2007 Race Season
March 18, 2007: On Your Marx, Get Set, Snow!?!?
Heat 1: Me (#22)
Run 1: 52.921 (40psi front, 38psi rear)
Run 2: 57.157 (38psi front, 36psi rear)
Run 3: 51.221 (35psi front, 33psi rear)
Run 4: 49.201 (33psi front, 31psi rear)
PAX: 43
From Run 1 to Run 3, the car was super sloppy. There was absolutely no chemical grip from the 225/45R15 Avon Tech R-A's, even though I was steadily removing air. The problem was two-fold: first, it was only about 45 degrees outside with constant 20 - 30mph winds, so the tires never warmed up; second, apparently I lost one of the clevis/cotter pin sets holding my end-links together in the rear. The right rear end-link was dangling free, so there was effectively no sway-bar in the rear. Looking at the wear-patterns on the tire revealed that the outer inch of tread wasn't even touching the ground.
With about 14 minutes between runs, I ran to my pit area, got replacement hardware (sort of saw this coming, so I brought replacement bolts), threw the car back together, dropped a bunch of air from the tires (each had risen about 4psi, so to go down 2psi required removing 6psi), and posted my best time by far.
The car was much more stable and communicative with both ends of the suspension working right. I think with another run or two I could have dropped at least another second.
Looking at the graph of my 3rd (red) and 4th (black) runs, it's clear how much more load the suspension could handle with the sway bar connected at each end!
Heat 3: Daniel Gohlke (#67)
Run 1: 49.938
Run 2: 48.444
Run 3: 48.564+1
Run 4: 47.697
PAX: 30
Considering that Daniel started where I ended (time-wise), I feel confident that we're getting close to the ideal set-up. The tire pressures might still be a bit high, and he never aired them down between runs, so he probably finished at 37 or 38psi in the front.
As he passed me, I could hear that old evil sound that originated at VIR: that of the brake caliper-carriers rubbing the inside of the rotors near the hub. I'll have to look into whether this is a common flaw, or if there's something on my car that has weakened. It may be time to pull that spare rear-end out of the shed.
Daniel was duly impressed with the car's performance, and even though our class has a miserable PAX modifier (0.860), I think with some practice we can be competitive.
March 25, 2007: #2 - March Madness...Continues
Heat 1: Me (#22)
Run 1: 66.877 (33psi front, 31psi rear)
Run 2: 64.341 (33psi front, 31psi rear)
Run 3: 69.812 (33psi front, 31psi rear)
Run 4: 68.748 (31psi front, 29psi rear)
Run 5: 62.432 (31psi front, 29psi rear)
PAX: 39
Runs 3 and 4 saw creative use of the "full-stop" technique that I mastered in the first autocross of the season. In #3, I plowed past a box gate at the end of a descending-radius sweeper and had to go into reverse to save the run. In #4, I got the car to drift really nicely through a slalom but carried too much speed down into another box gate. No reverse that time, but I did come to a full stop inside the gate.
I can tell I'm getting more ballsy in the car. I still found myself backing off the throttle a few times, though. This course had much longer straight areas, and I regularly saw the needle touching the red in 2nd gear. I tried 3rd gear a few times, but never with great results. I honestly can't remember if I used 3rd in the 5th run, but I might have.
Overall, I was very impressed with my time, and even the guy in the timing trailer commented on my final run being very impressive.
But then the Sun got the tarmac good and hot, and 3rd heat times were considerably quicker.
Heat 3: Daniel Gohlke (#67)
Run 1: 62.128
Run 2: 61.522+OFF
Run 3: 62.972+1
Run 4: 61.353
Run 5: 60.647
PAX: 30
Daniel had a lot of trouble keeping the tires stuck to the ground. There's still considerable pre-load in the front sway-bar (we never got around to fixing it), and in a gentle right turn, the brakes will lock at both right wheels. This is repeatable, so I know it's a mechanical issue. Also, the car will tend to push on a left turn, which I think is the same issue: pre-load.
A quick check of the sway-bars shows a fairly acute angle between bar and end-link at the rear, but not pre-load. This limits the load capacity of the bar, and may be causing a little lightness in the rear. At the front, the end-links are utterly immobile at rest, but the intersect-angle is much nearer 90 degrees, so only minimal adjustment should be necessary.
I also made initial contact with Courtney Cormier for doing my suspension setup, and I think I'm going to have to bite the bullet and mount that extra rear subframe: there's just too much rust on the original one, and phantom noises are starting to bug me.
31psi front and 29 rear seems to be just about the right setup for the Avon Tech R-A's. There's good wear all the way over to the edge of the contact patch, and the tires seem to be hooking up better. That's a lot lower than anyone has recommended (Tirerack said 38/34!), but anything higher just seems to make the car float.
