Dirt Modifieds

SHOCK DYNO TESTING SERVICE

Now that the racing season is over, this is the ideal time to start preparing for next season. Many of our customers send all their shocks in to be dynoed at this time of the year, so that they can be checked after a long season of racing.  To encourage all our customers to assess their shocks’ condition before the next season, we’re offering a reduced cost for shock dyno services on any A.R.S. shock—only $10 per shock until January 31, 2024. This reduced shock dyno offer will give you a chance to evaluate the condition of your shocks after a season of racing and at the same time review any new valving combinations.

When sending your shocks to us for service, please enclose a note with return address, phone number, and a brief description of what you would like done to your shocks. A shock maintenance form is available from our website. After the shocks are dynoed, we can call you with the results and discuss the outcome of your shocks or any new shock combinations. Many customers send all their shocks to us during this special dyno offer, so send your shocks in as early as possible to avoid any delays in preparing for next season.

Valving Updates

Over the last few years, some Modified rules have changed and now allow adjustable shocks. This is a big advantage in tuning as well as performance of the shock. The right rear rebound can be reduced when the track is fast or heavy to help free the chassis up. Then when the track dries out, the rebound can be increased to create more forward bite. The left rear shock is compression adjustable to fine tune how much compression dampening is required. Not enough compression allows the left rear corner to set down and make the chassis tight when rear steer is lost. Too much left rear compression kills forward bite. The front shocks are both built as rebound adjustable shocks. The right front is fine tuned with the rebound to make the front suspension turn. The left front rebound is also adjusted to hold cross weight in the chassis but not pull the tire off the racetrack. Four tires are always better than three tires especially for finishing the turn.

Left Front

There are a couple of things that need to be addressed in the left front shock dampening. The rebound holds cross weight in the chassis, which creates forward bite. Too much rebound pulls the tire off the ground and makes the chassis push mid-corner to exit. The rebound dampening requirements change on a short tight corner track versus a fast sweeping corner track.

The compression on the left front is adjusted for corner entry. If the chassis is tight on corner entry, you need to soften the compression. When the track dries out and your chassis gets free on entry, you stiffen the compression. After we dyno your shock, we will send you dyno sheets showing your complete adjustment range. We will mark your dyno sheets showing you how you need to adjust your shocks to accommodate changing track conditions.

Right Front

The right front is possibly the most important shock on the car. The rebound dampening in this shock controls the chassis attitude throughout the corner. Too much rebound hurts forward bite, and too little rebound unloads this corner creating a push condition. It is important to have enough low speed rebound to hold attitude but not too much high speed that it makes this corner too rigid.

The low speed compression needs to be soft enough to allow the chassis to get down on corner entry and enough high speed to keep the chassis from slamming the bump stop on corner entry. We have built special pistons just for the right front shock to accomplish these requirements.

This corner is very critical on shock and body lengths for different chassis builders. The right front shock body needs to hit the bump stop at the right time and rate.

Right Rear

The right rear shocks have a new valve curve (T/C) that creates more traction than ever before but still creates enough high speed control to run the cushion. This has always been the challenge to provide both of these requirements. The rebound range allows you to soften the rebound enough for heavy track conditions, and then stiffen the rebound for maximum traction. We lock in the compression dampening and adjust the gas pressure for heavy to dry/slick tracks. After we dyno your right rear shock, we will send you dyno sheets showing your complete adjustment range. We adjust this shock more than any shock on the car to accommodate changing track conditions.

We now change the right rear spring load more than ever. The standard is a 200 spring with spring rubbers. Whatever your spring combination is you need to stay on top of your load numbers as track conditions change throughout the night to create the correct balance.

Left Rear

The left rear shock provides enough extended rate to hold the left rear up and make sure the left rear corner does not fall down, and then the chassis loses the rear steer. A fine balance of compression dampening and gas pressure provides this combination. This shock’s main function is to hold the left rear corner up under deceleration or part throttle conditions. It does not provide traction except to keep the left rear bars in the correct angle which creates traction. This shock is very critical in making sure you have the correct combination to develop maximum traction.

Package 1 – $2,400
($2,500 with one C/O Kit)

Fronts & RR – 7200 series Rebound Adjustable shocks

Left Rear – 7200 series Compression Adjustable shock

This shock package contains 3 rebound adjustable shocks (L.F., R.F., & R.R. plus the left rear compression adjustable shock. All shocks are 7200 series base valve design. The shocks can be built with adjustable eyes or non-adjustable eyes that need to be removed for adjusting. Some Modified rules require removing the shock eye to adjust the shock.

Left Front

Left front adjustment allows you to fine tune the rebound to hold cross weight in the chassis which creates forward bite. Too much rebound dampening pulls the tire off the ground and makes the chassis push mid-corner to exit.

