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Discussion Starter #1
I purchased and installed a flex fuel kit from Advance Fuel Dynamics about 6 months ago and have since put on some miles and wanted to share some of my observations.

First I have to say I was highly impressed with the product from AFD. I expect a certain level of quality when spending good chunks of money. AFD meets and exceeds that, product is well made, the app works great, and the results are great.

PROS:
+Increased power
+Smoother idle
+Cheap high octane fuel
+CARBON BUILD UP KILLER!

CONS:
+Cold starts
+Increased oil consumption (maybe? I will expand on this below)
+Stock fuel pumps can't hang
+Lack of e85 in your area

So the short version is yes, I would recommend this kit and no, I have not seen any problems at all to this point. I am only 6 months in and around 6k miles, but so far its been flawless.

I haven't taken my car to a dyno, plenty of others have and shown power gains ranging from 20hp on a stock car/tune to 40-50 on a custom tune. There is more power without doubt. I pulled the intakes off when I did my last oil change to check the TB's and they were almost perfect. There had been some trace carbon on all 10 when installed, but there was NONE after 4k miles. I also noticed more carbon on my exhaust tips for the first 2k or so miles, which I would guess was a result of the e85 doing some cleaning. There is much debate on this in the car world, I am just sharing what I observed. The car runs much smoother and I love not having to pay $$$ for 91 because there is no 93 where I live.

The downsides are few, but they do exist. Most notably the stock fuel pumps just wont cut it. I am running a stock car aside from intake/exhaust and I have gotten 3-4 CEL's for low fuel pressure under extremely hard driving with 70% ethanol. The good news is that Member M V10 POWER has found a good solution that isn't too expensive. Cold starts can take a minute if you are running high ethanol, probably has a direct relation to the outmatched pumps. I did noticed that my oil consumption was somewhat higher than normal (~.5L or so), but oil analysis showed no scary numbers.
 

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Thanks for the review!! :thumbsup: Need to hear more from the genuine pigs out there running the E85 kits.

"Lack of e85 in your area" is definitely a killer. Convenience is key when you visit the pump once a week lol...
 

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Any concerns with piston ring wear? I don't remember where but I saw this somewhere, stated that this happens with stock S85s? I could be wrong. Thanks for sharing though, definitely worth it it seems.
 

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I’m confused how you’d see any power gains on stock tune, ethanol has only about 2/3 the energy of gasioline per unit of volume, so about the only way you can gain power is by advancing timing
 

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Discussion Starter #7
The kit consists of a power commander module(brain), 10 injector harnesses, and in line ethanol sensor.

The power commander is reading the ethanol content real time and using that data to increase or decrease the injector pulse. This corrects for the energy difference between gasoline and ethanol.

So essentially is just modifying the stock tune to correct for ethanol percentage only, not advancing timing. As I mentioned in the first thread, I have experienced a low fuel pressure code a couple of times while running ~85% ethanol and driving the car hard. This is because the power commander is correcting for ethanol, but the stock fuel pumps can't quite hang.

There is a simple fix, a couple of aem 320 fuel pumps will fit right in with some modification and give you plenty of fuel.




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https://www.instagram.com/p/BgIs7srFZlR/?hl=en&taken-by=troyjeup

That's the post i was referring too. Searching E60 stuff on Instagram and came upon this account. From what I've seen and read in the forums Troy has quite a lot of engine builds under his belt. Have been checking out his account and considering taking some of his pointers for better efficiency on our engines.

Not to get off topic. I think I misunderstood what he meant by not suggesting E85. I think he means on these knockoff tunes that try to squeeze maximum power for your money. The AFD kit is just bolt on but lets the car run the majority of the map variables, so i see no harm in that. Do you have or are considering a tune on the system?

That's a nice looking analysis sheet though, how's your fuel consumption? Not that it really matters on these cars but nice to see if the E85 helps at all with that. Also keep us posted on the oil consumption if you get to the bottom of it. Could it possibly be something maintenance realted?
 

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Discussion Starter #9
So engine damage like that is generally a result of running a lean tune, which would happen if the ethanol content was incorrect for the tune or the tune was poorly written.... I have been considering installing a wideband AFR sensor to monitor mine just out of curiosity because you WILL destroy your pistons if you are running too lean....

I am personally not thinking about getting a tune, there are several others who have on another thread and all seemed to be highly impressed. I appreciate the extra power, but I mainly did it because here in KS there is only one gas station withing 75 miles that has 93. The fact that I can run any combination of e85 and premium is a huge reason I bought the kit at all. I would not deal with having to switch between tunes every time I filled up with e85 or 91.


As far as the oil consumption, I mentioned it because I noticed it, but as you can see from the reports i have only had the car for about 10k miles and this was my longest oil change interval. I also was driving in cold temps for most of that time, and on one road trip i had to add half a quart of 5-50w (GASP) because i was in the middle of nowhere and thats all I could find lol. I am monitoring, but not concerned. I also plan on pulling one or two plugs and checking the cylinders with my bores scope this summer, will post pictures of that when I do.
 

