Monthly Archives: April 2013

Nostalgia Trip

They say “You can’t go back,” and by and large, “they” are right. I visited my boyhood home a few years ago, and it was a run-down and overgrown shell of the place in my memories.
Still, that reality doesn’t stop many of us from trying to drag the past up from the depths.

Such was the case for me and my family as we continued west on highway 80 outside of Salt Lake City – dutiful nod to Tooele as we went by – and into the stark salt flats of western Utah.
For each one of us, it was our first time west of Utah on I-80 in years. For me, it was the highway that brought me to Colorado to begin my college adventure. For Mom and Dad, it carried them east into retirement to their new home in Pagosa Springs after leaving their home and business of 20 years in Napa.

Our nostalgia trip continued at a low level as we motored steadily across Nevada – small memories of many a family road trip from Napa to Pagosa cropping up as we drove onward. In Battle Mountain, Dad recalled a biblical lightning storm we drove through one night on our way out. In another, Mom pointed out where they’d unloaded and watered the horses when they made their final move to Pagosa. In Elko, I recalled my unscheduled stop with the Nevada State Patrol as an 18-year old, who explained to my friend that 105mph was not an acceptable speed to be traveling, no matter how deserted the highway may seem.

And so on.

What really left all three of us struggling to remain dry-eyed was hitting the Calfornia border near Donner Pass, catching a whiff of the Sierra mountain air, and recalling all the family ski trips. Helping the sense that we’d stepped back 20 years in time was a steady diet of 90’s country music coming from Sirius – Garth Brooks, Reba McIntrye, ah, how far you’ve come. As we continued towards Fairfield and our turn south to 680 for Monterey, the feeling that we were traveling not so much westward, but back in time, grew stronger for all three of us.

We got to within about half a mile of the turn-off to Napa, but instead, southward we went to Monterey. Enough nostalgia…let’s build some new memories, eh?

Friday

One reaches Laguna Seca by skirting the east bay area after turning south from I-80. A few bone-jarring hours on California’s crumbling highways brings you south of San Jose, into the Monterey area.

April is an almost idea time to be in Northern California – and it’s almost one of the best places to be anywhere. The rain and gloom of January and February have given way, and the heat and brown dryness of July and August have not yet taken hold. The lush grass on the hills rolls and waves in the wind, and the low smooth shapes look like big green gumdrops put down by a giant’s hand. The hills are dotted with oak trees that beg you to hop a fence, pull off your socks, and go ponder life from the crook of a branch for a while.

Around the bottom of one such green-gumpdrop is the entrance to the Laguna Seca recreational area. A small sign marks your turn, and you then proceed STRAIGHT UP to the top of the cliff that they have built the race track on. A sign on the way out tells you that you are going down a 16% grade, and it feels every bit of it! A healthy dose of throttle is required to pull your rig up to the top of the hill that affords entrance to the track.

Laguna doesn’t have the same immediately intimidating presence that Road America and Circuit of the Americas do. Part of it is that you come down into the paddock from up high, rather than from the lowest point. Plus, there’s no looming presence above you, such as the climb to T14 at Road America, or the monstrous T1 climb in Texas. Rather, you pass over the track as it heads innocently up a hill, and you can see it sidle back into view around another as you descend into the paddock. It’s only as you hit the track that you realize what a roller coaster you’ve signed up for.


We arrived a bit early and queued up in a line outside the paddock for a while. John LaBrie met me, Lucian, and a few of the others, and the weekend bench racing began in earnest. John gave us our assigned garage spots, as he had bought out the row so that all the competitors could have garages at a reduced rate. This made for a lot of fun and information exchange in the garages, as nearly all the F1000 competitors were within a few garage spots of eachother.

Eventually we were let in, and we unpacked. It was dark by the time we were done, and as I made my way from the trailer back towards the garage, a car rolled up, the window rolled down, and Luci’s Romanian accented English emanated from within:

“Get in the car.”

Not much arguing with that, is there?

I got in the car, and off we went to dinner. Tomorrow: Racing!

Practice & Qualifying

Another thing that “they” say is “boy, the video doesn’t do the elevation change justice”, and boy is that true here.