June 17, 2007: #3 - Father's Day Follies
Heat 1: Me (#22)
Run 1: 55.690
Run 2: 54.552
Run 3: 55.262
Run 4: 54.420
Run 5: 54.894
PAX: 23
Heat 2: Daniel Gohlke (#67)
Run 1: 54.498
Run 2: 52.800
Run 3: 52.522+1
PAX: 16
We ran this event the day after getting the car back from the cage install. We expected problems, and we got 'em. Mid-way into my first run, antifreeze dumped out of the heater core onto my right leg. It didn't scald me, though, and we kept going. Antifreeze continued to pool in the footwells throughout the day, making us nervous about the engine's capacity for cooling itself.
Then we hit some real trouble when Daniel gashed his leg on exposed sharp metal. He had to cut his day short and go to Patient First for 4 stitches and a tetanus shot.
Overall, the car seemed to perform fairly well for not being calibrated. DeltaV eyeballed the suspension setup when they rebuilt the rear end, and while the car felt like it wanted to plow on left-hand turns, the GTech data doesn't back that up: we consistently saw 1.10+ G's on left turns, but never any more than 0.9 on rights. Acceleration is miserable at +0.36G (max) on launches, but hopefully the timing change will help that.
July 8, 2007: #4 - Frickin' C Mods!
Heat 1: Me (#22)
Run 1: 52.000 (31psi front, 29psi rear)
Run 2: 52.023 (31psi front, 29psi rear)
Run 3: 53.649 (31psi front, 29psi rear)
Run 4: 50.973 (30psi front, 28psi rear)
Run 5: 51.843 (29psi front, 27psi rear)
PAX: 41
RAW: 39
Heat was the order of the day. The car was running very well, the new seat position worked well, but heat was a huge factor. In the first heat, temps were already into the 90's, with ample sunshine on the pavement (a 2nd heat pyrometer reading of the asphalt showed 150-degrees F).
By the 3rd run, most of the cars in the first heat were already having serious traction issues, myself included. Tire pressure consequently came down, starting with 31/29 and ending with 29/27. Optimum pressure for the environment seemed to be 30/28, but even so, I couldn't hustle the car around very well.
The rear end seemed easier than normal to break loose, and after reading a couple of days ago, it looks like 2.5-degrees of negative camber is just too much for the double-wishbone suspension, and there's not enough of a contact-patch to lay down the juice.
Daniel fared far better than I....
Heat 2: Daniel Gohlke (#53)
Run 1: 49.486
Run 2: 49.162+1
Run 3: 51.136+2
Run 4: 49.196
Run 5: 48.716
PAX: 21
RAW: 17
I can't record his tire pressures because he didn't mess with them. He just let them be, and I have to assume that he was right around 30/31 in the front and 28/29 in the rears, but driving 3rd heat, it might have been higher.
Daniel won the class (by 0.003 seconds), and I secured my lock on last place, but I think his time could be better once the chassis has been dialed in a little better.
To help with that, I have new bushings, toe plates, a pyrometer, and a camber/caster gauge on the way. Hopefully we can find a nice unobtrusive area to test some changes to the suspension...
July 29, 2007: Gettin' Loopy
I didn't attend this one, as we were driving to Nags Head that day. Daniel did, though, and showed what the car could do.
Run 1: 40.029
Run 2: 39.357
Run 3: 38.609
Run 4: 38.608
Run 5: 39.504
Run 6: 38.682
PAX: 12
RAW: 13
Way to go, Daniel!
August 12, 2007: Cool August
Run 1: 42.279
Run 2: 41.900+1
Run 3: 41.214
Run 4: 40.958
Run 5: 53.450+2
Run 6: 40.049+1
PAX: 21
RAW: 18
This was another hot hot event, and with a very low turnout (37 drivers), we got 6 runs each over 2 heats. I haven't indicated my tire pressures because I didn't write them down and have since forgotten them. Suffice it to say that they came down steadily over the course of the event, and I soaked the fronts before my last run. I think I ran 31/29 for the first 3, and 30/28 for the last 3, but that quick dousing made a huge difference.
I also used a probe pyrometer to monitor actual tire performance throughout the event, and was surprised at (1) how cool the tires remained, only exceeding 120F one time, and (2) how consistent the temps were across the treads. I had expected to see massive differences due to the extreme camber angles that I've dialed in (~2.5 all the way around), but temps were very even. The only thing I did learn was that I had too much air, as center readings were 3 - 5 degrees higher than the shoulders.
Run 5's times were extremely off because of over-inflation, tire heat, and a big dramatic slide through the chicago box, resulting in my famous use of Reverse (I try to use it at least once per event).
Run 6, though coned, felt smoother, felt faster, and more controlled, and it wasn't me: it was 100% the tires.
Daniel did not show up to this event, so I can't compare my results to his, but getting the tire-setup more controlled should help his times improve, too, finally bumping him into the top 10.
One final note about this event: the previous weekend there had been a make-up autocross for one canceled in April. Turnout was extremely poor, but apparently the course was very well designed. VMSC officials decided to re-use the course, giving an extremely unfair advantage to those who had been there the prior weekend. Among them were some of the fastest drivers of the day. No penalties were assessed, no compromise made, and no attempts were made to even slightly alter the course (like running it backward). So, even though my results were not great, I feel like they don't compare well to those of others.
