Blower Hat Clearance Critical for Drag Racing Horsepower Gains

The Evolution of Blower Hats in Drag Racing

Blower hats have become an iconic part of the drag racing scene, evolving significantly over the years as the quest for more horsepower intensified. These specialized intake systems allow for forced induction from a mechanically-driven supercharger or "blower" to create huge power gains.

The Rise of Supercharging in Drag Racing

Supercharging became popular in the drag racing world in the 1950s and 1960s. Early systems were basic but helped improve the power-to-weight ratio substantially. As speeds increased, innovative racers and mechanics started experimenting with unique manifold and carburetor configurations.

The addition of a specialized hat on top of the blower opened up more options for tuning the air-fuel mix. But it also meant that hood clearance became a major issue. More power meant taller blowers and hats, leading to the stretched, scooped hoods that now define the look of many supercharged drag cars.

Finding the Balance of Power and Clearance

Getting the most power, while still allowing the car to be driven and provide driver visibility, required finding the optimal blower pulley size and rear gear ratio. Early blower hats focused more on function than form, crafted by racers themselves from steel or aluminum.

As supercharging progressed, companies started producing billet aluminum blower hats specifically designed for racing. Different styles evolved based on factors like engine size, fuel type, and intended racing class.

Blower Hats for the Modern Era

Today's cutting-edge blower hats balance maximizing power with meeting specific racing class rules and chassis needs. Most feature configurable inlets and outlets to fine-tune air intake and flow.

Different injection options accommodate various fuel types as racers push the boundaries of performance. Modern blower hat designs also incorporate intercooling concepts to increase power delivery.

Manufacturers utilize CFD and CAD software coupled with wind tunnel and real-world testing when designing blower hats. Racing teams then test combinations to find the optimal balance for their car, class, and driving style.

Important Blower Hat Design Considerations

Many crucial factors go into engineering a blower hat for peak drag racing performance. Prioritizing key parameters helps ensure the system achieves power goals without compromising drivability or safety.

Supercharger Compatibility

Blower hats connect directly to the supercharger, so ensuring a precise fit is critical. Most blower hat manufacturers design products for specific supercharger makes and models.

Racers must match the blower hat to their particular supercharger, whether it's a vintage-style roots type blower or a modern screw-type centrifugal supercharger. Properly mating the components eliminates air leaks while directing flow.

Air Intake Requirements

Since the blower hat mounts between the supercharger and engine intake, its inlet area significantly impacts power. Larger inlet openings allow more air into the system, up to the limit of the supercharger capacity.

Many blower hats have configurable inlets to optimize intake volume for different engine configurations. Some also incorporate integrated air filters or velocity stacks for smoother airflow.

Outlet and Manifold Fitment

The outlet side of the blower hat must align perfectly with intake ports on the engine heads. Various outlet designs accommodate different manufacturers, cylinder counts, head configurations, and racing classes.

Ideally, the transition between the blower hat and intake manifold maintains smooth, even air distribution to ensure maximum performance.

Avoiding Common Blower Clearance Issues

Boosting horsepower with a supercharger inevitably requires increasing blower hat height. Before installing new components, racers need to assess all potential fitment and interference problems.

Checking Hood Clearance

The extra height of the blower hat and scoop protruding through the hood must be test fit several times during assembly. Even a slight interference can bend panels.

Trial fitting with the actual supercharged engine components is ideal before painting or finishing body panels. Any sections of the hood that come close require protective strips to prevent rubbing.

Assessing Chassis Components

The raised blower hat location can also impact under-hood chassis components near the engine. Steering shafts and linkages may need to be modified, along with brake booster mounts and fluid lines.

Test fitting the height with the hood open helps identify any other items that require relocation to prevent damage from interference with the blower hat. Taking these steps ensures safe drivability.

Maintaining Driver Visibility

Supercharging is all about generating horsepower, but preserving good forward visibility is also imperative. The blower hat and scoop can obstruct sight lines out the windshield with an excessively tall stack.

Lower profile designs help keep vision obstruction to a minimum. Leaving the scoop removable also allows dropping the height for street driving when racing performance is not needed.

Carefully considering hood clearance reduces potential issues when boosting a drag racing car’s horsepower with a taller blower hat. Doing upfront test fits and chassis mock ups ensures maximizing power doesn’t compromise other critical areas.

FAQs

What is a blower hat?

A blower hat is an intake manifold that mounts on top of a supercharger to help direct airflow into the engine. It is used to increase the horsepower produced by forced induction in drag racing applications.

How does a blower hat create more power?

A blower hat optimizes airflow from the supercharger into the engine, allowing the forced induction system to push more air and create a bigger power boost. The large intake area and smooth transitions help minimize restrictions.

What clearance issues can occur with a taller blower hat?

The increased height of a bigger blower hat and scoop for more airflow can cause interference issues with the hood, chassis components like steering and brake lines, and forward visibility through the windshield in extreme cases.

Why is test fitting a blower hat setup important?

Doing multiple test fittings of the supercharger, blower hat height and hood clearance minimizes the chance of issues by identifying necessary changes to hoods panels, chassis, and components early before final assembly and painting.