm do what it needs to... all you need to control is fuel and spark. Thats it.
To address the ok it'll work but what if the ethanol content changes then it'll freak the @$@ out... Tough thats life... thats the nature of the beast. It doesnt always happen and sometimes it does. E85 is very forgiving and can run super rich to super lean but in the end it will still run. Do you honestly think everyone who runs e85 changes their tune bases off of weather and barometric and altitude changed everywhere they go? No they dont, they either stay in the same area, dont drive their cars in winter or just deal with it. If it runs like poo they check the ethanol content before every fill up if they are they concerned... it doesnt take long... if its wrong well drop the tank empty it use a different company that doesnt use crap gas. Around here there are only a few stations with crap e85 and we all know about it. So we dont go there, or we go to stations with blender pumps. E70 to E85 is only a half point difference in afr and people tune vastly different afr ratios than that and run just fine. Keep it simple... its not voodoo juice.
BTW from also looking at your tunes... can someone explain to me how to find where it has anywhere in the tune it says "I DONT USE LAMBDA IN ANYWAY SHAPE OR FORM?" i'm having problems finding this??? Just saying i thought lambda, millivolts, air to fuel ratio were all mathematical calculation but you guys are saying the tune has this in there somewhere. Just looking for proof is all.
Reverant GTP wrote:BTW from also looking at your tunes... can someone explain to me how to find where it has anywhere in the tune it says "I DONT USE LAMBDA IN ANYWAY SHAPE OR FORM?" i'm having problems finding this??? Just saying i thought lambda, millivolts, air to fuel ratio were all mathematical calculation but you guys are saying the tune has this in there somewhere. Just looking for proof is all.
Can you point to one file in a jbody tune that references lambda?
How many reference AFR?
FU Tuning
Ahaaaa there we go!... tell me in any pcm where lambda is referenced? Its not... its used to calculate afr.
lambda 1.0 is stoich of ANY FUEL... Lambda is a number used in calculation just like stoich is theoretical ratio of a fuel to 1 part oxygen to produce a byproduct that an oxygen(lambda) sensor wants to acheive
Please, please please (addicted to meth) tell me you see now how arbitrary saying "my pcm only reads mv not lambda" It is because in the end a pcm uses calculation... that is it... lambda is a measure of calculation... mv is a measure of calculation based off a lambda sensor... lambda 1.0 is 450mv any deviation is rich or lean... obviously a car uses volts because of electricity but in the end it sends those volts that then are calculated off a formula...
Reverant GTP wrote:Ahaaaa there we go!... tell me in any pcm where lambda is referenced? Its not... its used to calculate afr.
I do not have my laptop in front of me, but I know the LNF ecu's use and reference lambda.
Quote:
Please, please please (addicted to meth) tell me you see now how arbitrary saying "my pcm only reads mv not lambda" It is because in the end a pcm uses calculation... that is it... lambda is a measure of calculation... mv is a measure of calculation based off a lambda sensor... lambda 1.0 is 450mv any deviation is rich or lean... obviously a car uses volts because of electricity but in the end it sends those volts that then are calculated off a formula...
never said our ecu only reads mv. Our ecu reads the mv as AFR.
All oxygen sensor's/lambda sensor's give out a voltage, the ecu based on how it was setup/programed from the factory determines what the voltage means.
Yes the ECU does use calculations, it does for everything. It uses a caculation that reads AFR.
FU Tuning
"All oxygen sensor's/lambda sensor's give out a voltage, the ecu based on how it was setup/programed from the factory determines what the voltage means"
Fine we'll use your own words then... Forget lambda.. lets use this then. This statement applies to all pcms then yes?
And also you said lnf's use lambda... fine. Does LS? no Does GTP? no Does Subaur? no Does srt? no.... do they all run E85? YES
Lets try this again A Lambda value of 1.0 = Stoich, regardless of the fuel used.
Stoich for Gasoline = 14.7:1
So, 14.7:1 (gasoline) = 1.0 Lambda
9.9:1 (E85 stoich) = 1.0 Lambda
6.4:1 (methanol) = 1.0 Lambda
Therefore, using a gasoline calibrated wideband, AFR = Lambda value * 14.7
An example: Say I want to run 11.9 AFR's with gasoline. That is the equivalent of .81 Lambda.
.81(Lambda) * 14.7(Stoich gasoline AFR) = 11.9(AFR)
The Lambda value is what you want to reference as your target for whatever fuel you will be running in your car.
It doesnt matter if your pcm tune shows afr, lambda or millivolts... there is a calculation to turn them into each other... it is used to teach you how to tune amongst telling the car how to react. Just like anything else. Every platform had naysayers in the beginning yet over came... some of you need to open your eyes... plain and simple. Stop listening to the old school way of thinking that keep people stuck in the stone age. Sure there are certain points where it wil not work but for brads application or anything under what 1000cc? I believe thats what i was told your pcm can control... will work.
Reverant GTP wrote:And also you said lnf's use lambda... fine. Does LS? no Does GTP? no Does Subaur? no Does srt? no.... do they all run E85? YES
they also have the proper Stoich tables so you don't end up raping your MAF..... Stop trying to @!#$ trains..... You have some valid points, but your not comparing apples and oranges... There is a thing called "Theory and Reality".....
P&P Tuning
420.5whp / 359.8wtq
Forum Post / Reply
You must log in before you can post or reply to messages.
