| MIATA BUILD |
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 | |  | May 25, 2008 - I took the car out for a run on the local "Targa simulation" road.
It's rough and twisty and gets gravel on it. I wanted to play with suspension settings a bit as well as see how the car does with putting down the power out of corners.
The suspension setup worked just fine. One hammered area had the car moving around a bit much, but a slight tweak to the rebound solved that nicely. As for the inner wheel wheelspin on right hand turns - well, it doesn't seem to be a problem. I'm realizing that both the autocross course and the local gokart track are much tighter than most turns in the real world. On the "big track" at Pueblo I don't have a problem. So, I think I'll just let this slide - or just bung the Guru in for the race and avoid it completely.
I'm still driving at "fast road" speeds, though. There's an overall speed limit of 200 km/h (120 mph) during the race, and in the open sections I'm trying to imagine going 50 mph faster. And having Janel deal with me going 50 mph faster. She's been alongside me at 10/10ths on the racetrack, but I think it will be quite a different matter on real roads.
The list of things to do for the race is getting shorter, but no less critical. I still have to add a door bar (a different focus in the regulations here) , figure out how to mount my tools (and what tools to bring) and deal with a number of small things to ensure I don't have a hectic day running around St. John's to solve problems. But it's starting to look pretty good. So maybe I can start working on engine output again.
entry 460 - tags: testing, suspension | | |  | June 1, 2008 - We have to carry three safety triangles with us in the car.
No problem, so I picked some up at NAPA. Holy cow, they're heavy! That black base is full of sand or lead or depleted uranium or something, designed to keep the triangle upright in a hurricane. I'm going to do some small modifications here to make them a little more svelte.
entry 461 - tags: safety | | |  | June 1, 2008 - Autocross time!
This was an event put on by the Red Rock Racers, a group I started because we didn't have any autocrosses to go to! Problem solved, now there's one a month. And on the prettiest autocross course in the world.
We had a good bunch of cars out - a couple of modified STis (including one on Toyo R888s), a rotary-powered X1/9, some quick Miatas, an Evo and even a Isuzu I-Mark "Handling By Lotus". Everyone's a lot of fun to run with. However, they did have a little trouble keeping up with the Targa Miata. I took the fastest time of the day by a 0.8 second margin.
The car felt good, moving around nicely and easy to toss into corners and transitions. I was using the brake bias to adjust the handling of the car and it worked well. I didn't adjust anything on the suspension after my recent over-the-road testing otherwise.
The picture was taken on a fast right sweeper, and you can see there's a fair bit of body roll. It didn't seem like it from inside the car and it responds to transitions pretty well. But I was still having traction problems on rights, and looking at that roll makes me wonder if it is simply a matter of unloading the inner wheel completely despite all that droop. I'm going to play with some different sway bar and alignment settings, although having Janel in the car helped and I expect a cornerweighting session would also plant that right rear a bit more.
Another thing that concerned me a bit was my consistency - or lack thereof. I'm usually pretty good for putting down similar times, but today I was all over the place on the timing board. Still at the pointy end of the pack, of course, and I posted not only the fastest time but also the second-fastest and (I think) fourth and fifth-fastest. But there was a bigger range than usual. I'm not sure exactly why. I did manage to stay clear of cones all day though.
The car was burping coolant out of the overflow tank, but not showing signs of running hot. I think I might have a bad radiator cap that's venting early. Easy enough to check. Otherwise, the car ran flawlessly.
entry 462 - tags: testing, suspension, brakes | | |  | June 7, 2008 - My friends Axel and Steffi from Germany dropped by for a visit, bringing their son Tom (almost six years old) and friend Andre along with them.
Both Axel and Andre are pretty familiar with the car and were quite eager to see it. Apparently it looks better in person than in the pictures! Anyhow, while they were here we had a fun day of driving all over the place in a bunch of the cars.
entry 463 | | |  | June 7, 2008 - Of course, while they were here we had to visit the track.
And Tom jumped into the passenger's seat to take a few laps with me. He speaks German and Portuguese, I speak English and French. But a big grin comes across pretty well regardless!
So, how did the car do? Well, it handled everything with aplomb except for the track sessions. I took the car out first and soon discovered that it could not hold any coolant and overheated badly. After it cooled off, I pulled the radiator cap off and discovered that it was in terrible shape. I wonder if it was a temporary one from a junk car that I put in place while building? Anyhow, it's going to have to be replaced.
