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Just Married 05-15
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How-to: Tune N/A Using ECU Flash and other tuning information

Tuning Practices Disclaimer

In tuning there are no guarantees. Tuning can be dangerous and cause your engine to fail or damage, harm to your self and others, even death. There is always a cost, but when things are done safely and realistically you can achieve great results too. This will also void your warranty if you visit the Dealership and they check your ECU for codes. Before you go to a dealership always flash the original rom into the ECU.


Always practice safety All tuners before they begin any tuning session, they record every little single detail in a "notebook". The notebook will be your guide to your past, present and future throughout the tuning process. YOU MUST DOCUMENT EVERYTHING YOU DO. This is in order to back track problems and even repeat the same results again in a similar engine or platform. Remember you must know where you've been to know where your going.

Before we begin, please review FlashBlueRS's tutorial on how to use the hardware,
software and other information pertaining the options available to us 3G owners ECUFlash Tutorial


To Answer some of the most common questions I have been getting about tuning:

The all-motor way (N/A = Naturally Aspirated) to increase the power on our engines is to:

1. Modify Intake (WAI, CAI, Port and Polish Heads, etc)
2. Headers and exhaust
3. Throttle body and Intake Manifold
4. New CAMs
5. Increase Displacement (6G74, stroker kit, etc)
6. ECU Programming (Tuning)
7. Others...

The cheapest combination in my opinion is:

1. CAI or WAI
2. Headers and Exhaust
3. ECU Programming (tuning) - Voids Warranty
4. Increased Displacement (6G74 engine swap) - Voids Warranty

The more you add from the previous list, the more power can be achieved.

Engine Tuning Theory
"To tune an engine effectively, you will need to understand the theory of Volumetric efficiency, burn rate, spark advance, air/fuel ratios, temperature, air-pressure, detonation, and fuels" (Jeff Hartman, 2003)

Here is a video from Innovate Motorsports which talks about their LM-1, Tuning Theory and others.
(View Videos)

Volumetric Efficiency:
Is the ability of an engine to introduce air into the combustion chamber. The more air we can introduce into the chamber the more fuel we can inject and generate more power. Peak torque occurs at the engine speed and loading at which an engine is most efficient at ingesting air into the cylinders. Therefore, peak torque is also peak volumetric efficiency or VE.

Fuel Burn Rate:
Is the rate at which the Fuel Burns inside the chamber. It has been studied and found that the fuel burns the fastest at 11.1:1 (AFR).

Spark Advance:
Is which is optimally timed to achieve best torque by producing peak cylinder pressure at about +/-15 degrees ATDC (after top dead center piston position), increase octane requirements by a half to three-quarters of an octane number per degree of advance. Spark advance also increases cylinder pressure and allows more time for detonation to occur.

Air/Fuel Ratios (AFR):
Ideally, air/fuel ratio should vary not only according to loading but also according to the amount of air present in a particular cylinder at a particular time (cylinder VE). Richer AFR combat knock by the intercooling effect of the cooling heat of vaporization of liquid fuels and a set of related factors. The volatility of fuels affect not only octane number requirements but drivability in general. The chemically ideal AFR mixture, at which all air and gasoline are consumed in combustion occurs with 14.68 parts air and 1 part fuel, which is rounded to 14.7. This ratio is referred to as "stoichiometric" or "stoich".

At high loading and wide-open throttle. richer mixtures give better power by making sure that all air molecules in the combustion chamber have fuel present to burn. At wide-open throttle, where the objective is maximum pwer, all four-cycle gasoline engines require mixtures that fall between lean and rich best torque, in the 11.5 to 13.3 gasoline range. Since this best torque mixture spread narrows at higher speeds, a good goal for naturally aspirated engines is 12.0 to 12.5, perhaps richer if fuel is being used for combustion cooling in a turbo/supercharger engine.

Typical mixtures giving best drivability are in the range of 13.0 to 14.5 gasoline-air mixtures, depending on speed and loading.

Inlet air temperature increases octane requirements by 0.5 octane number per 10 degree increase. Temperature affects fuel performance in several ways. Colder air is denser than hotter air, raising cylinder pressure. Colder air inhibits fuel vaporization. But hotter air directly raises combustion temperatures, which increases the possibility of knock.

