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      07-23-2013, 11:59 PM   #23
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oh wow, im impressed - let me be the first one to make a non - contributing post to this thread.

e90 forum members are growing up

one of the most informative threads ive read in a very long time, though not based on a lot of HARD DATA, - great to read ! thank you all
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      07-24-2013, 01:07 AM   #24
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Originally Posted by jippii ensio View Post
Correct.
Lambda is what matters. It is just interpreted as "respective gas AFR" in the logs for consistency and convenience if you think positively The "true AFR" doesn't really matter.

Closed loop reads lambdas and adjust them automatically so that we don't need to bother about different AFRs of different fuels.
So basically the way this works with lambda means a person with a stock car could theoretically run full e85 and be ok after the car adapted to it, correct?

The only reason most or some people need bigger fuel pumps is because there lpfp is either tired or cant keep up above 400hp on full e85 correct? So for example, i have an open flash, if i updated my fuel pump i should be able to run full e85 without a procede and without the flex fuel kit?

If thats the case, how would Vishnu's flex fuel kit be better since the car tagets a 1 ratio on lambda anyways?
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      07-24-2013, 01:30 AM   #25
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Originally Posted by buster84 View Post
So basically the way this works with lambda means a person with a stock car could theoretically run full e85 and be ok after the car adapted to it, correct?

The only reason most or some people need bigger fuel pumps is because there lpfp is either tired or cant keep up above 400hp on full e85 correct? So for example, i have an open flash, if i updated my fuel pump i should be able to run full e85 without a procede and without the flex fuel kit?

If thats the case, how would Vishnu's flex fuel kit be better since the car tagets a 1 ratio on lambda anyways?
Your DME always asks for the correct amount of fuel. Flex fuel kit just adjusts the aggressiveness of the tune based on the ethanol content.
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      07-24-2013, 01:35 AM   #26
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Originally Posted by jippii ensio View Post
Your DME always asks for the correct amount of fuel. Flex fuel kit just adjusts the aggressiveness of the tune based on the ethanol content.
Ahh thats good to know. So there flex fuel tune and kit provides more timing ect.. interesting, but if you just want to run full e85 all you need is a pump that can handle it. Sweet! Thanks!
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      07-24-2013, 03:13 AM   #27
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Ahh thats good to know. So there flex fuel tune and kit provides more timing ect.. interesting, but if you just want to run full e85 all you need is a pump that can handle it. Sweet! Thanks!
Your upgraded fuel system still has a limit though. You can't flow straight e85 to the max. You need to detune it a little. That is what OpenFlash is for though, and the community here will surely help.

If you are seeking for the last whp, you could have e.g. 3 maps, straight e85, straight pump gas and a mix of 50/50 or 60/40. Out of these the mix map will be the most aggressive since your fuel system can flow all the fuel for all the power. You could start the map switching while filling in.

The easiest, no hassle and most expensive way would be to have flex fuel with an upgraded fuel system, but if you don't have Procede already, it might not be worth it.
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      07-24-2013, 03:26 AM   #28
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Originally Posted by jippii ensio View Post
Your upgraded fuel system still has a limit though. You can't flow straight e85 to the max. You need to detune it a little. That is what OpenFlash is for though, and the community here will surely help.

If you are seeking for the last whp, you could have e.g. 3 maps, straight e85, straight pump gas and a mix of 50/50 or 60/40. Out of these the mix map will be the most aggressive since your fuel system can flow all the fuel for all the power. You could start the map switching while filling in.

The easiest, no hassle and most expensive way would be to have flex fuel with an upgraded fuel system, but if you don't have Procede already, it might not be worth it.
I'm leaning towards the procede flex fuel kit. I purchased a Walbro GSL392 a week ago and have yet to install it. I like the flex fuel kit and originally wanted there pump with it but now im thinking i'll just stick with the pump i have now and get the flex fuel parts and a procede 2.5

I'm not really looking for max hp, but more so the easiness of the car adapting and being able to run different mixes well since summer and winter tend to have different amounts of ethanol.
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      07-24-2013, 07:46 AM   #29
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Originally Posted by jippii ensio View Post
Correct.
Lambda is what matters. It is just interpreted as "respective gas AFR" in the logs for consistency and convenience if you think positively The "true AFR" doesn't really matter.

