Free Tools for Enthusiasts

Professional Automotive Calculators, Zero Cost

Dragy analysis, injector sizing, tire comparison, gear ratios, and more. Built on real physics, not guesswork. No sign-up required.

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5 Free Tools
250+ Injector Database
100% Physics-Based

Our Tools

Professional-grade calculators, completely free

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Dragy Calculator

Upload Dragy screenshots for automatic data extraction, slope correction, and horsepower estimation.

  • Image Recognition
  • Slope Correction
  • HP Estimation
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Injector Calculator

Search 250+ fuel injectors, calculate sizing for your HP goals, and check duty cycle margins.

  • 250+ Database
  • Sizing Calculator
  • Duty Cycle
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Tire Calculator

Compare tire sizes to see diameter difference, speedometer error, and effective gear ratio change.

  • Size Comparison
  • Speedo Error
  • Gear Effect
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Gear Ratio Calculator

Calculate vehicle speed at any RPM in each gear. Essential for trans swaps and tire changes.

  • Speed vs RPM
  • Trans Presets
  • Visual Chart
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Compression Calculator

Calculate engine compression ratio from bore, stroke, chamber volume, and piston specs.

  • Engine Presets
  • Volume Breakdown
  • Target Calculator
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Why BitTuned?

Tools built by enthusiasts, for enthusiasts

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Physics-Based

Real formulas, not arbitrary estimates.

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Privacy First

Your data is never stored.

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100% Free

No paywalls or subscriptions.

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Works Everywhere

Desktop, tablet, or phone.

Learn & Understand

Not just calculators — we explain the why behind the numbers

Dragy 8 min

Understanding Dragy Slope Correction

Learn how slope affects your times and how to correct for accurate results.

Read Guide →
Fuel System 10 min

Complete Guide to Fuel Injector Sizing

Everything about flow rates, duty cycle, and choosing the right injectors.

Read Guide →
Fuel System 7 min

E85 Fuel Injector Requirements

How to size injectors for E85 and flex fuel applications.

Read Guide →
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Don't Have a Dragy Yet?

The Dragy GPS Performance Meter is the easiest way to measure your acceleration times with professional accuracy. Use our calculator to analyze your results with slope correction and power estimation.

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Ready to Crunch Some Numbers?

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🏁 Dragy Calculator ⛽ Injector Calculator