The straight at Laguna is not only not a straight, but it actually has a big crest that makes your approach to the Andretti hairpin pretty blind. The hairpin is not flat either, but comes
sharply off of the hill onto the flat of the valley floor. You shoot through the flat turns 3 and 4 before slingshotting up through the heavily cambered turn 5, then to the flat-and-blind T6.
Upward and upward you go after 6, wishing for another 50 horsepower as the car struggles to climb the grade. Brake when you see nothing but sky as you come up to the corkscrew, look for the tree with the orange marker on it, and turn left into thin air, and hope the track is where you left it. Gather up the pieces of the car at the bottom of the drop and look up – and I do mean UP – at Turn 9 as it approaches you (not the other way around it seems!). Gather your bravery and keep it planted through 9, feeling the car bump and skitter as it compresses into the fast, cambered hill.

Grab a gear and swing left for T10, again riding the curb heavily and slinging out the other side. T11 is surprisingly low grip, so it’s a bit of an early brake, put the left tire just shy of the
red curbing, and feed in the throttle for another trip down the front “straight.”

Another ride on the roller coaster please!

All that we had just a few minutes to learn in practice, and not too much longer to figure it out in our qualifying session. I managed to improve and get a relatively clean lap in the 26’s,
which was good enough to put me in second overall in our group, first in FB, and starting on outside pole. Not too shabby for my first few laps at the track!

Saturday – Race 1

Saturday’s race was for us, just a qualifier. Fastest laps in the race would set the grid for the two Sunday races, which are the ones that counted for points. Still, it would mean
valuable time to continue learning my way around the track.

Oh, and it’s awful fun to race instead of qualify, yeah?

While wandering back to my garage at one point, Kevin Mitz stopped by, sporting a conspiratorial look astride his pit bike.

“C’mere. Let me tell you something,” he said.

“When that green flag drops and you get down to the hairpin, I bet you can ride right around the outside of that Mazda and come out ahead on the way to turn 3. Just think about it.”

And with that, a wink and a twist of the throttle, he was off in a cloud of smoke, to parts unknown.

Out we went for the race. At the start, we lined up as usual, two-by-two. We approached the flag, and I started to fall behind just a bit. I burped the throttle to catch up, and the Mazda thought
we were starting the race, so he took off. I realized what had happened and hit the gas too, just behind.

Incidentally, at some point I’m sure a green flag waved, but I’m starting to realize that the green flag is mostly a formality that seems to be pretty much ignored. Yet another lesson learned.

Down to the Andretti Hairpin we went, the Pro Mazda and I very close together. Sure enough, the Mazda dove to the inside to try and protect his line. I braked late, and no doubt under the watchful eye and small smile of Mr. Mitz, around the outside I went, emerging from T2 in the lead, and off into the distance I went, making a mental note to thank Kevin next time I saw him zooming around the paddock.

Being as this was our qualifying race, it meant it was time to put some laps in, so while we had some clear track, I tried to put in the quickest laps I could, and as a few high 25’s on the dash by lap 3 and 4. I figured that would be good enough to be in the hunt, and right about then, I started getting into the lapped FM traffic.

The rest of the race was reasonably uneventful. The Pro Mazda caught up with me in traffic at one point, since I wasn’t pushing the issue at all. However, he broke a pushrod at the exit of the corkscrew shortly after, and pulled off, trailing behind him the hot smell of scorched jabrock. The two of us had checked out pretty substantially from the rest of the field, so under the checkered flag I went, happy to have run a good first race.

Sunday – Race 1

The grid for our first points race was a close one at the front, so close in fact, that Larry and I posted the exact same quickest time, down to the thousandth of a second. His second quickest lap on Saturday was faster than mine, so he would sit on pole, with me on the outside.

My only complication was that a post-race inspection showed one of my tires was not holding air. With all the tire folks packed up and gone, our only solution was to swap out a fresh tire for the RF, and hope that the tire would get scrubbed and going in time to avoid any funky balance the first few laps.

Our race start was similar to the first, with the start of the race beginning somewhat before the actual flying of the green flag. This time, I wasn’t able to beat the pole car around T1,
and Larry and I swept through turns 3,4,5,6, up the hill and into the corkscrew.

He and I continued for several laps locked together – each of us having our relative to strengths. His car seemed excellent in the slower 2-3-4 corners, and I seemed to gain some back in the run up the hill. His new Kawasaki pulled strongly out of the slow corners, and gave him a good gap down the front straight.

Still, I stayed close, and definitely through the traffic, I managed to stay close. Late in the race, I used some traffic at the T3 to do some blocking, and briefly led, before getting blocked
just as badly on the run to T6, and Larry jumped back into the lead.

We ran like this up until the last lap, just a few car lengths apart at most. On the last lap, coming out of the corkscrew, Larry slowed slightly, having had a balky downshift.
I jumped to the inside, and we hurtled through Turn 9 – the most intimidating turn on the track – side-by-side. True to his nature, Larry raced clean and gave me room, but ultimately I
had to back out of the throttle to hold the turn, and I followed him through 10 and up to 11.

