Like everyone else we get pretty hung up on looking at horsepower when it comes to drag cars. After all, how can one not be blinded by the light of a twin turbo Proline big block or a massive 900+ ci Pat Musi nitrous bomb? The fact remains that while horsepower is certainly an important ingredient to wining a race, the suspension of the car is the most vital part of the equation to get all of that grunt force trauma hooked to the ground. Because we think that lots of guys out there shopping for drag race suspension parts have some basic questions to be answered, we rang up Eric Saffell at AFCO Racing and quizzed him on the basics of what drag race shocks are doing and how you can best choose the right pieces to help your car perform up to its full potential.

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What’s a drag shock supposed to be doing?

“At base, the shocks in a drag car are controlling how hard the car is “hitting” the tire and how weight transfer is being achieved. Things like the rate of rise (wheelies), down track traction, and sixty foot times are all tied into the performance of the shocks on any drag car,” Saffell told us. Today’s raft of options in adjustable hardware can make for a confusing marketplace for a racer that is trying to discern exactly what setup their combo demands and we’ll get more into that subject a little bit later.

We were interested in learning about the evolution of shock absorber technology as it relates to drag racing’s so-called “small tire classes”. The fact that racers are hooking relatively tiny 275 radials with engines making thousands of horsepower amazes even the most old school racers out there. As Saffell told us, it wasn’t a quick road to figuring out what worked and what didn’t. “Early on as the small tire classes were growing, their level of data acquisition was virtually non-existent, or very limited at best. Obviously, having some data to read and analyze can help us a lot as we look to engineer a better project or tune the shock for a marketplace. Back then, we were lucky to even get a guy with a video camera watching the car. Pro Stock, Comp Eliminator, Pro Mod, and some other classes were using data acquisition at that time but it just had not gotten to the small tire ranks yet and there was very little (as compared to today) that we understood about that style of racing.”

Things progressed though as more racers became savvy enough to include detailed video of their cars leaving the line, they added basic data acquisition hardware and they started to share more of what they were learning with the industry. “We’re at a point now that AFCO has a state of the art electro-magentic shock dyno that we can download data into and see exactly what’s happening with that shock. The racers really need the credit when it comes to how we have gotten where we are. They were the ones that stepped up and made these data gathering devices part of their program and by allowing us to work with their data, our eyes were opened and we were able to improve right along with them.” At the bleeding edge of shock technology, companies like AFCO are  able to take a particular car into their shop for a couple of days and by using the stored data from the racer, the engineers are able to simulate different conditions on the shock dyno and then give the racer and idea of how they should have their shocks dialed in for certain situations. Nothing is foolproof though, Saffell reminded us, “I can’t say that we’re giving the racers an absolute shock tune up for every situation they encounter with our predictive work, but we can at least get them moving in the direction we think that they’ll need to go. Minimizing runs on a 3,000hp engine is paramount for many teams so for us to be able to give them some help and not put any more wear and tear on the car is a very big deal.” Honestly we had never heard of the predictive analysis work being done by AFCO or anyone else and that seems pretty darned trick to us!

According to Saffell, the primary driver of technology and innovation in drag shocks these days are the small tire racers we have been talking about. The “heads-up” world is so dynamic and ever changing with rules and regulations on a seemingly sliding scale that there is always some new wrinkle popping up that needs to be handled. “Our customers that use AFCO shocks in cars like Super Gas or Super Comp are benefiting from the years and years of experience and development work we have done on those combos. We’ve got scads of data on those cars because they’ve been around for so long. This small tire world, especially now with the data being collected by racers, is full of different combos that need different things and we find ourselves spending a lot more one on one time with these racers than we do our others. That’s just the way the scene looks now from our perspective.”

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What differences are there between a drag shock and something that we’d find in a pro touring car?

As far as exterior appearance, there’s not much that would tip you off one way or another. Specifically, if we were talking about a 1980s G-Body that used factory mounting locations a pro touring style shock and a drag shock would look virtually the same. It is what’s happening inside the shock that is actually the difference. “Our line of shocks and components is pretty modular,” Saffell said. “This allows us a very wide array of setups that we can use to fit a customer’s needs. If we’re looking at the difference between a drag racing shock and a shock designed for a car that is supposed to handle very well laterally, the major difference is the dampening curve.”

The dampening curve is the control of the shock’s internal shaft velocity or how quickly and at what rate said shaft moves up and down in the body of the shock. A drag shock is designed with far higher shaft velocities than a pro touring style shock is designed with. “What we’re doing inside the shock is controlling how quickly oil is passing through the valve. We have literally thousands and thousands of potential valving combos that we can build, so tuning is a process that can get very detailed.”

