The Slow Lane

A blog about autocrossing, some geeky stuff & Philadelphia.

Browsing Posts Made in: July 2008

Found the Source of that Tire Vibration

Ever since the first or second event of the season I’ve had a vibration at high speeds. I checked various things on the car and nothing seemed out of place. I took a look at the tires while they were on the car looking for flat spots and didn’t see any. I figured a weight fell off or a tire shifted enough to throw it out of balance and just lived with it since I don’t drive the car that far on my competition tires. I was changing back to my stock tires for the drive up to the Finger Lakes ProSolo and what do I see? A big old flat spot.
Flatspoted Tire
That explains that. The front brakes tend to lock up early on these cars and it looks like it finally caught up with us. After my experiences with mismatched tires on the Prelude I realize that I have to replace them in pairs. I hate the idea of throwing out a perfectly good tire so I’m gonna just run on this and keep a close eye on it to make sure it doesn’t cord. Hopefully I can get through August on it. We have the Al Holbert Memorial and possibly PA States that month. Both two day events.

Hitch giving me issues

It’s always a struggle with this car and attempting to put a hitch in so I can carry a tire trailer was no different. First of all the hitch I chose is from Hard Dog Fabrication. There are at least two others who make hitches for the Miata, but I chose them because Irene has a roll bar from the same company and it is of very good quality. Plus they are a small company in North Carolina, not a big cooperation. As usual the big problem is rust. The hitch installs were the rear tie downs go. A previous owner took all the tie downs out of the car but but the fasteners back. There is two screws, and two nuts on what appear to the studs per side to remove. One of the nut/studs snapped. One came off. On two others the nut and stud are just spinning. I got three of the four screws out. One of those snapped too. The “studs” are not really studs but bolts that are supposed to be held from spinning by a piece of sheet metal with a hex shaped hole cut in it. They also help hold the bumper on. I was able to barely get a socket up between the steel of the frame and bumper and on the bolt head. But the steel that is supposed to be holding the bolt is place is so mangled I can’t get the socket on the head. And the other bolt is so far up that there is no way to get anything on it.

So I figured that I could take off the bumper and gain access to the bolts. All the screws came out of the bumper w/o breaking to my surprise, but there was something holding the bumper on the car at the top underneath the rear panel. I dreaded taking the rear panel off as I was sure I was going to break a bunch of the plastic clips that hold it on. Surprisingly I didn’t. So I get the bumper skin all off and see that I don’t have any better access to the bolts then I did before. If I can take the plastic frame of the bumper off I can get to them. It appears to be held to the two brackets that are attached to the frame of the car by four bolts on top and two bolts on the bottom. Because you can’t put metal screws in plastic threads on the other side of the bolts are nuts that have clips that again keep them from spinning. All of these fasteners are badly corroded as well. :(

I tried taking them out but two of the nuts clips broke. Several other bolts started to unscrew but then felt like they were going to snap. At this point I really needed a sawzall to cut through the bolts. And I don;t have one. And I’m sure the apartment complex wouldn’t approve of me using one in the parking lot. So I had to bag trying to put it in. I wanted to carry my tires up to the Finger Lakes ProSolo on the trailer but it looks like I’m going to have to bum a ride for them or just drive up on them. I’ve held up from buying the actual trailer until I got the hitch in. I doing know when that is going to happen. I still have the manual steering rack sitting waiting to go in. And along with that the front alignment bolts need to get replaced. One of them keeps coming loose and banging around. So much yet to do to this car and not enough time.

Almost had it, 2008 Philly Event 5

The win that is. It slipped right through my fingers. Doug has been beating me by a second or two every event. I guess my lessons learned from the Tour about aggressive turn-in paid off. We were at Warminster and the course was a mixture of fast brave elements and painfully slow ones. The “Way out” was mostly fast. A slalom, a “wallom” (a slalom with some wall elements) with a shorter third element, and a semi tight chicane type maneuver that reminded me of last year’s Holbert a bit. But if you got the first part of the chicane right you were flat to the turnaround. After that was a nice slalom and then began the painfully tight offsets. The course designer stated he was trying something and it just didn’t work out. There were 5 offsets I think and they opened up progressively. The last one was very open and led into a fast three cone slalom. The finish had us on the rev limiter on almost every run. This was also the first real event with my MaxQ and I can say that the rev limiter is only at 55 mph. Im gonna have to do something about that next year if I’m going to keep up with the CRXes.

My first run as usual wasn’t anything special at a 66.x but on my second run I was able to improve to a 64.x. My main goal was to be aggressive with turn-in in the fast stuff and try to sting together fast segments. And then not kill myself on the slow stuff. Doug was making up some time by doing a not entrance to the three cone slalom on the way out and doing that netted me some more time. I got a little too aggressive with the slow stuff on the third run and didn’t improve. Doug was dirty on most or all of his previous runs but he laid down a 63.0. Eek. He still wasn’t happy with how he was doing the slow stuff and said that I was doing that part better than him. I tried to put it all together my fourth run as well and was surprised with a 63.3, which even more surprising was good enough for a second place! I don’t know what happened to Dan the Man but I had heard that he was battling with Justin Stone, who was on some new Toyos, so I thought we were behind those guys. But we were in the lead.

The bigger surprise is after packing up and doing back to the truck George was joking around about me sabotaging my co-driver. On the results Doug had a cone on his last run so I was in 1st!! I don’t remember the cone but wasn’t going to question it too much and I took home my mug. Two days later when the results came out that cone disappeared. It wasn’t on the cone confirmer’s sheets so Doug took the 1st back from me. :(

I played with the MaxQ data some when I got home. Some of Doug’s runs have bad GPS drift so it’s tough to compare exactly. But I was able to watch Doug’s and my runs together in real time and see who was faster in which section. I also got to make some cool color-coded course maps using gpsvisualizer.com and Google Earth. I was worried about the 20 mph auto-logging speed being too high because of my experience at Boeing. At Boeing manual recording might be needed but at most autocrosses the default settings worked just fine. I manually recorded my first run and then tried it with the defaults after talking to some others who have the same unit. Setting it up for two co-drivers was a breeze one I figured out that you had to hit the down arrow on the PocketPC to switch drivers. I was frantically flipping through the manual in grid. I’m very happy with that purchase. I haven’t had time to look at other people’s runs due to being busy with the wedding. But I think that will be a big help to my driving too.