Monthly Archives: June 2011

Tire Notes

Those of you following this log may have noticed a bit of schizophrenia with me and tires over the last season or so. Briefly, I’ve run Goodyears on the Stohr since I got it, but was forced into a Hoosier switch last August at Miller after I ran out of Goodyear rubber from the high tire wear there. Chris helped get me going on the Hoosiers, which worked beautifully at Miller, HPR, and at the Runoffs. However, I was uncomfortable with how long the R35’s take to get fully warm – about 1.5-2 laps in normal weather – so I reverted to Goodyears over the winter. However, once again at Miller in May, I found problems with the Goodyears, and once again I found myself on Hoosiers for a race.

After talking with the Goodyear rep in my area, he sent me a few sets of a new 22×11 rear tire they’ve developed, which is a new construction, more similar to the 20×9.5 they released a few years back. Along the way, we discussed pressures, and he verified that 18-19.5 hot was a usual common target, but that 16-17 was nothing to be afraid of. He relayed that any lower than about 12psi cold is too low, though he did have stories of some folks doing that.

We tried 12.5-13.5 at Elkhart Lake, and found that around 13.0 would lead to around 17.5-18.0 hot pressure. We’ll take more tire temps to see how that sets the temperature spread, and adjust as necessary. It’s worth nothing that the Goodyears still do come up in pressure quite a bit more than the Hoosier, which we start closer to 15-16 or so to arrive at 18-19.

At any rate, the new 22×11 tire seems to have excellent wear, grip, etc, so hopefully that will put an end to wearing out the rears much faster than the front, which has been the case ever since the excellent 20×9.5 became available. I’m eager to test at HPR and see how it all feels.

Jim also relayed that they are going to update the 22×10 in similar fashion to this new 22×11, and that will be available once the inventory of existing 22×10’s is exhausted.

Finally, it’s worth noting that on my 10.5″ rear Jongbloeds (7.5 + 3.0), I had to use a 1/8″ spacer to push the wheel out just a skosh to get it off of the inner fender from rubbing, due to the extra tire width.

Misc

Some other misc notes:

  • Bobbin Spacers – as mentioned below, Wayne has some .032 spacers that will fit on the floating rotors to reduce the float down into the .005 to .010 range. They can go either directly under the “hat” of the bobbin, or on the back side of the rotor, just under the head of the bolt that secures the hat to the rotor. I found that putting them on the back/under side of the rotor was a better location, as otherwise the rotor is moved inboard by that .032 thickness (give or take). In the rear, that was enough to put the new vented rotors uncomfortably close to the nut which holds on the bolt that attaches the caliper. Putting the spacers on the rear floating rotors definitely helped, as I had far fewer issues with knockback coming into Canada corner after installing them.
  • 4-pot calipers – Nothing to report here as yet – they will be on the car for the HPR double.
  • VoltPhreaks Battery – Tony Hwang at Volt Phreaks has been very on-the-spot about answering questions and providing possible answers as to what caused my car to shut off on the opening lap at Elkhart, and Chris’s battery to die completely. Likely on mine is water on the terminal for the on/off switch shorting the switch. My solution will be to try and relocate the battery so that the switch is higher up and further out of water’s way, and to try and insulate the terminals better, and finally throw some dielectric grease on there to further keep water out. One other interesting option he raised was the ability to change the switch such that it can *only* turn the battery on, not turn it off. Finally, he relayed that the new, 3-pin plug like my battery has can be used for charging the battery even if it has discharged below its cutoff point, which may be useful some day…but I hope not.

 

Serendipity

Once again, it was time to load up the family bat-truck and bat-drive to bat-Wisconsin to go out to Road America for the June Sprints. Hiiii-yooooo!

After a disasterous weekend at Miller, we had re-armed ourselves with better tools, a fresh setup (complete this time…), and confidence borne of self-delusion. A quick look at the entry list showed no fewer than 12 DSR’s, only one of which was not a Stohr, and only perhaps two of which – one being yours truly – would not be packing a built engine.

The drive out was completely uneventful – flowing easily through Wyoming, Nebraska, Iowa, and eventually to Wisconsin, which does, I might add, have the worst roads outside of  Oklahoma.

