My Li’l Abner Experience: Texas Speedwerks R56 Prototype Springs
Product Review by Michael E. Wright
Photos by the Author and Nathan Freedenberg
So Li’l Abner was a mattress tester and I’m only testing springs; Texas Speedwerks springs for the R56.
I don’t consider myself a car guy, but I’ve always been fascinated by them. There are four characteristics that have determined my car buying choices. First, the car had to be a head turner, and not just a gear-head head turner. Nothing as subtle as, “Look at the Brembos on that Chrysler 300.” Second, it had to be reliable, and third, it had to be easy to maintain. Think Volkswagen Thing, Checker Marathon, or my dream car ’76 Bicentennial Edition Convertible El Dorado. Lastly, it had to be able to carry my bicycle to where the fun begins.
So naturally I drove pickup trucks. I was country when country wasn’t cool. I was still country when SUVs had been cool for two decades. Then my daughter turned 16, a pickup, a Suburban, and a Pacifica wasn’t the right combination for the newly three-driver family. I average 70+ miles a day so with two cars that could carry all five of us I could justify a commuter car for me. I now had a fifth characteristic; excellent gas mileage. I couldn’t find a car that could carry both my mountain bike and road bike and still got the gas mileage I wanted. So I reduced my requirement to one bike. I was making trades between cars that I knew I wouldn’t enjoy driving after the new car smell went away when I saw the billboard “Mini Cooper 40 mpg, 41 with a tailwind.” Head turner for sure, German reliability, and when I checked the price it was right. Reading reviews the only downside was “It’s not a car, it’s a cult.” Big deal, I’m not a follower.
I test drove a JustaCooper (for the uninitiated, that’s a non-S Cooper). I knew better than to test drive an S because horsepower is a one-way door. What a ride! When my mom wanted a sporty four-on-the-floor we got a Pinto. Man did I prove that car was bulletproof. The Mini was all that and much, much more. I didn’t drive any of the other econoboxes that I was considering. On Boxing Day 2007 I became a Mini owner. That’s not right, I became a motorer. Soon I was going to MetroplexMINI.org’s Happy Hour West (NSFW, but you knew that). Next thing I know, I’m signing up for a Driving Event (DE) at Motorsport Ranch in Cresson, TX. Another one way door, I’m hooked.
So I start looking for performance mods. K&N makes a Cold Air Intake for the JustaCooper, and a muffler shop could make it a lot louder, but straight line speed is not my thing. I want better cornering. I know from my mountain bike experience that the more speed you carry into the corner, the faster you’ll be out of the corner. When I switched from hard tail bikes to full suspension things got way faster.
Then I discover that while there’s a lot of stuff available for the previous generation MINIs, there’s next to nothing for the R56. You really have to look hard to tell the difference on the road, but just beneath the skin everything has changed. The bonnet release has changed sides, the exhaust manifold comes out the front instead of the back of the engine and the speedometer is on steroids. There is no ignition key, you just plug the Starship Enterprise into the docking port on the dash.
So I post some rants about the lack of R56 aftermarket options, and get some deserved snide replies. One day I see a post on NAM that indicates TSW (Texas Speedwerks) is getting ready to market their sport spring for the R56. There are other springs out there and even some coilover setups for the R56. However, coilovers are out of my price range and all the other springs have progressive rates as well as more drop than I want. I’m an electrical engineer by training and trade. The equations that determine the performance of electronic systems are the same as those that determine that performance of mechanical systems. Non-linear systems usually have unpredictable performance, so I wanted linear springs. So I messaged Scott at TSW asking when I could get a set for SK8BRD. He replies that they just got their final prototypes and that they are looking for a guinea pig; I supply the car, they supply the springs, and they do the install. If I like them I keep them. We set up to meet at TSW World Headquarters on a Saturday. They’ll need four hours since they need to do some testing and measurements. Prediction is a one inch drop in front, ¾ inch in back, and a higher but linear spring rate.
