Monday, March 21, 2011

(134) Why I don't care about numbers

What? This chump doesn't care about numbers? But he drives racing cars! Performance sheets should be his life!

Yes, it's true. I do not give two beans about performance specs, horsepower, skid pad Gs, 0-60 times, or any of that nonsense. I care about lap time and the data from the data acquisition system, but only as a reference. Those are pretty much the only numbers I pay attention to, except when I'm looking at a rulebook.

Why? Well, let me try to answer that. I suppose I should begin with a story.

Recently, Ford released the Mustang Boss 302 edition. It's a very stunning car. It's very performance oriented. It's lighter than the regular GT. It's got bigger tires, more power, brighter paint. It's even got an option to remove the rear seats and fill the space with a strengthening beam.

You can also have a ridiculously large front spoiler fitted.

MotorTrend tested the car at Mazda Raceway Laguna Seca. Everyone wants to know if it's faster than the Shelby GT500.

It's pretty safe to say that it is. By some four seconds. It set a 1:40.2, which is seriously quick. Just how quick? Well, let me put up some performance stats and you can see if you can guess which cars it beat and which it didn't.

First, the Boss 302.

Ford Mustang Boss 302

Horsepower: 444
Displacement: 5.0 liter V8 naturally aspirated
Torque: 381 lb/f
Drive Type: rear-wheel drive
Curb Weight: 3630 lbs
Weight Distribution (front/back): 55/45
Gearbox: 6-speed H pattern manual
0-60 MPH: 4.0 seconds
Top Speed: 155 MPH
Power/Weight ratio: 269 hp/tonne

Nissan GTR (R35)

Horsepower: 472
Displacement: 3.8 liter V6 twin turbo
Torque: 434 lb/ft
Drive Type: all-wheel drive
Curb Weight: 3828 lbs
Weight Distribution (front/back): 54.8/45.2
Gearbox: 6-speed double clutch
0-60 MPH: 3.3 seconds
Top Speed: 192 MPH
Power/Weight ratio: 271 hp/tonne

Audi R8 4.2 FSI quattro

Horsepower: 414
Displacement: 4.2 V8 naturally aspirated
Torque:318 lb/ft
Drive Type: all-wheel drive
Curb Weight: 3432 lbs
Weight Distribution (front/back): 44/56
Gearbox: 6-speed H pattern manual
0-60 MPH: 4.3 seconds
Top Speed: 186 MPH
Power/Weight ratio: 266 hp/tonne

Chevrolet Corvette Z06

Horsepower: 506
Displacement: 7.0 liter V8 naturally aspirated
Torque: 471 lb/ft
Drive Type: rear-wheel drive
Curb Weight: 3161 lbs
Weight Distribution (front/back): 50.7/49.3
Gearbox: 6-speed H pattern manual
0-60 MPH: 3.6 seconds
Top Speed:198 MPH
Power/Weight ratio: 352 hp/tonne

BMW M3 (E92)

Horsepower: 414
Displacement: 4.0 liter V8 naturally aspirated
Torque: 296 lb/ft
Drive Type: rear-wheel drive
Curb Weight: 3562 lbs
Weight Distribution (front/back): 51.9/48.1
Gearbox: 7-speed dual clutch
0-60 MPH: 3.9 seconds
Top Speed: 173 MPH
Power/Weight ratio: 256 hp/tonne

So, give these cars a mull over. Which do you think is the fastest?

If I had to pick a winner, on paper, it would be the Z06. It's got the most power. It's the lightest. It has really good weight distribution. It's not as fast to 60 MPH as the GTR but it's pretty quick. The top speed is also the highest. But who cares what I think, lets get to the times.

These times are according to MotorTrend.

BMW M3 (E92): 1:42.96
Chevrolet Corvette Z06: 1:40.90
Audi R8 4.2 FSI quattro: 1:40.75
Nissan GTR (R35): 1:40.45
Ford Mustang Boss 302: 1:40.21

And there you have it. One of the weakest-looking cars on the spec sheet is the fastest.

