Please Do Not Run E-85 on Stock Injectors.

[Jn2]

Compare your commanded lambda vs actual against this commanded lambda vs actual.

Remember that the error between commanded lambda and actual lambda makes no contribution towards Injector pulsewidth(IPW). Also I believe he mention that the commanded PID for him wasn't registering correctly.

Below I am attaching a screenshot on of my 50% ethanol runs. This run saw IDC's of 79.2% and IPW's of 12.5ms. My fuel trims are always within +/-2% during the pull as well. Ignore the low spark advance, I was hunting down some false knock that ended up being bad gas.

My pump is on a e70 blend right now so I cannot post true e85 results, but you can clearly see that even at 50% ethanol I am at ~80% IDC. Now increase my fuel demand by another 15%(since I am already on e50) and I would be around 92% IDC. My number is a bit safer than Term's 97%, which just goes to prove his point. do you really want to take a gamble on which end of the tolerance your car is on?

Shaun posted there is a 6% injector tolerance at the factory so you could end up like me, in the low 90% IDC range on a semi warm day, or you could end up like term, in the high 90's IDC range on a semi warm day. Also as temperature drops, IDC increases, because of this I will prob never run e85 through my car, a 92% IDC when it's 80* outside will only grow as temps drop into the low 30's and 40's.

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[markmurfie]

Having the wrong stioch value would not cause both your commanded eq and short term fuel trims to be slant in the chart. The only two things that would, would be a bad maf table or your wot lambda table values growing/shrinking with change in RPM . You say yours are .85 flat then your commanded and stft in the chart should be also. They are not, therefore your maf values are wrong.

 

[Jn2]

Having the wrong stioch value would not cause both your commanded eq and short term fuel trims to be slant in the chart. The only two things that would, would be a bad maf table or your wot lambda table values growing/shrinking with change in RPM . You say yours are .85 flat then your commanded and stft in the chart should be also. They are not, therefore your maf values are wrong.

You referring to me? Bc my commanded/actual Lambda and STFT/LTFT are quite flat.

 

[markmurfie]

Remember that the error between commanded lambda and actual lambda makes no contribution towards Injector pulsewidth(IPW). Also I believe he mention that the commanded PID for him wasn't registering correctly.

Below I am attaching a screenshot on of my 50% ethanol runs. This run saw IDC's of 79.2% and IPW's of 12.5ms. My fuel trims are always within +/-2% during the pull as well. Ignore the low spark advance, I was hunting down some false knock that ended up being bad gas.

My pump is on a e70 blend right now so I cannot post true e85 results, but you can clearly see that even at 50% ethanol I am at ~80% IDC. Now increase my fuel demand by another 15%(since I am already on e50) and I would be around 92% IDC. My number is a bit safer than Term's 97%, which just goes to prove his point.

Shaun posted there is a 6% injector tolerance at the factory. You could end up like me, in the low 90's on a semi warm day, or you could end up like term, in the high 90's on a semi warm day as well. As temperature drops, IDC increases, because of this I will prob never run e85 through my car, I try and cap myself around e60 just to avoid potential failure.

See this is a much much better example of proper maf values. At almost 7700rpms you are just over 44lb/min. Term was claiming 47lb/min at a much lower RPM. commanded lambda and actual lambda represent the error in the maf values. If the car thinks it's moving more air than it really is it will run rich. You will Max out your injector unnessicarily. Your seeing exactly what I predicted earlier if term corrected his tune.

Also take into account with higher %E you will have more fuel being sprayed in the intake. This means it's very unlikely you MAF will increase. It's going to remain where it is or even be less. This PDF is a study on how to use MAF values to better estimate E content. Page 65 is the effect on the filing model equation.
Http://www.google.com/url?sa=t&sour...YJCBdY6R1AQ4M_euw&sig2=ticNgTnE5lUXc7DLuSoegw

 

[Terminator2]

Having the wrong stioch value would not cause both your commanded eq and short term fuel trims to be slant in the chart. The only two things that would, would be a bad maf table or your wot lambda table values growing/shrinking with change in RPM . You say yours are .85 flat then your commanded and stft in the chart should be also. They are not, therefore your maf values are wrong.

Ignore the commaded EQ PID it doesn't function correctly. Yes it's off about -2% total fuel trim max now that I fixed stoich. On 93 same MAF settings started at 0 and went to -2 and in those logs started at 0 and went to -6 max. They are now 0 to -2 like they were before.

 

[Terminator2]

See this is a much much better example of proper maf values. At almost 7700rpms you are just over 44lb/min. Term was claiming 47lb/min at a much lower RPM. commanded lambda and actual lambda represent the error in the maf values. If the car thinks it's moving more air than it really is it will run rich. You will Max out your injector unnessicarily. Your seeing exactly what I predicted earlier if term corrected his tune.

Also take into account with higher %E you will have more fuel being sprayed in the intake. This means it's very unlikely you MAF will increase. It's going to remain where it is or even be less. This PDF is a study on how to use MAF values to better estimate E content. Page 65 is the effect on the filing model equation.
Http://www.google.com/url?sa=t&sour...YJCBdY6R1AQ4M_euw&sig2=ticNgTnE5lUXc7DLuSoegw

My MAF is actually almost dead on. My airflow is usually in the 45lb/min range in 80-90* temps it hits 47lbs/min on cool dry mornings You are not listening though my commanded lambda is not 0.89 like that genaric PID reads it's 0.85 right there and the richest it hits is 0.82 actual as read by both of my widebands until the STFT pulls out -3% To correct. My stoich was too rich by 4% hence my LTFTs being -3 on one bank and -4 on the other. -3+-4=-7 which is my total fuel trim right there. Now that I fixed my stoich my IDC came down 1% with my new injectors. Even taking that into account I was still extremely close to maxing my injectors out in 80* temps. Add in one cold 40* morning where airmass is greater by 7-8% and it would be at 100%.

Old 93 octane log with same exact MAF period values just correct stoich. 0.85 commaded 0.84 actual total fuel trims -2 here LTFT zero STFT -2. Needed to be -3. My MAF is not off!!! My trims are better than they were stock. MAF almost 47 here. Actual is just under 46 once corrected. I haven't bothered taking 2-3% out of 125uS area of my period vs MAF table because I'd rather it be 2-3% rich in case I get E-90 instead of E-85.

 

[shawn3210]

So what kind of injectors does every recommend getting?

 

[pwnall1337]

So what kind of injectors does every recommend getting?

courtesy of Terry [MENTION=10926]beefcake[/MENTION] . make sure to hit him up if you need injectors at a great price!

 

[Jn2]

Forgot to update the thread, but my IDC's went from 79.2 to 85% with no changes to the tune and e55. Only thing that changed was a cold front that came in. Temps dropped to mid 50s.

Will post more tomorrow when temps are set to drop to mid 30's.

 

[Terminator2]

So what kind of injectors does every recommend getting?

LU47s

 

[Chach805]

LU47s

And those are good for the Flex Fuel Tune? Both e85 and pump gas

 

[Jn2]

And those are good for the Flex Fuel Tune? Both e85 and pump gas

Yes, the same one posted like 4 posts up.

 

[Chach805]

Yes, the same one posted like 4 posts up.

10-4

 

[Terminator2]

And those are good for the Flex Fuel Tune? Both e85 and pump gas

Yes they are plenty big to flow enough for E-85 and easy to tune for unlike some injectors out there. They should be good until about 600hp on 93 and well over 500hp on E-85.

 

[dubster99]

I'll be selling my 47's in a few weeks if anybody wants them!

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