Such was the ease of the drive that we even executed our first overtake of the weekend, meeting accidentally with Chris Farrell at a truck stop in Iowa, and beating him out of the pits. As is his custom, he naturally passed us again later that “lap”, as we stopped for bed in our usual Walcott, Iowa truck stop. We picked up our usual Cruise America RV bucket-o-rattles in Milkwaukee, and headed north to Elkhart, greeted by a low, gray, sky, and some intermittent, indecisive rain.

After a bit of a wait outside of T14, the RA staff took us to our spot in the west paddock. We set up our new Holliday canopy, which turned out to be a godsend for the weekend, zipped up, and headed into town with Chris for dinner at the Paddock Club. Mmmmmmm!

Thursday

Luck was with us, as Thursday dawned with sunny (enough) skies, and a dry track. I had re-mounted a set of my overheated 9.5″ and 10″ Goodyears from Miller, in order to get the
brake bias sorted out on the car. Having installed new pedals and new master cylinders, I thought that if I was going to square off some tires, it might as well be some old ones.
Additionally, simply re-learning the track after 9 months was on the to-do list.

The first session out was fairly anticlimactic, as the throttle cable slipped forward in its mount, giving me no more than about 70%, then 50%, then maybe 30% throttle. I rolled around the track for a few laps just to get my eye back in a little bit, then came into the pits. Right on – 5 laps in one of my two sessions on a $300 test day. Great value so far….yeah right. However, I can now say that I have done Road America flat out. That’s right ladies and gentlemen – not one lift. That was some exciting 40mph, let me tell you – hah.

We fixed the throttle cable – new with the new pedal assembly courtesy of Mr. Loshak – and buttoned the car back up for the second session. Now proceeding at something more than walking pace, what with an operational throttle pedal, I noticed right away that it seemed like the car was bottoming a lot in the front. Every time it did, the car would skip sideways, and generally, there was very bad oversteer midcorner. I thought to myself “ah, wonderful. Another weekend of trying to catch a car that’s trying to kill me.” I fought with it for a few laps, trying to at least get some sense of braking points and get used to the new pedals. As with Sunday at Miller, I was using my left foot to brake, but the combination of the new master cylinders, wonky bias, and a not-very-delicate left foot did indeed lead to some squared off tires.

I soldiered on for a while, but after the oversteer progressed to where I dirt-tracked my way around the carousel, I came in before I fell off the island.

Based purely on the rubbing up front, I immediately raised the front 2 turns of the pushrod, about 2/16 of an inch. Desparate to find some solution, I rolled over to Chris’s setup pad again and rolled the car on, where the front showed to be about 1 1/16″, even after I’d raised it! We raised it another 2/16, to about 1 3/16, and ended up lowering the back some, for a net rake reduction of approximately one metric buttload. Confidence was high that this would stabilize the back end, since it was no longer poking up in the air and dragging the nose on the ground.

Friday

Friday’s morning practice, the car finally felt normal again, like it had at HPR last year, and at the Runoffs. Good stability in the corners meant I finally had the confidence to push it,
and improved from my embarrassing 2:12-ish to a 2:08.30, a respectable time. We didn’t change much for the first Q session, only adding a slight touch of rear flap to stabilize the rear end a hair in the faster corners – probably more for driver confidence than anything.

This was also the first outing for the new construction 22×11’s that Goodyear had sent me to replace the 22×10’s that were damaged at Miller. The statement from Goodyear was that they’d act a lot more like the new 9.5’s, which is to say, less pressure gain, more consistent wear and grip. That certainly seemed to be the case, as wear looked outstanding, and they certainly felt like a better tire compared to the old 10’s. I noticed just a bit of extra wear on the inner shoulder of the left rear, likely from the carousel, and took a hair of camber out on both sides of the car, ending up around 0.2 to 0.3 of a degree (negative).

The day began to cool somewhat, so Q2 began to look like it would be a good one for us. Turns out is was, as the small wing change worked very well, and I was able to break into the 2:07’s, good enough for 5th in DSR and 11th overall. As it turns out, so did almost everybody else, as something like 4th to 13th on the grid were in the 2:07 range, and Bootz, Downing and I were all separated by less than a tenth of a second. This was shaping up to be a real good fight in the mid-pack. As hoped, reducing the rear camber took care of the wear on the LR, so at that point, I left the car alone. Unheard of, right?

