For those who don’t know, I have been working with the folks at Advanced Fuel Dynamics to review their PROFLEX Commander Kit for the E46 M3 N/A application in order to run E85 fuel in the E46 M3 stacked on our B-Spec Tune.  Advanced Fuel Dynamics was founded by Ryan Truax, a highly regarded E85 tuner for high horsepower cars in the motorsport world. He developed AFD and his flex fuel kits due to an issue that he consistently ran into when trying to create E85 based maps: E85 fuel was never consistent at the pump. This lead to efficiency and consistency issues as the E85 fuel was never consistent with the tuning. As a result, E85 tunes would have to be extremely conservative, essentially negating the power gains that running E85 is supposed to provide not to mention dangerous.

After some research his team discovered that E85 at the pump could vary between 51%-83% ethanol. Additionally, when developing the kit for the E46 M3 he saw that the E46 M3 would have differing ethanol percentages every fill up for the first 20-30 miles because of different separations in the tank. With so many variables surrounding a stable ethanol number, he instead developed an unique plug and play system that would account for changes in the ethanol content specific to each car called PROFLEX Commander flex fuel kit. 

What is E85 and Why Do I Want to Run It?

E85 stands for 85% Ethanol and 15% gasoline. E85 is a 104 Octane fuel alternative to gasoline. Ethanol is the best performance fuel out there if blended, used, and tuned properly. Ethanol is an octane enhancer because it is a great oxygenator and acts like a solvent that cleans fuel tanks and lines.  Most modern ECU have a trim allowance to accommodate 10%-15% ethanol to adhere to gasoline standard of containing up to 10% ethanol. However, a flash tune or flex fuel kit is required to go beyond ~E20 or 20% Ethanol. Failure to do so will run your car very, very lean. The closer you get to E85, the more performance benefits you will see.

Ethanol benefits:

  1. Power: Helps the DME from pulling timing, resulting in more power and smoother delivery. This creates faster flame speed and oxygenated fuel More air = more power
  2. Environment: Lower emissions due to fewer carbon deposits
  3. High Octane: 104 Octane
  4. Cooling: Ethanol doesn’t allow heat saturation and has a cooling effect due to alcohol properties
  5. Cleaning: Cleans valves and pistons because it condenses fuel thus achieves a cleaner burn across entire cylinder
  6. Price: $2.00/gallon on average, with the occasional E85 day courtesy of Pearson Fuels ($0.85/gallon!)
  7. Smell: E85 is not nearly as pungent or strong as gasoline – especially if you are running catless. The smell is hardly noticeable and instead smells somewhat “sweet”

E85 Ethanol Myths Debunked

Ethanol will eat my fuel lines! E85 is not corrosive, it is actually a cleaner. The blend has a lot of lubricants from the other 15% gasoline and additives in that special gasoline blend. The corrosiveness lies within the gasoline portion of the E85 called the aromatics. This causes the permeation or corrosiveness. With that said every modern day car is designed to handle some amount of ethanol in the fuel system due to fuel standards in the United States.

Ethanol attracts water into the fuel system! Water is introduced by temperature variations which causes condensation. E85 Ethanol is hydrophobic so it is not any more hygroscopic than gasoline, meaning that it does not absorb that much moisture from the air. The difference is that an E85 blend is designed with this in mind vs pure Ethanol. In E85 fuel, ethanol will suspend and carry the water but not actually absorb it. Majority of the water is already in the gasoline portion of E85. When this separates, this is where issues happen. Legally, 2% water is allowed in the fuel. The problem is that moisture comes from the other additives mixed in with the ethanol.

In regards to the separation that I mentioned earlier – E85 ethanol does not have affinity to water. However, when E85 sits for too long with headroom, it will tend to separate into 3 distinct layers: gasoline, ethanol, and water from top to bottom. Complications can occur when water hits the spark plugs first. This is the reason why blending is such a crucial stage of your fuel delivery system. Keeping the fuel in motion via the fuel regulator will mix the fuel, reducing the chance of separation. All observations noted above applies to gasoline as well. To avoid this, fuel stabilizers have been developed keep the fuel blended and avoid separation.

