Spec E30 Adopts a New Ground Control Spring Package

My first exposure to Spec E30 came in 2007 when I was asked to be race director at the Championships event in Mid-Ohio. There were other cars classed in my race group, but I felt it was my duty to read and learn the rules as best I could before I could be an effective race director. Keep in mind that the race director also was the class compliance director at that time in NASA Championships history. The Spec E30 National Director was Carter Hunt, the man who co-founded the series a few years prior, who I worked with closely at that event.

My first impression of the class was that I liked the rules because they were simple compared with other classes I was involved with at the time. There is something to be said for simplistic rules within a racing series, and I know this appeals to many people. Having a cool, iconic car of the 80s doesn’t hurt, either!

After I drove a Spec E30, I noticed one thing in particular that I didn’t like about the car, and it was that the springs were too soft for the weight of the car. Keep in mind, that my personal car at the time weighed 2,200 pounds and had 800-pound front, and 600-pound rear springs on coilovers, so I was used to driving a well-sorted car, in terms of suspension. I quickly realized that the E30s didn’t turn very well and that you had to be patient with your steering inputs while the soft springs allowed the car to roll over until the bump stops were engaged, then the car would actually steer, somewhat, on the Toyo R888 that was the spec tire of the day.

My early impressions were that they were fun cars to drive, but they didn’t handle as precisely as I was used to, and it was a true challenge to be able to drive the car fast.  It had adequate braking, but you didn’t want to use the ABS. The best part was that everyone had the same issues with the car, which made this a true driver’s series. The rules were strictly limited on what you could do to the car, which wasn’t much. This made it an affordable series, right out of the box, which was what Carter Hunt intended: an affordable, fun racing series.

Tire temperatures, pressures and track temps combined with onboard TraqMate data helped testers better understand old and new Spec E30 suspension setups.

The Spec E30 springs have always been the H&R race spring. I’ve used H&R springs for a long time on my cars, and I know they’re a quality piece, and when paired with Bilstein Sport shocks, it’s also an affordable suspension package, but let’s talk about spring rates.

We will use the BMW 325is springs for comparison because they are actually slightly stiffer than the 325i suspension. The stock front 325is springs are 118 pounds and rears are 265 pounds. A nice comfortable spring for driving to work every day, but not so good for the rigors of racing. The spec spring of the H&R Race spring has a much higher spring rate than the stock springs. They are in fact, stiffer and are the same diameter as the stock springs so that the installation is straightforward. They are simply a replacement spring, just stiffer.  The front springs are 315 pounds and the rear is 570 pounds — more than twice as stiff as stock, and they lower the car’s ride height about an inch and a half, effectively lowering the center of gravity, which improves the handling of the car. This combination has worked well for a spec series, but the issues I noticed also have been brought up by many of the drivers in the series. Some conducted their own research and come up with a possible affordable solution, and it’s one I’m already familiar with.

The car I raced back then that had the 800-pound springs on it also had a Ground Control coilover kit I installed. It was the cheapest way for me to have coilovers without the huge cost of a manufactured coilover. It allowed me to remove the lower spring perch on the front struts and weld on a collar. Then a threaded sleeve would slip right over the shock or strut tube and sit on the collar. Then I could use a smaller diameter spring instead of the stock springs that take up the space I would rather use for more negative camber adjustments. Just like that, it’s a coilover!

This shows the difference between old and new front springs. The new front spring rate is 535 pounds and the rear spring is 700 pounds.

It also allowed me to use any shock I wanted at the time and afforded me the ability to improve my car’s handling without the expense of a true coilover. I’ve always viewed this option as one available for the series, however the costs associated with it were always higher than what I would deem affordable. That was until recently. With the cooperation of a few shop owners and drivers working with Ground Control, they were able to come up with a package that would work with the current shock package and be affordable. I tend to be cynical, so we would need to do ample testing to see what the springs actually would do, good or bad. Without testing, there is no way to know if this package will work. I required a test day at a high-speed track and a slower-speed track to collect data on the current spring package and the proposed new spring package.

Three-time Spec E30 Champion Sandro Espinosa mounts a new set of tires before testing the Ground Control spring kit at Carolina Motorsports Park.