September 16, 2007
Heat 1, Me (#22)
Run 1: 45.759 (32psi front, 32psi rear)
Run 2: 43.953 (32psi front, 30psi rear)
Run 3: 43.839 (32psi front, 30psi rear)
Run 4: 43.496 (31psi front, 29psi rear)
Run 5: 44.546 (31psi front, 29psi rear)
PAX: 13
RAW: 15
The best I've ever done!
The morning started off cool, with temps right around 69F, so I wanted to start with a litte more air in the tires. Apparently there was a bit of miscommunication, though, and Daniel put 32psi in the fronts and rears, instead of 30 in the rears. The car had absolutely no grip.
Down came the pressure, and I pulled off 2 seconds for it. I knew I felt fast, but after my 2nd run, Daniel was impressed. And it only got better. The 4th run, my fastest, didn't feel as composed as the 3rd, and I know I bobbled a turn and lost at least 1/10 of a second. Why is that important? Because Daniel only beat me by 0.157 seconds! Usually there's a full 2-second gap between us, but evidently my time at VIR paid off hugely.
Only minor adjustments between runs, and primarily to account for the fact that I kept flattening cones. But, luck was very much on my side, and both of the cones I flattened just stood right back up in the box, so no cone penalties! W00t!
We still haven't adjusted camber at all, so I know the car still isn't at its maximum performance potential, but it seems that I'm getting closer to mine.
Heat 2, Daniel Gohlke (#71)
Run 1: 43.572+1
Run 2: 45.083+OFF
Run 3: 43.339
Run 4: 43.211+1
Run 5: 44.325+2
PAX: 12
RAW: 14
Daniel tied his previous best PAX.
Unfortunately for both of us, it took 8 or 9 days to get results, so it's tough remembering the specifics of what went into the effort.
The battery failed after Daniel's last run. I actually had a jumper with me, so I had no trouble getting home.
Top 1/3 finishes for both of us! Yay!
November 11, 2007: Part V of the Virginia Club Championship
Heat 1, Me (#22)
Run 1: 60.792 (32psi front, 30psi rear)
Run 2: 58.242 (31psi front, 29psi rear)
Run 3: 58.073 (30psi front, 28psi rear)
Run 4: 56.917 (29psi front, 28psi rear)
PAX: 23
RAW: 20
Finding grip was the challenge of the day (the event was run in ~50 degree weather). Looking back at the tire pressure changes I made, and at those across the season, it's clear that the front Avons need to be at 29psi, whether it's hot or cold. Anything more than that and the car simply has no grip up front.
I repeatedly plowed past a pivot cone in my first 3 runs, and the right front tire was consistently much hotter and higher in pressure after the runs. On the last one, though, with the "right" pressure (and slightly better driving), I got the line I wanted.
I would have liked to have had one more run; I knew during that run what I was doing wrong, and likely would have wrung out another 0.5 seconds, putting me in line with Mr. G's times.
The car otherwise held up quite well, with consistent bumps, bangs, and thumps from the suspension and rattles from where the fire-bottle had been removed (AFFF doesn't like sub-freezing temps).
Heat 2, Daniel Gohlke (#69)
Run 1: 58.414 (29psi front, 28psi rear)
Run 2: 56.829 + 1 (29psi front, 28psi rear)
Run 3: 56.492 (29psi front, 28psi rear)
Run 4: OFF
PAX: 20
RAW: 18
Yeah, Daniel won again. Shocker. ;)
He's much smoother, but was really trying to over-drive the car today, which manifested in a couple of attempts at sideways-driving.
He got it right in the end, though, and with one less successful run managed to best me by a full half-second.
November 25, 2007
Heat 1, Me (#22)
Run 1: 51.344 (29psi front, 28psi rear)
Run 2: 50.121 (29psi front, 28psi rear)
Run 3: 48.932 (29psi front, 28psi rear)
Run 4: 48.674 (28psi front, 28psi rear)
Run 5: 47.925 (28psi front, 27psi rear)
PAX: 12
RAW: 14
After a season of wrestling with tire pressure, I think today I finally got it right.
This was a fast, fast course on a cold and overcast day, and I never lacked grip. Others were complaining all day about not being sticky, but we've been fighting the tires all season, and just starting a couple of psi lower seems to have worked wonders.
Each run was almost a full second better than the one before, and I found myself deep into the red-line several times in the last two runs (pictured below).
Great course, and a great way to end the season!*
*Just before my first run, I had trouble disengaging 1st gear. Then I had trouble re-engaging that or any other gear. The clutch was engaging about 1 inch off the floor. I completed my first run, popped the hood, and to my surprise, there was no fluid loss. The problem went away and returned a few times throughout the day. It turns out one of the bolts securing the clutch slave is gone, and pressing the clutch pedal is rotating the cylinder slightly. New bolts are on order.
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Page 1: Stats & pics
Page 2: 2006 events and work
Page 3: 2007 work
Page 4: 2007 events
Page 5: 2008 work
Page 6: 2008 events
