Tuning FAQ

What is E-Tuning?

E-tuning or Email tuning is calibration of a vehicle remotely.  We modify the calibration of the vehicle to ideally control your car.  This takes into account many things: Fuel type, Elevation, temperature changes, fail-safe conditions and much more.

What Platforms do we E-Tune

Our list is changing and growing constantly.  But you can simply go through our E-Tuning Home, then select your desired tune medium (for example, EcuTek).  Then your car may or may not be an option under that medium.

Is an E-Tune better than a Canned map?

Yes, an e-tune gets you much more than what Canned or OTS map has to offer.  Some of our features include:

  • Fuel pressure fail-safes
  • Flex-Fuel
  • SD calibration
  • Alternate fuel calibration
  • Water-meth calibration
  • Safety nets added
  • Launch control
  • Flat foot shifting
  • Location specific calibration
  • and much more

How do I install my EcuTek Map?

We have a dedicated write up to help you get through setting up your EcuTek software:

EcuTek Setup

How long does it take?

Well, it can vary greatly.  The better the build, the easier it is to tune.  You will be contacted after your purchase to start the e-tuning process.  Revisions generally take 24 hours, but can be done faster.  Mechanical issues do increase tuning time required.  And in extreme cases if mechanical issues prohibit tuning, or excessively delay it, extra charges maybe incurred.

Why Should I E-Tune over a local company?

Tuning is a very knowledge and experience based field.  Depending on your location, you may have a hard time getting our level of expertise from a nearby shop.  This is where e-tuning shines.  You get all the latest and greatest from a company that lives and breathes ecu calibration.  We take immense pride in our work, and strive every day for improvement.

What happens if I have a mechanical change after the E-tune?

Generally we charge per hour for re-tuning after a mechanical change.  Each situation is specific, so please contact us before you make any changes that require calibration.  If changes are significant the full tune rate applies.

Will we look over data logs from current or older tunes?

Yes, comprehensive diagnosis is available for a fee.

Do we require a wideband

Not always.  Good parts get good results.  Cheap parts end up costing much more in the long run.  With our extensive experience we can quickly get to the bottom of any issue.  Sometimes if we run into a systemic problem, or something that we need a wideband to completely diagnose, then we will require it.  Poor quality injectors will ALWAYS require a wideband.  This is due to their uneven flow characteristics during linear voltage increases.  Please contact us with vehicle specific questions.

Do we offer refunds?

Generally speaking no.   Each tune is vehicle specific, and take a large amount of time to carefully craft.  We do look at each situation and use our best judgement.

What is Feedback Knock

It is a type of immediate correction pulled from the Subaru ECU.  A common misconception is that Feedback knock is always detonation or the car running in a dangerous condition.  Many things can cause Feedback Knock.  The most common that we see is a loose heat shields and intercooler brackets.  Since the sensor is simply looking for a specific frequency, all you need is something at that range to trigger it.

You should be aware of feedback knock, and figure out when and where it’s happening.  Often it’s a repeatable condition.  If you have more questions please contact us.  Logs are very beneficial for determining the validity of the knock.

SI Drive Modes


SI drive from Subaru opened up a world of opportunity for tuners.  By introducing calculation into throttle position, we are able to adjust the calculated value to net desired results.  What does this mean for you, the owner?  Here are some features we pack into our SI drive tunes:

  • 3 unique maps per S / I / S#
  • Variable boost based on mode/gear
    • Boost target adjusts
    • WGDC adjusts
    • RPM weighing
  • Throttle ramping per mode
  • All factory protections are left in place

What is Flex-Fuel?

We have a dedicated article to help answer any questions regarding flex-fuel:


What is Speed Density tuning?

At it’s core Speed Density is an airflow equation.  It calculates airflow based off of manifold pressure and charge air temperature instead of MAFv.  There are advantages running an SD set up on your car.  For those with large turbochargers requiring very large intakes, a MAF system simply isn’t practical.  SD also allows for much tighter control over calculated airflow, giving us a finer margin of precision when calibrating.  Here is an example of an SD table:

Values have been changed from ideal to protect intellectual property.  

Can’t find your answer here?

Contact us:



How would you know?  What would you look for?  Often we get asked at what point do I need to upgrade my regulator, and why.  Well if you have an 08+ STi you more than likely have read into the dreaded “GR Stumble”.  The 08+ STi runs a parallel to series fuel system.  It is when the switch between happens, fuel pressure drops.  This causes is what you feel as a stumble.  Here is an example of a replacement kit on a 08+ STi.  We have used COBB’s fuel pressure differential to monitor and adjust for discrepancies in pressure at the rail.excessive_fuel_pressure_01

Green is Boost

Red if Fuel Pressure

White is injector scale

What we see from this log is the regulator not bypassing enough pressure when fuel pump duty increases.  You see this right before we hit peak torque, or our boost target.  The pressure should scale identical to boost, it shouldn’t spike above the delta in boost pressure.  This tells us the regulator isn’t big enough for our application.  Which, in this example, it’s an older STi style OEM regulator.  We simply swap it out for a larger aftermarket unit, and we are good to go!


Above is an example of a larger upgraded regulator.  If you have any questions on what is needed for your specific application please let us know.  We stock and supply many various aftermarket regulator options.

Water Meth Injection

Water/Methanol injection is a system that sprays water, methanol or a mixture of both into the intake tract.  Flow rates will be around 20-25% of total fuel consumption.  Most kits come with a controller to regulate the volume of flow, activation pressure and a disabling fail safe.  A properly set up system has little risk and increases the effective octane from 91 to around 95/96.  The best part is windshield washer fluid is a great pre-mixed form of water/methanol.  Here is a video of a 500+AWHP STI running water methanol injection with a proper fail safe.

Yes water methanol injection can be safe to run, be sure to have everything calibrated correctly!

Is E85 Safe?

Yes, it’s an amazing fuel that I wish we had more access to in Utah.  Flex-Fuel is ideal when running E85 to compensate for allowed variations of ethanol at the pump.  Mapping when calibrated correctly yields race gas gains at pump gas prices.  With advances in ECU understanding cold starts and warm up are no longer an issue.  Many early concerns were regarding the more corrosive nature of the fuel.  However in any of the 2000 or newer vehicles we haven’t had any issues.   Here is our Flex-Fuel write up:

Flex-Fuel VS E85

What is Launch Control

It is a secondary rev limit used below a set vehicle mile per hour.  This allows the car to hold a lower RPM at wide open throttle.  Building boost to deliver more torque from the line.   Most vehicles see around 7-10psi of boost with the average launch control.  There are both spark and fuel based launch control.  Both when used excessively can cause damage.

What is Flat-Foot Shifting?

Flat foot shifting is leaving the drivers pedal down on a manual vehicle when shifting.  Yes, you leave your foot floored like an automatic while you shift.  When engaged the Flat Foot slowly lowers rpm while keeping boost in the intake manifold.  The effect is the car holds about 1/2 of targeted boost on shift.  Flat Foot Shifting eliminates turbo lag after the initial spool up when used.  Stand alone ECU’s and EcuTek have the ability to change target fueling and timing during flat foot shifting.  This is very useful in protecting the motor.

Didn’t find the answer to your question?  Please read though our articles and or feel free to contact us with the links attached.