I originally made this for Got3800.com, but that shit went sour real fast because that site just straight up sucks...so here it is for all of you!
***I have copyrighted this piece of information, so do not distribute without my consent please
***
Alright everyone...I have been asked many times on how to E85 tune a 3800 powered vehicle and would like to help. This is strictly one way you could go about tuning for E85 fuel.
Things needed :
Tuning Software
- DigitalHorsepowerTuner or HPTuners VCM Suite (Preferably HPTuners VCM Suite for this writeup)
- Laptop
- Some basic tuning knowledge
Parts
- Wideband A/F Ratio Gauge (AEM Uego/Autometer/Defi/etc...)
- Aftermarket Fuel Injectors (Preferably 65# or bigger)
- New Fuel Injector O-Rings
- Aftermarket Fuel Pump or ZZP Rewire Kit (Preferably Walbro 255LPH FP or Rewire)
- Fuel Filter
Other
- Local Gas Station that carries E85 (and hopefully a few others)
Optional
- Boost Gauge
- Fuel Pressure Gauge
***While some will argue that you do not need a Wideband to tune for E85, I strongly encourage that you have one because the extremely high ethanol content of E85 makes the stock Narrowband numbers super unreliable. TUNE AT YOUR OWN RISK. This write up does not cover how to tune on Narrowband numbers.***
***This writeup does not cover other installs that may be involved***
E85 Info
- E85...a common misconception as to what it really means. The "E" in "E85" is merely a symbol for "Ethanol." The high ethanol content in the mixture makes this fuel a very desirable fuel for automotive enthusiasts. The "85" in "E85" is the percentage of Ethanol. This value generally ranges from 70-85%.
-Because of the high content of ethanol, the octane rating of E85 is an outstanding 105 octane (maximum ethanol content). This means more bang for the buck!
-Because of the high ethanol content, E85 burns MUCH cooler than your standard gasoline. This means good news for you, as knock will be eliminated.
-Because of the high ethanol content, E85 burns much faster than gasoline, but takes much more to ignite at a safe rate. This is where the aftermarket injectors come in.
-Because of the high ethanol content, E85 is MUCH cheaper than pump gas (in most places).
-Because of the high ethanol content, E85 will lower your gas mileage. Your tune will determine your gas mileage more than the fuel.
You may have found a trend. Because of the high ethanol content, E85 is a supreme fueling alternative!
The Write Up!
Okay...enough yip yapping. Here comes the "how to". Lets deal with the hard-part install first.
Wideband A/F Ratio Gauge
Okay people, this step is crucial. Without one, you will NOT be able to tune for E85! Widebands' read in whole numbers, not millivolt readings like the stock sensor. The whole numbers are exactly that...whole numbers. They give you an EXACT A/F Ratio which is vital for tuning E85 or even pump gas!
Install...
Fuel Injectors
You will (if you have not already) need aftermarket injectors. The stock injectors are not nearly capable of flowing enough E85 for safe operation. I have found that for boost levels under 10 PSI, 42.5# Injectors are not a bad choice. For any boost level over 10 PSI, you will want 65# Injectors or bigger. Either way, make sure you install new Fuel Injector O-Rings. This is where a boost gauge would come in handy, so you can see what size injectors you need.
Remove old, install new...(Boost Gauge too if desired)
Fuel Pump
You should (if have not already) think about what you want to do with your fuel system, a rewire or a new pump. Either is a great choice, but for higher horsepower levels I recommend an aftermarket pump.
Remove old, install new...but for the rewire, follow my other write up located at this URL location.
http://www.got3800.com/forum/viewtopic.php?f=37&t=1669Fuel Filter
Running E85 in your car, over time, will get rid of the sediment in the fuel tank because of...wait, you guessed it...the high ethanol content! Changing the fuel filter AFTER the first 1000 miles of running E85 will ensure a fully pressurized fuel system. Change it again at 1500 miles and 2000 miles, then you should change it in regular intervals. This step is huge! Your fuel filter will become clogged if not changed out during the running of E85 in your system! Check your fuel pressure with the gauge after each change if you would like.
Remove old, install new (times 3, and Fuel Pressure gauge if desired)
Perfect...hard part's are installed and ready to go! A few things must be done prior to filling the car up with E85 for the first time!
Tuning
This is the most vital key to getting the car running correctly on E85...the tune. Without it, your car would not run correctly on this new fuel and you could risk severe engine damage!
Injector Flow Rate vs. KPA Table
This table is perhaps the most important. Why you might ask? This table will determine how much fuel is going to be flowed versus how much boost is being pushed. These values are directly proportional and matter ALOT! E85 requires 30% MORE fuel over pump gas to be flowed into each cylinder. This calls for custom IFR table values!
