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High Helix vs Standard Helix Blower Rotors
There has always been lots of questions about Standard Helix vs. High Helix Blowers.
For many years all blowers had a 60 degree twist to the rotors – this is called a standard Helix.
A 60 degree rotor will flatline, or quit making more boost at somewhere around 7500 RPM Blower Speed.
So regardless of how much overdrive you continue to try and use, nothing happens that helps make more power – in fact it will slow down a bit due to the effort to drive the blower faster and faster, as well as making lots of heat. The heat isn’t much of an issue with Methanol, but is with gas, big time.
A High Helix rotor is either 120 degrees, or in the case of our XR-1 Blowers, 124 degrees.
How does this help?
A high Helix blower will go to about 11,000 RPM before it quits making additional boost.
NOTE: We are discussing Blower speed, not engine speed, so if a blower is driven at 40% overdrive and the engine is turned to 7000 RPM, the Blower is Turning 140% x 7000 RPM = 9800 RPM, so everything after around 7500 and above has been a waste.
High Helix Rotors take less Horsepower to drive, and run much cooler than 60 degree rotors.
The myth is that a 60 degree rotor makes torque and a 120 degree rotor makes high RPM HP. Not entirely true:
Both make the same torque within a few %, but the High Helix “Keeps” making power way up the RPM scale, so it is, in fact, making more HP at high RPM, since it didn’t quit at 7000-7500 RPM.
For many years all blowers had a 60 degree twist to the rotors – this is called a standard Helix.
A 60 degree rotor will flatline, or quit making more boost at somewhere around 7500 RPM Blower Speed.
So regardless of how much overdrive you continue to try and use, nothing happens that helps make more power – in fact it will slow down a bit due to the effort to drive the blower faster and faster, as well as making lots of heat. The heat isn’t much of an issue with Methanol, but is with gas, big time.
A High Helix rotor is either 120 degrees, or in the case of our XR-1 Blowers, 124 degrees.
How does this help?
A high Helix blower will go to about 11,000 RPM before it quits making additional boost.
NOTE: We are discussing Blower speed, not engine speed, so if a blower is driven at 40% overdrive and the engine is turned to 7000 RPM, the Blower is Turning 140% x 7000 RPM = 9800 RPM, so everything after around 7500 and above has been a waste.
High Helix Rotors take less Horsepower to drive, and run much cooler than 60 degree rotors.
The myth is that a 60 degree rotor makes torque and a 120 degree rotor makes high RPM HP. Not entirely true:
Both make the same torque within a few %, but the High Helix “Keeps” making power way up the RPM scale, so it is, in fact, making more HP at high RPM, since it didn’t quit at 7000-7500 RPM.
Street vs. Race – There is no disadvantage from High Helix; they are perfectly at home on a Street Rod, Boat, Drag Race, Mega Truck, Pulling truck-tractor, or Land Speed Record, and continue to contribute above 7000 rather than giving it up.
