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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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.

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!