We stole the cap off Janel's car and went out again. Still a problem, possibly due to air bubbles after a big coolant blow-off with the bad cap. But the radiator did come out of an older car, so I'll pull it and clean it.
This track is excellent for testing cooling systems. It's at high altitude, has low humidity and has low average speeds - it's a worst-case scenario for cooling. The high was also getting pretty close to 90F. So if the car's ever going to have cooling problems, this is where. We were also running longer sessions than usual here. I don't anticipate cooling to be a major problem in Newfoundland, but if I can keep the car happy here after 15 miles of full throttle in second gear, I'll never have to worry about it.
Otherwise, the car did pretty well. It was at the track along with The Seven, which does have the tendency to make anything feel a little fat and slow. The Targa car has a very different handling balance because it's built for a different purpose. It's less prone to oversteer (no, really!) and more forgiving - as it has to be. But I think some of the things I learned building the Miata will get transferred to the Seven, just as the knowledge from the Seven helped me build the Miata.
entry 464 - tags: testing | | |  | June 7, 2008 - At the end of a long day of driving.
We bolted the hardtop back on, I did a few checks of the car and it was time to get to bed. The Glenwood Springs Rally put on by the MG club was in the morning!
entry 465 | | |  | June 7, 2008 - At the crack of dawn, Janel and I took off for Glenwood Springs to try our hands at a TSD (Time-Speed-Distance) rally.
There's actually a TSD aspect to the Targa in the Grand Touring class, but we're not running that. Still, we figured the experience would be a good one, allowing us to spend some time in an organized rally environment that's fairly low pressure. And with cool cars. There were at least 60, including two or three other (stock) Miatas and a newer Corvette. Pretty much everything else was a classic.
Let me tell you, rolling up into a parking lot full of vintage cars in a stickered-up and Martini-liveried car with a full rally computer, well-broken in race rubber and your names on the roof makes you feel a little conspicuous. And people certainly don't believe you're novices!
entry 466 - tags: testing, skills | | |  | June 7, 2008 - Janel, hard at work watching for instructions.
A TSD is more of a treasure hunt than the Targa is, and there wasn't as much navigation as we would have preferred. They have to be run in rural areas, though, and rural in Colorado means you don't get a lot of turn-offs because you're usually running along a valley or climbing a pass. Still, we did get much more familiar with communicating with each other, dealing with problems ("I said slow down!" "But it's sooo boring!") and Janel got to spend lots of quality time with the trip computer.
All joking aside, despite the warnings of others never to do a TSD with a loved one, we had no compatibility problems. Both of us were in pretty good spirits throughout the day. This was probably in large part due to our rally computer. See, the required average speed varied fairly frequently thoughout the stages. But for us, we set the Coralba to display the average speed and simply reset the tripmeter at each change. So I could simply look at the display and see that I was 0.1 mph high, or we could stop and wait until our speed dropped to the ideal level. Normally there would be much work with stopwatches and calculators along with a lot of stress. Our biggest problem was my apparent inability to drive very very slowly at times. We didn't get lost, though. That's the important thing. And any frustration was tempered with humor instead of anger.
We also learned quite a bit about the car. It turned out to be an excellent shakedown test as we'd never spent 12 continuous hours in the car before. First off, both Janel and I found we need more padding in the seats. My memory foam must not be thick enough. Our butts were asleep before we even got to the start line, over an hour from our house. Also, the car is hot and noisy on the highway and cracking the windows seems to draw in exhaust fumes through a number of small holes in the transmission tunnel. The latter is easy to fix. Hot, well, that's probably not going to be a big concern in Newfoundland. Noisy - it's time to look for some transit headsets. We won't be at a sustained 80 mph on the transits, but even the background nose at 40 would get tiring over the course of the day. I'm going to throw some light sound deadening at the back of the car to see if I can help this at all. I think I'm also going to go to a 4.10 rear end instead of my current 4.30, as I don't need such short gearing.
Mechanically, the car was faultless. Some sadistic organizer put a 20-minute stop in at Leadville. That's about 10,000' up, and you should have heard the poor carburetted British cars trying to struggle back to life. Let's hear it for fuel injection!
