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BMW 3-Series (E90 E92) Forum
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Negative effects of using Ethanol blends?
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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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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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07-24-2013, 01:35 AM | #26 |
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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!
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07-24-2013, 03:13 AM | #27 | |
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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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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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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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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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07-24-2013, 10:29 PM | #34 | |
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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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07-25-2013, 11:13 AM | #36 |
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Drives: 2011 335i xDrive Msport
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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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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, 08:56 AM | #40 | |
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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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07-26-2013, 09:29 AM | #42 | |
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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
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07-26-2013, 09:42 AM | #43 | |
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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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In time maybe the computer will be further unlocked. Would be nice. |
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e85, n54, tuning |
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