Saturday comes and I meet the Metroplex MINI cult for breakfast, fill up the car for the 40 mile drive to TSW. I get there and pull into the garage; much cleaner than my garage. The TSW team springs (no pun intended) into action. My car gets its ride height measured, the car goes up on jack stands, and the wheels come off. The new springs look fantastic, some pictures are taken. The front struts come off with only a small difference in procedure from the previous MINI model. The running commentary assures me that these guys know what they are doing. In comparison it looks like the stock spring is at least two inches taller than the TSW spring. I’m a little worried about dropping the car too far, but we press on. Then the rears come off. Again compared to stock, the TSW springs are way shorter; much shorter than I expected given the predicted ¾ inch drop. They get installed and we take some measurements. Ride height is a little lower in back but actually higher in front! Time to go for a test ride and let the springs settle. The roads around TSW World Headquarters are all concrete slab with some significant dips and heaves if you know where to find them. Jeff knows where to find them. First right hand turn and I can already tell that the car is more predictable. The next left was the icing on the cake. Expansion joint slap didn’t happen. The car is soaking up the road. The last turn is a tight left hander across a busy road. I slow down early to let traffic by so that I can take the turn at speed and hit the big bump after the turn hard. More traffic appears. Jeff says “You’re not going to make it.” We made it. One short blip on the front side of the bump, another on the back side and all four wheels are hooked up and ready for action. Back into the garage for more measurements. Things have settled but not very much. I’m tasked to take some more measurements after putting some miles on the car.
On the drive home I suddenly notice that I’m going faster than I intended. What happened to all that road whine? I’m going to have to find some other way to gauge my speed. Close to home I take another hard left that I do every day. Whoops, the car went where I told it to, not where it usually goes. File that away.
So far I’ve gotten way more than I bargained for. I wanted better suspension for the track and I’ve got that. I’ve got a track day scheduled for Eagles Canyon Raceway (ECR) in two weeks and I’ve got comparison data from my GPS the last time I was there. The kicker is that there is less cabin noise, a smoother ride, and better cornering. A plus for me is that the ride height drop is small. I wanted performance not looks. My car looks fine until I park next to a lowered car.
I said earlier I know all the math associated with mechanical systems because they behave like electronic systems. So when I got springs to make my track day experience better, I fully expected to have a harsher riding car. Instead I got the opposite. The car rides smoother and corners better. It’s time to do the math. There’s a good article on Wikipedia about the math behind a shock absorber, springs and the mass they support (see links in sidebar). This kind of system can exhibit three kinds of behavior. Under-damped, Over-damped, and critically damped. Most cars are over-damped for good reason. An under-damped car (one in which the shocks have failed) will bounce and wallow down the road. I’m sure everyone has seen the front of an older car going up and down even on a smooth road. An under-damped car is hard to control so manufacturers avoid this like the plague. They all tend toward over-damped. The car suspension performance won’t be optimal, but it will be predictable until the shocks fail. In reality, a critically damped system cannot be achieved in the real world. Temperature changes affect spring rates and shock rates. There are two ways to get from over-damped to close to critically damped. Get a softer shock, or a stiffer spring. TSW has created the stiffer spring.
Another point I pondered is the lack of road noise with the new springs. I had attributed the highway whine to the runflats. I think I might understand why the highway whine is gone. It’s one of two reasons; may be a little of both. The first is preload. Remember how the TSW springs were way shorter than the stock springs when neither were installed? Stock springs when installed have a lot of preload, the springs must be compressed a lot in order to remove or install them. Again, Wikipedia has a good article on preload (see links in sidebar). Whatever force is applied in preload must be overcome before the shock/springs start to work. So small amplitude, high frequency road noise might not overcome the preload on the system and therefore get transmitted to the cabin.
The second reason is that all systems have a natural frequency. The TSW springs lower the natural frequency of the system and might just absorb that nasty highway whine.
Did I mention that they also test fitted end links, rear lower control arms, and the TSW jack points? They all fit the R56 and the jack points are staying on my car. Lucky me!
