9/3-4/16, High Plains Raceway
Another great race week end! NASA Rocky Mountain is a great organization – well managed, smooth, safe, and lots of fun people.
The new fender mounts seemed to work well. I watched them very closely during the week end. No evidence of failure. You’re welcome, David. 😉
How did we do? Great! I didn’t set any track records. But I did set a new personal best of 2:02! For me, that’s Smokin’ Fast. 🙂
I started to here some clunking from the rear. Check out the “Rear End” page for some trauma updates.
7/1-3/16 Pueblo Motorsports Park
Spent three days at the track again. Friday was a practice day, Sat and Sun were race days.
Did pretty well, but had some difficulties. I was running rear fenders for the first time. I like the rear fenders, because it prevents all that rubber and junk from being flung around.
But, the brackets didn’t hold up, and the fenders came in contact with the tire. Nearly caught the fender on fire, and ruined a couple of good Hoosiers. Oh, well. Back to the drawing board.
5/28-30/16 High Plains Raceway, Byers, CO
HPR is a great track, I love racing there. Some high speed straights, banked uphill sweepers, and some slow technical corners. Challenging, and just a boat load of fun. I’ve been racing at this track in my Cobra since it opened. The best I have ever managed was 2:06.554. Not bad, but not stellar, either.
The weather was about as perfect as you could ever ask for: Cool air, and warm sun. Air temps around 65-70* for good safe power, and track temps >125* for nice sticky tires. Perfect!
Saturday and Sunday we really struggled. The car would intermittently die; like shutting off the key. Most often when I was slowing down, like behind a slower car or coming in to the pits. But not when hammering the gas or the brake. If I pushed in the clutch and let the RPM’s drop to zero, count to 2 or three, and pop the clutch it would start right up again.
We checked over everything, looking for a loose connection somewhere. Changed out the TPS and CPS. Searched through the ECU and dash data logs. Nothing showed up.
Finally found it near the end of the day on Sunday. It was a bad circuit breaker for the fuel pump. It would just occasionally open and kill the pump. Then close again. We replaced that CB, and the problem was solved. Weird.
Sunday was a great day, especially since the car was running so good. Excellent weather, and low traffic – a lot of people didn’t stay for the third day. Learning to drive this car is a challenge (which is why I built it). It corners very flat, doesn’t seem to have any bad habits, and I haven’t really found the edge yet. It’s there, I’m sure of it. I just haven’t found it yet.
Turn 11 is a sharp, somewhat low speed corner with a steep up hill exit. My favorite corner. I had to be very careful there, as too much throttle would make the back tires spin.
Top speed seems to be about 135 in 4th gear – 3.55 rear gears, 275/50-15 tires. I could upshift into 5th, but the OD probably wouldn’t get me any extra speed or time, and then I’d have to downshift twice for turns 4 and 5.
As the day went on, we collected data for the tires and suspension; temperatures and pressures mostly. Based on that, we made subtle changes. The car just kept getting faster. My fastest lap of the day was 2:01.637! Amazing! Almost 5 seconds faster than my previous personal best. I’m impressed. But I’m pretty sure the car has more in it.
The driver of the Blue Corvette is very good. Any day I can keep up with him is a good day.
Entrance to turn 3.
The corkscrew. Those Beemers are very fast.
There is a pot of gold, but it’s not out there in the grass. 😉
So, what did we learn? Lots. Tire pressure varies from corner to corner; but all are <18psi. Pressure changes were made based on tire temps, and not just hot pressures. Without tread temps, you’ll be way off. This track also needs an asymmetrical alignment. Also, tire temps only got to the mid 130’s. Maybe I’ll try an autocross tire?
This car needs fenders. Without fenders, it throws rubber and junk all over the place. Bashed my side view mirror, and hit me in the arm a few times. It’s kinda funny to see a big chunk of rubber shoot forward, hit the ground and bounce, and then you drive in to it. Not good for the cars behind you, either. I’ll work on that.
And, this car needs some kind of windshield. I don’t mind getting hit by the bugs, rubber, and junk. That’s why I have a full face helmet. But at triple digit speeds, there’s a lot of helmet buffeting. It makes it hard to see the next corner coming up, and I’d brake too soon.
And, finally, keep in mind of your safety. According to the AiM MXL data logger, this car will pull 2 lateral G’s! (and I bet there’s more) You can get this! ————>
4/16/16 Pueblo Motorsports Park
Finally got to a real track day. As you already know, I race with The National Auto Sports Association, Rocky Mountain division http://www.nasarockymountain.com. I do not race wheel to wheel for a number of reasons. I race in TT (Time Trials), in the unlimited class.
This event was held at Pueblo Motorsports Park, in Pueblo, CO. It’s a fun track, and I always enjoy racing here. There are some fast sections, small elevation changes, and some slow technical corners. A good variety that can really challenge the driver. The Exocet did pretty well on the short track, and I was anxious to see how it would do on a bigger track.
I went down on Friday to get some practice time in; check tire temps, make suspension changes, etc. Well worth it, as I learned so much in a short period.
My cobra is slightly heavier, and makes about 100 more HP than the Exocet. I generally run 1:45-1:46. My best there is low 1:44. On the long front stretch I can hit about 145-150mph. So that’s my bench mark.
Friday was a pretty good day, weather wise. Warm enough to drive without a jacket. Tire temps got up to 130-140*. My best lap time 1:46. Clearly, the car has too much camber, as the temp spread was about 20* all around (goal is 7*).
With FM’s adjustable upper rear control arm, adjusting camber in the rear is pretty easy, and only takes a few minutes. No need for alignment tools. The front is more difficult, and requires alignment tools; so I left that alone for now.
