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      10-10-2016, 12:27 AM   #1

Drives: 2013 F30 ACF Tuned 385xi
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Talking Tuning Technicals with ACF Performance's Ricardo and Alex

Hey guys,
This is Alex and Ricardo from ACF Performance. ACF Performance is an emergent automotive performance company dedicated to excellence, innovation, and accessibility.
We specialize in tuning and have engineered custom engine components and kits that allow for true optimization of your vehicleís power and speed.
For our first post as a Vendor, Ricardo would like to clarify some questions regarding flash-tunes.

The most conflicting information Iíve seen these days concerns the so-called Backend Flashes. To begin with, the BEF only exists because there is another mod; in our case, itís the JB4.

The JB4 basically is a boost controller device; a very well designed and intelligent boost controller. The F-Series BMW DME has an incredible processing speed and operates in closed-loop almost constantly for fueling, boost, and spark. It also tolerates huge trims when in closed-loop operation, which means that if you add more air, the DME will compensate for more fuel without bothering the higher fuel trim. Here is where the JB4 shines, because in high boost operations, it does that with more precision than the stock ECU. With that being said, let`s review what the JB4 does and doesnít do.

A JB4 Does:
  1. Controls boost according to fueling capabilities, octane rating (using knock sensor reading) and inside DME tolerance
  2. Increases the supply of fuel, manipulating the rail pressure. Don`t misunderstand this concept- if you are using stock flash, it will still be targeting the same AFR as before. This doesn`t mean that the car will run richer mixtures, but that you will be able to push the turbo more before getting fuel starving from the HPFP
  3. Controls Water Methanol Injection or Port-fuel Injection. This is another improvement in fueling supply, as it gives more breath to the stock fuel system before getting fuel starvation from the HPFP
  4. Has many built-in functions and safety features that will avoid some tuning related problems (running extremely lean, overboosting, etc.)
  5. Gives us the possibility of supporting other pressure sensors (which is really important for upgraded turbo guys!)

So why would you need BEF if the JB4 does all of these cool things and extracts good amounts of power?
  • First comes safety. Running more boost without adjusting the AFR to compensate for the extra heat generated by more horsepower may lead to many mechanical problems, excessive engine wear, and premature oil degradation. This is why the JB4 map 1 and 2 seem so conservative to most people. These are the safest boosts that you may apply while maintaining a controlled combustion behavior with the worst-case scenario fuel and environment. When people want more than map 2, they suggest adding meth injection or to start blending Ethanol... The meth, or ethanol, acts as additional fueling (remember the HPFP issue), and oxygenated fuel (adding more oxygen to the combustion = more power) reduces the intake temperature, increasing the resistance against knocking. We know that it will give the engine some extra room for stress before suffering from excessive heat in the cylinder/exhaust due to either a lean mixture operation, or a not-so-rich mixture (as is required at this power level). Therefore, controlled combustion temperatures both improve safety and target a richer AFR.
  • Secondly, power isn`t related to boost alone. There are a dozen other tunable parameters that can be used to extract the best tuning results (ignition timing, injection timing, valve timing and lift, throttle response, fuel mixture); So, using improved tables for all of those parameters may lead to a car that is not only faster, but more pleasant to drive, making the power and torque delivery substantially different. Since the JB4 doesn`t control all of those variables, we can say (and prove) that a good flash-tune can outstand JB4`s map 2 while maintaining (or even lessening) stress on the powertrain.
  • Thirdly, it enables tuning of the ECU limiters. One thing that the JB4 doesn`t do (at least not yet!) is get rid of the speed limiter. Upgraded turbo guys will understand when I say that you will be disappointed when less than 20 seconds from standing still, you will hit that bummer at high speeds. There are also limiters that can cause throttle closures when exceeding certain amounts of boost; this can only be disabled by changing DME parameters, so that you can target higher boost with the JB4.