On to the motor sports side of things. I’d done one autocross with SK8BRD completely stock, so I go to the second one with high hopes. There is one other JustaCooper in my class; he also ran the last event I entered. Since he is really straight stock, my hope was that with new equipment that I would shellac him the way he did me previously. My car seemed twitchy, but my sixth run was really smooth and I’m ahead by .8 seconds; a seemingly insurmountable lead. Then on his last run my time is bested by .3 seconds. At least I’m in the hunt now.
We’re closing in on track day at Eagles Canyon Raceway. I wear a Garmin Forerunner 305 GPS while driving on the track, and did a track day at ECR in July. That data would serve as a baseline to see what the new springs would do for me. Friday I get an inspection and alignment (standard practice after changing suspension components), and I’m ready to go for the weekend. Saturday morning I’m at the track doing the usual, staking my claim in the paddock, applying sunscreen, checking tire pressures. The atmosphere is positive, however one of the other rituals is to admire other drivers’ equipment and explain why that is something that you would never do to your own car. At the drivers meeting the chief instructor explains that you may need to back off the throttle (on the track this is called lift) because some of the better drivers are in cars that only have 200 horsepower. My car only makes 118 horsepower; I decide that I’m not lifting for anyone.
I’m talking to one of my previous instructors, Mike, when my instructor for the day, also Mike, shows up. We talk a little and go out to the track. One slow lap, and I show him the line that I was taught on my last trip to ECR. We pick up the tempo on the second lap, and things go all weird. Everything I thought I knew about how this car handled is gone. I learn a new level of instruction. When you do things right, your instructor is quiet during the turn and explodes with “YES YES YES” after the turn. When you could do better the instructor says “GAS GAS GAS” during the turn. On the second lap I got a “thank you for not hitting the brakes when the car was going sideways.” A reprimand, obviously I’ve got a lot to learn about the new way the car handles. First session ends and after a long, and greatly positive feedback session. I head back to my paddock spot.
What happened is that the car much more willing to turn than it was the last time I was at ECR. It wasn’t an understeering beast before, but now it really wants to turn. I don’t know if I’m good enough for the car I own. Second session comes around and now it’s a different story. I take a much lighter hand on the wheel, I here a lot less “GAS GAS GAS” and a lot more “YES!” Just before the third session we talk about my goals. Specifically, do I want to solo? I want to get faster, I don’t want to give up the option to have an instructor but I’d like the opportunity to practice on my own. We decide to work on the things that will let me pass the solo check ride. With two sets of eyes in the car safety issues aren’t likely to happen, but to solo the management must be convinced that the student’s situational awareness is high. After the third session, I’m given the opportunity for a check ride during the fourth. Fourth session check ride comes off without a hitch. It’s the end of the day, tomorrow my first session will be solo, second session with an instructor.
“What size ribeye do you want?” Some might consider the menu limited at Sweetie Pie’s Ribeyes, but a large hunk of dead animal is exactly what I needed after a day at the track. I check into the motel, call home, and am dead asleep by nine. And up at three; I’m nervous about being alone on the track. I realize that the instructor has been a crutch and I need to cut the apron strings and leave the nest. Grab the bull by the tail and face the situation. And stop mixing metaphors. I fall back into a restless sleep.
At the students meeting Sunday morning I win a model M3. My blue cammo number 88 Dale Jr. PJ/driving pants get rave reviews. I’m still nervous as I climb into the car. My session starts, and at the first turn the nervousness evaporates. In fact, instead of trying to please the instructor I find myself concentrating on the line and keeping the car calm. The next session with Mike back in the car with me goes well; we talk about the things I need to work on. I’ll be on my own again for both afternoon sessions.
