Strange Engineering Talks Drag Brakes, Shocks, and Suspension Tuning

Stephen Kim Nov 8, 2013 0 Comment(s)
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Whether your rearend has 10 or 12 bolts holding it together, Strange Engineering has piles of axles, gears, and differentials waiting on standby in case something goes kaput. For the heretics among us, it even has premium Dana 60 and 9-inch hardware to lure you to the dark side. Through decades of success in the highest ranks of drag racing, Strange has established itself as one of the premier manufacturers of driveline components in the industry. What sometimes gets lost in that hoopla of driveline success is that the company builds some serious drag brakes and shock packages as well. In fact, Strange was one of the first companies to offer carbon brakes in Funny Car and Top Fuel, and countless Pro Stock teams rely on Strange shocks every weekend. Naturally, this technology trickles down into the company's street/strip product line, which means that the big winner is your average weekend warrior. To get an inside scoop on all of Strange's state-of-the-art brake and shock technology, we had an eye-opening chat with Jeff Stange. We even bugged him for some helpful suspension tuning tips.

Drag Brakes
The needs of a commuter car that endures the grind of stop-and-go driving are far different from a drag car that decelerates only in short bursts. Since the brakes in a drag car require far less heat capacity than in a commuter car, it's possible to greatly increase braking performance while also reducing weight. For example, the front rotors and calipers on an LS1-powered fourth-gen Camaro weigh about 70 pounds, while Strange Pro steel drag brakes weigh just 37 pounds. "To reduce weight, our Pro steel brakes have an optimized thin rotor web with lightening windows, heat distribution slots in the rotors, and aluminum calipers and caliper brackets. We even fully machine the billet aluminum hubcap to save weight," Jeff says. "For maximum stopping power, Strange Pro steel brakes feature 11.25-inch rotors and large four-piston calipers. Our calipers have a unique directional design where both 1.750- and 1.625-inch bore pistons are used. The directional design allows for more even pad loading, wear, and heat distribution. The result is maximum braking force, consistent pad wear, and outstanding pedal feel."

Strange Engineering Carbon Brake 3 2/11

Weight of a Different Kind
Everyone knows that drag brakes reduce static weight, but they also reduce unsprung weight and rotating weight. "Reducing unsprung weight should always be the first priority in weight reduction, as it will provide the most bang for the buck. Reduction of unsprung mass allows for better tire contact over rough surfaces because as the wheel has to accelerate up and down, there is less inertia or momentum that must change directions," Jeff explains. "Reducing rotating mass has a similar effect, but this time we are talking about rotational acceleration and deceleration. The response time is improved in both cases, and when properly tuned, it allows for improved tire contact over rough surfaces, and less energy consumed in the acceleration and deceleration of the wheel and tire. Depending on the class, most people try to get a car as far below the legal weight as possible. This allows the driver and crew to strategically place the weight where it might be more beneficial for performance and vice versa."

One- vs. Two-piece rotors
Strange utilizes both one- and two-piece rotors in its brake kits, and Jeff says that there are definite pros and cons of each design. "One-piece rotors usually run truer than two-piece rotors that bolt together at the hub. There is no hardware that can come loose or fail with a one-piece design, and it eliminates the potential of the hub cracking due to the difference in growth rates between a steel rotor and an aluminum hub," he explains. Furthermore, Strange one-piece rotors incorporate a slotted design, which weakens the rotors radially to create a path for heat distortion. When a rotor heats up and distorts, the gaps in the slots close up, helping a rotor maintain its flatness. On the other hand, two-piece rotors also have their advantages, which is why they are used in Strange's Pro Series 2 brake kits. Since these rotors use aluminum hats, they are 0.7-pound lighter per rotor than their steel counterparts. "The floating rotor construction of a two-piece design allows the rotor to expand with temperature without being rigidly connected to the hat," Jeff says. "This results in increased heat capacity, significantly reducing the chance of the rotor warping. Also, using a flat disc allows us to process and manufacture two-piece rotors differently than a one-piece rotor. Our choice of materials and our manufacturing process results in a rotor that is far less prone to deformation over long-term usage."

