Pre-Dyno Checklist



Things You Must Have For a Proper Tune


Dyno machines are expensive. Accumulating expert-level tuning experience takes years. Building or leasing a building where you are allowed to install a dyno is difficult. For all these reasons, time on the dyno costs money. Thatís just the way it is. To make your dyno time go smoothly and to avoid extra dyno charges, please carefully read the following list of things you must have for a proper dyno tune:
  • Fresh fuel (less than 2 months old) of the same type and octane rating that you plan to use whenever you are running your Realspeed tune.

  • At least a half a tank of fuel or more. All power-adder cars, cars running E85, or any car requiring a lot of dyno time should come in with a full tank. If we have to use up dyno time refueling your car it will cost more than just the price of the fuel.

  • A fitting in the exhaust for our dyno wideband air/fuel ratio sensor (O2 bung). In some cases we can use one of the factory rear O2 sensor bungs. In others we will need a separate sensor bung welded in. Call Realspeed for clarification before your tune date.

  • Proper registration, insurance, license plate, working seatbelt, headlights, turn signals, brake lights and safe suspension and brakes, so that we can perform a street test drive to make final adjustments to the tune. Real-world driving adjustments are included in the price of a Realspeed tune. However, if we canít safely test the car during your original tune appointment you will be charged for any follow-up adjustments that are required.

  • Good ignition wires and/or coils with no burns, no cracked insulation and tight connections to all spark plugs.

  • Good fresh spark plugs of the correct type, heat range and gap. Dyno time is expensive. Spark plugs are relatively cheap. If the car is misfiring even the slightest it will degrade the quality of your tune. When in doubt, change them. Call us for recommendations before your tune appointment.

  • No exhaust leaks between the engine and the muffler. ANY leaks located from the engine back to a distance 1 foot rearward of the rear-most O2 sensor will compromise the accuracy of the tune.

  • No excessive fluid leaks (oil, antifreeze, transmission fluid, rear end fluid). You will be charged for cleanup.

  • No fuel leaks whatsoever.

  • No unresolved trouble codes or ďcheck engineĒ lights. Unless the check engine light is for something that you have specifically discussed with us ahead of time, donít assume it will be fixed by the tune alone. To properly calibrate the tune, all sensors and equipment must be working properly and no trouble codes should be present.

  • No vacuum leaks (air leaks) anywhere in the intake manifold or air intake tract from the air filter to the engine. We have special equipment to check for leaks. Call us ahead of time to make an appointment if you are not sure.

  • The fuel filter must not be clogged. Consult your ownerís manual for recommended service intervals. If you have modified your car to substantially increase its power then you will need to change the fuel filter more frequently to ensure adequate fuel flow though the factory sized filter. (ie. if the factory service interval is 30,000 miles you should change it every 15,000 if you have added a supercharger).

  • Tires with enough traction for the power level you plan on making. Donít show up with 5 year old all-season tires if you are planning on making more than 450 horsepower. If you canít get traction on the street in 3rd gear, we canít get traction on the dyno. Get some drag radials.

  • Matched tires of the same diameter on the left and right side, in good condition with no cracked or dry rotting and no exposed cords. Top speed on the dyno usually ranges from 120 to 170 mph, depending on the vehicle. Make sure your tires are safe for these speeds.

  • Driveshaft bolts securely tightened. U-joints in good condition. All driveline components and fasteners tight, secure and in good condition. This should be obvious, but we have had to stop more than one dyno session because the driveshaft was about to fall out.

  • The cooling system must be working properly. We cannot tune a car that is overheating. We can fix your cooling system for you, but you must make an appointment for that BEFORE your dyno tune.

  • The alternator must be in proper working order and the battery in good condition.

  • For supercharged vehicles: GT500s, Lightnings, 03/04 Cobra or any car with an intercooler pump, please make sure your intercooler pump is working before you arrive. You should be able to see the coolant circulating in the reservoir when the engine is running

  • If your vehicle is over 7 years old or sits unused for more than 6 months, we highly suggest you remove your fuel injectors from the engine and have them professionally cleaned. During the tuning process the tuner/calibrator is measuring the Air/Fuel ratio from only one (or two) location(s) and making the assumption that all fuel injectors are flowing the same rate. If you have one or more poorly flowing fuel injector then some cylinders will be starved for fuel while others will get too much fuel. Reduced performance and possible engine damage will result from this condition. Engine damage due to unevenly flowing fuel injectors is NOT the responsibility if the tuner.

