Using a Transbrake for Maximum Launch with a Powerglide Drag Racing Transmission

Using a Transbrake for your Powerglide Transmission

Drag racing has always been about pushing limits. Going faster, quicker, and reaching new levels of performance. And the quest for speed starts with the transmission. For hardcore drag racers, the Powerglide transmission paired with a transbrake offers the ultimate in quick, consistent launches.

The Powerglide is revered for its durability and strength, making it perfectly suited to handle the demands of drag racing. Originally introduced in 1950 by General Motors for use in passenger cars, it has cemented its place in drag racing history. The simplicity and lightweight aluminum construction make the Powerglide transmission ideal for the dragstrip.

How a Transbrake Works

A transbrake is a device that locks the transmission output shaft, allowing the engine to build maximum rpm before launching. As soon as transbrake is released, all of the energy from the high revving engine is unleashed, creating an explosive launch.

The transbrake utilizes the transmission's intermediate clutch pack to lock the rotation of the output shaft. When engaged, hydraulic pressure is applied to the intermediate clutch pack, holding it tight to prevent the output shaft from turning.

With the output shaft locked, the engine is able to rev up against the resistance, creating power. As soon as the transbrake is released, the clutch pack opens and all of that pent up horsepower is unleashed as torque to the rear wheels.

Benefits of Using a Transbrake

The transbrake brings several important benefits:

• Consistent launches - Since engine RPM is already at max before launch, it eliminates bogging or tire spin on takeoff.
• Increased torque at launch - More RPMs means more power ready to be applied instantly.
• Faster 60ft times - Hard, instantaneous launches maximize momentum off the starting line.
• Adjustable launch rpm - The launch rpm can be optimized based on traction.

By pre-building maximum power before releasing the clutch, the transbrake provides consistent, lightning quick launches that maximizes the car's performance potential.

Setting up a Transbrake on a Powerglide

While you can buy complete transbrake kits for Powerglides, many racers choose to piece together custom systems to get the ideal setup dialed in for their combo and racing goals.

Here are the components needed to add a transbrake:

• Transbrake valve body - Replaces the stock valve body with one designed for transbrake operation.
• Transbrake solenoid - Activates the intermediate clutch to lock output shaft.
• Transbrake button - Mounted in cockpit to allow easy activation by the driver.
• Accumulator pistons - Help provide smooth and consistent transbrake engagement/release.
• High quality sprag - Upgraded sprag assembly can handle the abuse of transbrake torque.

The valve body is the most critical component, as it directs fluid flow and pressure to control clutch apply. Quality parts designed specifically for transbrake use are strongly recommended.

Tuning the Transbrake System

Proper setup and tuning of the transbrake is critical for maximum performance. The goal is to find the optimal launch RPM that balances traction and power. There are a few key factors in tuning:

• Clutch pack clearance - Clutch packs must have proper clearance range, around .050"-.060". Too tight will cause harsh engagement, too loose allows slipping.
• Accumulator charge - Gas charged accumulators must be adjusted to fine tune transbrake release timing.
• Line pressure - Increased line pressure ensures clutches have maximum holding capacity at high RPM.
• Solenoid balance - Precisely match solenoid timing to ensure even clutch apply.

Testing and adjustments are made by performing transbrake launches at the track, and observing the reaction of the car, incremental changes are made until the ideal combination of quick release and traction is achieved.

Transbrake Safety Tips

While the transbrake can deliver incredible performance, there are some important safety factors to keep in mind:

• Start with low launch rpm and short bursts to test components.
• Use high stall converter matched to engine power.
• Install transmission temperature gauge to monitor fluid temps.
• Allow time for transmission to cool between runs.
• Use transmission fluid designed for racing conditions.
• Build transmission with high quality parts designed for racing.

Following careful testing procedures and using robust components designed for drag racing will ensure safety while unleashing maximum power.

Choosing the Right Transbrake System

When selecting parts for a custom transbrake Powerglide, here are some top manufacturers to look for:

Transbrake Valve Bodies

• ATI
• B&M
• Hughes Performance
• J.W. Performance
• Neal Chance Racing Converters
• TCI
• Transmission Specialties

Accumulators and Solenoids

• Sonnax
• TransGo

Racing Torque Converters

• Coan Racing
• Dynamic Converters
• Hughes Performance
• Neal Chance Racing Converters
• Precision Industries
• TCI

The transbrake has become a must-have tool for serious drag racers looking to dominate on the dragstrip. Paired with the legendary Powerglide transmission, the transbrake enables consistent, lightning quick launches to shave precious seconds off your ET. With the right setup and high quality components, the transbrake will launch your rig into hyperdrive the instant the green light flashes.

FAQs

What is the benefit of using a transbrake?

A transbrake allows the engine to build maximum RPMs before launching, enabling consistent, very quick launches off the starting line. The stored energy from high RPMs is released instantly at launch.

What is the best transbrake launch RPM range?

Most racers launch between 5,500-8,500 RPM depending on the combo. Lower RPMs for street cars, higher RPMs for all out race vehicles. Testing is needed to find the optimal launch RPM.

What wear items need to be upgraded with a transbrake?

Upgraded sprag, clutch packs, accumulators, valve body, and torque converter are typically needed handle the extreme stresses of transbrake launches.

How does a transbrake affect my transmission tune?

Higher line pressures, adjusted accumulator timing, and clutch clearance tuning are needed for smooth transbrake engagement and release. Expect more frequent rebuilds as well.

Is a transbrake easy to install?

A basic transbrake can be installed in a few hours, but proper setup and tuning will take extensive track testing. Hiring an experienced trans technician is recommended.