Increasing altitude reduces octane number requirements by about 1.5 octane numbers per 1,000 feet above see level.


When an engine knocks or detonates, combustion begins normally with the flame front burning smoothly through the air/fuel mixture. But under some circumstances, as pressure and temperatures rise as combustion proceeds, at a certain point, remaining end gases explode violently all at once rather than burning evenly. This is detonation, also referred to by mechanics and tuners as knock or spark knock.

Preignition: It is another form of abnormal combustion in which the air/fuel mixture is ignited by something other than the spark plug, including glowing combustion chamber deposits, sharp edges or burrs on the head or block, or even overheated spark-plugs electrode. Heavy, prolonged knock can generate hot spots that cause surface ignition, which is the most damaging side-effect of knock. Surface ignition that occurs prior to the plug firing is called preignition, and surface ignition occuring after the plug fires is called post ignition. The preignition opposes the pressure generated by the piston resulting in power loss, engine roughness, and severe heating of the piston crown.
* Understanding Detonation is extremely important. To learn and gain more information please click on the following link Detonation vs. Pre-Ignition

More info to come... feel free to add information

Some Sources
*How to Tune and Modify Engine Management Systems (Motorbooks Workshop) by Jeff Hartman
*Car Hacks and Mods for Dummies by David Vespremi
*Engine Management: Advanced Tuning by Greg Banish

Optimizing the Fuel Map:

There is simply no way to fully optimize an engine management system without a dynamometer and a wideband air/fuel-ratio meter or fas exhaust gas analyzer. If your extremely patient and methodical, air/fuel ratio information, Datalogger and a stopwatch can yield good results. However, an engine calibrated on a dynamometer of almost any kind will almost definitely run suboptimally rich on the street and track. To produce smooth performance under all conditions, when you are done with dyno calibrations, you'll need to road test and recalibrate to eliminate hesitation, stumbling, and surging in ordinary driving, as well as hunting in idle.


Tuning the 3G N/A

3G Tuning Optimization Method (Basic):
- Ensure the engine is in good health and that is not blowing smoke or has any other symptoms
- Ensure the map is rich enough to ensure the engine is safe (Stock is pretty rich in the mid to high rpm vs load)
- Ensure your Wideband O2 Sensor and reader are installed correctly and, reading properly.
- Idle car until it warms up
- Monitor and Datalog all sensors using EvoScan or Mitsulogger during the Warm up.
- Once engine is warm and dataloggers are active, rev gently up to 3K then gently again up to 6K. While doing this watch the sensors for AFR and Datalogger information for knock and, other sensors.
- Turn car off and analyze the data to ensure everything is good for a test run.
- Turn car on and do some 2nd or 3rd pulls running the Dataloggers also logging the AFR through the Wideband.
- Return back and analyze data. This is the most important part. You need to analyze and take into consideration everything that was posted about VE (Air flow), AFR, Fuel Burn Rate, etc. This is an area where you need to be good at analyzing, using logic, critical thinking and problem solving. Use the information posted and reference information to understand what approach to use.

Analyzing the Data: (Basic Scientific Approach)
- Once you have Datalogged the AFR and all other sensors during the 2nd and 3rd WOT Pulls we are ready to begin.
- Using the EvoScan, Go to Log Graph and Review Saved Log. Open the logs where you did the 2nd and 3rd pulls.
- In the Log #1 only select the following only:
* Airflow/Rev
* Engine RPM
* Timing Advance
* Load Calculated
* Wideband A/R Ratio
* EGT = Only for a moment to make sure the temps are good (More info to come) then remove.
- At this point you will see 5 lines in the Graph. This is so you can view and point where the AFR is at what load, rpm and timing. Also you can use the Airflow measurements to see where the VE is the best to take advantage and aim for 12.5 to 13.1 (which is usually around mid rpms and best TQ).
- Once you know where the load is look for it in the High and Low Maps for Timing and Fuel. These are the areas you need to work on. Always modify the High and Low maps for Timing and Fuel. But always keep the Low maps in a richer more retard level to protect your engine.

