1. What is Stall Speed?

Stall speed is the maximum engine RPM that a torque converter can reach when the transmission output shaft is prevented from rotating. It's a critical parameter for torque converter selection in automotive applications.

2. How Does the Calculator Work?

The calculator uses the stall speed formula:

Where:

• \( HP \) — Horsepower of the engine
• \( Torque \) — Torque output in pound-feet (lb-ft)
• \( 5252 \) — Conversion constant (where HP and torque curves intersect)

Explanation: This formula estimates the optimal stall speed for torque converter selection based on your engine's power characteristics.

3. Importance of Stall Speed Calculation

Details: Proper stall speed selection ensures optimal launch characteristics, prevents engine bogging, and maximizes acceleration performance. Choosing the wrong stall speed can lead to poor drivability and reduced performance.

4. Using the Calculator

Tips: Enter your engine's peak horsepower and torque values. Use values measured at the same RPM for best results. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the 5252 constant?
A: 5252 is the RPM where horsepower and torque are numerically equal in the imperial system due to the conversion formula: HP = (Torque × RPM) / 5252.

Q2: How does stall speed affect vehicle performance?
A: Higher stall speeds allow the engine to reach its power band faster, improving acceleration but may reduce fuel efficiency and create more heat.

Q3: What stall speed is typical for street applications?
A: Street vehicles typically use stall speeds between 1800-2800 RPM, while performance applications may use 3000-5000+ RPM stall converters.

Q4: Can I use this calculator for any type of vehicle?
A: This calculator works for most automotive applications, but specialized vehicles (racing, towing, etc.) may require additional considerations.

Q5: What if my calculated stall speed seems too high or low?
A: Verify your input values are accurate. Consider consulting with a transmission specialist as other factors like vehicle weight and gearing also influence optimal stall speed selection.