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So engine damage like that is generally a result of running a lean tune, which would happen if the ethanol content was incorrect for the tune or the tune was poorly written.... I have been considering installing a wideband AFR sensor to monitor mine just out of curiosity because you WILL destroy your pistons if you are running too lean....

I am personally not thinking about getting a tune, there are several others who have on another thread and all seemed to be highly impressed. I appreciate the extra power, but I mainly did it because here in KS there is only one gas station withing 75 miles that has 93. The fact that I can run any combination of e85 and premium is a huge reason I bought the kit at all. I would not deal with having to switch between tunes every time I filled up with e85 or 91.


As far as the oil consumption, I mentioned it because I noticed it, but as you can see from the reports i have only had the car for about 10k miles and this was my longest oil change interval. I also was driving in cold temps for most of that time, and on one road trip i had to add half a quart of 5-50w (GASP) because i was in the middle of nowhere and thats all I could find lol. I am monitoring, but not concerned. I also plan on pulling one or two plugs and checking the cylinders with my bores scope this summer, will post pictures of that when I do.
Ahh i see, definitely makes sense of what he is referring to. I too have plans of installing additional monitoring options. My beast is approaching the 110k mileage so im building up a list of upgrades and mods i want to do to fortify and prolong as much as possible.

I do not have a lack of 93 octane, but like the majority of us have the lack of E85 pumps. Still up in the air of whether i get this myself because of that.

Funny you mention 5-50w oil. Actually on my list to switch to that permanently. Thats for another thread, let me not steer off topic again, haha. The oil consumption doesn't seem that out of the ordinary given the oil change interval and the long distance at the time. Definitely post back with any findings :M5thumbs:
 

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Umm if you’re getting fuel pressure codes, your car is running lean - to keep afr in check the ecu is requesting longer injector pulses and the pump can’t deliver the volume of fuel. Ergo lean condition.

Also again where is the extra power supposed to come from without a tune that advances timing ? Presumably the e85 piggy back just adjust the pulse to keep stoich around 10 for e85. Obviously you don’t get any extra power from that.
 

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Reads just like an advertiser... Getting your car dynoed before and after would be more substantial. Posting someone elses graph give me doubts.

The benefit of E85 is 104 octane rating. An engine needs to be built to take advantage of that. Just switching fuels has minimal gains, IMO - not worth the expense...unless you don't have 91+ octane - which is hard to believe.

I run it in my 535 CHP muscle car and it runs the same on 93 or E85 at the strip. I switched in preparation for a supercharger on a 10.9 CR engine (old style engine!).

~13 mpg also kills the daily driver routine.
 

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Discussion Starter #13
Yes, for the brief moment that the fuel pressure drops the car is going to be lean. Running lean for a couple of seconds will not hurt anything. If the car was running lean consistently it would throw a CEL because I still have all of my O2 sensors.

Most fuel is 10% ethanol, so if the stock ecu is not correcting for it. The kit automatically corrects for this, ergo this correction results in increased output.

There are several other members of this forum who have dynoed their cars, and the attached dyno sheet on the OP is one of them. Yes, an aftermarket would provide you with more power via altering the timing and fuel delivery. What is even better is that this kit will work seamlessly with a tune.

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Discussion Starter #14
If you're worried about MPG, perhaps a prius or insight would be a better vehicle for you. The S85 runs 12:1 compression, which is pretty close to most "built" NA applications, so yes I do not like running 91 which is all I have within an hour of where I live. I also like topping off with e85 at 2.12$ a gallon, after correcting for the mileage drop its the same price as 87.


Listen guys, I didn't come in here and scream and shout about massive gains in power. I said I personally noticed more, and the dyno sheet DOES have the before and after. It shows roughly a 21hp gain, which I would call modest. There is a potential for more due to the increased octane rating. All I did was share my observations, I even stated the reason why I got the kit was lack of 93 not to get power.

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Most fuel is 10% ethanol, so if the stock ecu is not correcting for it. The kit automatically corrects for this, ergo this correction results in increased output.
I’m not so sure that makes any sense, the ethanol mandate came in 2006 and all manufacturers aimed to have their cars run a bit richer as a consequence (which is why widebands will show you ~14 rather than 14.7). Any any case without that correction a car set up for 91 would run leaner/hotter on e10 (ie use Lamba value of 1 for 14.7 when on e10 you should be at 14.1), and make more power.

I suspect the extra power you’re feeling is the car running lean, which goes back to Troy Jeep’s thing about kabooming piston rings. I personally wouldn’t touch it using the stock fuel map, or stock fuel pump.
 

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Discussion Starter #16
That doesn't make sense, all cars are constantly trying to achieve lambda. O2 sensors and ecus do not use AFR, they use lambda and they are constantly adjusting fuel trim to maintain this. Regardless, I have bad news for you, the whole "running lean" theory is fake news. Hooked up the data logger this morning for a quick drive (spirited, as always) and saw no lean condition.