Saturday the weather was miserable. Pueblo was at the southern end of a big snow storm. We got rain, sleet, high winds, and a little snow here and there. Some areas north of us got 4 feet of snow. That’s right…. 4 feet – in April. Needless to say, I did not drive at all on Saturday.
People asked me how the car did in such bad weather. I tell them it did really well. It waited very patiently in the trailer until I was ready. 🙂
The weather on Sunday was a lot better. Dry, and slightly warmer. But needed to wear a jacket all day. The sun never really came out, so the track never got warm. Despite some hard running, tire temps never got above 100*. Not even close to their operating range. But heat was better in the back with less camber, with a temp spread of 12*. Still need to take some camber out.
The long front stretch was a challenge. With a heavy head wind, car couldn’t get over 125mph or so. Best lap time for the day was 1:48. Considering conditions, though, it wasn’t bad. I ended up about third fastest for the day, with less than a second away from second fastest – a well sorted Beemer.
So, what’s next? Obviously, some suspension changes. Tire temps show a little bit if understeer, so I’ll change the wing angle a little. I have a punch list of items to take care of; Increase seat angle, and such. The used Miata brake master cylinder was leaking below the reservoir, so I’ll change those bushings. The axles are spewing grease and making a mess. couple other small things.
All in all, the car did well for it’s maiden voyage. Next up is High Plains, a big track with some really high speed sections.
Went back to PPIR again this morning. I had made a few changes and wanted to see how they worked.
The track was better today. Warmer surface temps, with cooler air temps. In the beginning, there was no wind. Around noon, though, the wind kicked up again to make things more difficult. Pikes Peak International Raceway
I moved the seat back about 2″, and that made a huge improvement. My legs are an excellent fit, now. but I still feel kind of hunched over the wheel. Now I think I need to lay it back about 5-10*. That shouldn’t be too hard. Easier to turn the wheel, too.
The engine is still spewing oil out of the left breather. The oil ends up in the cockpit , and under my shoes. I’ll change that from an open breather to a remote catch can breather, and that should help. It has an LS6 valley cover with integral PCV valve, so I don’t need to worry about that. I need to work on a better system than what I have. I need to seal up the fire wall a bit better, too.
The power steering pump was spewing oil. I replaced the cap and removed some of the oil, and that’s resolved. It doesn’t seem to be getting too hot, either. So the cooler is doing it’s job pretty well.
The engine ran very well. I have a 190* thermostat, and temps never got above 200*. The fuel cut is annoying, so I’ll need to change that. I spent a about 75 minutes on the track, in multiple sessions. I burned about 9 gallons of fuel – E-85. 8-9 gallons per hour, not bad at all. When I get time, I’ll try to download and review the data from the MXL dash.
I changed alignment settings. I decreased camber front and rear, and kept the same caster and toe in settings. Better! There’s a more even temp spread, and the car seems to handle better.
I still get a lot of oversteer coming out of a corner. It’s real easy to overwhelm the rear traction with too much throttle. I added a little bit of rear wing, and that seemed to help without slowing me down on the straights. But this is a short track, and speeds are not that high. We’ll see what happens on a faster track.
The least amount of camber I could get in the rear is 2*; that’s it. couldn’t get any less with the stock arms. I have a set of FM’s adjustable rear arms. Later this week I’ll swap them in and see if I can get a little less camber back there. That might also help the tire rub issue. If it doesn’t, I’ll swap to a 25mm spacer.
Front: 1.25* Camber, 5.0* caster, 1/32″ toe out.
Rear: 2* camber, 1/32″ toe in.
Car felt very stable at stupid fast speeds. According to the GPS, my fastest lap was a 2:02.2. A personal best! If it had a better driver, this could be one seriously fast car. 🙂
First track day! I took time off work, and went down to Pikes Peak International Raceway for some testing. This is the first time it’s been driven off my street. I was lucky, and had the track all to myself today. That was fun. Sunny, but cold and really windy. Track temp was only 75*, air temps around 50*.
There are some bugs that need to be worked out. The breather was spewing motor oil. And the power steering reservoir was leaking. Kinda messy.
And the alignment isn’t what it should be, based on tire temps. I started out with the alignment settings recommended by 949 Racing. But I think it needs a little less camber.
The brakes are awesome! Love these big ‘ol Wilwoods.
My Cobra has an older style TKO transmission that I bought 12-13 years ago; before the 500 and 600 versions. It’s a solid transmission, big, heavy, and dead nuts reliable. They are just tough as all get out. The Exocet has a stock T56, right out of a Firebird. All I did was change the shifter and add fluid. I really like this T56. The throws are short, and the action is as smooth as silk. MUCH better than my old TKO. Wish I could easily fit a T56 into the Cobra. There really is no comparison, the T56 is that good. At some point, though, I’d like to remove that and install a custom built dog ring T5 – that would save about 50 pounds! 50 pounds is a lot of weight.
I’m really not that happy with the AIM MXL Pista data logger and dash. It didn’t map the track well. And it stored the runs as single laps. Maybe that’s good, and maybe not. I really haven’t learned how to read the data logs yet, so it could just be operator error. I’ll keep playing with that.
Man, this is a small car! I thought the Cobra was small. This is a really tight fit. I had to cut off some of the padding to make room for my left arm. And I need to move the seat back a little bit. Maybe an inch or two.
This car is going to be fast. It’s really quick, and once I learn how to drive it and get it dialed in, I think it will be considerably faster than my Cobra. My best lap time so far has been 1:02.7. Today, I hit 1:03.9 without pushing it too hard.
Now it’s really getting fun!