Okay, almost faultless. The suspension got a nice dirt bath after we spent about half an hour trying to maintain 38 mph on a fairly rough road, and it's creaking badly. I think I just need some bushing lubrication underneath.
A long day, but a good day.
entry 467 - tags: skills, testing, ergonomics, computer, seats | | |  | June 7, 2008 - The holy grail!
A competitor from previous Targas lent us a copy of his route book from 2007. It's day 3, and it's marked up by his navigator both before and after the event. This page is the infamous wooden bridge.
This is fantastic. I have in-car footage of the entire event. Now we'll be able to compare it to the book to get a better idea of how the book corresponds to the new world. It's 2006 video and the 2007 notes, but it's close enough. I can't wait to see how some of the notes in the Greenspond stage correspond to the roads. It looks tough!
There are also the times for the various stages included. For those who have asked me why I didn't go turbo - I'd have to go faster. For example, on the Musgrave Harbour stage, I have to complete the course in 3:18 with an average speed of 110.4 kmh to avoid penalties. The aftermarket turbo Miata would have to do it in 3:07 or 116.9 kmh. That's a significant enough difference. If I'd built a 1990 Miata instead of a 1994, I'd have 3:22 to complete. But then I'd be stuck with about 400cc less engine displacement (have to keep the original block) and a weaker, less effective rear end. So I think I'm pretty good there.
There's a schedule of the day included as well. Looks like our 12-hour day today might have been good practice. Ugh.
entry 468 - tags: skills | | |  | June 8, 2008 - One of the things on my "to do" list after the TSD was to swap out the differential.
This will actually accomplish a number of things. It will let me see if a different differential still has the traction problem on right turns. The previous diff was from a 1999 Miata. The current one is a Type 1 Torsen, which acts a little bit differently and can handle a wider split of available traction.
It will also raise my gearing a bit. Right now, it's a bit on the short side. I had originally figured I'd run the 4.30 because it gave me a 120 mph engine speed of 6120 rpm. 120 mph is the maximum speed allowed in the Targa. But the gearing's just too short, and I'm always looking for another one. So I'm going to try a 4.10. 120 mph speed drops to 5835 rpm and I can reach 42 mph in first if I have to. You can play with Miata gearing on the Flyin' Miata website - the default setting just happens to be my new setup.
I'm also testing out some new polyurethane differential mounts. It will make my shifts a bit more precise. It's not that hard to do a 2-5 shift, and it'll really slow you down. This will help. Besides, it's a new product for Flyin' Miata so I had to give it a shot.
entry 469 - tags: drivetrain | | |  | June 8, 2008 - I spent some time patching up holes.
I think the exhaust fumes were affecting us pretty badly in the car on the way home. Cracking the windows open actually caused a problem, as it would pull air into the car from all the holes in the transmission tunnel. Very hot air. I usually drive the car fully closed up or with the windows fully open, so I'd never noticed this before. It's easy enough to fix. Small holes got rivets, big holes got rubber plugs.
While doing the diff swap, I also crawled underneath and took a good look for holes. I found quite a few, actually. The car had an Autopower roll bar in its previous life so there were 8 or more holes left over from that. There were also a number of unused bolt holes that I covered with waterproof foil tape. It should make a big difference.
entry 470 | | | June 10, 2008 - Testing results.
The influx of hot air seems to have succumbed to my patching and the car no longer smells like exhaust fumes. So that's good.
The car is much happier with the 4.10 rear end. I've always liked this gearing combination. The stiffer mounts in the differential have cut down on shifter movement and the car shifts very nicely now. So that's an improvement. There should theoretically be an increase in NVH from the new mounts but it's rather hard to tell in this car!
I took the car out to the track again for a few laps, just to see if the rear end was hooking up any differently. And the answer is nope. Maybe a little bit better, but I can still spin up that right inside wheel if I am being aggressive. It takes a turn that's tighter than any that would be used on the street - aka, that would be found in the Targa - but I'm starting to obsess about this a little bit again. On the theory that the car is rolling too much and the rear sway bar just can't deal with this much articulation, I stiffened up the low-speed compression. While the car get a bit happier in transitions (I need to spend more time with this adjustment, as I should be able to really make it pivot nicely) it didn't make a significant difference.
I do really have to thank the guys at the Grand Junction Motor Speedway for working with me and letting me drop in once in a while. When I left today, they were surprised that I'd only taken a half dozen laps!
