This weekend I made the trip down to Buttonwillow Raceway to compete in VARA’s annual Octoberfest event (Septemberfest?). The turnout was quite healthy with over 140 competitors, and the wknd featured two special races: the All German Car race and the Formula Vee Challenge. VARA rekindled the Saturday night potluck dinner and it was a smashing success. While the weather was quite hot and humid, 98F and scattered thunderstorms, there were still quite a few spectators in the stands.
This weekend’s groupings had me racing with a different group than usual. I normally race with the B-Sedan and C-Sedan group, but instead GTL was combined with H through D- Prod. It was fun to get to watch the guys I’m usually dicing with, but it left me with less competition in my group. Turned out to be a blessing in disquise as the Wagon finally met up with the thermal limitations of a stock radiator. I could only run 3-4 laps flat out before the engine temps became unacceptably high, and then I’d have to loaf around for a few laps to get the temps under control. A large AL radiator was in the plans, but I was curious how far I could go without one, I guess I found out… And this weekend’s ‘Golden Wrench’ award goes to Team Wilkins for first finding and then fixing their broken oil pickup tube on Saturday, and going on to take third in Sunday’s race after starting dead last.
Two highlights of the event for me was seeing the Historic Group out on track (instead of in a museum somewhere), and getting to drive the 3MC Motorsports 240Z on Friday’s test-day. John LaChappelle graciously offered me a few laps in my old car to try out a new racing gearbox he had recertly installed. The car has continued to be developed under his stewardship, and it was a real joy to be back at speed in this wonderful car.
Gracie’s new ride…
Yesterday I went to Infineon Raceway to watch my buddy John Teaby celebrate his 59th birthday by making a return to SCCA racing. Some years ago he was a SCCA National front runner in small-bore, but he’s making his return in SCCA’s newest big-bore class, SS. He’s racing his Factory Five Cobra and it’s wearing the livery from his new sponsor, Libertine Films.
My posts have been far and few between this summer as a busy work schedule has kept me out of the garage. I finally got around to pulling the cover off the Wagon for the first time since my last race wknd over two months ago as I had just put it away dirty and left it in the corner… Last time out I lost fifth gear in my close-ratio Comp tranny and so I needed to pull it out. In its place I installed my ‘spare’, a 280Z five-speed that has similar 3rd thru 5th gear ratios. Of course 1st and 2nd are really low for racing and it’s a brass synchro box instead of steel synchros, but it will do while I get the Comp rebuilt. Problem is the Comp tranny uses a flanged output shaft, while the Z box uses a splined output shaft, so I had to prep a fresh driveshaft for the trans swap. I took a stock 510 4 speed driveshaft, had it shortened to fit in the IRS Wagon, put in some new u-joints, and had it balanced up. South Bay Driveline handles these duties for me and does a great job. While I had the car up on the lift, I removed the 4.38 welded r180 diff and put in my spare 4.11 welded r160. I finally got a NISMO Comp LSD unit for my 4.38 and will work on getting it ready while my trans is getting fixed. Next race wknd will be in Sept with VARA at Buttonwillow Raceway.
I love vintage racing, but I really love rollcages, seatbelts, helmets, and firesuits…
VARA, the Vintage Automobile Racing Assocation, has added a new class to its vintage racing format. Seeking to expand their reach, they now have a ‘Club Racer’ class for modern race cars. Some club members had a modern race car they wanted to bring along as well, and some late model racers wanted to come out and check out the “vintage scene” while getting in an affordable race weekend. Either way, it’s a great idea and a great deal! VARA’s next event is their annual Octoberfest race weekend at Buttonwillow Raceway, featuring a special German car Challenge Race. The event takes place Sept 10/11, 2011.
*Click image to enlarge*
What a great word. HABOOB - noun, \hə-ˈbüb\, definition of : a violent dust storm or sandstorm, especially of Sudan.
Last night as we flew into Phoenix Sky Harbor Int’l Airport (PHX), my fellow crewmember captured this shot of a dust storm rolling across Mesa, Arizona. It was being pushed by a large thunderstorm behind it.
Trail braking is an advanced driving technique that all racers must eventually master, like ‘driving the line’ and ‘heel-n-toe shifting’. Trail braking is when the brakes are continued to be applied beyond the corner turn-in point and gradually released up to the point of apex, as opposed to the normally taught practice of releasing the brakes before starting the turn-in. This practice is used for creating weight transfer towards the front tires, thus increasing their traction, reducing understeer, and aids in steering the car more effectively. It also allows for a more accurate corner entry speed adjustment. Once a driver has mastered trail braking, it will help to enter corners at higher speeds.
The alternative is: do all of your braking in a straight line, release the brakes entirely, then turn in. The trouble with this technique is that when you release the brakes, weight and traction will be removed from the front tires just when you need them to be loaded enough to help turn the car into the corner. So the car may have the tendency to understeer away from the corner. This is typical behavior for street cars (engineered with built in understeer) that have been adapted for racing. Also if you do not trail brake, there is a period (from release of braking to apex) when spare grip is available. Overlaying your braking and turning inputs means that you can use the entire grip available in this section of the corner.
At first it’s recommended to brake lightly into the intial turn-in, and then as your skills increase, continue brake application deeper into the corner. This skill will allow you to delay braking on the straight-away even further. The best corners to first practice in are slow and sharp corners, where it is both easier and most beneficial. With further practice you can use trail braking with your left foot in medium-speed corners while continuing to use the right foot to cover the accelerator. Then once you finish braking, move to neutral throttle, and then to progressive acceleration just before the apex. Neutral (or balanced) throttle is when the driver feathers or covers the throttle, applying just enough power to keep the car at a constant speed, not accelerating nor decelerating.
TRAIL BRAKING BENEFITS:
- helps you turn the car into a corner better by maintaining the transfer of weight onto the front tires, giving them more traction, and helping compensate for any understeering tendency the car may already have
- braking deeper in to the turn, therefore being able to brake later on the straight-away and maintaining maximum speed longer
PITFALLS:
- requires additional finesse from the driver at a very busy point on the racetrack, possibly exceeding the driver’s skill level
- excessive use of the front brake can result in a loss of grip as the front tire’s adhesion is split between braking and cornering forces, actually causing more understeer
- due to an exaggerated weight transfer to the front, the rear tires may lose grip, and result in mild oversteer
- if the brake bias is set to nearly neutral (instead of the usual front-bias), heavy braking may cause the rear wheels to lock, effectively causing the vehicle to spin
- excessive braking - you may simply slow down too much
The Grip Circle
The maximum grip level that a tire can give is depicted by the outer circumfrence of the Grip Circle. A tire can give max grip while cornering, braking, accelerating, or a partial combination of these. Trailing the brakes gives you the opportunity of using 100% of the tire’s grip from the braking point on towards the apex of the corner. So as your cornering traction requirements increase towards the apex you must reduce the braking inputs so as not to exceed the tire’s limits.
Trail Braking