On the entrance to 11, I realized my only hope was that he had another downshift issue, so I went all the way to 1st gear instead of 2nd for the corner exit, hoping I might be able to get a
good run by. Luck was with me, and the same problem struck Larry again on the exit of 11. Only inches from his rear wing, I couldn’t dodge to the inside, so I opened the steering,
channeled a little bit of Alex Zanardi vs Brian Herta, and went across the curbing, over the astroturf, through the dirt and into the overrun concrete, full throttle the whole way.
I bounced across the rough stuff and back onto the track, and we drag raced to the finish, with me taking the checkered flag by a few feet.

My first pro race win ever…what a feeling! I yelled into my helmet and pumped my fists like any triumphant racing driver. YES!!

Sunday – Race 2

To further illustrate just how close Larry and I raced during the first points race, we were separated by just a tenth of a second on our quickest laps. He got me yet again, so for the third time, I’d be on outside pole. This time, Lucian Pancea was just behind us in third place, having gotten in a good lap during the race. Turns out with two straight rear control arms, his car was a lot faster!

My education of how race starts *really* go was completed at the beginning of the third race, with me being a bit slow on the uptake yet again. Larry and Lucian headed for the hills a bit before I did, and I could do nothing but watch as they headed down the front straight. Larry’s big Kawi gave him strong legs on the top end, and Luci’s special ‘low drag’ diffuser gave him some impressive top end speed. He waited VERY late on the brakes for lap 1, and led Larry around the Andretti hairpin, and into the lead.

The two of them raced as closely as Larry and I did in the first race, with me steadily a few tenths behind. Certainly I was making no headway, but it didn’t seem like I was losing much ground either.

I gained in my strong spots up the hill and through 9-10-11, but lost out on the straight each time as they used their advantages to pull away.

Unfortunately, the interesting race didn’t get a chance to develop much further. Shortly in, John LaBrie was the unfortunate recipient of a failed engine, and the resulting mess took many laps to clean up. On the restart, predictably enough, there was another big accident, in the form of a FM yardsale at the exit of T4, and the starter stand waved an exasperated checkered flag.

So, it was a 3rd place finish for me, having been suckered pretty badly at the start for the third straight race, but a lesson well learned.

But, two wins and a third place with a deep field of F1000’s, at one of the most intimidating tracks I’ve been to…job well done!

Best of all, I have a new flag to put on my wall…first pro racing win. What a happy milestone.

Next the guys travel to Seattle for the next round. I won’t be there to join everybody due to budgetary limits, a topic which generated much good natured ribbing in my direction. Luci threatened to bring in the Romanian Mafia (“they come in the night, nobody knows you are gone”), Dennis claimed he’d call in the Moldovan mafia (“We’ll take your stereo”), and Jose, straight from Juarez, said that La eMe would do any cleanup that the first guys left behind. Who knew I was part of such an international group of good natured mobsters?

Be that as it may, it’ll be a few months of development, and then time to come loaded for bear at Sears Point Raceway…just as long as I don’t disappear in the night and appear in Kent, Washington around the end of May.

They say you can’t go back, but going forward sure looks good – I can’t wait!



Sunday – Race 2

In-Car from following Pro-Mazda

F1000 Weight Update

Recording this stuff here as much for my own benefit is to that of anybody listening this blog. I’ve swapped out some wing parts, and with a little attention to weight,
I thought it was time to re-weigh the car. With no fuel, otherwise ready to go, and my butt sitting in it:

223 226
280 273

for 1002#, and a 44.8% front weight distribution. Looks like soon I may need to add some ballast…hmm!

Test Day

After a lot of preparation and test-fitting of items, we headed out to High Plains Raceway last weekend with no fewer than 3 front wings, and two complete rear wing assemblies,
to see if we could find some additional downforce/efficiency for the car.

We tried the Stohr factory wing, as well as a Pennon F2000 wing, and saw no major difference between the two. Then we tried a new wing designed by Zebulon Motorsports and that seems to have been quite a success! More on this to come.

At the rear, we compared the factory setup with the smaller element beam wing, versus a larger chord beam wing from an older revision of the Stohr F1000. Interestingly, the same
profile used for the DSR’s lower wing element seems to work very well as a beam wing for the F1000 as well. More to come on this as well.