ACFís position about BEF, Flash-tune only, or JB4 only is:
  • Flash-tune Only:
  • Recommended for customers who look for bolt-ons while using a stock turbo (that will be near the safety limit- around 18psi- with all of the supporting mods). We provide the option for you to come to an ACF representative that will handle everything concerning having your car tuned and tested in-house. If you, however, are confident removing the ECU and completely understand everything involved in custom tuning a vehicle, we can exchange data logging and ECU shipping until we find the best result for you. We also offer extremely safe basemaps that are 100% guaranteed to work with the worst-case fueling and environment, but they may not maximize your carís speed. The effect of the basemaps is comparable to that of a JB4 map 2, it will save the labor of doing successive tuning, and costs less to complete.

  • We recommend this for upgraded turbo customers, not because of the boost control as said before in other threads, but because of the N20 TMAP conversion. Iím fairly certain that its possible to enable the stock N55 ECU to understand the N20 TMAP with a flash-tune, but the complexity of the labor involved may not justify the work (and the JB4 already does this in a very clever way). To customers who are more performance-aggressive and would like to have a killing map for short bursts- the JB4 can make this happen!

    JB4 only:
  • Since today`s flash-tunes are better than the JB4 (and will be improved upon even more since new tables are still being discovered), we no longer use the JB4 in ACF shops. We only advise people to go the JB4-alone path when there is not easy access to good tuning or tuners. The current F-Series flash-tune still requires ECU removal and shipping of the ECU to one of our offices; for custom tunes, additional tuning and logging are required to match each vehicle/owner/fuel/expectation. We do not advise our customers to ship us their DME`s in an ordinary way (this can be really dangerous if not done by professionals or the like). So if you don`t have access to a BMW expert mechanic, the skills to do the ECU Removal yourself, or you don`t feel comfortable with doing data logging, just get a JB4; within 40 minutes, you will gain good power and a faster car.
We and many other tuners have plenty more opinions about this subject, but we hope this information will enlighten people about tuning and tuners.

Later on we will talk about our experience with Flash-Tune visibility capabilities by BMW Dealers, and also share some experiences weíve had over the years.

Also, we will be posting our flash-tune dyno results for the N55 and N20 with varying bolt-on mods very soon, look out!

Best Regards,

Alex Peterson
ACF Performance, USA
Chicago, IL

Ricardo Freitas
ACF Performance
Owner / Master Tuner
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      10-10-2016, 12:43 AM   #2
@obriennathaniel_f30 on Instagram
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      10-10-2016, 07:26 PM   #3

Drives: 2014 335i XDrive MSport
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Very intrigued to see the results! Looking forward to scheduling my tune.
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      11-06-2016, 08:58 PM   #4
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Great post, looking forward to any updates!
2015 SO M3 6MT

2015 BSM M235xi | Enzo Big Turbo Kit | Enzo Flash | JB4 | Garrett GTX3586 | TiAL BOV | TiAL Wastegate | Enzo Manifold | Enzo DP | PDU PI | Fuel-It Stage 2 LPFP | ATM FMIC | ER CP | Tuningwerk Exhaust | HRE FF15s

F Series N55 1/4 Mile World Record: 11.2s @ 127mph (Pure Stage 2)
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      03-22-2017, 01:13 PM   #5
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Bumping up this thread as I would like to see what you guys have come up since you made the post and had time to tune some cars. Keep this post alive and updated!
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      03-22-2017, 06:18 PM   #6

Drives: 2013 F30 ACF Tuned 385xi
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Originally Posted by D041987 View Post
Bumping up this thread as I would like to see what you guys have come up since you made the post and had time to tune some cars. Keep this post alive and updated!
Things have been slow result wise due to the winter we've had here in Chicago but we've got several products about to drop in the next couple weeks, fuel pumps, turbos, and lots of tuning results. Check out FB for the latest but we'll have some larger posts and updates coming soon!
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      04-15-2018, 10:13 PM   #7
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what's the ACF website? google comes up with a company in Brazil....
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