Closed loop reads lambdas and adjust them automatically so that we don't need to bother about different AFRs of different fuels.
Ding ding ding........

The light finally went on for me.

This question has been plaguing me for a while now, but thinking in terms of a closed loop lambda rather than relying on what the datalogs returns (a false gasoline relative AFR) makes perfect sense now.
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      07-24-2013, 07:48 AM   #30
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oh wow, im impressed - let me be the first one to make a non - contributing post to this thread.

e90 forum members are growing up

one of the most informative threads ive read in a very long time, though not based on a lot of HARD DATA, - great to read ! thank you all
We all just put on our dumb hats and poker faces while trolling the other forum in order to keep the drama levels up over there.

All they do is talk about us for the most part.
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      07-24-2013, 07:51 AM   #31
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I tried running 30% ... Extra load on hpfp caused it to fail. Prob going to seek out other alternatives
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      07-24-2013, 08:01 AM   #32
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well the hpfp is bad by itself, maybe E30 speed up the inevitable. i have been running E50 for about 1 year and all is fine, for now.
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      07-24-2013, 08:43 PM   #33
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So I have read/seen a lot of people talking about using E85 blends, (E30 etc), and getting HUGE power gains out of it when tuned correctly.

Why have I not really seen ANYTHING/or ANYBODY talk about the negative effects of using it?

For example, these fuel pumps are going bad for many reasons, but American's using Ethanol in our normal gas being a root cause (true or not I am not sure).

Or I've heard diesel mechanics discuss ethanol frying piston rings on gasoline motors,
OR
Damaging the entire fuel system because ethanol is naturally corrosive.

Since the system is not designed to run E85, there has to be significant negative impacts on the motors/fuel system that can not be corrected by different fuel mapping? Or am I just plain wrong?

I live in Colorado where E85 is readily available, and I could use all the help I could get at this altitude.

Any input from experts?

Thanks!
Search using my username. I've been in some discussions about this.
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      07-24-2013, 10:29 PM   #34
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We all just put on our dumb hats and poker faces while trolling the other forum in order to keep the drama levels up over there.

All they do is talk about us for the most part.
This is the problem with the community on both sides, the us and them mentality.......

Sorry for the off topic.

But I definitely agree that the this thread is helpful and a credit to these forums.

Given the information I might just hold off on running E85 until I can investigate the brown gunk more. That and I spent most of my spare cash already.

Last edited by Kabnine; 07-24-2013 at 11:06 PM.
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      07-24-2013, 11:34 PM   #35
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That's the stuff I have been thinking about!
Increasing fuel by 30% is fine, no biggie.
But what about the tank, pumps, seals, fuel lines, changing oil type or just increase change intervals, injectors (apparently sugar build up, fixed by techron treatment(s)), etc etc?
From what I have heard, the systems in today's cars are already modified to handle ethanol by default, because there is already ethanol in a large portion of gasoline not branded as ethanol. Someone correct me on this, if I am wrong.
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      07-25-2013, 11:13 AM   #36
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Probably the biggest issue with E85 is that most of the time it is not 85% ethanol. There are 3 blends of fuel I have heard of; winter, spring/fall and summer. I have seen E85 vary from 65% ethanol to 85%. The fuel trims for a wide range like that are pretty significant. Most guys I know have at least 2 maps and do an ethanol content test when they fill up if they don't have a ethanol content gauge.
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      07-25-2013, 11:23 AM   #37
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Probably the biggest issue with E85 is that most of the time it is not 85% ethanol. There are 3 blends of fuel I have heard of; winter, spring/fall and summer. I have seen E85 vary from 65% ethanol to 85%. The fuel trims for a wide range like that are pretty significant. Most guys I know have at least 2 maps and do an ethanol content test when they fill up if they don't have a ethanol content gauge.
Good point. Winter blends are without question lower in ethanol %, so adjust accordingly. Since I “only” run E30, I usually fill the tank with closer to E40 were the E85 actually E85. So I build in some headroom to prevent the situation you’re talking about. As you use more and more E85 (and the timing that comes with it), obviously you need to be more on top of that. Not smart to guestimate for E50 and a tune that is likely pretty aggressive in terms of advance.
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      07-26-2013, 03:46 AM   #38
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The term afr is literally air:fuel ratio. That means it's a RATIO of air to fuel. Like a recipe, 14.7 parts air, one part fuel for gas. LOTS of air, one part gas. Lambda of one. E85, 9ish parts air, one part gas. Less air per gas, so takes more (since the air is constant at your boost target). Lambda of one still.