Between tuning different pistons with varying numbers and sizes of ports for the oil to flow through, adding or subtracting the pyramid of washers the numbers get dizzying. “The shock dyno is our most valuable tool for tuning and designing new packages. If we’re managing shaft speeds for a particular application, we can spend as much time as we need on the dyno trying different internal parts to get where we think we’re close and move to the next phase of on-road testing. Like the racers who we work with, we want our street customers to know that they’re getting a tested and proven product out the door.”

The double edge sword of all of this in a drag shock is the fact that it needs a high shaft speed on the starting line to deal with the instant application of force by the driveline and then it needs to settle down and provide the driver with a good feeling of stability and control down track. The true “magic” in the process and why AFCO products are found under so many incredibly fast cars is that they’ve spent years and years, making countless test runs and shock dyno evaluations to come up with ways to achieve this end goal.

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Adjustable, non-adjustable, or double-adjustable?

This is a question lots of racers ask themselves when buying a shock and Saffell had some great advice, “At the end of the day we always ask the customer what their expectations and budget are because for most racers, those are the two mitigating factors in making a decision on what product they need. But, there’s another factor that we need to take into account and because we’re dealing with racers it is doubly important and that’s making sure that the customer is getting a shock that car grow with their program as it changes. We all know that from season to season and race to race changes are being made to make cars quicker and faster. Having a product under the car that can respond to those changes is really important.”

For most of the street and strip cars that call the tech line, Saffell said that their typical recommendation is a single adjustable shock that the user can adjust the extension or rebound on. This is helpful because the driver can have the car set up tighter on the street for cruising and road trips but then get to the strip, loosen the shocks up by simply twisting a knob and have a hard hooking car. The compression valving is preset and non-adjustable from the factory.

For harder core racers a double adjustable shock is really the ticket these day. With the ability to control both of the major functions of the shock, high horsepower cars can be tuned to differing track and starting line conditions easily and precisely. By adjusting both ends of the shock, so to speak, a racer can have the benefit of softening the hit on the tire to get the car off the line and then managing the compression to keep it stuck to the track. For many racers this is an area of trial and error where log books, data acquisition, and experience play a huge role. As each car is really its own animal, there are no truly “universal” shock settings. There are ways to move, but you need to hone your combo in as a specific machine.

“When we take a tech line call we really try to get as much information from the caller about the car as we can to help them go in the right tuning direction,” Saffell said. “When someone calls up and tell us that their car is spinning the tires on the hit of the throttle we need to figure out if they are hitting the tire too hard and causing a bouncing or hook/spin situation or maybe they’re setup too soft and are leaving being “in” the tire instead of having the car “on” the tire and driving out of the starting line without that bouncing or hook/spin situation.” Saffell added, “Every car and every combo is a little different so we take each call as it comes, get as much data as we can, and try to steer the racer in the right direction. If you can provide video or hard data for us to see, it makes our jobs easier and we can typically get some good information to the racer.”

All this being said, the front end of the car has to be working as well. If the front end is full of worn out junk components, the rear shocks are already starting at a disadvantage and no matter how much tuning you may never have the car working properly because the front of the machine is letting you down. It is a system that needs to be working in harmony.

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Care and maintenance

“We all know that the on track miles are not what puts the wear and tear on a shock,” Eric said. “It is all those off track miles with the car on a trailer or driving down the highway that puts those shocks to the test. I normally recommend that people use a 1″ or so hold down strap on top of their other straps to add some load to the rear end of the vehicle when towing. Limiting that movement is critical to extending the life of the shocks.”

Saffell told us that he performed a test where he loaded his personal race car on a trailer and followed it down the road watching it bob up and down. After 20-30 miles he stopped and placed his hand on the shocks only to find them to be nearly too hot to touch. That’s how hard they were working with the car just riding on the trailer.

“We want people to be paying attention to the components by inspecting to make sure that no oil is leaking from them and that there’s no visible trauma to the shock body,” Saffell said. “Customers running Pro Mod, and  other classes that are violent and require the shock to be in a severe duty environment we recommend that they send their shocks in every year for a rebuild and inspection. The typical sportsman racer should see 3-4 seasons out of a set of shocks before they need to come in and get pulled down for a detailed inspection, have new oil added, and get prepared to be reinstalled under the car.”

Like anything else to do with racing, maintenance is important to the success of your operation. Shocks are one of the hardest working parts of any drag or competition car and they often get overlooked because their work is both silent and hidden under the car. We hope this piece has shed some light onto the world of drag shocks for you and maybe answered some questions you had harbored.

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