GeorgeCo.org

Stealth Action Photos

Thanks to the NCC website, I just got some photos of the Stealth in action last week at Sykesville. There are a couple of things to note in these photos. The first one is under hard braking, just turning-in to a fairly tight right turn, body roll isn’t bad and the front doesn’t seem to be really loaded.

The second thing I notice is how much better the paint looks on the door and front fender than the rear quarter panel. That’s because I haven’t painted the rear quarter panel yet. I’m also thinking that if I really want to stick with the whole black-out theme, I need to tint the windows and paint the chrome trim black as well.

And the Beat Goes On

It was a beautiful morning for an autocross. The National Capital Chapter of the BMW CCA held another points event at the MD State Police Training Facility in Sykesville. I was eager to get the BMW back on the road, so I gave it a try, even though the U-joint beats the drive-line like a madman. The 16 inch MINI wheels and R-comps are a bit too tall for the E30. I can’t quite get lock-to-lock without some rubbing in the wheel well. In the future, I’ll have to stick with the RA1s on the 15 inch wheels instead.

The steering rack performed flawlessly. It’s probably psychosomatic on my part, but it seems easier to steer and more responsive to input. Maybe that’s because the system is holding pressure and not just pumping fluid into the boots. The drive-line is something I’m going to have to deal with. I think I progressed backwards today: my fastest run was the first one; slowest the last. I found as I went on, that the vibration became worse and by the end, I couldn’t give it full power without shaking the whole car.

I also managed to finally finish painting all of the calipers last week. Red calipers must be good for .2 secs a run…

Update: 6/14/09. Just checked the results and I won my class!

Driving the Shenandoah 29-31 May 2009

It was a beautiful weekend to be at the track. (Actually, there are no bad weekends to be at the track. Except maybe when it snows — been there, done that.) Except for a brief deluge, it was sunny and warm all three days. I really appreciate the Friday IA days. I get more track time in that one day than I do in the rest of the weekend. So much in fact, that I almost ran out of gas.

The two videos below show the last run session on Sunday for the A Group. The groups all had about 12 students each which was an ideal size for this track. We were also fairly close in speed, with a few faster than the MINI (OK, most) and a few slower. This was also the first time I’ve run with another MINI on the track that wasn’t driven by an instructor. It was cool to see the difference in performance between the R53 (mine) and the R56. With about 20% more torque, the new turbo really pulls away on the straight.

The skidpad was interesting. I don’t know what BSR has done to it, but you’d think a skidpad was supposed to be slick. This one had an amazing amount of grip, even when soaked. We were hitting speeds above 42MPH before getting any understeer. It wouldn’t be a problem except there isn’t much run-off area when you start to spin or push outside of the wet zone. I managed to get the MINI to oversteer by increasing the pressure differential between the front and rear tires. When the tires were cold, it really came around with just a throttle lift. When the tires were hot, we had to induce it with the E-brake.

There’s your problem…

I’m no expert mechanic, but I suspect that there steering rack belongs somewhere under the car…

Day 1 of the steering rack adventure is complete. Without making too much of a mess, I managed to get all of the hoses off, fluid drained, and the old rack removed. The tie-rod links proved to be a pain, but after much wrangling, the whole thing finally came out.

If installation is the reverse of removal, do I have to bust my knuckles and pinch my fingers in the same places as I put it back together?

CDC Autocross, 23 MAY 2009

Since the BMW is still on jack-stands in the garage, I decided to take out the MINI for the Capital Driving Club autocross at Bowie Stadium this weekend. It was sunny and hot, but fortunately, not yet so humid. I was competitive with the other MINIs that were running, but I wasn’t up there with the top 15 this time. No grip on the dusty course (at least that’s my story and I’m sticking to it…)

You can see from the photos above that the course was quite dusty. It started with a clockwise half-loop into half a figure-eight and another half-loop into a short slalom. Across the top of the parking lot through as series of tightly spaced off-set gates with a quick right-left-right-left, followed by a loop to the finish. You sort of get a feel for it from the video, but the camera mount is too low to see the cones. I’ll have to figure out another way to mount the camera in the future.

Thanks to the CDC group photo pool for the photos of my car. I also posted a bunch of photos from heats 1 and 3 to the pool as well.

BMW Not Ready for Prime Time

I was hoping I’d be able to make it to the May NCC HPDE at Summit Point at the end of the month without having to replace my steering rack, but no luck. The boots are full of fluid. There’s also a vibration in the drive-line which probably indicates the U-joints are shot.

Of course, this model doesn’t have replaceable U-joints so you have to replace the whole drive-shaft. The good news (as such) is that a replacement isn’t that expensive, and a good, re-manufactured and balanced shaft is only about $400. Of course, you have to drop the entire exhaust from the header back to get to it…

Since there’s no way it will be repaired before next weekend, I thought I catch up on some of the details I skipped when I rushed on to the track in March.

I’ve always really hated how the stock rotors and calipers just rust away. If you’re running the old bottle-cap wheels, you never see it, but with the open track wheels it really looks poor. Hopefully the extra coating won’t add to the heat build-up.

And no, I didn’t forget the retention spring. I’m just letting the paint dry before putting it back on.

518 HP MINI

I recently lost my cell phone which turned into an opportunity to get an iPhone. There are a couple of interesting automotive apps available for iPhone so I thought I’d test a couple of them.

The image above shows the Dyno results for the MINI using an app called Dynolicious. It shows a 12.82 second quarter-mile at 137.4 MPH and a peak horsepower of 518 HP. In third gear. On a public street…. OK, so maybe the calibration was off a bit. My second run after calibration showed 229 HP, but I didn’t capture the image. I think that’s still about 10% too high, but more realistic given the previous Dyno results at 197 HP.

