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PRE TUNING CHECKLIST

Pre-Tuning Checklist: Ensuring a Successful Tuning Session

Proper preparation is key to achieving the best results from your tuning session. Many tuning issues arise due to mechanical problems that could have been identified and resolved beforehand. Follow this checklist to ensure your vehicle is in optimal condition before your tune.

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Section 1: Mechanical Engine Health

A healthy engine is essential for a successful tune. We recommend performing a compression test and a cylinder leakdown test before your appointment:​

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Compression should be tested on a warm engine, with fuel injectors unplugged and the throttle fully open. A variance of more than 10%+ or ~20+ psi between cylinders indicates an issue that must be resolved before tuning.

  • Leakdown Test: Cylinder leakage should not exceed 7%. If leakage is detected, further diagnosis is required to determine the source (intake/exhaust valves, piston rings, head gasket, etc.).

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Additionally, check for oil or fluid leaks and ensure that all turbo oil feed and return lines are properly installed.

For DIT Subaru WRX models (2015-2025), carbon buildup is a known issue beyond 30,000 miles. Walnut blasting is the only effective method to restore performance, potentially recovering 10-50whp.

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Section 2: Airflow, Turbo, and Vacuum Integrity

  • MAF Sensor & Intake System: Clean the intake filter and MAF sensor. Ensure the MAF o-ring is properly sealed.

  • Pressure Testing: Check for leaks in the intake, charge piping, intercooler, turbo, and vacuum lines. Leaks can lead to improper air-fuel ratios, affecting performance.

  • Exhaust System: Inspect for leaks from the exhaust manifold to the tailpipe. Leaks before the turbo reduce power and affect tuning accuracy.

  • Blow-Off Valve (BOV): Ensure it is properly lubricated, sealed, and functioning. Ensure proper spring strength is installed – questions, contact us!

  • Turbo Health: Check for excessive shaft play. A worn turbo should be rebuilt or replaced before tuning.

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Section 3: Pre-Tuning Maintenance & Safety Checks

  • Fluids: Ensure all fluids (engine oil, coolant, transmission, differential, brake, and clutch fluid) are at proper levels. Change oil and filter if over 3,000 miles.

  • Fuel System: Use the correct fuel octane and have at least half a tank. If switching fuels, plan for proper draining and refueling.

  • Check Engine Light (CEL): Resolve any active CELs before your appointment.

  • Fuel Injectors: Vehicles older than five years should have injectors cleaned and flow-tested.

  • Electrical System: Ensure good grounding and check for exposed or poorly connected wires.

  • Fuel Filter: Replace if clogged to prevent fuel delivery issues.

  • Spark Plugs: Replace Iridium/platinum plugs over 15,000 miles old.

  • Alignment & Drivability: The vehicle must drive straight and safely onto the dyno under its own power.

  • Brakes & Tires: Ensure they are in good condition for both dyno tuning and post-tune road testing.

  • Battery & Alternator: Confirm these components are functioning properly to avoid tuning interruptions.

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Section 4: Pre-Dyno Tuning

  • Dyno testing and calibration are not simple or inexpensive services. The equipment itself represents a significant investment, and developing the level of experience required to properly tune vehicles takes years of hands-on work. Even finding and operating a facility capable of housing a dyno comes with its own challenges. Because of this, dyno time is valuable, and proper preparation is the difference between an efficient session and unnecessary added cost.

  • To ensure your tuning session goes smoothly and avoids delays or additional charges, the vehicle must arrive fully prepared. Fuel is one of the most overlooked areas. The car should have fresh fuel—no older than a couple of months—using the exact type and octane you plan to run long term. At minimum, the tank should be half full, but higher horsepower setups, ethanol vehicles, or anything expected to require extended dyno time should arrive with a full tank. Time spent refueling during a session takes away from tuning time and increases overall cost.

  • The exhaust system must allow for accurate air/fuel monitoring. This typically requires an accessible O2 sensor bung for a wideband sensor. In some cases, a factory rear O2 location can be used, but others may require a dedicated external sensor. On the dyno, we have multiple options for wideband's so no extra effort or expense required.

  • The vehicle must also be roadworthy and safe to operate. This includes valid registration, insurance, and all basic safety equipment such as working lights, seatbelts, and signals. A proper road test is part of the tuning process to verify real-world performance, and if the car cannot be safely driven, any additional follow-up required will be billed separately. Suspension, brakes, and overall drivability should be in good condition, and the car must be able to operate straight and stable under load -ENSURE YOUR ALIGNMENT IS WITHIN SPEC!