Now, I admit, these times are all very close (except the M3, it got annihilated). You take 2 different drivers and have them drive all these cars and you'd probably get two totally different orders. Ambient temperature or weather may have a part to play, but I really have no idea about that. For the moment I'm assuming these times are fair.

Reading a spec sheet to ascertain how fast a car is has fatal flaws. Humans are terrible calculators. Humans tend to see large/good numbers and it will adversely effect the calculation in an emotional way. I love big engines, so I saw 7 liters on that Corvette, immediately assumed the engine had what we call "usable power" (power down low as well as up high in the RPM band), which, in reality, it may, or it may not. On top of that the rest of the numbers looked swell. The big parts that were not shown were tire sizes (you need big, grippy tires to put that power down, especially in a lighter car) and gearing (if you have really tall gears, such as in the case of fuel economy, it saps some of that acceleration)

That's why it's really, really important to drive a car to figure out how fast or good it is. Case in point, the new Mustang V6 versus the Nissan 370z. I've test driven both. The Nissan has 30 more horsepower than the Mustang, but the Mustang feels faster when you put your foot down despite being heavier. This is because, I think, the 370z has slightly taller gearing. Both cars have more or less the same 0-60 time (5.1 seconds) according to the journalists I've read. Incidentally, I do like the Z more than the 'Stang overall, but that's just me. I actually don't know which would be faster on a track. They might be fairly close, but they might not.

There is more to it than just gearing, though. Engine map and torque curves have huge roles to play in acceleration, especially from low RPM. It's really hard to quantify those effects on the speed of the car on a track. Maybe an engineer could, but you or I? Nah.

Even harder to quantify is car setup. Put simply, how does it handle? The car could be set up to generate skid pad numbers but if you try and take a proper corner with trail braking and throttle application, what happens then? It could be a complete dog. What about bumps? Off camber, or banked corners? How's the aerodynamic balance, does that little wing that pops up at 70 MPH do anything or just make more drag? Can the brakes go for more than two laps without getting cooked? And tires, oh my lord don't forget about tires. Compound, size, construction... a car can gain or lose 5, 10, 15 seconds per lap with tires, depending how long the course is. Really awesome tires might not even raise the skid pad numbers that much.

In the end, my ultimate point is that performance numbers tell you almost nothing about the car. Paper and asphalt are completely different surfaces.

Thursday, March 17, 2011

(133) What came first, the license or the school?

SCCA driver school was a scream!

We arrived at the track on Thursday afternoon to unload the car. Thunderhill Park is in some absolutely gorgeous country, with big sky dominated by dramatic clouds and sun, set amidst rolling green hills dotted with cows and set with a backdrop of snow covered peaks to the west. The weather report indicated the possibility of rain, but only towards the end of the weekend. For the first couple of days, at least, we were fairly safe from falling sky.

 Loaded up, let's roll!

We got up bright and early to get to the track, get registered and get my gear and car teched. Technical inspection is a big part of the SCCA. With so many people bringing such a vast variety of cars to a race, you need a good system in place to make sure those vehicles and the various pieces of gear are safe and legal per the racing regulations.

Tech went more or less smoothly, except for one hiccup - we didn't have the car's log book, which needs to be filled out for every event the car attends. We eventually managed to get a temporary log book until we could get the permanent book updated. Crisis averted.

Next up was a good old fashioned driver's meeting. David Arken would be supervising Group 2, my group. Juan Pineda would be my instructor. Group 2 was composed of mostly more experienced drivers, and some faster cars - there were a couple Mustangs, two big Porsches and an oddity called a Qvale Mangusta. The rest were all Miatas. During the meeting, David encouraged us to make a list of areas we wanted to develop over the weekend. These were mine.

Day 1: learn the line and the gearing, learn the car's basic handling traits on street summer tires, work on getting a feel for the apex speeds of each corner, learn the passing zones on the track.
Day 2: mount and adapt to the shaved-slick Toyo RA-1 tires, pick up the apex speeds considerably and really work the tires, work on shortening braking zones at the end of the day.
Day 3: dial in the final braking distances for each corner, push the trail braking going into the corners, work the passing zones and become fluent in their use.