However, this is not to say that it is completely unsafe or dangerous to start a car that has been sitting. It is just a good general practice to be wary of the fuel separation phenomena – AFD has tested cars that sat for 7-8 months with pump E85 and starts up just fine.

Ethanol will instantly destroy my engine, fuel pump and injectors! Ethanol will actually prolong the life of your motors. However, there is some truth to the fuel pump and injectors working harder to compensate for the higher fuel demand. The duty cycles and pulse duration are increased when car uses E85 fuel. In short, the increased wear and tear on the fuel pump and injectors will result in a slightly shortened life.

E85 has worse MPG! This is technically true – not because lower energy level, but because the fuel system literally demands more E85 fuel itself. This is offset from the cheaper cost of E85 and performance gains. To see the difference, compare miles per dollar.

What is PROFLEX Commander kit?

Advanced Fuel Dynamics PROFLEX Commander E85

Simply put, the PROFLEX Commander kit is a full bolt on performance flex fuel system that allows for all mixtures of E85 and 91 blend. They have kits for many makes and models, but we are reviewing the one made for the E46 M3 specifically.

The kit plugs into the OEM injector wires through a harness and replaces the factory fuel lines in order for your car to allow for any mixture of E85 fuel without any other hardware changes! The flex fuel sensor is located after the regulator right before the fuel rail so that an accurate ethanol reading is sent back to the Commander unit. The Commander unit will dictate how much fuel should be sprayed by the injector based off the flex fuel sensor. The Commander unit also detects startup and runs a special procedure in order to achieve a stable cold start idle. You can also monitor ethanol content through their mobile app via Bluetooth connectivity on their flex fuel sensor. Install is fairly straightforward and takes about 1-2 hours for the DIY capable. DIY Guide coming out soon, stay tuned!

What does PROFLEX Commander kit include?

  1. PROFLEX Commander Unit that is specifically designed for the E46 M3 S54. In essence, it is a secondary brain that manages the E85 fuel injection, cold starts, and monitoring live ethanol data.
  2. Flex Fuel Sensor. This sensor has a bluetooth connectivity so that you can monitor your ethanol percentages right on your phone!
  3. Plug and Play wiring harness for S54 engine. This harness is professionally made, very high quality harness that plugs right into your OEM connectors.
  4. E85 Compatible Fuel Lines with Quick Connects that connects to OEM fitment plugs for E46 M3.

Q: Don’t I need an E85 fuel pump or upgraded Injectors?

A: No. According to AFD, their kit is specifically designed for the E46 M3 OE fuel pump and OE injectors.

Q: Will I run correct AFRs and will fuel trims be affected?

A: Yes. With this system, the car will always run correct AFR at any blend at any throttle position even with a pump gas tune like B-Spec. There is no dead time at high rpm and the fuel trims will not have to compensate based on rpm or load. Fuel trims might change a little bit initially due to their system accounting for the ~10% in regular fuel, but other than that there won’t be changes during normal operation. PROFLEX system is also not reliant on the O2 sensors.

Dyno Testing

The dyno testing was done to measure the power difference between a 91 octane on B-Spec tune and AFD PROFLEX Commander with E70 mix stacked on our B-Spec tune. AFD claims 20whp gain. But does it really gain that much?

Disclaimer: AFD sponsored us the PROFLEX Commander Flex Fuel Kit for review.