  • Ignition components need to be in excellent shape. Coils and plug wires should be free of damage, with no cracks or weak connections. Spark plugs should be fresh, properly gapped, and matched to the setup. Even minor misfires will negatively impact tuning accuracy, and considering the cost of dyno time, it makes no sense to risk issues caused by worn plugs.

  • The exhaust system must be completely sealed. Any leaks from the engine through the exhaust—especially near the O2 sensors—will affect air/fuel readings and compromise the tune. Fluid leaks must also be addressed beforehand. Oil, coolant, transmission, or differential leaks not only create safety concerns but also require cleanup, which will be billed accordingly. Fuel leaks are absolutely unacceptable and must be fixed prior to arrival.

  • There should be no unresolved check engine lights or diagnostic trouble codes unless they have been specifically discussed in advance. The tuning process relies on accurate sensor data, and any faults within the system will interfere with calibration. Similarly, the intake system must be completely sealed, with no vacuum or unmetered air leaks anywhere from the air filter to the engine. If there is any doubt, proper testing should be performed before the appointment.

  • Fuel delivery must be consistent and unrestricted. A clogged or aging fuel filter can limit performance and cause dangerous lean conditions, especially on modified vehicles where fuel demand is higher. Maintenance intervals should be adjusted accordingly for higher horsepower setups to ensure proper flow.

  • Tires and driveline components must be capable of handling the intended power level. Worn or low-quality tires will struggle for traction on the dyno just as they would on the street, limiting what can be accomplished. Tires should be matched side to side, in good condition, and rated for the speeds the vehicle may reach during testing. Driveline components such as driveshafts, U-joints, and fasteners should all be secure and in proper working condition, as failures here can immediately halt a session.

  • The cooling system must function correctly, with no overheating issues. Vehicles that cannot maintain stable temperatures cannot be safely tuned. Likewise, the charging system must be in good condition, with a properly functioning alternator and a healthy battery to ensure consistent voltage throughout the session.

  • For vehicles equipped with forced induction systems that rely on additional cooling components, such as intercooler pumps, those systems must be verified as operational before arrival. Failure of these components can quickly lead to unsafe conditions under load.

  • Electrical grounding is another critical area that is often overlooked. The engine, ECU, and wiring harness must all have clean, secure ground connections. Poor grounding can lead to inaccurate sensor readings, drivability issues, and inconsistent tuning results.

  • On older vehicles or those that have been sitting for extended periods, fuel injectors should be professionally cleaned and tested. Uneven injector flow can cause imbalanced fueling across cylinders, leading to reduced performance or potential engine damage. At minimum, running a high-quality injector cleaner through multiple tanks prior to the session is recommended, followed by fresh fuel for the actual tuning process.

  • Fresh oil and a filter change are also strongly recommended, particularly if the current oil has significant mileage or has been contaminated from previous poor running conditions. If there is any uncertainty about engine condition, it’s always best to perform a compression test or have the vehicle inspected prior to scheduling dyno time. Discovering issues during the session does not eliminate the cost of time already spent.

  • For newly built engines or vehicles that have been apart, extra attention is required. Cooling systems should be properly bled of air, and the engine should be heat-cycled and checked for leaks before arriving. Initial startup procedures and system checks should be completed ahead of time, as these are separate from the tuning process and require their own appointment if assistance is needed.

  • It’s important to understand that the purpose of a dyno session is to calibrate the vehicle—not to diagnose and repair every underlying issue. Mechanical or electrical limitations cannot be overcome through tuning alone. If a component such as a fuel pump, MAF sensor, ignition system, or clutch cannot support the desired power level, no amount of calibration will compensate for that limitation. Any required repairs or upgrades will need to be addressed separately, and dyno time will still be billed regardless of whether the session can be completed.

  • Proper preparation is ultimately the responsibility of the vehicle owner. While inspections can help identify potential problems ahead of time, some issues may only become apparent once the car is under load. Taking the time to prepare the vehicle thoroughly ensures a smoother process, better results, and avoids unnecessary costs during your tuning session.

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Final Step: Define Your Tuning Goals

  • Communicate your expectations with your tuner ahead of time. Some goals may require hardware changes or fuel upgrades, so discussing this in advance will set clear expectations and help achieve the best results.

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By following this checklist, you’ll set the stage for a smooth and successful tuning session. Proper preparation ensures better performance, reliability, and overall satisfaction with your tune!

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