Saturday

Saturday we had just a single qualifying session in the afternoon. I spent the morning motoring around in the golf cart, saying howdy to everybody I could find and generally enjoying the Wisconsin springtime.

The day shaped up to be a warm one. As such, we decided to put our other set of new tires on the car for scrubbing. My logic was, if conditions were good, I could set a really good time, and if not these would be a nicely scrubbed set of tires for the race.

As it turns out, it was pretty warm, and I could do no better than a low 2:08 again. I spent some laps chasing Bill Goldkind, and even had what felt like a real flier drafting behind him, but the stopwatch thought otherwise. Such was the case for many, although Lawrence did lower his pole time to a 2:03, and Chris’s scarcely believable weekend of awful luck continued, so the expected battle at the front did not develop.

Our only excitement post session was a fire drill to remove the seat and seatback, when we learned that overfilling the tank enough will eventually lead to fuel coming out the breather vent. Eek.

Sunday – Race

The pictures make it obvious: Torrential rain.

Somewhat of a portent of things to come was a chill in the air Saturday night when I finally wandered back to our RV in the trees. For the first time since arriving on a rainy Wednesday,
I had to don a long-sleeve shirt to stay warm. Sunday morning, while we waited for our session, a small cloud stopped by, wetted down the paddock for a few moments, then ambled onward, unaware that it’d put all of us into a whole new state of mind.

Soon enough, all of us in the paddock were checking, checking, and re-checking the radar and the skies leading up to the race. I was pacing around with my iPhone, looking for the
best of the all but nonexistent signal out there in the Wisconsin countryside. Eventually I stumbled on somebody’s wireless (login/password “default” and “password” – hah), and was able to get weather updates. Green belts seemed to be splitting on either side of Elkhart Lake. 9:00 came and went, then 9:30, then 10:00. 10:05. 10:07. 10:08. Soon enough, we had to make the call, and climb into the car.

During that tense 90 minutes, I was pacing back and forth between my trailer and Chris’s, trying to glean any last minute words of advice on the art of racing in the rain —
where is Denny Swift when you need him? — and getting plenty of helpful advice. We got the rains ready, dug out the dive planes, rain-X’d the visor, and I briefed my dutiful crew
(aka Mom and Dad) on how to change it all. Everybody else was doing the same. Funny the questions you don’t think to ask until you need them: What pressures do I run in wets? (I ran 18) I sure hope they’re taller than the dries like everybody says (they are). Do you put Rain-X on the inside of your visor too? (I did).

In the end, despite all the hand-wringing, sky-checking, dead reckoning, refresh-button-clicking, and divining-rod consultation, every single car came to grid on dries…whereupon
the heavens opened and began drenching us all.

As soon as it started raining, we all scrambled to try and get everything changed in time. Instead of the usual calm wandering around on grid with the occasional crewperson chatting on his radio to his driver, there were dozens of folks scrambling, falling, slipping, squatting and milling around in the effort to get cars up, tires changed, and back on the ground. In retrospect, though we didn’t know it at the time, I think they gave us all time to get everything changed, since the rain was just pouring down.

I radioed Dad to head back to the trailer and grab the rain tires and jacks, since I’d concluded that the crew, though willing, are, after all, in their late sixties, and probably
wouldn’t be able to change the tires in a timely fashion if we had to change during the race. However, Dad made it back with everything piled on the golf cart, and began changing the
tires. To finish the job, I owe an enormous thank-you to Critter and Mrs. Critter for helping Mom and Dad to complete the tire swap – with tires on the correct corners – and dive
plane installation on my car after they got Doc squared away. That was really a wonderful thing to have done for us – thanks guys.

During the madness, we also maxed the rear flap (aka “The 5th Element”), and put a gurney on the upper element, which Chris had given to me a little while before.