Note that the Y axis for bank 1 is on the left and bank 2 is on the right. I will try and upload the whole log in the form of a chart, but I don't use photo bucket and the pic is too big right now. Very normal numbers, not at all consistently lean.

Also if I had been running lean for the last 4k miles, there would likely be warning signs in my oil analysis.

I am sure that Troy has seen some engines that have been TKO'd by tune by mail packages for e85. That being said, I have not heard of one member (there are several running this kit) who have experience any damage as a result of running lean.
 

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Lambda of 1.0 that ecus are trimming for is the calibrated o2 sensor voltage that corresponds to the desired stoich AFR the car was set up. That is, whatever the fuel map has as optimal stoich mix that gets adjusted based on load/rpm etc.

For example if you fill your tank up with nitromethane, your car wouldn't last more than a couple of minutes before melting pistons due to a lean condition, even though the ecu would have lambda trimmed at ~1.0 That's because 1.0 Lambda on your car corresponds to 14.1:1 stoich mixture, whereas the proper stoich mixture for nitromethane is around 2:1. This is the same fundamental issue as with E85, the car is trimming to to the wrong AFR for the fuel type.

Good primer with math:
Air / Fuel Ratios for a Wideband Oxygen Sensor - Hot Rod Network
 

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Discussion Starter #18
Alright man, I will try this again. All of what you are saying is right, if you are running a carburetor or a PCM that is not flex fuel compatible (which means you have to input the correct value to achieve lambda and it will not change unless you reflash).

So, like I said previously there is an in line ethanol sensor that determines the amount of ethanol which the power commander uses to adjust the fuel trim for that particular percentage (based on the table value for that particular percentage of E). The stock ECU is not capable of this, which is why you need the power commander and the injector piggyback.

If you run e85 in a non flex fuel car, it will be unable to correct to lambda because as you correctly stated, lambda would be wrong for e85. The o2 sensor would detect the lean condition, but be unable to correct because it would be too far outside the parameters thus resulting in a CEL and likely engine damage.

There is no way to "fool" an O2 sensor, they detect oxygen. It makes no difference what fuel you are using, it only matters how much oxygen is remaining after the combustion event. You do not "calibrate" o2 sensors for a fuel, it simply relays a voltage that is the dependent on the amount of O2 present. The computer will use the data from the O2 sensor to try and achieve lambda, which again is a FIXED NUMBER in a non flex fuel car, the only way to change the number is to change the tune.

Lets use GM flex fuel vehicles as an example. You simply install an ethanol sensor and using a tuner enable the flex fuel function (which has the tables with all the math that you linked, already done) and BOOM, you have a fully flex fuel vehicle.

That is exactly what this kit is. The reason you need the power commander and the injector piggyback is because BMW never made a flex fuel S85, so the ecu doesn't actually have flex fuel capability. You could tune it, using the corrected data, and theoretically be fine, but I would never do that. E85 is highly inconsistent in its actual ethanol content (as are regular blends).
 

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Eflex fuel

I just installed a ( brand is Eflex fuel ) Eflex fuel E85 kit on my 2008 M5 , only drove it ( round trip ) about 30 miles. I don't drive the car much but here are my first thought. Car drives and idles smooth ( but it did before too ) . I feel a minor increase in power. I did drive the car hard on the way back ( I had a 1/8 tank of 91 octane when I started ) from the gas station. So basically I put 5 gallons of flex fuel in ( not calling E85 because its not will explain below ) drove it 15 miles to gas station ( my app was showing 38 % ethanol ) I then put 5 more gallons in it and drove it home hard. did not get above 40 % on app . had no fuel pump issues no codes ( like low fuel pressure ) and duty cycle on injectors did not go over like 75 to 80 % on HARD acceleration . And when I got home my water temp was like 176 ish ( so cooler ) Ok so I have been reading and I guess here in AZ they run E54 at the pumps , I tested what I had left in my gas can and it looks closer to E42 ish Ill post a picture.
From what I read at E50 and above there is little gain in HP so if I am getting E50 ish then I should not see duty cycle issues with injectors and pump but still get the gains of E85 ( on my stock M5 ) ???
https://photos.google.com/share/AF1QipOpDLaC-PREf5jPn-YHEAIpk0TULreuhjcb7xLAa1Fs8AwbPf-3vrHc7WCayQzLZg/photo/AF1QipNg3zretfpGQ5mS2AMbAbgN6CWE4DrDqD7Oei0Y?key=VDZUOTROcjE3TGVKWFBPRERJVXBEcW1NaWZ5eE9R
 

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Has anyone had a detonation issues following the flex fuel mod and tune? A very reputable SoCal shop that everyone would recognize advised against flex fuel and tune because they do not believe any existing products effectively detect ethanol content and then properly adjust timing in real time. They basically said the tune will be optimized for the gas in the tank at the time of the tune which will result in detonation issues when e content drops or premium unleaded is used. Thoughts?
 
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