The Ground Control kit comes complete. It has all the parts you will need, whether you have the Ground Control camber plates or another manufacturer’s camber plates. The front spring rate is 535 pounds and the rear spring is 700 pounds. Also in the kit are the sleeves, adjusting nuts and a rear bump stop to keep the rear spring in place when the suspension gets fully unloaded. As I will show in future article, the kit is easy to install.

The first track we used for testing was Carolina Motorsports Park in Kershaw, South Carolina. It’s a tight little track with technical, connected corners and a tricky flat-out, high-speed kink. I did not do the driving for the test days. Instead, I wanted expert drivers who were familiar with the tracks we were using. For this test, we used a three-time Spec E30 Champion driver Sandro Espinosa. We drove laps with the H&R springs and then with the Ground Control kit, and here is what the data showed: Maximum cornering load numbers were the same, because the limiting factor is the tire. With the stiffer suspension, the cornering g loads peaked sooner and maintained the g-load peak longer. Lap times with the stiffer springs improved by a few tenths, nothing crazy, but the goal was not to make the cars faster, just better to drive. Feedback from the driver was that the steering inputs net an instant response, meaning the car is easier to drive. After the day of testing and collecting data points in many areas, it was my turn to drive the car.

I didn’t know what to expect. Given what I had been told, combined with my previous experiences, I wasn’t expecting a dramatic change in the car. My mindset when I climbed into the car was that the change would be minor. It was a cold fall morning and getting the tires up to temperature was my first hurdle. Even before they began to work as they should, I could feel the car was easier to drive. Steering inputs delivered an instant response and reaction. Instead of begging the car to turn, it just turned! Additionally, I was able to feed in power for corner exits, and if I over-slowed a corner entry, I could somewhat recover from mistakes without terribly upsetting the chassis and removing what grip I had. I was not as fast as the hot shoe driver in the car, and still 3 seconds slower on my best lap as I continued to learn the track. This is not a track you master in one weekend. As I got out of the car for the weekend, I was impressed and excited for the potential this simple kit had for the class.

The previous springs for Spec E30 were soft for the weight of the car, so drivers had to be patient with steering inputs. The soft springs allowed the car to roll over until the bump stops engaged, then the car would actually take a set and steer.
The new kit sells for $489. Testing showed lap times a few tenths quicker, but the new spring package was adopted not to make the cars faster, but easier to drive.

The next track we visited was Road Atlanta. For this test, we were able to secure Continental Tire Sports Car Challenge driver, Seth Thomas, who races for Bimmerworld, and is knowledgeable on BMWs. We found similar results with the Ground Control kit when compared with the H&R’s. With the higher-speed turns, the corner g loads would peak quicker and sustain longer by comparison. His reaction to the car after the spec springs were installed was to put the other springs back on! In terms of speed, the lap time difference was only a few tenths faster than the current spec springs. Not a huge gain, but again, the goal was to never make the cars faster.

The new spring package also was tested at Road Atlanta, with pro driver Seth Thomas driving.

Then I got to drive the car. Road Atlanta is not an easy track to learn. It presents a lot of challenges and there are so many tricks to the track that it’s difficult to cram all that data in your head to put down a fast lap. I was still well off the pace of the front group.

Road Atlanta is an amazing track, and Turn 1 is scary in a Spec E30! You never know if the car will stick or not. With the Ground Control kit on the car, the Turn 1 experience was much more confidence-inspiring, as were other fast turns where a minor mistake can end badly. Confidence in any car, is key to being able to go fast. This kit definitely will help the mid- to back-of-the-pack drivers have more confidence in the car, to push harder.

As cynical and resistant as I was to this change, driving the car and seeing first hand how easy it is to install on the car, combined with Ground Control willing to work with us on keeping costs as low as possible, made it easier for me to agree with and fully support making this change.

Knowing the Championships at COTA will be a huge event this year, it makes sense for everyone to get this kit as soon as possible to sort through the new setup faster so that the huge field of Spec E30s at COTA will be a nice, tight race!

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Images courtesy of Shawn Meze and Brett Becker