Eventually the 5, 3, 2 and 1 minute signs were given, and I reluctantly surrendered my umbrella. There was so much water I spun the tires just trying to get moving. Visibility
was perhaps 10 feet, and the faster we went, the more spray we all kicked up. The rain lights were laughable – visible maybe at 20 feet, but beyond, there was nothing but a wall of spray.
At the big bump near the pit-exit, I felt the cold water run in and start soaking the backs of my legs, and as it turns out, that’s about the time the camera quit working. So sad. My visor
was instantly covered with water from Doc ahead, despite a healthy coat of Rain-X. Little drips from the upper surface of the visor started falling into my eyes. Note to self – more weather stripping on upper surface. Fortunately, I’d kept my helmet on and visor down during the whole time the rain had started, so I had no fogging whatsoever during the race.

After we were out of pit lane and onto the track, as far as I knew, my universe shrank to about the nose of the car and the visible 20 or so feet ahead of me. I couldn’t even see Doc’s
rain light for all the suspended water. I spent some time on the opening lap trying acceleration ( surprisingly good ), braking ( also not horrible but let’s wind the bias back a few thousand turns ), and cornering ( don’t even think about it ), and concluded that the car was OK in a straight line, but managing the back in the turns was going to be really tough.
Just after turning into Canada corner, the car shut off – no dash, no nothing. I’d experienced that a few times before with the VoltPhreaks battery when I had a bad cable, so I reached
up to the dash switch which turns the battery back on. The car came back to life, but died again a few seconds later. I thought to myself “well this is going to be a fun race…”, and turned the battery back on. Mysteriously, it never happened again. Other than the camera, it appears I suffered no water-related electrical problems at all.

The start was a complete mess, as we never really formed up into a grid that I could see. I never did see the green, but Tom went screaming by me, as did a pink-ish CSR, so I hit the
throttle too…a little. So much spray was ahead of my 6th-row starting spot that I had absolutely zero idea who or what was ahead. I backed out of the throttle as we neared turn 1, thinking to myself “well, at least when I hit the wreck of cars at turn 1 it won’t hurt as bad this way”, but by some miracle, everybody had made it through. We headed down to T3, and Downing spun off of the inside, as did somebody else to the outside – maybe Mucha from the look of the lap chart.

I spent the first few laps just trying to keep the car on the island and see where I was going. As the others have mentioned, the amount of spray kicked up from the tires, tunnels,
and wings was staggering. Just like the books say, the racing line was a disaster. Big puddles were at most of the apexes, caught by the curbing, as they were at corner exits. I found
myself driving in the middle of the track and squaring off the corners. For the first few laps, during which traffic was heavier, I constantly had my left foot covering the brake pedal in
case a wreck appeared out of the spray. Once the field strung out a bit, I went back to using my right foot, since it has so much more finesse in these tricky conditions.

As I gained confidence and started using more and more throttle on the straights, a sample lap would be something like this: Cross the start finish line in 4th gear, shift to 5th
somewhat past the start stand. Ease out of the throttle as soon as the brake markers appear out of the haze, and ease it down into third gear. Drive around the middle of turn 1, and come off throttle completely for the river running across the exit of T1 or the car will lurch sideways and spin up the rear tires. Accelerate full throttle to T3, brake gently and again, drive around the middle of T3, avoiding the apex and track-out puddles, exiting on about the inside third of the track. Full throttle up to 6th gear down to T5. Again, ease out of it when the #5 brake marker becomes visible, and gently shift down to second. Lots of deep water here since the apex of 5 is down the hills from 4 and 6. Often the car would hydroplane and the wheels would stop turning, so I’d ease off pressure until it was rolling again, then try to turn it. Wait until pointed straight and past the deep spot at corner exit, then full throttle up to T6. Ease it down again, driving around the middle of the corner, into 2nd gear. short acceleration to 7, then up to 4th on the run down to T8. Run the inside coming up to T8, as the water was shallower there, then move towards the middle of track in the middle of T8. The carousel was surprisingly tractable the whole time, and could be driven pretty normally but for the huge puddle near the curbing at the end. Same for the kink, which even developed two drier tracks by the end of the race, as did the run down to Canada corner. Brake again as soon as the brake marker appears from the gloom down under all those wet trees, and drive around the middle. There was a large deep spot across the track near the exit, so stay totally neutral throttle with as little side-load on the car as possible. Two of the deepest spots were between the curbing of T13, so you had to thread between the middle and let the rear wheels spin up a little bit. As with many of the corners, T14
had a large puddle at apex, and a river crossing the track on exit, so once across that, I could go wide-open, and accelerate full throttle up the front straight into T1.

