Power as a margin of safety

We were on our way back home from a win at Lake Superior Performance Rally (LSPR). I had just attended my very first stage rally, and did so as a crew member for my friends. Kevin, the owner and driver of a thoroughly used 80’s FC Mazda RX-7 had just driven to a convincing win in the Regional Open 2WD class, with Jay as his codriver. Most notably, Kevin’s naturally aspirated rotary engined car topped another 80’s FC Mazda RX-7 running in the same class, one that had traded its original rotary for a V8.

Kevin has had his rally car for years. For me, he is inextricably linked to this car; he’s had it as long as I’ve known him. I didn’t realize how many years he’s spent with this car until I was hanging out with his folks at a bar (they had come up from Chicago to spectate the rally) and they reminisced about when Kevin brought the car home for the first time… in high school. Damn, how many people these days can claim that they still own (and regularly drive!) their high school car?

So the idea that Kevin wouldn’t rally this car forever and ever and ever was something I couldn’t fathom.

As Kevin complained during a quiet period in the rally weekend that he wished he had more power, I pointed out that power apparently didn’t help the competing RX-7, which had a V8 under the hood.

Yeah, but having power gives you a larger margin of safety, Jay pointed out.

How so, I asked.

Jay noted that stage rally is all about risk control. The most important aspect of stage rallying is simply finishing the rally (as the dozens of cars DNF’ing could attest to). Going flat out on a straight bit of road or taking a corner very aggressively all have their inherent risks; a good driver will know when it’s worth the risk to push for more speed, or when to back off in order to save the car — or save themselves from a driver error.

It is much less risky to go really fast on a long straight than it is to go really fast through a corner. However, if you’re in a low horsepower car, you can’t go that fast on long straights. Therefore, in order to make time, you necessarily have to push hard in the corners, and that’s unfortunately where the riskiest elements of stage rally lie. Thus, power as a margin of safety: it afforded you the option of taking less risk — you didn’t necessarily have to push as hard in corners because you had the less risky option of making up time on straights.

I suppose Jay would know. He and his father have an early 80’s Toyota Celica prepped for stage rally, and just like Kevin’s car, it’s very much on the low horsepower side of the spectrum.

This stage rally was last month, and I’m still stewing on this concept. It sounds obvious in hindsight, but I had never thought of looking at power in this way. Maybe that’s because I come primarily from an autocross background, where power is important but no so important that other factors (e.g. weight, handling, tire grip) played perhaps outsized roles in the success of a competition car.

After all, I ran an NC Miata for the longest time against Honda S2000s in the same autocross class: STR. Sure, the Hondas had 60 more horsepower than I did, but I could keep up, thanks to the fact that we were on the same tires but I was driving a physically smaller and lighter car.

But autocross doesn’t have straights. (Sure, autocrossers will bitch about some courses being “Corvette courses” when they see a straight that is 60 yards long, but that doesn’t come close to what you’d find on any surface street or race track!) No (real) straights means that the advantage of power is greatly diminished. Hell, I’d argue that in an autocross context, power takes a back seat to torque.

Now that I’m running my Miata at race tracks, and attempting to run competitive events (and not just track days or HPDEs), it plain as day that power matters a lot. The S2000 that I could keep up with in autocross now leaves me in the dust on the race track. Unfortunately, I’m classed to compete against similarly modified Honda S2000s and Mazda RX8s, all cars that despite their larger size and weight are more than capable of making up for that deficit with more power than my little NC Miata could ever hope to make.

This was brought to sharp focus at this year’s SCCA Time Trials Nationals. I didn’t bring my Miata as it was stuck at home with an unknown transmission issue, so I brought along my Fiesta ST instead, but I still kept tabs on what was going on in Tuner 4, the Time Trials class I would have been competing in with the Miata.

Tony set a new class record for Tuner 4 in his Honda S2000. If I had been running my Miata this year, he would have been my competition. He set a brand new class record, running a 2:19.649. Here’s a video of his lap:

Holy shit. Holy shit.

Suppose that I was driving my Miata this year and wanted to beat Tony for the top spot on the podium. My Miata simply doesn’t have the acceleration that Tony’s Honda S2000 has, so it logically follows that for me to beat him, I’d have to take corners faster than he does. Then I watch that video, and he’s in 5th gear going into Corner 5, the same corner where I nearly hit the wall when I lost ABS last year, and think to myself, there’s no way in hell that I could drive faster than he is driving in those corners. Maybe someone with a lot more skill and bravery than I could do it, and perhaps with a truck and trailer and didn’t need to drive his or her competition car back home. (Then again, Tony’s car was in fact driven to and from California, so that perhaps throws the self-preservation excuse right out the window!)

During the PittRace Time Trials this year, I was locked in a battle with a Volkswagen GTI for the top spot in Tuner 4. Fortunately for me, the driver of that GTI had driven PittRace plenty of times before, and we were in the same run group, so I could follow his bumper and use him to learn the track, as it was my first time ever at PittRace. I had just a minor advantage over the GTI in the corners, but the GTI would put about three car lengths on me on the back straight.

The GTI ultimately had to retire due to transmission woes, leaving me with my only first place finish at a Time Trials National event, but it was my firsthand experience with what the luxury of having power can do for you. I had to work my tush in the corners to keep up, and in hindsight, had that GTI not DNF’d, the only way to beat him was to be even braver than I (thought I) already was in the corners.

The Miata, which I never really had any complaints about power back during its autocross days, now has a power deficit that is so immensely obvious on track that I now catch myself thinking of ways to add power. Perhaps I could throw a Rotrex supercharger on the motor? Maybe swap a 2.5L into the engine bay? Maybe do both?

And so my respect for the folks who can go really fast in underpowered cars grows. Driving an underpowered car successfully against higher powered cars really is Expert Video Game Difficulty Level driving.