Frequently Asked Questions
What is tuning?
Is it worth it to have my stock car/truck tuned?
Why should I get tuning rather than a handheld unit?
Why do you need a wideband to tune wide-open-throttle?
What is meant by a MAF-based tune or system?
What is meant by a Speed Density tune or system?
What is a 2 or 3 bar tune?
What does Open Loop and Closed Loop mean?
What is tuning?
Computer recalibration or "tuning" is the process of reprogramming the factory engine computer to allow the vehicle to operate properly again after modifications have been made as well as optimizing settings to get the most power out of your setup.
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Is it worth it to have my stock car/truck tuned?
Factory vehicles are calibrated very conservatively and without (to an extent) performance in mind. Stock vehicles really wake up with minor adjustments to ignition timing, fueling, transmission torque management (if an automatic) and a few other items. These items and more (specific things like speedo fixes from larger tires or gears) are all a part of a Basic tune or a mail order tune.
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Why should I get tuning rather than a handheld unit?
This tuning is custom and tailored to your car, not a canned tune. These units also provide a very limited range of adjustability compared to custom programming. Even the Basic tunes are one-offs made for your application after speaking with you about what can be modified and what you are hoping to gain and should expect. Custom tuning allows for many changes not possible through handhelds, even for bolt-ons cars.
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Why do you need a wideband to tune wide-open-throttle?
The oxygen sensors that come in your car/truck work really well at maintaining a solid cruising air-fuel ratio (AFR). Once the AFR deviates much above or below this cruise AFR, narrow-band (factory) O2 sensors lose their accuracy. Because of this, a wideband is needed to be able to view more of the AFR spectrum; particularly that area around wide-open-throttle which is much richer than cruise.
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What is meant by a MAF-based tune or system?
Our cars come from the factory with a device called a Mass Airflow Meter (MAF) that measures the air entering the engine. Even minor mods like air-lids and other "cold air kits" alter the course of flow through the MAF which skews the factory's calibration. Most of the commanded fueling that a car uses comes directly from this measure of airflow. Most cars will be tuned using the MAF for accuracy of fueling and drivability.
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What is meant by a Speed Density tune or system?
Speed-density calibrations use fueling calculations that come solely from static tables referenced against the Manifold Absolute Pressure (MAP) sensor, Intake Air Temp (IAT) sensor, Engine Coolant Temp sensor (ECT) and few other items. This calibration is well suited to very radical setups with very large duration camshafts that can cause reversion issues with a MAF tune at idle and low speed.
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What is a 2 or 3 bar tune?
2 and 3 bar tunes are actually special operating systems that are speed density and designed for higher horsepower boosted applications which will max out the MAF. These operating systems require the corresponding 2 or 3 bar MAP sensor and allow the PCM to "see" boost (the stock PCM is blind to MAP levels that result from boost) and adjust fueling accordingly. This is particularly important for turbo charged applications which can make boost in many different RPM ranges based on engine load, unlike superchargers whose boost is physically tied to rising engine RPMs.
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What does Open Loop and Closed Loop mean?
Closed Loop (CL) refers to a control sub system in the PCM that allows the engine computer to make adjustments to idle and part-throttle fueling based on feedback from the narrow-band oxygen sensors. This makes fueling more consistent (in most cases) and helps with highway economy and general drivability. Open Loop (OL) operation means that fueling is calculated and metered from the MAF (unless in speed density where no MAF is used) and other static tables alone. OL is sometimes desirable in instances such as aiding the operation of a very large camshaft with lots of overlap at lower RPMs. This overlap allows fresh air to escape into the exhaust which "fools" the factory oxygen sensors into thinking that the engine is lean. This can have the effect of causing over fueling at these low RPMs as the PCM attempts to correct a scenario which it perceives to be lean.
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