Warning About 10% Ethanol Fuel Mix
07-05-06, 12:28 AM
#51
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Originally Posted by Rotary Experiment Seven
Keep tuners employed bah....Just add the fuel yourselves. If you have a wideband you can verify the change in a/f ratio. I do this in my cobra to compensate for weather changes/
Also like teh articel sez teh a/f ratio gonna change with alcohol neway.
07-05-06, 03:41 PM
#55
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Originally Posted by cardzrule
So you saying E10 iz based on a mass ratio? Mr Stevens sez its by volume. I think ur numbers r wrong dood.
Also gas aint 14.7:1 stoich unless u mean leaded. Mr Stevns sez gas is like 14.5:1 and MTBE gas is as low as 14.1:1 for stoich. So goin from MTBE to E10 should be like equal for AFR neway. What teh AFR gauge sez is another story tho coz depens on how lambda is set.
I dont think ne1 understands it. I had to ask my science teacher to xplane. I aint seen ne1 yet who understands it without asking a science teacher.
Like teh Mr rx-7 tt article sez, if ur AFR gauge is set at 14.7 AFR for stoich then ur readings r totally wrong dood.
Also gas aint 14.7:1 stoich unless u mean leaded. Mr Stevns sez gas is like 14.5:1 and MTBE gas is as low as 14.1:1 for stoich. So goin from MTBE to E10 should be like equal for AFR neway. What teh AFR gauge sez is another story tho coz depens on how lambda is set.
I dont think ne1 understands it. I had to ask my science teacher to xplane. I aint seen ne1 yet who understands it without asking a science teacher.
Like teh Mr rx-7 tt article sez, if ur AFR gauge is set at 14.7 AFR for stoich then ur readings r totally wrong dood.
It's obvious who doesn't know what they are talking about.
07-05-06, 03:42 PM
#56
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Originally Posted by cewrx7r1
Maybe so, but noticed the thread died, and no one even added or commented on it. That is the 3rd gen forum mentality and why many of us single turbo people do not go there too often.
Notice the response here, we care about our cars more!
Notice the response here, we care about our cars more!
07-05-06, 05:10 PM
#57
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Originally Posted by Mr rx-7 tt
"Dood"
It's obvious who doesn't know what they are talking about.
It's obvious who doesn't know what they are talking about.
V
https://www.rx7club.com/forum/showth...hlight=ethanol
07-05-06, 05:47 PM
#58
"pure" gas is 14.7, that's what the automotive world has been using, that's what the tuner's have been using, you might trust your science teacher but don't come crying when your engine blows because you had the wrong stoich AFR.
Moving on, notice how many posts you have? notice how many posts others have? They've been on the forum longer than you have, so don't presume to know more than they do. I have a low post count, and I don't know much, so I try not to act like a smartass, and instead, try to learn. It keeps me from rubbing people the wrong way. You should try it, you might like it.
Moving on, notice how many posts you have? notice how many posts others have? They've been on the forum longer than you have, so don't presume to know more than they do. I have a low post count, and I don't know much, so I try not to act like a smartass, and instead, try to learn. It keeps me from rubbing people the wrong way. You should try it, you might like it.
07-05-06, 06:36 PM
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http://forums.evolutionm.net/archive.../t-175567.html
"No, the LM-1 does not measure Afr, it measures Lambda. Then it multiplies Lambda with the programmed stoich AFR to produce the AFR display.
With 10% ethanol blend, running in closed loop at stoich (AFR programmed to 14.7), would display still 1.00 Lambda and 14.7 AFR, because the LM-1 does not magically know what fuel you are using. If you programmed it to 14.1 AFR fuel, it would show 1.00 Lambda and 14.1 AFR.
Widebands (and 5-gas analyzers) do NOT measure some magical AFR. They measure Lamda. There is a second way to calculate Lambda aside from the familiar actual_AFR/stoich_AFR. It's
Lambda = %O2_of_air / (%O2_of_air - %O2_of_exhaust)
This is how a wideband measures Lambda. The term %O2_of_exhaust can go negative if the gas is rich. In that case it means the amount of additional O2 needed to get the gas to stoich.
If you run open loop though and tuned the engine to for example 12.5 AFR (gasoline) and then switched to the ethanol blend, you would run leaner (both in Lambda and AFR) because you need higher fuel flow to compensate for the lower stoich value. If you programmed the LM-1 to 14.1 AFR as stoich, you would then see the correct 12.5 AFR value, but then 12.5 AFR is too lean for the fuel used.