The second image shows the results for the BMW — Even though it still says MINI — which I suspect are more accurate. I’m really most interested in initial acceleration so the chart really tapers off as soon as I get into third gear. I was trying to compare the BMW to the MINI to see which is quicker off the line for autocross. I decided to try a second app as well called PocketDyno+ which I thought was a bit easier to use and set-up than Dynolicious, but doesn’t produce the really cool charts you see above. The results were interesting.

The MINI has about 25% more HP than the BMW; weighs about 200 lbs less, and is almost half a second faster covering 1/8 mi; but in the first 60 ft — which is what really counts in autocross — the BMW is faster by .15 seconds. Both cars are running the same Falken ZE 912 tires and the test was conducted on the same stretch of road under the same conditions. I suspect the effect of the weight transfer on the FWD MINI negates the superior power and torque available until the cars starts moving, and then it plays less of a role in straight-line acceleration.

CDC Autocross Event #4, Summit Point, 9 MAY 2009

On Saturday I finally made it to a CDC autocross event. This one was held at the Triple Skid Pad at Summit Point — same place as the BMW Club event, only this one wasn’t a sogfest. BSR has finally paved the aprons around the inside of each skid pad and cut-out, but the infield is still very soggy. The course was fairly simple, but because of the lack of grip, was actually quite challenging. I wasn’t sure if it was going to be wet so I took both the RA1s and the Hankook slicks. I ran the morning runs with the RA1s and then the slicks in the afternoon. Right off the bat, the slicks were 3 seconds faster and ended up being almost 5 seconds faster.

The video is from the last run. I still haven’t fixed the audio, so you want to turn down the volume.

The results aren’t posted yet, but I suspect the winner was in the low 47 second range. I’m hoping for a top ten finish. My best was in the high 48s. As a comparison, my best on the RA1s was in the low 53s. I probably should have heat-cycled the Hankooks before running them last month at the first SCCA event. They really had much more grip this time, even on the slick surface. I think they are going to work out well this year and seem to be wearing fairly evenly so far.

The only down side was the poor fellow driver in the Lotus Elise who went off into the mud only to turn up a 30-pound rock with his front splitter. With a large “whack”, bits of carbon-fiber were flying everywhere. I’ve been told the only way to make repairs is to buy a new clam shell for the front half of the car. That’s an expensive weekend.

SCCA Championship Event #1

This past weekend featured the first SCCA Autocross event of the new season at FEDEX field. It was a chance to test out my new suspension and tires. During the winter, I picked up some Hankook Ventus Z214 competition tires from Frisby Race Tires. For a while, they had a special on the C50 (medium) compound in 205/50R16 for about the same price as a regular street tire. So I grabbed a set, repainted the white Kosei rims, and had them mounted up. (The new rim color is as close to “brake dust” as I could find, thus saving time from cleaning.)

Sunday turned out to be in the ’90s — very unseasonably warm for April around here. I was worried about overheating the new tires on their first use. They were not heat-cycled so I knew they would be a bit slippery anyway, but I’m very happy with them. I ran with 38-40 lbs in the front and 35-37 lbs in the rear. I can probably drop it down a pound and start off with 35/33 cold instead of 36/34 which I had. The new springs are also a bit softer than the old ones, but once I got used to them I could make them work for me. I dropped 2 seconds over the four runs, with the last two runs being exactly the same down to the thousandth of a second. Odd.

I came away from the event thinking I hadn’t done that well, but ended up placing 6th out of 16 in my class (street mod). I always compare myself to G Stock, which is where I probably should be running, where I would have placed second. One day, maybe I’ll bite the bullet and make my car eligible for that class again.

H&R Sport Springs for the MINI

I’ve been having some problems with the MINI’s suspension lately. First was a thumping sound in the right rear, and the left front seemed to bottom out on even the slightest bump in the road. That and the fact that my family won’t ride in the car anymore because of the harshness of the ride, finally got me to thinking of changing the suspension again.

The photos above show the old TSW springs compared to the new green H&R springs. The new springs look to be quite a bit taller, but that’s somewhat deceptive. The H&R springs are progressive and have extra coils at a lower rate so they do not slip when the strut is fully extended such as when the car is on jack stands. Shorter springs will slip when not in compression and then you have to reseat them before lowering the car.

One of the added benefits of having shorter springs and shorter struts is that you can remove the entire strut assembly without having to separate the ball joint at the hub. With the standard strut height, there isn’t enough movement in the lower control arm and axle to get the strut out of the housing. With the shorter strut, you can just drop it out.

The front H&R springs appear to be a bit wider than the TSW springs they replaced. That means I’m going to loose a bit of negative camber once I get it realigned. We took a quick trip once I had it all back together and the harshness is gone. Seams in the road no longer bottom out the suspension.

Once installed, the rear has the same ride height as before. I cut down the bump stop by a half inch so I’ll have a bit more suspension travel now. It turns out the retaining nut on the right rear strut was almost completely loose. That may have accounted for the noise I was hearing. I reassembled the strut and tightened everything. If there’s still a sound there, then it’s either in the swaybar or in the subframe.

I measured the ride height before and after the change. The rear ride height is the same, but the front is about an inch taller. That splits the difference given the two inches it was lowered previously from stock. I also found the source of the “whump” in the front. There was no bump stop installed on the front left strut. The strut was bottoming out against the camber plate.