Can you tell I've done this before? Basically, my overall goals for the school were to learn a new car and a new track. I got much more out of it than that.

The first activity after the meeting and introductions was to conduct drive-arounds in street cars at slow speed to familiarize ourselves with the track. None of us had actual cars with enough seats, so we used Juan's V10 dually truck. This offered a unique view of the track, as you can imagine. It was very informative and I got my first taste of V10 power at the wheel.

The configuration we would be using was the original short course of Thunderhill. It essentially splits the track at the halfway point and cuts back onto the front straight in turn 8.

I decided to start by driving the car on a set of treaded tires Ed gave me in case it rained. These were not full on rain racing tires, rather summer tires designed for street use, so they wouldn't get completely wrecked by high heat in dry conditions.

 Suited up, strapped in, let's race!

This turned out to be a good choice because they provided a lot of feedback. And when I say a lot of feedback, I mean the tires were screaming louder than the engine. Many of the corners at Thunderhill are pretty high load - turn 4 and turn 5a both torture the tires pretty good.

The first session was nice and slow, and I followed Juan to learn the line inside the car. The car was fairly loose on these tires with less grip. I ended up using those the whole first day. The only real problem with the car surfaced as I pulled out of pit lane and made my first hard shift into 3rd - crunch! A used up synchro gear in 3rd. The synchro is the device that ensures the teeth of the gears mesh perfectly. Without it, you really have to move your hand slowly if you want to avoid crunching things. That's hard to do when you're racing.

I talked to Ed about it, and he said I should just "use it up" and he'd drop a whole new transmission in when we got back. So I tried to baby it as much as possible. It got steadily worse as the weekend progressed, but it held together. Tough car.

 Racin' hard with Juan.

Thunderhill itself was proving very fun. The track produces some really good racing, even if it's not quite as interesting to me to drive as Mazda Raceway Laguna Seca or Infineon Raceway - lots of long sweepers that are really good for passing and race craft, but you kind of find yourself looking at cloud shapes if you go through them on your own. The passing, though, is mostly unconventional. Passes on the outside of turn 3, an off-camber increasing radius corner, are my favorite.

During the first day I learned that this little Miata is really a great handling race car. It's cooperative under brakes and turns in positively. The road car has a lot of body roll, but the racing spec car doesn't. Lots of camber means lots of grip in high load corners. The interesting dynamic is that with such little power, you need to rethink your lines. I was turning in much too late at first and leaving too much room on the exit of corners for the car to work. The Miata only has 110 horsepower, so with grippy tires, even at full throttle, the car isn't really burning rubber while accelerating. That means you can (and should) turn in much earlier and take a more "geometric" line.

On the second day we put on the shaved RA-1s. These tires had a bunch more grip than the street tires, and less tread squirm. I could no longer break the back end loose with the throttle unless I really hustled the car into a slow speed corner. To my surprise, the shaved-slick tires still gave off plenty of tire noise. They were also much more durable than I expected. I figured they would peak during the first session and then fall off all weekend, but instead they continued to gain grip and never seemed to get baked and fall away. They should last a good long time. We just adjusted the front pressures by 1.5 pounds and the car handled really good.

The SCCA continued to test us through day 2. They covered all kinds of situations on track, including a simulated red flag situation. The instructors were constantly drilling us on flags, especially the yellow, and going over any mistake thoroughly. Juan was pushing me on race craft and we had a couple of pretty cool battles out on track.

 Cookin' going into turn 1 at about 90 MPH. Seen here apexing too late - walk that apex back a few feet and I'm golden.

On day 3 we ran two more practice sessions, and then it was race time. We were to have two races, 20 minutes each. The twist was that the instructors were going to place us on the grid in such a way that we were challenged. They wanted to see us sweat, and how we dealt with it.

The first race was fairly intense. I started about mid-pack, and I followed my row mate, Duane Polsley in his red Miata. He advanced through the field and I followed. The lead Miatas all got by Filip Trojanek in the Mangusta into turn 5 - I just barely squeezed by with them. Filip re-passed me down the main straight, but I got a run on him through turn 2 and re-re-passed him on the outside into 3. The Mangusta had a lot of power, about 3 times as much as my Miata, but the Miata handled about 3 times better. The Mangusta had street suspension, and was rolling over in the corners like a lazy whale. Filip was working really hard to make that thing corner.

