continued from above
So long story short, the wider Mustang wasn't well suited for this course. At all. I was driving my ass off and just could not get the car to put any power down on this cold, slick surface. The uber-tight turn-arounds were also killing time, too. The tires didn't work worth a damn in the cold temperatures, yet after my first 4 runs (which are run in quick succession) the tires were badly overheated - front and rear. Tire pressures crept up by over 10 psi. Yikes. Another Toyo equipped STR Miata had similar troubles - no grip - and their tires made equally loud noises compared to the others (and they were uncharacteristically off the pace).
Watching cars in the 2nd heat of the morning, while I was then working course, they looked quicker as the track temperature began to rise. Sure enough, Ledbetter and Ken O were both running almost 3 seconds quicker than my heat 1 times. Not good, but not surprising.
After the lunch break the temps were in the 60's for heat 3, when I ran again. This time I moved my spray bottle, air gauge and gear over to the exit of the course, where I'd have about 60+ seconds between runs waiting in a short line, to pile out and spray tires/check pressures. Luckily I had some help this time (Ledbetter's co-driver Sherrie) and she bled tire pressures down while I sprayed and sprayed the quickly overheating Toyo R1Rs between runs. I held up the flow into the start line a bit, waving them around, but these tires were just boiling hot after each run - even with ambient temp still in the 60°F range. Rear wheel spin was still ridiculous but with lower pressures (dropped to 35 F/32 R for this lower grip lot) I could at least get
some forward motion going on these runs. Still had some push in the tight turn-arounds but with this back-to-back run format there's no time to make real set-up changes (other than pressures and shock knobs, which I did). To me, running an event "the SCCA way" (with time between runs to make adjustments) makes for a more useful use of the time.
My 4 afternoon runs were 2 full seconds faster than my morning 4, which is an unusual gain for me at this site, even over that much ambient/track temperature change. I guess after 23 years you'd say I'm "a seasoned autocrosser" and don't tend to pick up huge amounts of time after my first 3-4 runs, so I chalk that 2 sec gain up to the set-up changes (lowering tire pressure), tire spraying (lots of water!), and warmer track temps. Still, I was well off the afternoon pace. Ledbetter's later 4 runs got .8 sec faster than earlier, and Ken O was almost 1 sec quicker as well. That left me still pretty far back from both...
When I checked times on the computer and print-outs throughout the day there were only 3 cars in class 3, which I led to the end. It appears some Honda looks to have been moved into the class. Who knows? I couldn't hear a thing from the announcer that was useful - just a bunch of clowning. Just look at the the times from Chris Ledbetter (STX BMW 328is) and Ken Orgeron (STU legal E46 BMW M3), the only other competitive STX and STU RWD cars. They were both on different tires (Chris on 255mm RS3s and Ken O on 285mm Dunlops) and ran in hotter times of the day (heats # 2 & 4) but both of them crushed my times... Ledbetter was 1.7 sec quicker and Ken was 1.1 quicker. I worked course when they both ran and they looked so much more stuck down - still skating somewhat on the slick TMS surface, but not the excessive wheel spin and loudly squalling tires like the Toyos were doing on the Mustang.
Lessons Learned: My times on that tight-assed course were a bust, but I learned that Toyo R1Rs are not
all that in the cold, yet they can easily overheat - even in cooler temperatures. I won't make a run on these ever again without massive water spraying afterward. We'll get more accurate (pyrometer) data on this phenomenon at the big tire test we're going to do in 2 weeks. I left my video camera mount at the shop, so I couldn't take any in-car video - which would have been good for a laugh.
We now have an extensive "trailer load list", with this and many other items listed and checked before each event. Also, bring a co-driver or find a helper at autocross events that have back-to-back runs like this, if you hope to check tire pressures and spray tires between runs, or if you'd like to make even the smallest of set-up changes. Lastly - know who the course designer is up front, or find a course map before you go to the trouble and expense of making an event. The NTAXS event folks always put on a great event, but this particular course really didn't work with this 71" wide car (several other "wide car" drivers said the same).
What's Next?
The latest things we're working on include finding some man-sized track wheels (18x10" or wider) and better track-worthy tires (not street tires). Not wasting any more time running NASA TTB class on skinny street meat with the rest of the class on wider Hoosiers. We've finally stumbled upon some 18x10" wheels that came off of a GRAND AM Mustang FRC500, shown below.
I've purchased seven of these 18x10" Forgelines but I need to get them from North Carolina to Dallas, TX - anyone that wants to make some $ delivering the wheels from I-95 in NC to I-20 in Dallas, please PM me. UPS is pretty spotty on delivering wheels to me that aren't boxed properly (these will likely have tires) so I'll either try to find space on an existing traveler's truck or call a freight company. Thanks!
We'll check, measure, and possibly rebuild these 3-piece wheels after they get here and hopefully they fit the 2011 with some wider tires. I'm going to try the 275mm Continental slicks or something similar (R6), which will allow us to stay in TTB and hopefully lower lap times a good bit.
We also got in a set of 265/35/18 Hankook RS-3 tires to test with in STX. I'm not too fond of the Toyos after that fiasco last weekend. Figured since we have 2 set of 18x9" STX wheels, a private auto-x test coming up, and the Toyos and Yokohamas, why not try the Hankooks at the same time? I've even managed to borrow a set of 18x9.5" wheels with 275/35/18 Dunlop Star Specs mounted... we'll test those and ponder those numbers as well. This will be as scientific of a test as we can manage: durometer, pyrometer, data logging, and timers with 3 competitive drivers over many runs. I will share this test as a tech article. Yes, GRM does a very nice series of autocross tire tests almost every year, including one on the "140-200" hot street tires, but they always seem to use light, small cars with narrower sizes than the 265mm we need. And from the rumors I've heard some of the ultra-small sizes have "unique compounds" that are softer than the wider tires we use have. Our autocross data seems to sometimes prove some long standing data inaccurate, which is mostly based on the narrower sizes. So....we'll see.
May the best tire win!
Last but not least, the APR GTC-300 CF wing arrived yesterday.
I'm working up a set of stands that will fit the Mustang and another to fit the E30. This wing could be used at track events like the UTCC in July (E30?) or for NASA TT events (Mustang). On the Mustang, in TTB I'm already taking a +4 point hit for a "non-OEM wing configuration" (the OEM optioned rear cosmetic wing delete), so with this carbon 6 foot wingspan perched up above the roofline,
I will bloody well get my 4 points worth.
Sorry if I seem a bit grumpy in this post, but well... I am a grumpy old bastard.
The bushing install made a
total mess of the shop and took longer than it should have. At least we know the shortcuts for this one, now. And I can't disguise my disappointment in the results from the autocross, and the course layout was far from my favorite. I'm sure the predominantly S2000 & Miata guys loved it, as it worked great for those cars. And being that the club caters to those cars, I can't fault them for that.
Until next time,