Twisting Knobs...

The C-E shock must be removed from the car to set the valving. First, hold the shock upright and run it through it's travel ten or twelve times. This purging effectively removes any aeration inside the shock. If you "stroke" the shock upside down or sideways, air is allowed into the shock and you won't get the adjustment right.

Many AVO, Hal Corp and QA1 drag race shocks are similar when it comes to adjustment. The shock absorber doesn't have to be removed for adjustment. Once it's installed in the car, all changes are handled externally by the adjustment knob. After installation, the knob is accessible through the side of the spring (typical front applications).

The shock setting system works like this: Turn the knob counterclockwise. The "end" of the adjustment (where it will not turn and click any further) is the softest setting. By turning the knob clockwise, each click will increase the shock resistance. Typically, these shocks have an adjustment range of 12 clicks (it will go further, but you run out of usable adjustment range). The actual range works like this: six clicks clockwise equals 50/50 valving (approximately). The full stop counterclockwise (front shock baseline) has valving that's similar to a 90/10. As you can see, this offers a very large range of adjustment. Once you go past six clicks clockwise, the adjuster works primarily on extension (rebound). When the shock is past this point, the valving is quite stiff, and probably won't be needed for a drag application.

Fully depress the shock (maintain the upright orientation) and line up the notch on the collar with the setting range on the shock body. With the shock still depressed, rotate the adjustment collar clockwise until a click is heard. This means that the internal adjustment mechanism is now engaged. Rotate the notch on the indicator until it reaches the desired setting ("XF", "F" or "R"). You can now reinstall the shock.

Which End Do You Adjust First?

So, you have the shocks. You know how to adjust them. And you know how to install them on your car. Now what? Although it seems like the right thing to do, the initial setting on your adjustable shock absorbers should not be at the center point of adjustment. The first thing you need to do is to baseline the shock absorbers. In the case of the C-E shocks, set the front shocks on the loosest setting ("R" or 10/90). Likewise, the AVO-Hal Corp-QA1 front shocks should also be set on their lowest value (the knob setting fully against the counter clockwise seat). These "soft" settings allow the front end to lift as quickly as possible, transferring as much weight as possible to the back of the car. Additionally, these settings offer a considerable amount of compression. That means that the nose will settle down slowly.

Next, set the rear shocks for a baseline. In the case of the C-E shocks, set the valving at the 50/50 value (code "R"), which is the softest setting. The AVO-Hal Corp-QA1 shock is slightly different. In the case of an automatic car, turn the adjustment knob three to four clicks clockwise. Stick cars should have slightly more damping -- five to six clicks clockwise should be the baseline. Once the baseline is established, make a short pass (first gear and part way through second gear only) with the car. The following are the steps you should take when tuning the front and rear shock combination:

Step #1: Front or Back? If the car wheel stands excessively or bounces on the gear change (more likely), adjust the front shocks first. If the car rattles the rear tires, wheel hops or has way too much body separation, then adjust the rear shock absorbers first.

Step #2: Front Shock Adjustment: The idea is to get a smooth transition in the front-end movement as the car launches right through the first gear change. Bouncing and jerking motions do not help the launch or the ET for that matter. If the car is violent on the launch and physically jerks the front wheels off the ground, the shock setting is too soft or loose. If the car bounces on the gear change the shock needs to be stiffer. When the car bounces on the gear change, it's coming down on the front suspension travel limiter, then bouncing back up again. Obviously, if the shock is set too tight (stiff), then the front won't move sufficiently to transfer weight. On a similar note, a too-stiff setting on the front shock will bounce the car on the tire after the launch. Don't get this confused with bouncing off the limiter.