So how did the car do? With less than half the horsepower of most of the other cars on the track, it’s no surprise that I didn’t pass that many cars. What is surprising is how much speed I could carry through the turns and on to the straights. Even with the long straightaways at ECR, I did have to lift to let all but the dedicated track cars by. My last session an M3 waved me by as soon as we got the green flag, then followed my line the rest of the session. My best lap before TSW springs (and jack points) I averaged 57.6 mph. My hot lap for this weekend average was 60.5 mph. In a world where a tenth of a percent difference will win or lose races, the five percent I got with the springs will put the competition behind the horizon. On top of that, I’m a much better driver because of them.
- Excellent fit and finish
- Improved handling
- Less Noise Vibration and Harshness
- Front end height, this will be fixed in production
Everyone could benefit from putting a set of these on their car, unless you’re determined to slam it to the weeds, or you are enough of a track maniac to use double adjustable coilovers. They definitely exceeded my expectations, so on a scale of 1 to 10, I give them a ten.
About the author
Mike Wright began motoring in December of 2007. He and his wife Karen reside in Bedford, TX, and are kept busy raising three children. Outside of the MINI, Mike enjoys playing guitar, swimming, biking and running. Mike is an Ironman finisher.
Critical damping math
Texas Speedwerks Response
Thank you for taking the time to review our R56 Sport Springs. We would like to take this opportunity to discuss a few technical aspects regarding our final production springs.
It’s a well known industry trait that EU car manufacturers typically rely more on the struts and shocks to provide the ride and handling characteristics they are seeking, just as American manufacturers tend to rely more on spring rates. At TSW, we firmly believe that the best suspension system is one where the spring rate is matched up with the effective rates of the struts and shocks.
On the older MINI platform (R50/R52/R53), MINI chose to use springs with the same effective rates at all four corners (around 165 lb/in) – tuning for the Sport and JCW suspensions was done via changes to the dampening and rebound curves of the struts and shocks via valving changes. We can’t say for sure, but it sure appears that MINI did the same thing on the R56 platform.
TSW settles on a spring rate by taking data from the two major components in the suspension system – the spring rate of the OEM springs, as well as the data from dynoing the OEM struts and shocks. Data gathered while testing the OEM Sport and regular springs showed a dramatic difference versus the older MINI platform – namely, MINI settled on a lighter spring in the front around 160 lb/in, and a higher rate in the rear around 212 lb/in (give or take a few pounds). The corresponding results of the strut and shock dyno showed similar curves to those of the previous generation, but they were slightly different. We noticed that the R56 had less understeer from the factory than the prior generation, which is in line with our findings on the spring rates and dampening.
The spring design process begins by specifying the change in static length we were aiming for in order to get a change in ride height, while also bumping the spring rates to match the OEM valving in the dampers and offset the effect of lowering the car. By bumping the spring rates, the goal is to provide a better ride while also dramatically improving the handling dynamics of the car. On the first set of prototypes, we achieved the goal of improving handling, but failed to achieve the ride height we wanted. This necessitated a change in static length, which also necessitated a change in wire diameter and wind pitch. The second set of prototype springs hit both marks we were aiming to achieve.
Final Rates and Ride Height
The final rates we settled at were 225 lb/in in front and 269 lb/in in the rear, while the final ride height goal of a 1” drop in front and a ¾ -7/8” drop in the rear were achieved. The result is a ride that is markedly better than stock, with handling characteristics that are significantly better as well. Likewise, the final rates are designed to work well with either the OEM struts and shocks or aftermarket units like the Koni Yellows that provide the capacity for some adjustment.
At TSW, we choose only to provide cold wound, linear rate springs. We would bore you with the math, but suffice to say that spring rate is a function of wire diameter, profile and wind pitch on these setups. We choose cold winding as it provides a spring that maintains its rate and ride height much better over time. And, we choose linear rates as it provides much better, more predictable response mid-corner. The combination of cold winding and a linear rate offer up the benefits that a TSW spring set is famous for,
namely excellent and consistent performance for the life of the springs.
Again, thank you for the opportunity to test our R56 Sport Spring set and the chance to respond in regards to how we design and engineer our springs. At TSW, we feel that second to modifying the nut behind the wheel (via autocrossing and HPDEs), suspension should be the first place you look to make your MINI faster.