As complicated as that sounds, on top of that, each lap it seemed like there was something – braking a tiny bit too late and feeling like “is this the lap where I throw it off track?”, finding
certain spots wetter or drier than the lap before, and constantly feeling the car twitch and lurch when the rear end started to slide. Even worse is when I’d start to get closer to another car, and all thoughts of trying to find the best line would go straight out the window, and my only priority would be finding a way to see where I was going.

Eventually I noticed that I was passing cars pretty regularly – first a few CSRs. I tip-toed by a small crash in T8 – it looked like one of the French cars and maybe Bill Goldkind got together with each other, so I snuck by as they got moving again. Eventually I came up behind Lawrence around T13, who looked like he was holding on for dear life. I followed him through 14, 1, and 2, keeping about a car-width to the side so I could still see where I was going – see Pepper’s picture of Lawrence, Lee and I in his album – that’s when I was about to sneak by. In T3, he got his outside wheels in the large puddle at exit and had such a lurid sideways lurch that I could read the “DSR 1” on the side of his car. I braked as gently as I could in case he spun, but he somehow got pointed straight again and I was able to accelerate by down to T5.

Before that, somewhere along the line I got by Lee Alexander – I think down near T13 somewhere, after coming up behind him around the turn 8 area. Following him down to Canada corner was unbelievably hairy – I couldn’t see a thing!

In the final few laps, I began to lap more and more S2’s, but I could see one car ahead with a low-mounted wing. As far as I could tell, I was behind Farrell, Dempsey, and Bootz, so I knew that must be Bootz. I kept running as I had been, looking for the more-and-more drier areas that developed, and began to even be able to carry some corner speed and put some lateral load on the car. Turns out it was indeed Bootz, who came up on Dave Knaack and passed him in T6. I caught Dave between T6 and T7, and caught Tom in T8. He took a very wide line around the carousel, so I snuck by him on the inside in the carousel, in which he made plenty of room for both of us.

I ran the next two laps just as I’d run the others, looking for the least wet spots I could, and eventually took the checkers. I was ecstatic to have finished the race, both from the
car working OK, and for the reason that it’s the first time I’ve ever raced in the rain! I figured I was in maybe third place, since I’d never seen Doc or Chris Farrell, and was hoping that
maybe I’d made the podium. I drove down pit lane after the cool down lap, and saw Mom, Dad, and Critter/Marsha/Pepper going crazy. I thought “Yeah, I finished, thanks guys!”, and began to turn into the paddock. The guy at the end of the pit lane started towards me with the flag and I thought “well, one of the black Stohrs, he probably has me confused with the winner”. He handed me the flag and I said something like “Isn’t that for the winner?” and he replied “Yeah, that’s you!”

Ensuing was perhaps the slowest victory lap in the history of the world. Taking a lesson from Lawrence’s celebration last year, I made it last as long as I could, and waved maniacally to
everything – workers, spectators, chipmunks, tree branches, the tow-truck driver, you name it.

The pictures pretty much tell the story of the rest – Dad and I grinning like idiots, Mom crying, and some good fun on the podium with the champagne.

No doubt the natural order will reassert itself in September, and we’ll see the usual suspects back at the top of the order, but for now, I’m really happy to have my 15 minutes and be able to say I won a race like this one.

Conclusions

First and foremost, finally, happily, amazingly, the car is back into the range where it’s driveable again. Sometimes it seems like this car is extremely sensitive to some setup changes, and relatively insensitive to others. Let it be known that rake is really important in this car!

From a reliability standpoint, the VoltPhreaks battery remains a question mark, due to those two isolated shutoffs, and Chris’s failed completely. As part of my loot for winning the race
was $500 to Ballistic Performance, I’m going to order some 12-cell batteries to keep as backups (or maybe primaries?), and call the VoltPhreaks
guys to see what the story is there.