Then the chase was on to catch the other Miatas scrapping over the lead. I caught Cameron Rogers in his black Miata, and we proceeded to have a multi-lap chase. I tried him a couple of times on the outside of 3, again, my favorite place. But he wouldn't have it and always got away from me in turn 4. I eventually tried an optimistic pass in turn 8, but he stayed to my outside and took the position back going onto the front straight. The next time, I got a better run and did it again, only this time it stuck.

 Cameron fighting the good fight.

I could see Duane up ahead battling with a big ole black Mustang piloted by Jim Gillespie. They were having quite a fight so I just put my head down and took off after them. I eventually caught them, and I waited for Duane to either pass Jim or to make a mistake.

I followed them for a good number of laps, then we caught lap traffic. I tried to capitalize on it but the timing didn't work out that way. I passed two cars on, you guessed it, the outside of turn 3.

Then came the last lap. I knew my only place to pass Duane was turn 8. I decided to pass there. It wasn't wise. I threw it in, and Duane moved over to protect his line. I didn't expect this, so I jinked sideways. My tires locked briefly (turning the wheel while threshold braking is not good) and I went into the grass on the inside. I was going to shoot across the track, and I was praying Duane saw me and slowed up enough to not peg my passenger door. He was heads up and missed me, but I lost a position to Cameron and finished 3rd of the Miatas. Lesson learned. Don't be greedy.

Rather than typing out the 2nd race, just watch it!

Race 2 footage. Wonderful view. Not.

This is the first time the GoPro has really let me down. It just tried to light up the interior of the car too much, and by doing so really overexposed the view through the windows. You can't really see the track, but you can see the cars that are close to me. I need to find a new way to mount the camera inside the car. I may have to put it on the dash, but I would like to get as much of my wheel and pedal work as possible.

The transmission was getting very bad by this point. Hard shifts were wearing down 3rd gear and it was hard to get the gear to go in at some points.

As the footage ends, a full course yellow comes out. The clouds had been threatening rain all afternoon, and it started to come down. Not hard, but just enough so that as I went through turn 3 at 50 MPH, I could feel the traction loss. I retired to the pits, since I was on slicks, just as the race restarted. Most people followed me in.

All in all, a really good weekend. I survived, the car survived (though the transmission was toast), learned much. I absolutely can't wait for the season to start in April. As Juan wrote in my evaluation booklet, "this is going to be a fun season!"

Saturday, March 5, 2011

(132) Car tailoring

Today I met with Ed to get the Miata fitted to me for the SCCA driver school. Fitting a race car is a precise thing. You need to be positioned to effectively use the controls, to see out the car, to not get tired while driving, and to be situated as low as possible so that the weight balance of the car is affected as little as possible. It's even harder when the seat isn't on rollers and you have fifty bolts to undo to move it. It's all a big compromise.

Needless to say I didn't fit right when I first got in. Ed's going to readjust the seat and we'll try again Wednesday. If it still doesn't fit right and we can't just use pads to correct it, we'll get another chance on Thursday just before we leave for driver school.

The school itself is going to be held over three days at Thunderhill raceway. The school is going to involve all of the normal flag, starting and grid procedures of an SCCA race weekend and we'll be put through our paces to demonstrate that we understand all of them. As a licensed driver, I will have a single instructor assigned to me for one on one coaching all weekend. I should get about six hours of track time, and at the end of the weekend there will be two races.

A big part of SCCA is managing traffic, and that means the groups will have a few wild cards in them. My group is mostly Miatas (like I've mentioned before, Spec Miatas are extremely popular here), but there are a couple of Porsches and a Mustang from what I can see, so I'm going to have to look in the mirrors occasionally.

The groups themselves are small, around 20 cars or less, and Thunderhill is a long track, so we are running the short configuration. It's going to be awesome. I'll grab lots of GoPro footage.