Problem is the O2 has no idea how much gas you just injected. Was the "one" part of gas a teaspoon or a gallon? It knows only lambda and calculates afr based on a formula for gasoline. It also has no idea how many parts of air your engine ingested. Only how much comes out. I wish people would report in lambda, kinda like I wish we used metric in the US.

And you're right, it's questionable the necessity of the flexfuel monitor. In fact, all major manufacturers did away with ethanol sensors years ago in favor of lambda tuning and accurate fuel monitoring. You can calculate ethanol percent from injector pulse width, fuel pressure, mass air flow (calculated from VE tables vs pressure and temperate) and lambda. Ding ding ding winner winner chicken dinner.

Back to lurking.
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      07-26-2013, 05:06 AM   #39
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Just say NO to METRIC

Otherwise you will become Canadian!

But that's a really good explanation of Lambda.
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      07-26-2013, 08:56 AM   #40
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The term afr is literally air:fuel ratio. That means it's a RATIO of air to fuel. Like a recipe, 14.7 parts air, one part fuel for gas. LOTS of air, one part gas. Lambda of one. E85, 9ish parts air, one part gas. Less air per gas, so takes more (since the air is constant at your boost target). Lambda of one still.

Problem is the O2 has no idea how much gas you just injected. Was the "one" part of gas a teaspoon or a gallon? It knows only lambda and calculates afr based on a formula for gasoline. It also has no idea how many parts of air your engine ingested. Only how much comes out. I wish people would report in lambda, kinda like I wish we used metric in the US.

And you're right, it's questionable the necessity of the flexfuel monitor. In fact, all major manufacturers did away with ethanol sensors years ago in favor of lambda tuning and accurate fuel monitoring. You can calculate ethanol percent from injector pulse width, fuel pressure, mass air flow (calculated from VE tables vs pressure and temperate) and lambda. Ding ding ding winner winner chicken dinner.

Back to lurking.
Good explanation and all correct. One thing to note though is that even if DME is able to calculate the ethanol content, it does not use the information for maximizing the performance. If you just fill in e85 to a stock car vs to a flex fuel sensor car that uses the info for maxing the performance, the results will be very different. The stock DME keeps the performance rather constant, whereas e85 tune is far from constant

That's why flex fuel sensors are used to some extent in the tuning world.
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      07-26-2013, 09:16 AM   #41
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Originally Posted by jippii ensio View Post
Good explanation and all correct. One thing to note though is that even if DME is able to calculate the ethanol content, it does not use the information for maximizing the performance. If you just fill in e85 to a stock car vs to a flex fuel sensor car that uses the info for maxing the performance, the results will be very different. The stock DME keeps the performance rather constant, whereas e85 tune is far from constant

That's why flex fuel sensors are used to some extent in the tuning world.
This could even be possible through the DME. Siemens produces ECUs for many auto apps and potentially flexfuel options are available, but just need to be activated. If large swings in fuel mass is adjustable, why not other parameters.
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      07-26-2013, 09:29 AM   #42
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Thinking something like this then:

The best ratio for gas mixture is 14.7 parts air to 1 part fuel.
The best ratio for e85 mixture is 9.8 parts air to 1 part fuel.

The O2 sensor does not know how much air or fuel you started with. It only knows oxygen levels left in the spent exhaust.