Right Front

Right front rebound controls the chassis attitude throughout the corner. Too much rebound hurts forward bite, and too little rebound unloads this corner creating a push condition. It’s important to have enough low speed rebound to hold attitude, but too much high speed rebound makes the chassis too rigid. The special right front piston allows the chassis to get down and turn on corner  entry and still have enough high speed compression to keep the chassis from slamming down.

Left Rear

Left rear shock is compression adjustable to provide enough range to hold the chassis up and make sure the left rear corner does not fall down and lose attitude. Too much compression makes the chassis too rigid which hurts traction. Too little compression will allow the chassis to fall too quick and lose rear steer. The base valve in this shock allows you to reduce the pressure and not make the chassis too rigid.

Right Rear

Right rear shock is rebound adjustable which allows you to soften the rebound enough for heavy track conditions and stiffen the rebound for maximum traction. We lock in the compression dampening and adjust the gas pressure for heavy to dry/slick tracks. We adjust this shock more than any shock on the car to accommodate changing track conditions.

The Schrader valve can be removed and plugged if required by your racing series rules.

Package 2 – $1,650
($1,750 with one C/O Kit)

Fronts & LR – 7200 Series Mono Tube Non-Adjustable Steel Shock

Right Rear – 7200 Series Mono Tube E-Model Adjustable Steel Shock

 Fronts & Left Rear

The 7200 Series shock is a large steel body mono-tube (gas) shock. This shock uses CNC machined aluminum internal parts designed for racing with no aftermarket parts.  This shock is designed for racers that are required to use a steel body.  This shock contains the latest base valve technology to provide low rod pressure which maximizes traction.  The advantage to the low pressure design is for when the racetrack becomes slick and tires lose their grip, the pressure is not increasing.  This provides more consistency from the first lap to the last lap by decreasing spring rate build up in your shock.  This shock comes with a Schrader valve to fine tune the gas pressure.  If your race series will not allow Schrader valves, the shock is available with pressure pre-set and cap in the port hole to make it legal. This is a Non-Adjustable shock. This shock accepts 2 1/2″ & 5″ O.D. Springs and is available in 6″, 7″, 8″ & 9″  shaft lengths.

Right Rear

The 7200 Series shock is a large steel body mono-tube (gas) shock. This shock uses CNC machined aluminum internal parts designed for racing with no aftermarket parts. This shock is designed for racers that are required to use a steel body. This shock contains the latest base valve technology to provide low rod pressure which maximizes traction. The advantage to the low pressure design is for when the racetrack becomes slick and tires lose their grip, the pressure is not increasing. This provides more consistency from the first lap to the last lap by decreasing spring rate build up in your shock. This shock comes with a Schrader valve to fine tune the gas pressure. If your race series will not allow Schrader valves, the shock is available with pressure pre-set and cap in the port hole to make it legal. This is a E-Model Eye Adjustable shock. This shock accepts 2 1/2″ & 5″ O.D. Springs and is available in 6″, 7″, 8″ & 9″ shaft lengths.

Package 3 – $1,400
($1,500 with one C/O Kit)

All Four Corners – 7200 Series Mono Tube Non-Adjustable Steel Shock

All Four Corners

The 7200 Series shock is a large steel body mono-tube (gas) shock.  This shock uses CNC machined aluminum internal parts designed for racing with no aftermarket parts.  This shock is designed for the racers that are required to use a steel body.  This shock contains the latest base valve technology to provide low rod pressure which maximizes traction.  The advantage to the low pressure design is for when the racetrack becomes slick and tires lose their grip, the pressure is not increasing.  This provides more consistency from the first lap to the last lap by decreasing spring rate build up in your shock.  This shock comes with a Schrader valve to fine tune the gas pressure.  If your race series will not allow Schrader valves, the shock is available with pressure pre-set and cap in the port hole to make it legal.  This is a Non-Adjustable shock.  This shock accepts 2 1/2″ & 5″ O.D. Springs and is available in 6″, 7″, 8″ & 9″ shaft lengths.

Package 4 – $1000
($1,100 with one C/O Kit)

All Four Corners – 2200 Series LB Twin Tube Non-Adjustable Steel Shock

All Four Corners

The 2200 Series shock is a large body twin tube steel shock.  This shock uses CNC machined aluminum internal parts designed for racing with no aftermarket parts.  This shock was designed to fir the rule of “Steel Body Shock” that saves the racer money.  This shock in Non-Adjustable.  The smooth body shock will accept a coil-over kit that slides over the body.  The large steel body shock accepts 2 1/2″ & 5″ O.D. Springs and is available in 6″, 7″, 8″ & 9″ shaft lengths.