To give an extreme example:
Nitromethane has a stoich value of 1.7. This means for every pound of air entering the engine you need 0.59 pounds for fuel to get to stoich. For gasoline at stoich you need 0.068 pounds of fuel per pound of air. Both values are at Lambda 1.0. If your engine runs max power at 15% rich (Lambda 0.85 or gas AFR 12.5), you could leave the LM-1 at 14.7 gasoline setting and tune to 12.5, irrespective of fuel. That's what RICE RACING meant. That's fine for tuning if you are used to AFR. If, on the other hand, you want to calculate a VE table for the engine, using measured AFR, MAP, displacement, inj. duty cycle and IAT, THEN you need to know the real air-fuel-ratio and stoichiometric value.""
"No, the LM-1 does not measure Afr, it measures Lambda. Then it multiplies Lambda with the programmed stoich AFR to produce the AFR display.
With 10% ethanol blend, running in closed loop at stoich (AFR programmed to 14.7), would display still 1.00 Lambda and 14.7 AFR, because the LM-1 does not magically know what fuel you are using. If you programmed it to 14.1 AFR fuel, it would show 1.00 Lambda and 14.1 AFR.
Widebands (and 5-gas analyzers) do NOT measure some magical AFR. They measure Lamda. There is a second way to calculate Lambda aside from the familiar actual_AFR/stoich_AFR. It's
Lambda = %O2_of_air / (%O2_of_air - %O2_of_exhaust)
This is how a wideband measures Lambda. The term %O2_of_exhaust can go negative if the gas is rich. In that case it means the amount of additional O2 needed to get the gas to stoich.
If you run open loop though and tuned the engine to for example 12.5 AFR (gasoline) and then switched to the ethanol blend, you would run leaner (both in Lambda and AFR) because you need higher fuel flow to compensate for the lower stoich value. If you programmed the LM-1 to 14.1 AFR as stoich, you would then see the correct 12.5 AFR value, but then 12.5 AFR is too lean for the fuel used.
To give an extreme example:
Nitromethane has a stoich value of 1.7. This means for every pound of air entering the engine you need 0.59 pounds for fuel to get to stoich. For gasoline at stoich you need 0.068 pounds of fuel per pound of air. Both values are at Lambda 1.0. If your engine runs max power at 15% rich (Lambda 0.85 or gas AFR 12.5), you could leave the LM-1 at 14.7 gasoline setting and tune to 12.5, irrespective of fuel. That's what RICE RACING meant. That's fine for tuning if you are used to AFR. If, on the other hand, you want to calculate a VE table for the engine, using measured AFR, MAP, displacement, inj. duty cycle and IAT, THEN you need to know the real air-fuel-ratio and stoichiometric value.""
07-05-06, 07:43 PM
#61
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Hey Chris, good info... that is one of the reasons why most tuners like tuning using lambda instead afr. It makes it much easier to tune no matter what gas you're in and also provide a better method on how rich/lean you need to add/taken out based on %..... give me a call when you get a chance, I lost your number and forgot to call you back last week....
Originally Posted by Mr rx-7 tt
http://forums.evolutionm.net/archive.../t-175567.html
"No, the LM-1 does not measure Afr, it measures Lambda. Then it multiplies Lambda with the programmed stoich AFR to produce the AFR display.
With 10% ethanol blend, running in closed loop at stoich (AFR programmed to 14.7), would display still 1.00 Lambda and 14.7 AFR, because the LM-1 does not magically know what fuel you are using. If you programmed it to 14.1 AFR fuel, it would show 1.00 Lambda and 14.1 AFR.
Widebands (and 5-gas analyzers) do NOT measure some magical AFR. They measure Lamda. There is a second way to calculate Lambda aside from the familiar actual_AFR/stoich_AFR. It's
Lambda = %O2_of_air / (%O2_of_air - %O2_of_exhaust)
This is how a wideband measures Lambda. The term %O2_of_exhaust can go negative if the gas is rich. In that case it means the amount of additional O2 needed to get the gas to stoich.
If you run open loop though and tuned the engine to for example 12.5 AFR (gasoline) and then switched to the ethanol blend, you would run leaner (both in Lambda and AFR) because you need higher fuel flow to compensate for the lower stoich value. If you programmed the LM-1 to 14.1 AFR as stoich, you would then see the correct 12.5 AFR value, but then 12.5 AFR is too lean for the fuel used.
To give an extreme example:
Nitromethane has a stoich value of 1.7. This means for every pound of air entering the engine you need 0.59 pounds for fuel to get to stoich. For gasoline at stoich you need 0.068 pounds of fuel per pound of air. Both values are at Lambda 1.0. If your engine runs max power at 15% rich (Lambda 0.85 or gas AFR 12.5), you could leave the LM-1 at 14.7 gasoline setting and tune to 12.5, irrespective of fuel. That's what RICE RACING meant. That's fine for tuning if you are used to AFR. If, on the other hand, you want to calculate a VE table for the engine, using measured AFR, MAP, displacement, inj. duty cycle and IAT, THEN you need to know the real air-fuel-ratio and stoichiometric value.""