Before we dive into the numbers, there are a few important things to mention so you have a full understanding of the results. See below for the notes:

  • Test car for both runs is Oscar’s TiAG M3, not Andrew’s AW M3. So baseline is different.
  • Mod list for both runs:
    • Stock airbox has a BMC panel filter
    • Macht Schnell Intake Elbow
    • F1 Autohaus Ceramic Coated Header
    • SGT V1 Exhaust
    • B-Spec Tune
  • Running Chevron 91 ACN octane and E70 mix without ANY additives or octane boosters to simulate real world environment
  • All dyno runs done with hood open

European Auto Source is our choice dyno facility to ensure consistency as we prefer to do testing on the same dyno with the same operator, Steve. The 91 octane run is one of my healthier runs from late last year under cooler conditions, and the E70 run is from 4/28/18 around ~ 85 degrees F ambient temperature. 

The results? End result with AFD + B-Spec + E70 was 315.25 whp and 243.80 wtq, the B-Spec + 91 was 295.85 whp and 239.87 wtq.

After doing several runs we saw peak-to-peak gains of +19.4 whp and +3.93 wtq.  The dyno video shows fuel being dumped as I was testing Ignition Cutoff feature for an upcoming B-Spec tune new feature, it is normal trust me!

Advanced Fuel Dynamics PROFLEX Commander E85 - E46 M3 Dyno

We noticed that the 91 octane run dropped off early at 7.3K. We believe the culprit is the quality of the 91 octane fuel and the car was pulling timing due to the poor gas. I did the cardinal sin of filling up while a tanker was filling up the station tanks, however I was late to the EAS dyno appointment. It is common to see the S54 pull timing at higher rpms when bad gas is used. California really gets the short end of the stick too – all the more reason to switch to E85. Even then, we predict that on high quality 91 octane fuel it would taper to about ~300whp (we have an older dyno sheet for Oscar’s TiAg that did 297 WHP before on better 91 gas (Shell V Nitro+). Notice the E70 tapers much better at the higher rpm which means car is hitting timing targets.

This would still net PROFLEX Commander a 15whp+ gain using the older dyno numbers. Very impressive indeed.  

Advanced Fuel Dynamics PROFLEX Commander E85 - E46 M3 Dyno


This is a E46 M3 dyno chart on a Mustang dyno published by AFD and you’ll notice it is very similar to ours. Note that Mustang dynos (AKA Heartbreaker dynos) will have lower numbers than a Dynojet because they put more load on the wheels. We are primarily interested in the deltas and shape of the curves for comparison.

Our stock BMW E46 M3 test car put out a baseline 270HP on pump gas. After plugging in our PROFLEX Commander and adding E85 the car made 291HP on 75% ethanol. The 21WHP gain is felt across the entire the entire rev range, making the car faster both low and high in the RPMs. The customer feels a notable difference when running E85 over gas with the PROFLEX Commander. -AFD

Advanced Fuel Dynamics PROFLEX Commander Review

The primary reason I reached out to AFD was because I was intrigued by their claim that the kit works with any tune (and because I’m already running E30 on my F30 335i). I’ll admit I was a bit skeptical at how knowledgeable they were to make a claim like that.

I had the opportunity to speak with Ryan, William, and Dan from AFD and immediately felt relieved within the first 5 minutes of our hour long call. These guys are very experienced, knowledgeable, and technical about tuning and E85. Their “Ethanol Experts” have experience in tuning race cars in the motorsport world such as high horsepower evolutions/speed boats/open seaters and fully understand the science behind ethanol and all of its properties.

I have tested this kit stacked on top of our B-Spec Tune out for 4 months to provide a full, comprehensive review. In this time, I have autocrossed, tracked, and drove long distances in order to really put the kit through its paces. Here is how I would rate the product in price, performance, and quality.


The Advanced Fuel Dynamics PROFLEX Commander Flex Fuel Kit runs for $800 retail. Considering the hp/$, this kit is very reasonably priced. The only reason this did not receive full points is because it is not technically a “steal.” Those who truly want to go E85 will find that the benefits of the kit will justify the cost, and in-time, the cost-savings of running E85 will add up. Take advantage of the limited time discount code at the end of this post!