***How To Change the IFR Table Correctly***
- 1.) Put in the values for PUMP GAS for your new injectors. Depending on the size of the fuel injectors, this table will vary quite a bit which is why I cannot offer you values off of the top of my head. (PM me for a custom IFR table)
-2.) You now need to SUBTRACT 30% from those values. Do this by multiplying each value by .30, then subtracting that number from the original value. This will give you a new number that will tell the PCM to flow 30% more fuel.
Done! This table is finished and needs no more modification for proper usage of E85. Pretty easy right? Lets continue...
Base PE vs. AFR Table
This table is another vital table to the proper tuning of E85. This table is going to be your commanded AFR that the PCM will execute.
***How To Change the AFR Table Correctly***
1.) This is a very simple step. In the table, you want to look for the consecutive values that are all the same. Generally, this is where the engine reaches close, above or exact operating temperature, ~ +-20 degrees Fahrenheit. Set these values to 11.7 if not already done.
This step is now complete, move on...
MAF (Lb/M, Hertz) Table
This table is important for a more steady, drivable and fuel economic tune. This table fine tunes the AFR's based on how much air the motor is sucking in. If you do not have a MAF (MAF delete with Volumetric Efficiency Tune), you will need to modify the VE table accordingly.
***How To Change the MAF Table Correctly***
- 1.) This step needs to be completed AFTER the first initial drive on E85. Just for the future, you will need this table editor to tune the MAF, or you can tune it manually by looking at the future scan and make changes accordingly. But for most, you will want this table. It makes the MAF Table perfect. Download link is below.
http://uvscanning.com/forum/download/fi ... 60f401418c
***DO NOT UPLOAD THE TUNE AT THIS TIME, DO NOT!!!***
All tuning is done! Pretty simple isn't it? It really does not take much to convert the tune to run on E85! Go ahead and save the tune as "E85Tune.hpt" for HPTuners.
Okay...time to fill your car up with E85 for the first time! Go ahead and run the car down on E, try and get it as empty as possible, but don't get too low! You still need to make it to the station. Now, the moment of truth, go ahead and grab the E85, yes, the yellow E85 nozzle and insert it into the gas tank. Pull up the trigger and take a deep breath. You are so close! Now, go ahead and get back into the car and bring up the laptop and the E85 tune. Wait for the fuel tank to fill up, get out and make yourself static free to prevent any...unwanted incidences. Now, get back into the car and upload the E85 tune. After PCM calibration, you will hear the fuel pump re-prime or you will see the dash indicator lights come back on. Don't start it quite yet, bring up the HPTuner Scanner and connect it to the car. If the scanner is now reading, you are ready for your first start up.
Go ahead....start the car. It should start up quite easily as the motor is already warm. Let the car idle for a minute or so to get used to the new tune. While you are sitting, you may notice a change in the exhaust note, a change in the motor pitch/sound, or the sweet smell of corn. All these are completely normal on E85 operation!
Go ahead and drive off...it should drive just as it did before. Drive around normally for about 15-20 minutes, with different changes in load and acceleration. After about 20 minutes, the PCM should have learned everything it needs to. Fuel trims, shifts, etc, it should all be good to go!
Alright...the moment you have been waiting for! Wide open throttle...go ahead and give it 100% throttle, if comfortable doing so. You need to take it to the top of a shift, and to redline to get a good scan. You need to look at a few things on the scan after you go WOT.
1.) IDC (Injector Duty Cycle) - This value should NOT reach over 100%. If they are, you are maxing out your fuel system! Anything over 95% should be carefully looked at. Anything below, you are alright!
2.) A/F Ratio - These should be watched on the Wideband during WOT. These values theoretically should match that of the Base PE vs. AFR table (11.7). If the Wideband indicates a lean condition (12.0 or higher), you need to drop those values in that table. Drop by .1 increments each time. If it indicates a rich condition (11.0 or lower), you may (if you wish) lean out the A/F Ratio.
3.) KR (Knock Retard) - This value should always read 0, while most of us have it and there is little we can do about it. Some will say none is acceptable, while others say up to 2* is fine. I will leave it at your will to decide what is safe and what is not...If KR is present, you need to drop the A/F Ratio in the Base PE vs. AFR table. If it is not knocking, you have nothing to worry about!
4.) Fuel Trims - These values should be locked in at 0.0 at WOT. Any other value at WOT will indicate a need of a MAF tune. At cruise, these values should not exceed +-3.0. If in excess of that, you will need a MAF tune. Use the table editor provided earlier to tune the MAF.
Each person's first scan will vary. Upload the new tunes accordingly and tune as much as you need! The closer dialed in the tune is, the better the car will run.
You will experience hard starts on cold mornings. You may need to edit the Cold Startup AFR Correction table. This is completely normal as ethanol needs to be very hot to ignite. Just keep cranking, it will start!
I hope E85 has worked out for you and you have an awesome and fun experience tuning and using E85!
Author - Marc M. Chandler
Date - May 22nd, 2009
Copyright - 2009 All Rights Reserved.