Carbon Brakes
Carbon brakes have been popular in Pro Stock, Funny Car, F1, and exotic supercars for quite some time, and now Strange offers them for drag cars as well. According to Strange, the main advantage of carbon brakes is that they do not fade with increased temperature like cast-iron or steel brakes. Instead, carbon's coefficient of friction increases as rotor temperature increases. In other words, the hotter the brakes get, the harder they bite. Likewise, carbon is far more stable when subjected to multiple heat cycles. "In drag racing, brakes go from cold to extremely hot very quickly. The majority of OEM brakes use cast-iron rotors, but in drag racing applications cast iron is extremely prone to thermal shock, which can lead to a complete failure where the rotors can actually explode," Jeff explains. "Steel rotors are far more durable than cast iron in this regard, but after a lot of heat cycles, steel can begin to warp. However, none of this is an issue with carbon brakes. Strange introduced carbon to Top Fuel cars in the late 1980s, primarily for safety. Teams soon recognized that carbon brakes are significantly lighter than steel brakes as well. A complete Strange carbon brake kit weighs just 8.5 pounds."

Strange Engineering Carbon Brake 2 6/11

Carbon Caveats
Despite the advantages in stopping power, durability, and weight of carbon brakes, steel brakes still have their benefits. "There are certain applications where carbon is not as effective. For instance, most Super Comp racers like brakes that bite immediately before the finish line, and steel rotors are a better fit for this application," Jeff says. Likewise, carbon brakes require more maintenance as well. "Carbon brakes will become less effective over time if they are contaminated with oil or brake cleaner, which is why nothing should ever be used to clean carbon rotors. Once a rotor gets contaminated, the offending contaminants must be baked out of the rotor to restore it to nearly new condition. Strange currently offers carbon brakes for Top Fuel, Funny Car, Pro Mod, and Pro Stock applications."

Shock Line
With a rich history in the highest ranks of NHRA drag racing, it's only natural for Strange to apply its track-proven shock technology to street applications as well. The company offers a variety of different models of shocks for both high-end tube chassis drag cars as well as bolt-in shocks for stock chassis applications. At the entry-level end of the spectrum are Strange's single-adjustable steel body shocks and struts valved for street/strip driving. The next step up is Strange's double-adjustable steel body shocks for late-model Camaros that are valved for drag setups. The company offers a multitude of aluminum-body shocks as well. "We have both single- and double-adjustable bolt-in shocks for most American muscle cars. They are offered as direct replacements and as coilovers," Jeff says. Likewise, these shocks can be mounted with either polyurethane bushings or Heim bearings. "For all-out racing applications, like Pro Stock, Pro Mod, and Super Gas, Strange has single- and double-adjustable struts with integrated spindles and optional lower control arms. These strut packages include the strut body, spindle, springs, aluminum steering arm, tie rods, bearings, and seals."

Strange Engineering Shocks 7/11

Single or Double Adjustable?
When shopping for a shock, one of the first choices that must be made is whether to go with single- or double-adjustable shocks. While single-adjustable shocks definitely have their limitations, novices can easily get in over their heads with a double-adjustable shock. "Strange's single-adjustable shocks adjust both the compression and rebound at the same time in a predetermined ratio of compression to rebound. These settings have been refined over the years to our customer's needs," Jeff says. "Our double-adjustable shocks allow independent tuning of the compression and rebound force curves. This allows tuning for a wider variety of conditions. Low-grip surfaces due to temperature, or an early season green track, require as much suspension tuning flexibility as possible. With both types of shocks, you are trying to minimize the extra motions of suspension oscillations. In low grip conditions, less rebound and more compression can produce better grip and still minimize oscillations. In general terms, the least amount of damping will produce the best grip, but the trade-off is vehicle stability. Double-adjustable shocks allow a finer line to be drawn."