**Section will be in constant updates.

Working the Fuel Map
- You should notice that the AFR is great until mid to high rev. If this is the case then concentrate on that area (Example: 80% to 100% load area from 3K to 7K rpm). Lean the area accordingly and using as reference the information posted earlier about AFR. If you love Rev'ing (hitting the max RPMs) your engine then go for the rich mean top TQ, which is usually around 11.5:1-12.8:1 AFR for N/A applications.
- Once done redo all the previous steps in Beginning section and return to the fuel maps until you achieve your goals. Warning!!!!!! Do not over lean!!!!!! Practice safety and go always for the Rich mean top TQ (Usually around 12.8:1 to 11.5:1). Don't let the power search fool you, the engine might keep making more power but it will not be worth it.
- This is a little hard, but worth it. Now we need to find out which AFR did the engine use as a reference. Look at the AFR log and use it to determine where the AFR are in the Fuel Maps. There you will find which areas the ECU used as reference and what worked the best. Trace (the 4 farthest points) the AFR throughout the Fuel Map and you will see that it will appear to have the shape of a box, but not perfectly shapped. Inside this box is where you need to concentrate. Everytime you do this you will get more and more precise. But as easy as it might sound, is not. Also its time consuming, but the results are great. (Feel free to discuss this approach)
- Return again and datalog everything. If you find the engine is running to lean or to much Knock "STOP" hitting the gas and drive slow. Start again and rich up the areas where the knock occurred and redo the leaning process. Until you reach your goals. Aim to 0-2 knocks in this process, if you can achieve 0 knocks that would be even better and perfect.

Working the Timing: (Here will follow a similar strategy used in "Working the Fuel Map")
- Before we begin, you must make sure you are running at safe levels of AFR. Safe levels are no leaner than 13:1 (But if temperature and altitude changes, it might hurt your engine so, always run richer). Always work the AFR maps before the timing. Also you will need to go back and forth between Fuel Maps and Timing so keep your notebook close.
- Start your car and Warm it up. Once warm start the datalogger and record some 2nd or 3rd pulls.
- Sit down and analyze the knock if any. Once they are removed is time to continue.
- Take the 2nd and 3rd pull logs, and locate in the High and Low Octane Ingition Maps where the ECU is on the timing. Somewhat over lap the high with the low over each other. Its a long process but after a while you wont need to do this since you can visualize the data in you mind. But KEEP NOTES.
- Begin to analyze and determine where you need to advance timing. Normally I personally begin to add between 80%-100% load. Make sure you use the data you gathered from the previous step. Add 1-2 degrees at a time depending on the data you gathered from the timing in the logs. The goal here is to achieve peak cylinder pressure at 15 deg. After Top Dead Center (ATDC which is a Piston location) from the spark.
- Warm up the car. Find a friend to help you out in this step or if you have EvoScan setup the Alarm sound when the Knock hits 10. Close the windows so you can hear the alarm (don't forget to raise the volume to max ;) ). Do some 2nd and 3rd WOT (wide open throttle) runs. If you hear the alarm go off STOP HITTING THE GAS!!
- If you had knock go back to the logs and find where the timing was retarded and adjust timing and fuel accordingly.
- Do not push the engine to far, this is where people damage their engines. Set a realistic goals and a safe margin in your fuel. Do not allow your engine to knock above 10 knocks. Everyone has an opinion on how much they can handle. I personally find that if there is knock the ECU retards timing so, anything above 10 knocks is bad in timing, fuel and on the engine.
- There are different forms of knock view theory section for information.

Working the Limits:

- Rev Limit can be set safely to 6990 max. But make sure that the mixture is rich enough to make it safe. Technically there is not benefit to setting the RPM limit that high unless you have done head work (Port and Polish) and installed Stage 1+ Cams or Nitrous/FI :D
- Speed Limit: No need to mess with it. Period ;)

Working Acceleration Enrichment:
*Once you have reached your AFR and timing in the maps, here you can find that little kick that makes the engine just a little more Torquee :) Those of you that are on a Dyno, leave at this point. This can not be measured in a Dyno. Here the road is your friend, and the wideband as usual. If your extra sensitive that day, even better.