In all, it appears that we found some nice downforce gains for no loss in straight line speed, so we will see if that is borne out at Laguna later this month, and just as importantly, at Miller Motorsports Park later this year. Keep it going!

How To: Shock Pot Install

It’s been a very long time, but after CoTA, I embarked on a project that was new enough to me, and what seemed like uncommon enough in the formula car world that I decided to
do a how-to writeup on something, in case it helps other folks out there. This time, it was the installation of shock pots on the car, to help with gathering data on suspension travel, downforce, and more!

All of us with formula cars wonder how much downforce the cars really make. We hear all kinds of numbers, some realistic, some not-so-realistic. With that in mind,
and with an eye towards trying to back up what by highly calibrated buttometer tells me about the downforce and grip the car has, I decided to install linear potentiometers
aka “shock pots” on the car for the 2013 season to get some real measurements about downforce, suspension movement, chassis roll, and all that kind of good stuff.

Here is what it took on the Stohr:

Supplies:

What Why Where
shock pots (x4) 100mm is the ideal length for our car, as it allows for the pots to be installed almost 100% in-line with the shock, without having to worry about droop travel. Veracity Racing Data
Upper Mounts (x4) An easy/cheap solution is plastic cable tie mounts with a hose clamp (see below) McMaster-Carr
hose clamps (x4) For clamping the above mounts to the shock bodies Autozone, etc.
1.25″ button-head 10-32 bolts (x8) For screwing through the plastic mount to act as a stud for the shock pot Any fasteners store
-3 AN Nuts (x20) attaching shock pots to the studs Pegasus, or any racing supply
1″x1″ Angle Alum. for making extension for rear bellcrank (see below) Home Depot Racing, etc.
1/4″ and 1/2″ 10-32 alum. spacers for spacing eye-end mounts updwards Home Depot Racing – specialty fastener boxes
1 1/2″ 10-32 hex-head bolts black oxide or stainless, for welding to bolts (below) Any fasteners store
AN5-13 Replacement Suspension Bolts (2-4x) to weld a threaded stud on for mounting the pots. For the Stohr, this was AN5-13 Pegasus, or any racing supply

Installation:

One goal when installing shock pots is to try to get them lined up as closely with the shock as possible, to reduce the motion ratio between the shock and the pot. When the shock
moves 1″, you want the pot to move 1″ as well. This makes the calculations as easy as possible. On the Stohr, this was possible in the front, but not in the rear, as we will see.

First, take your plastic saddles, and install a 1.25″ button head in it with an AN nut and washer, with the bolt head on the inner/curved surface of the saddle. Next, put a hose clamp through the mounts of the saddle, and attach the hose clamp to the top of the shock body, above the shock collar. This provides you with a stud facing upwards that you can attach the shock pot to. Use a second AN nut to act as a standoff that will set the height of the pot when it’s installed. A third nut will secure the pot after it’s in place, further down the line. Do this for both front and rear.

At the front, for the Stohr, you will need to move the factory shock canister mount. Set them aside for now. Weld the 1.5″ 10-32 bolts to the head of the replacement suspension bolts, so the threaded portion of the 10-32 is straight up in the air. Install another AN3 nut to act as a spacer, similar to before.

To relocate the shock canisters, I suggest putting them in the middle, inboard of the shocks, as pictured. If you need them, I have more of these shock mounts, drop me an e-mail.

Some pictures. Note that in my install, we used 50mm fronts, as I worked with CSU, and donated the two fronts for their FSAE Car. With 100mm pots, you would not need the aluminum extension that we used.

Some notes from the pictures: Set your height of the “standoff” nut so that it will clear your spring and collar. On my car, the challenge was clearing the Hyperco hydraulic perches, hence the need for 1.5″ standoff bolts to be welded on the eye-end suspension bolt. The canister mounts I had cut locally on a water jet, and I have many extras. Pictured are a similar mount from Rick Iverson, found on ApexSpeed.com

In the rear, things are a bit more complicated. The bodywork is close enough to the suspension bolts on the bellcrank that you cannot do the same weld-a-stud-on trick as the front. So, you have to make a lever arm, which means that there will be a motion ratio for the rear. We’ll cover that later in the setup.

Up at the body end, attach a plastic saddle with bolt and hose clamp, similar to before. This time, angle it inwards approximately 30*, since we’ll be moving the other end of the shock
pot mount inboard as well.