The O2 sensor reports in terms of lambda. If the lambda value is 1.0, the fuel is burned optimally, and started with the right mix. Whether you start with gas at 14.7:1 or e85 at 9.8:1, the lambda will be the same at the O2 sensor.

So are the datalogs reporting the gasoline equivalent AFR while using E85.

Since gasoline stoich is 14:1 this means that the O2 sensor is returning a lambda of 1 (all oxygen burned) but you are probably really running a richer AFR for E85 than what is showing.

In the end, a lambda of 1 would simply mean you are burning the all the oxygen that is required by the E85 blend in the tank.......but the more ethanol you run, I would guess that lambda gets closer to the 9:1 stoich that ethanol needs in order to burn all the oxygen molecules in the AFR.


Maybe someone has answered your question already, but I'm in a hurry and figured I'd post my quick explanation.

Oxygen sensors ( or the Wideband oxygen sensors on the N54) don't actually read AFR -- they read lambda. AFR is just a calculation made by the 02 sensor controller/ECU/DME. This is why I was taught to tune and datalog my Corvette using lambda vs. AFR.

When you put your car on a dyno, the 02 sensor on the dyno is likely calibrated for a lambda of 14.2- 14.6:1 -- or something close. So even with pure E85 in the fuel tank, the 02 sensor is going to show AFR in the 14:1 range at idle and cruise. The engine is actually running at 9:1 (or whatever the stoich point of the fuel is), but the 02 is just showing what it was calibrated for.

As an example, the AEM wideband I have in my C6 is calibrated for 14.5:1 stoich AFR. If I keep the display in AFR mode, it isn't going to be totally accurate depending on the ethanol content of my fuel. It will show ~14.5 AFR when the engine is running stoich (or 1.0 lambda). This is why lambda is a better value to look at. Lambda=lambda=lambda.

Hope that helps
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      07-26-2013, 09:42 AM   #43
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Maybe someone has answered your question already, but I'm in a hurry and figured I'd post my quick explanation.

Oxygen sensors ( or the Wideband oxygen sensors on the N54) don't actually read AFR -- they read lambda. AFR is just a calculation made by the 02 sensor controller/ECU/DME. This is why I was taught to tune and datalog my Corvette using lambda vs. AFR.

When you put your car on a dyno, the 02 sensor on the dyno is likely calibrated for a lambda of 14.2- 14.6:1 -- or something close. So even with pure E85 in the fuel tank, the 02 sensor is going to show AFR in the 14:1 range at idle and cruise. The engine is actually running at 9:1 (or whatever the stoich point of the fuel is), but the 02 is just showing what it was calibrated for.

As an example, the AEM wideband I have in my C6 is calibrated for 14.5:1 stoich AFR. If I keep the display in AFR mode, it isn't going to be totally accurate depending on the ethanol content of my fuel. It will show ~14.5 AFR when the engine is running stoich (or 1.0 lambda). This is why lambda is a better value to look at. Lambda=lambda=lambda.

Hope that helps
Yup......finally got it - Thanks!

Lesson learned......know what your datalogs really mean.....the numbers are not always real.
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      07-26-2013, 09:49 AM   #44
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Good explanation and all correct. One thing to note though is that even if DME is able to calculate the ethanol content, it does not use the information for maximizing the performance. If you just fill in e85 to a stock car vs to a flex fuel sensor car that uses the info for maxing the performance, the results will be very different. The stock DME keeps the performance rather constant, whereas e85 tune is far from constant

That's why flex fuel sensors are used to some extent in the tuning world.
Of course it wont stock, it wasn't designed to even run E85 stock. Just saying the ethanol content sensor isn't a necessary thing, there are other ways to deduct fuel type. Although it's nice to have for flexfuel. Also, remember most aftermarket standalone systems lag 5-7 years behind current tech, sometimes more. A sensor is really helpful for cars that have lots of open loop in the tune or are slow to address fueling (ours takes milliseconds to potentially max out trims, which are not mechanical limits on our platform simply limits on the values in the software/flash).

In time maybe the computer will be further unlocked. Would be nice.
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