Shocking Possibilities: Choosing QA1 Single or Double Adjustable Shocks (Videos)


More and more Mopar owners are looking to get more out of their cars than the cars were ever built for. Thankfully, today’s enthusiasts can find success in using versatile parts that can perform in a variety of functions – like QA1’s adjustable shocks. For many generations of American hot rod and muscle car builders, shock absorbers had to be purchased to work for one specific application. Daily driven cruiser cars could purchase factory replacement shocks, while drag racers looked for drag specific 90/10 shocks, and road racers were in a class of their own trying to find foreign application shocks to work for their vehicle. Today, QA1 has made shock absorbers that are not limited to one application, but rather excel at all of the above.

To understand what QA1 has done by creating their adjustable shocks, it is best to take a step back and understand what a shock absorber does. A shock absorber is used to control the compression and rebound of a suspension. While there are several different styles of shock absorbers, basic construction will include an oil filled chamber that creates pressure as a piston and shaft pass through the chamber, both on compression and extension. This pressure is used to convert the moving (or kinetic) forces into heat.


Shocks are infinitely varied across applications, but all can be measured by their compression and rebound control forces. For example, a traditional “90/10” drag shock has 90-percent of its force used to control compression and 10-percent of its force to control rebound. A setup like this would make the compression control strong and stiff, while the rebound only is controlled by the latter tenth and thus the suspension is able to unload very quickly.

These shocks are ideal for the front of drag cars as they allow the front suspension to unload quickly off the start line, transferring weight to the back tires and assisting the car’s hookup. Shock absorbers for track cars are set up very differently. A shock is used to help control body-roll around corners, keeping the car planted, and helping it absorb bumps at high speeds found along the track.

With so many differently tuned shocks set up for specific applications, purchasing shocks can get overwhelming. Determining what type of shock is right for your Mopar can be a cloudy decision. This is where QA1’s single and adjustable shocks come into play. Unlike standard shocks, QA1’s adjustable shocks can be changed at the turn of a dial to work for any application. These shocks can literally be used to drive comfortably across the country, arrive at the strip and be adjusted to be a no-holds-bared drag shock. These adjustable shocks are a huge breakthrough for any project car because they eliminate the need to specialize the car for one specific use.

Just like the standard shocks we discussed, QA1 adjustable shocks have an oil filled chamber, piston and shaft, but what makes these shocks different can be seen in other key components. These shocks use a twin tube construction; this means there is a main tube that the shaft and piston travel though. As fluid is compressed it is transferred into a larger tube that makes up the outside body of the shock.

The forces required to transfer the fluid in and out of the outer tube affect the damping characteristics of the shock. The twin tube design is also used to help cool the shock oil, as the oil is dispersed around the shock heat can be dissipated. As opposed to a mono tube shock, twin tube shocks do not need an air charge, which helps twin tube shocks to avoid leaks and maximize shaft travel in a confined space. These characteristics can be found in fixed rate twin tube shocks of all kinds, but making the shock adjustable is where the real engineering has come into play.

To better understand exactly how the turn of a knob can determine compression and rebound forces, Mopar Connection talked to Damian Brase at QA1 who explained, “The force of the moving piston creates pressure inside the working cylinder in the shock that is bled off through bleed holes in the piston, or in the case of our adjustable shocks, through the adjuster mechanism at lower speeds. At higher pressures the Deflective Disc Valves or shim stack opens allowing additional oil to flow through the piston similar to a pressure relief valve in a conventional hydraulic system.”

“The adjuster mechanism acts changes the preload on a spring loaded valve in the base of the shock changing the forces in the shock. The single adjustable shocks have one circuit that adjusts compression and rebound simultaneously while the double adjustable shocks have duel circuits, one for compression and one for rebound,” Brase continued.

In basic terms, the adjuster mechanism is used to control fluid transfer between the inner and outer tube, this fluid transfer rate is adjusted at the turn of the knob and this changes the shock’s behavior. QA1’s single adjustable shocks have 18 different settings, making the shock easily able to perform in any application. Dialing in the optional shock settings for drag racing can be done in a few passes, and if settings are recorded, this launch can be matched at drag strips with ease over and over again.

Above: The ability to adjust from a daily driver to a race ready set up is the reason we have QA1 adjustable shocks on our project Brazen ’69 Charger. We chose the double adjustable shocks for our application, but single adjustable shocks can also be the right choice for a project.


Double adjustable shocks come into play more for the hard core racing types. These shocks have 18 compression adjustments and 18 rebound settings. This can make for a combination that can be minutely adjusted to compliment individual race tracks. These shocks are utilized best by those that are happy to work on their car and continuously fine tune the ride characteristics both on and off the track.

For decades hot rod and muscle car enthusiasts were forced to set up their cars for a specific use, changing disciplines meant ordering parts, and breaking out the socket sets. Today, thanks to QA1’s single and double adjustable shocks, owners are able to completely change the handling characteristics of their Mopar with the turn of a knob. Both QA1’s single and double adjustable shocks allow drivers to make their car handle great on track and be adjusted in pits at your local drag strip and even tackle the slog of freeway traffic on the way home.

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Kyle Cunliffe

Off-Road/Truck Editor Growing up in Southern California many would expect Kyle to spend his days looking for the next gnarly wave to catch. Luckily waves don't have a throttle or steering wheel so his attention was devoted elsewhere. Kyle can nearly always be found looking for a way to go faster, or get over an obstacle just a little bigger than the last. Because he wasn't a trust fund baby he has spend years working on his own vehicles to keep the excitement going.

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