Next up is High Plains Raceway, so it will be interesting to see if all of this mucking about with parts has actually translated to any real laptime at my home track.

The Latest Lessons

It’s been several months since the last update, but it’s been a pretty slow few months.

HPR Double Regional

The first local regional race at High Plains Raceway was a bit of a letdown. There were so few wings-and-things entries that they lumped me, and FB, and two FC’s in with the FF’s and such, which made for a pretty low-key weekend. I focused on getting the car debugged from its winter projects.

One significant issue from the weekend was the aforementioned control arm bracket (see below) coming adrift again on the RHS control arm. A quickie presto-chango welding job by Chris Doyle (a thousand thank yous) fixed that guy in place so I can quit worrying about that forever. A brief off on the outside of T3 when I took a bit too much curb was about the only
other excitement from the weekend. Cold weather, insane wind, and low turnout made this one pretty forgettable.

The lessons from Miller (see report – coming soon) did foster some to-do items:

  • Pedals – Discovering that brake pedal pressure would bind the throttle completely explains my left-foot braking issues. We “solved” it with WD-40 for the Miller weekend,
    but that was spooky enough to become the last straw. Lawrence Loshak was kind enough to send me his OEM WF-1 pedal set, and we’ve fitted it to my car. I’m putting new Tilton “short” masters in place. I had planned on staying with 7/8″ masters for the firm pedal feel, but as Pegasus only had 13/16, I went with those. Word from Stohr is that they are actually using 3/4″ masters these days to provide a bit more bite and modulation, though at the cost of pedal firmness. Hopefully the 13/16 will be a bit of a Goldilocks combo.Naturally, replacing the pedal set means new solutions for the throttle cable return, throttle cable, pedal stops, master cylinders, brake line plumbing, clutch pedal stop, and
    all sorts of nonsense. I’ll be figuring all that out this weekend.
  • Brakes (Calipers) – I also decided, based on the high wear from the rear 2-piston calipers, to finally go with the 4-piston rear caliper. The Brembo kit just isn’t in the cards,
    so the car’s complete configuration will be 13/16″ masters, 4-piston front (1.75″ pistons) and 4-piston rear (1.38″ pistons).
  • Brakes (Rotors) – Also on the topic of brakes, I noticed that I continued to have soft pedal after long sweepers, indicating knockback still happening. I replaced the front
    floaters with the original fixed rotors, and when that didn’t fix the problem, also replaced the floating rears with the solids. That seemed to take care of the problem.Chris noted that the new Brembos have a lot less float – maybe .010 or so – than the Stohr parts (maybe .040?). A quick call to Wayne confirmed that has been an issue, and they have bobbin “spacers” to reduce the float down to that .010-.015 range, that is purported to not only solve the excessive-float-knockback problem, but also the issue that some have experienced of getting progressively worse vibration when braking as the floating rotor heats up over the course of a session. Will test and report back.
  • VoltPhreaks Battery – I took the time to install the on/off button for the VoltPhreaks battery onto my dashboard over the winter, since if the battery shuts itself off (due to low voltage) with the bodywork on, it’s a huge production to fix the problem. However, both at HPR and Miller, I noticed that the battery shut off during my sessions with the cable connected. Disconnecting the cable solved this problem. I exchanged the cable with VoltPhreaks, who said my old cable did look a little worn, so hopefully this problem is solved. the aux-plug that I installed over the winter has been useful for the first start of the day, for me to start off of a PC680 I carry around, but beyond that, the littleVoltPhreaks battery is performing admirably.
  • Steering Stiffness – Another winter update (see below) was the 2009-style updated steering geometry, via new lower control arms from Stohr, and the Luxon CNC’d uprights. However, I haven’t experienced any of the reduced steering effort the change is purported to supply. From talking to Wayne, it is possible that the bearing is installed too tightly in the control arm, so I’ve dropped these at a machine shop to see if they can hone the housing in the control arm and hopefully loosen up those bearings, thus providing easier steering  effort. At tracks like HPR and MMP, this will be a big deal. Even in the Carousel at Road America, that would be a welcome change.