  • At a bare minimum it is a good idea to run a high quality fuel injector cleaner such as Redline Fuel Injector Cleaner though the engine for at least 2 tankfuls before your dyno tune. It is preferable to run the fuel injector cleaner prior to the tune and then put in fresh fuel without any injector cleaner for the actual tuning session.

  • An oil and filter change is a good idea prior to tuning if it has been more than 3,000 miles since the last oil change, or if the engine has been repeatedly flooded from a poor tune or any other reason.

  • If you are unsure of the condition of your engine, please make an appointment to have us perform a compression check and a visual inspection of the engine before your tune appointment. If we find a problem with the engine during tuning you will still be responsible for the majority of the cost of the tune session. It is better to check things out ahead of time.


Important Notes for New Builds and Cars That Have Been Sitting For a Long Time
  • If the engine or cooling system has been apart, bleed all of the air out of the cooling system before your tuning appointment. Preferably get the engine up to temperature and let it cool completely at least two times to check for leaks and top off the coolant before arriving for your tune.

  • We can perform the first start of your brand new engine to make sure the fuel, ignition timing and oil pressure are safe, and to bleed the cooling system, but you must MAKE AN APPOINTMENT AHEAD OF TIME. Initial engine startup & setup is a separate operation from a dyno tune.

  • The engine, engine computer and wiring harness must all be grounded properly with good, clean and tight connections. All factory grounds must still be present. Ground wires cannot do their job if they are bolted to a painted or powdercoated surface. The computer uses the difference between ground and a reference voltage signal for almost all of its sensors. Poor grounds will cause erroneous computer readings, poor performance, possible misfires and a poor tune result. THIS IS PROBABLY THE MOST COMMON PROBLEM WE SEE WITH OLDER CARS THAT HAVE BEEN WORKED ON BY OTHER PEOPLE.

  • We are seeing lots of problems with clogged fuel injectors. Many cars that were running fine when they were parked have seriously clogged fuel injectors when they are restarted a year later. Never trust used fuel injectors unless you have had them professionally cleaned. During the tuning process the tuner/calibrator is measuring the Air/Fuel ratio from only one (or two) location(s) and making the assumption that all fuel injectors are flowing at the same rate. If you have one or more poorly flowing fuel injectors, then some cylinders will be starved for fuel while others will get too much fuel. Reduced performance and possible engine damage will result from this condition. Engine damage due to unevenly flowing fuel injectors is NOT the responsibility if the tuner.


Mechanical Limitations


The tunerís job on the dyno is to develop and fine tune a calibration specific to your vehicle, not to fix every single thing that is wrong with it. If your car requires mechanical repairs, those can be addressed by our mechanical/install facility and will be charged separately from the dyno tune.

A dyno tune cannot, by itself, fix certain mechanical or electrical limitations. For example, if the fuel pump on the car cannot deliver sufficient fuel for more than 400 horsepower, no amount of computer tuning is going to make the car produce 600 horsepower. As Greg Banish, respected calibration engineer and the author of Designing and Tuning High-Performance Fuel Injection Systems said, ďI canít fix that with my keyboard.Ē The same can be said for Mass Air Flow (MAF) sensors, ignition systems, O2 sensors, supercharger bypass valves, poorly designed tubing causing MAF turbulence, slipping clutches, radiator fans, water pumps, vacuum leaks, clogged exhaust systems, bad engine grounds, alternators, electrical wiring or a whole host of other problems and limitations.

If you are unsure of the condition of any of these things please make an appointment for us to inspect the car prior to the dyno tune. Even so, some problems may not become apparent until the car is on the dyno. As the car owner who has decided to modify your car, you are responsible for the repair or the modifications necessary to overcome these limitations, whether you chose to pay Realspeed to fix them or to take the car back and fix them yourself. The cost of the time on the dyno will still be charged even if we canít complete the tune due to a mechanical or electrical limitation of your car.














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All parts listed are for the Ford Mustang unless otherwise noted.

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