To make the pivot for the rear bellcrank, cut a piece of 1×1 angle aluminum into 4″ lengths. Cut three inches off of one leg, as pictured below. Line up the edge with the “leg” still on it
with the end of the machined relief in the bellcrank, and mark/drill your hole for the lower shock bolt. The remaining leg should fit flush up against the flat portion on the inboard, forward-facing surface of the bellcrank.

Drill a 3/16″ hole for the shock pot 1 3/16″ from your shock bolt. 1.25″ is too short, as the bodywork will interfere. 1.5″ is too long, as the pots will interfere with eachother as the
suspension travels through its motion. It’s a tight fit!

Use one of your 10-32 button head bolts, and push it up through the bottom of your mount. Put a 1/4″ 10-32 spacer on the other side, then an AN nut to secure the bolt. Your shock pot will rest on that bolt, and can then be secured with one final AN nut on top.

Do the same on the opposite side, remembering to make a mirror of your first mount, rather tha a duplicate.

Run the wiring for all four pots, and tighten the small locknut at the very bottom, near the pot’s rod end.

Configuration and Setup:

Now that the pots are installed, the next challenge is in configuring them. I’ll talk about configuration on an AiM EVO4, but the concepts are similar for all dashes…I hope ;-).

One easy way for wiring them is to plug all four into an AiM expansion box. This makes them easy to remove as a unit if desired. However, one of the uses for potentiometers is to get a histogram of shock velocity, which you can use for making damper changes. To get meaningful information for the damper traces, you must log at high frequencies – 500Hz or more. The AiM expansion boxes support a max of 100Hz per channel, so you will likely want to install the pots directly into the EVO4 logger itself, which supports up to 1000Hz per channel, for a total of 5000Hz logging.

Next, you must configure the pots in AiM. You want to set these up as “Distance Based Potentiometer”, and set the low as “0”, and the high to the size of the pot, in our case 100mm. Depending on how you oriented your pot during install (typical is with the body on the side of the shock body), at the bottom of the screen, you may set a negative or positive number for the max travel used on the pot (i.e. 100 or -100), so that the pot’s outputted mm reading changes in the direction you want for your calculation:

You will want to name them LF_POT, RF_POT, or similar. This is so you can later multiply by your motion ratio in your math channels to get to shock travel:

        LF_SHOCK = LF_POT * POT_RATIO_F
        RF_SHOCK = RF_POT * POT_RATIO_F
        LR_SHOCK = LR_POT * POT_RATIO_R
        RR_SHOCK = RR_POT * POT_RATIO_R

Finally, to zero out the pots, set the car on the ground, do your setup, and in the AiM studio, click on “Device Calibration.” The four pot channels will be listed, and you
can simply click the “auto calibrate” button. You’ll have to do this each time you make a ride height change etc, so that you are always starting from zero on your suspension
travel inputs.

Calculations and Math Channels:

The next number to be aware of is any motion ratio between your shock pot and the shock itself. In our install, the front is exactly linear with the shock,
which means it is 1:1 with the pot, so no motion ratio adjustment is needed. For the rear, remove a spring, and move the suspension through its travel, and compare
the ratio of movement between the shock and pot. For us, the shock moved .7612 for every 1″ of pot travel, so that is our motion ratio for the rear.

For calculating things like downforce and roll, you will need to know the motion ratio of the wheel/tire and the shock, what is commonly known as the motion ratio. On the
Stohr, it is approximately .92, depending on where you are in your suspension travel (it is regressive as you move into bump).

Those motion ratios, plus your springrates, can be plugged into math channels to calculate downforce levels on your car, as well as roll angle and much more. For getting those
math channels, I would suggest contacting David and Ellen Ferguson at Veracity Data.

I would suggest using the “Constants” feature for things that will hold relatively constant, such as your front and rear motion ratios, front and rear shock-to-pot ratios,
and your springrates. Remember you’ll have to update your springrate in your calculations every time you change them, or your downforce calculations will be off!

Finally, note that all these math channels will slow down loading of your channels, as it has to run through all the additional calculations. Here are some of the additional calculations you
might want:

        LF_SUSP = LF_SHOCK * MR_F                                  --> suspension travel from damper travel and motion ratio
        FrontRideHeight = (LF_SUSP + RF_SUSP) / 2                  --> ride height from average of pot readings
        FrontDownforce = FrontRideHeight/25.4*(2*Ks_FRONT*MR_F^2)  --> front downforce from ride height, front springrate, and front MR.
        FrontRollAngle = atan((LF_Susp-RF_Susp)/(53*25.4))/DEG2RAD 
        DownforceBalance = 100*FrontDownforce/(FrontDownforce+RearDownforce)

Happy Testing!