- Ensure your AFR and Timing are in safe parameters. Here your perception of acceleration and engine responce will take effect as your measuring point.
- Add 1% to the table and datalog. Make sure your AFR and knock are good, but mostly your knock.
- Keep adding 1% until you feel the car is not giving you a bigger responce. Then remove and through out the range until you reach your happy spot.
- Don't over do it since you will eventually generate knock and retard the timing.
- On the 3K range do not increase to much because you need that area to be responsive for downshifting which makes usually that area richer when that happends.

Other usefull Information

Injector scaling and injector voltage latency

i've just installed a set of precision 1000cc injectors and i'm trying to get them setup right so i can start working on the maps.. here is a conversation i've had with malibujack for anyone else that needs the info.

If your idle (low) is good and close to zero, but your mid trim (cruise trim) is still positive, then you can increase the latency at the 12.5 and 14v (approx) slightly until they are both reading about the same, whether it 5 and 5 or whatnot, as long as its the same then you can move on..
Then you cruise around a bit, if the trims are positive, it means its adding fuel, so reduce injector size a little bit, and do it again, and vice versa, if they are negative, increase the injector size slightly.

Ultimately what you will end up with is mid and low trims should read as close to zero (or 100 in evoscan) as possible, and the O2 feedback should hover around 0, with it swinging occasionally, but no more than +/-10

Finally, if your idle trims begin to drift, even though you got your long term low and mid trims in check, you can use the open loop fuel map to add or remove a little fuel until the trims are good.

Now you have the injectors properly scaled, and you can tune the open loop maps since they will be a bit whacked after you scaled the injectors.

The short hand notes..

Low trim greater than mid trim, add latency, mid trim greater than low trim, lower latency, once trims are the same, alter injector size accordingly.. Finally adjust open loop fuel maps to your desired AFR.

If you find you have to crank the engine quite a bit before it fires, or if the car swings lean when the idle speed drops (or engine load increases) then you have to look at the latency values below 14v

** Unverified information
Injector scaling and injector voltage latency

Matching the Injector to the Engine

To calculate the injector size for a particular application:
Injector Flow Rate (lb/hr) = Engine HP(1) x BSFC(2) / Number of Injectors x Injector duty cycle(3)

Injector Flow Rate (cc/min) = Engine HP(1) x BSFC(2) x 10.5 / Number of Injectors x Injector duty cycle(3)

NOTE: Unless otherwise noted, all injector flow rates are calculated at a fuel pressure of 43.5 PSI (3 BAR).
(1) Whenever possible, use actual dyno results for engine horsepower. If no dyno results are available, consult with your engine builder for a horsepower estimate.
(2) BSFC is usually a number between 0.4 and 0.7 for gasoline engines. Although BSFC can be estimated, it is best to determine an actual number on a dyno. If a dyno is not available, the following numbers can be used as a rule of thumb:

* For naturally aspirated engines, estimate BSFC to be 0.4 to 0.5
* For nitrous engines, estimate BSFC to be 0.5 to 0.6
* For forced induction, estimate BSFC to be 0.6 to 0.7
* For rotary engines, estimate BSFC to be 0.6 to 0.7
* For engines running methanol, double the appropriate gasoline BSFC (e.g. a forced induction methanol engine has a BSFC between 1.2 and 1.4)

(3) Injector duty cycle should be 0.8 (80%) or LESS. Numbers higher than 80% are generally NOT RECOMMENDED. If maximum injector duty cycle is not known, use 0.8 as an estimate. Remember that these numbers are ESTIMATED and cannot be considered as accurate as actual numbers achieved on a dyno! Always verify engine performance information on a dynamometer!

To calculate the horsepower capacity of injectors based on their flow rating:

Fuel injectors max HP (lb/hr)* = Injector flow rate x Number of injectors x 0.8 / BSFC


Fuel injectors max HP (cc/min)* = Injector flow rate x Number of injectors x 0.8 / BSFC x 10.5

Injector flow rate conversions:

Fuel injectors flow (lb/hr)* = Fuel injector flow (cc/min) / 10.5

Fuel injector flow (cc/min)* = Fuel injectors flow (lb/hr) x 10.5

Injector Selection Guide
Information Source has been verified

Other Usefully information and Tuning Methods

Tuning Via EGT vs, Wide Band/ Narrow Band Meters

Installation and Tuning With an EGT meter

Further discussion of ECUFlash Tuning: Tuning and ECU Flash
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