Strange Engineering Shocks 2 8/11

Clickety Click
All clicks are not created equal. Jeff says turning the adjustment knob one click on one brand of shocks is very different than turning the knob one click on a different brand of shocks. "With high-end shocks, you're looking for a wide adjustability range in addition to durability and nice fit and finish. A lot of companies market the number of adjustment clicks that their shocks offer, but after conducting extensive dyno testing we have found that having a lot of clicks doesn't always mean that a shock offers a wide range of adjustments," Jeff explains. "At Strange, we focus on the change in valving that results from each click. We still have 10 external clicks on our shocks for rebound, which is much less than many competitor's shocks. However, there is a very noticeable difference in valving between completely soft and completely stiff. This maximizes the range and the effectiveness of the shock as a chassis tuning component."

Coilovers
Due to the compact size and ease of ride height adjustability, coilovers have become very popular in street/strip applications. For those on a tight budget, Jeff says that a non-coilover suspension can still perform extremely well. Even so, coilovers offer several important advantages. "A coilover system allows you to adjust the corner weights. There are a variety of spring rates and load heights available with a coilover arrangement, and the height adjustment allows fine-tuning for the correct corner weights," he explains. "Likewise, coilover systems are easy to adjust and compact by design. On the flip side, the disadvantage of a coilover is that if the spring ends are not parallel, the spring can start rubbing against the shock body. This changes the spring rate and damages the shock. That's why we exclusively use Hyperco springs. A lot of people think that springs are just springs, but they are a very important part of the suspension. Ruining an expensive set of shocks with some cheap springs is never a good idea."

Strange Engineering Coilovers 9/11

Reality Check
As one of the easiest sets of components to access and adjust, it's not surprising that the shocks are one of the first places racers turn their attention to when dialing in their cars at the track. Granted that shock adjustment can be an extremely effective suspension tuning tool, it can't cure an inherently flawed suspension setup. "Remember that the suspension system needs to be tuned as a whole, and shocks are just one part of the total system," Jeff explains. "Spring rates, instant centers, weight bias, suspension friction, and tire pressure are all part of the system. Sometimes a better solution to a specific traction problem might arise from adjusting other parts of the suspension system. If you really need to adjust the instant center, but you're changing the shock valving instead, the results will be less than ideal."

Tuning Tips
Racers often get overwhelmed when trying to figure out how to adjust their shocks based on how their car is driving. Some suspension maladies are so common that experts like Jeff have entire notebooks filled with tips on how fix them. Perhaps the most universal of problems is a car that blows off the tires coming out of the hole. "Softer front shock rebound will provide quicker weight transfer, and in the rear shocks, less rebound and more compression will help. That said, the ideal approach would be changing the spring rates and adjusting the instant centers," Jeff advises. "It is all about making the tire produce grip, and if you load it too fast it will bounce and unload the suspension. If you load a tire too slow it will not achieve maximum grip. Every tire likes to be loaded at a specific rate, and 1 pound of air pressure can have a greater effect than one click of the shock."

Strange Engineering Shocks 3 10/11

Tire shake is another common issue, and one that's much easier to address. "What's happening during tire shake is that the tire is running over itself," Jeff says. "The car is planting so hard that it stretches the tire too far, and the rotating tire then tries to plant on the stretched section of tire. To correct this condition, you have to slow down how quickly the chassis reacts to power input to get the car up on the tire. More damping is the answer, and increasing the compression and rebound valving on the shocks will help."

One of the most frustrating problems a drag racer might experience is a car that consistently pulls to the right or to the left. The first step in diagnosing this problem is checking shock adjustments to confirm that they are adjusted the same from side to side. "If the shocks are adjusted the same, remove the rear shocks from the vehicle, pull the springs off, and hand-stroke each shock to confirm that they compress and release similarly. If not, contact Strange Engineering so we can test and inspect the shocks on the dyno," Jeff advises. "Adjusting the spring height on the shock may be the best solution at the track. Putting more preload on the tire with the least grip will help equalize the tire loads during launch. Check rear suspension alignment to make sure everything is square."

Strange Engineering Coilover 11/11

Sources

Strange Engineering
Morton Grove, IL 60053
847-663-1701
www.strangeengineering.net
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