"No, the LM-1 does not measure Afr, it measures Lambda. Then it multiplies Lambda with the programmed stoich AFR to produce the AFR display.
With 10% ethanol blend, running in closed loop at stoich (AFR programmed to 14.7), would display still 1.00 Lambda and 14.7 AFR, because the LM-1 does not magically know what fuel you are using. If you programmed it to 14.1 AFR fuel, it would show 1.00 Lambda and 14.1 AFR.
Widebands (and 5-gas analyzers) do NOT measure some magical AFR. They measure Lamda. There is a second way to calculate Lambda aside from the familiar actual_AFR/stoich_AFR. It's
Lambda = %O2_of_air / (%O2_of_air - %O2_of_exhaust)
This is how a wideband measures Lambda. The term %O2_of_exhaust can go negative if the gas is rich. In that case it means the amount of additional O2 needed to get the gas to stoich.
If you run open loop though and tuned the engine to for example 12.5 AFR (gasoline) and then switched to the ethanol blend, you would run leaner (both in Lambda and AFR) because you need higher fuel flow to compensate for the lower stoich value. If you programmed the LM-1 to 14.1 AFR as stoich, you would then see the correct 12.5 AFR value, but then 12.5 AFR is too lean for the fuel used.
To give an extreme example:
Nitromethane has a stoich value of 1.7. This means for every pound of air entering the engine you need 0.59 pounds for fuel to get to stoich. For gasoline at stoich you need 0.068 pounds of fuel per pound of air. Both values are at Lambda 1.0. If your engine runs max power at 15% rich (Lambda 0.85 or gas AFR 12.5), you could leave the LM-1 at 14.7 gasoline setting and tune to 12.5, irrespective of fuel. That's what RICE RACING meant. That's fine for tuning if you are used to AFR. If, on the other hand, you want to calculate a VE table for the engine, using measured AFR, MAP, displacement, inj. duty cycle and IAT, THEN you need to know the real air-fuel-ratio and stoichiometric value.""
07-06-06, 12:12 AM
#62
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Originally Posted by cardzrule
Like teh Mr rx-7 tt article sez, if ur AFR gauge is set at 14.7 AFR for stoich then ur readings r totally wrong dood.
I never said I was doing that, my PFC not only has the O2 FB function turned off, but I also run with the ISC idle control removed.
Last edited by cewrx7r1; 07-06-06 at 12:23 AM.
10-04-06, 06:15 PM
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Originally Posted by GoodfellaFD3S
With a power fc, you can just go to the PIM volt menu and take the fuel from 100% to 103.5% at each 1000 rpm point.
Doing it this way.. It adds more fuel at each 1000 RPM from idle..
regardless of boost right???
Damn wish i was in my car with the commander..
10-04-06, 06:17 PM
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Originally Posted by cewrx7r1
With the PFC I went to the PIM volt and did 103.5% for 4.0 and 4.5 volts which covers 10+ psi of boost.
This method leaves everything alone, but increases fuel above 10PSI..
right??
10-04-06, 06:32 PM
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Originally Posted by pluto
Good call!!! I would expect 5% more fuel for 10% ethanol though since it burns 2x as fast so 10% of that should equate to 5% more fuel....
Pardon my other reply..
Steve says add 5% more fuel.. over 4.0, 4.5 volts(over 10psi)
or over the whole rpm??
thanks
10-04-06, 08:42 PM
#67
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Originally Posted by pluto
Hey Chris, good info... that is one of the reasons why most tuners like tuning using lambda instead afr. It makes it much easier to tune no matter what gas you're in and also provide a better method on how rich/lean you need to add/taken out based on %..... give me a call when you get a chance, I lost your number and forgot to call you back last week....
I started a thread on this: *in single turbo section*
If your used to petrol AFR numbers their meanings and you can respond to them faster then there is nothing wrong with using this scale as your reference, many tuners i know around the world and also ECU companies stick to using petrol AFR scale no matter if their tuning blends of fuels of straight fuels be it nitromethane of Methanol or anything between
No point learning new values if they dont naturaly sit with you, at end of the day there is no reason to do so either
01-24-07, 06:40 PM
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Originally Posted by cardzrule
Mr Stevens my science teacher says that is called energy content. I aint never heard of nothing called BTU density. Is that metric stuff or something?
but seriously you need to alter the fuel into the engine based on the stoichiometric ratio not its BTU to keep the engine seeing the same "tune" as pointed out in some previous post. its a mass based system not volume either.
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