The material that the commander unit, sensor, and harnesses are high quality materials. They were very similar to OEM grade. The fittings were perfect and require no trimming or modifications.

In terms of reliability of the product, I have had no issues related to the kit at all in the 2,000 miles I have driven it. I have run many mixes between E30-almost full E85 from mostly Shell and Chevron. Octane levels are all different at each station and could sometimes have “bad gas”, but the PROFLEX kit takes care of that for me by automatically adjusting to the ethanol levels. Their mobile app to monitor what ethanol mixture is in the tank is extremely accurate and useful for me to keep track of how much and what’s in there.

Cold start has also been perfect every time in the last few months. AFD really did their homework as cars are known to have a hard time starting up with E85. The idle is consistent and stable with no hiccups or hesitations in power delivery which would indicate fuel pump or injector issues.


The power gains are addicting. On the track/autocross, the car felt great throughout the entire day with no cooling issues. The MPG was predictably worse meaning I had to refuel early but the performance it’s definitely worth it. The E85 helped with the B-Spec Tune timing targets, and I could feel the car meeting the targets even under high heat. This told me that the cooling effects of E85 was working and higher octane meant that timing was more consistent at high rpms. I could tell when accelerating out of turns and on the straightaways that the car pulled much harder and smoother than on 91 octane.

My Conclusion

In short: the AFD PROFLEX Commander kit makes power both safely and reliably. The kit retails for $800 and in our opinion, is well worth every penny. And while the performance gains are amazing, lets not forget about the ease of use and the overall improved driving experience.

Flexibility: E85 is not as abundant as regular 91 octane, which can be a hassle if you have to run strictly E85. One of the greatest benefits of AFD’s PROFLEX kit is that it will adjust for any amount of E85 and 91 octane. That way, you can still fill up with normal 91 octane whenever you are running low. When you have E85 near you again, just fill up, and reap the benefits. Pro-tip: if your local E85 station is far from you, buy some fuel jugs and use those to stock up on E85 at home to save some trips.   

Smells: Everyone knows – going catless means smells. Bad smells. However, E85 burns cleaner and the smell is hardly noticeable. This may be useful for some people that are scared of running catless in the city.

MPG and Price: As mentioned before, the fuel system demands more ethanol so it makes sense that MPG will decrease (roughly 18.37% for me). On 91 octane, I averaged 20.2 mpg mixed hwy/city and 16.8 mpg mixed hwy/city on an E70-E85 blend.

Price of E85 is about $2.39/gallon vs $3.79/gallon for Premium 91 at the time of writing. MPG is lower, but I’m actually going more miles per dollar with E85! If you don’t mind making more trips to the gas station, then E85 will technically help your wallet. See below for the cost comparison.

Fuel Tank (16.648 Gallons)MPG$/GallonPrice (Full Tank)Miles (Full Tank)Miles/$1$50 Fuel Spend
91 Octane20.23.7963.1336.295.33266.49

Prior to installing the PROFLEX, we had tossed around the idea of developing an E85 tune. Once I tested the kit, I realized that there was no need for one. The flexibility offered by the kit is unparalleled compared to a flash tune and does not make sense from a customer standpoint to restrict yourself with an E85 tune when this alternative is available. If you are looking to go E85, we would really advise customers to use the money towards purchasing the AFD PROFLEX Commander Flex Fuel Kit instead.

The guys at Advanced Fuel Dynamics are truly knowledgeable about the fuel industry and are very helpful. If you are interested in this product and have questions about it, I’d recommend contacting them directly. Don’t forget to mention this review too! For more information visit Advanced Fuel Dynamic’s product page: PROFLEX Commander for BMW E46 M3 and their FAQ Guide

E85 power without the E85 hassle
  • 10/10
    Reliability - 10/10
  • 10/10
    Performance - 10/10
  • 8/10
    Price - 8/10

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