I'm probably going to swap all the control arms out. The bushings seem to need lubrication again. That's odd, because I've run these sorts of bushings for years in the past without any noise. But that dirt road really seems to have done a number on them and they sound terrible. So the arms have to come out at least partially, so why not experiment? I will check to make sure it's not dry sway bar bushings, which I don't think were very well lubricated on installation. Remember, I installed them at the track and didn't spend a lot of time greasing. Hmm.
edit - I did check, and it is the ungreased front sway bar bushings. Duh. The control arms are fine.
One reason to swap out the arms is because I've managed to accumulate a set of 1999-05 control arms. The rears have only 1700 miles on them so they have nice fresh bushings, while the fronts are higher mileage. The later arms are more heavily reinforced for more strength.
Third, I'm also hoping it'll let me get a little more camber up front, which will allow me to run a smaller (or no) rear bar, which will help with the rear traction.
First, I'll check the cornerweights to see if the right rear is out of whack. The traction problem is not as bad with a passenger, and of course I'll have a passenger during the race! I can tell when I'm going to have problems with the traction, as it's all due to the weight on the right rear wheel. Actually, it's the weight on the right rear and the antics I get up to in order to provoke it.
entry 471 - tags: testing, drivetrain, ergonomics | | | June 10, 2008 - Hot.
It's a toasty day outside today (about 83F/28C) and the temperature inside the car was getting pretty warm on track. As I mentioned earlier, it's a hot little track to run. But even driving home it was warm. According to my pyrometer, the driver's footwell was 145F (68C). Obviously the ambient temperature will be lower during the Targa, but I am going to be generating lots of heat and I'm a bit concerned about some of the parts on the transmission tunnel. The intercom is right on top of it and is warm to the touch, while the brake proportioning valve is also getting the worst of it. So I think I'm going to find myself some adhesive heatshielding and see if I can cut down on the tunnel temperature from underneath.
entry 472 - tags: ergonomics | | |  | June 10, 2008 - I don't know why I didn't do this earlier.
On 1994-05 Miatas, there's a plate that covers a big open area above the radiator. The Targa car didn't have one - and even the stock ones wouldn't be ideal, as they leave room for a hood latch.
So I made my own out of aluminum. It's nothing special, but it will perhaps convince some wayward air to take the productive route through the radiator instead of being lazy and simply going around.
entry 473 - tags: cooling | | |  | June 10, 2008 - With a nice long list of things to do on the whiteboard in the garage, I decided to do something else.
I've had a box full of cams sitting in the garage for a couple of months now. It's time to give them a shot.
The golden ones are just gorgeous in person. They're stage 1 cams from Integral Camshafts. The others are stage 2 from the same company, but ground on a set of stock cams - a set of 1999-05 ones, interestingly. They're both designed for hydraulic lifters which is good, because that's what I have. One big advantage to the hydraulics is that I can simply bung these in without having to mess around with shims.
How do they work? Well, the car fires up and runs fine. It has a very lumpy idle. I'll check the timing tomorrow night and then take the car on a run on Thursday. No track time, just a burn down the highway to see if it wants more fuel or less. That's a really crude way to tell if it's making more power - a thirsty engine is a powerful engine.
entry 474 - tags: engine | | | June 12, 2008 - I put the car on the cornerweight scales last night.
No surprise, the right rear was the lightest corner of the car. That's how Miatas are. But it wasn't extreme, and the cross weights were actually pretty good.
I drove the car to work - the long, long way - this morning to see how it likes the new cams. It feels pretty good, although I just cannot make it idle at all. Of course, when I got to work, I found out that I had the closed loop autotuning turned off, so the car didn't do any fuel tuning. Whoops. I'm going to double-check the cam timing to make sure it's at least close, then probably change idle modes in the Hydra to the "big cam" setup that uses the TPS instead of MAP.
entry 475 - tags: suspension, tuning | | |  | June 16, 2008 - I swapped out all the control arms for new ones this weekend, as planned.
I'll get it aligned on Wednesday, then we'll see what effect this has on the car. It does appear that I have more negative camber up front, which is good. Not very much of it, but more.
While I was under there, I welded this little ramp on the lower rear control arms. The adjuster for the shock protrudes through the arm just slightly. It's not something I'd be worried about in any other car, but just in case I drop a wheel off the edge of the road this should provide a bit of protection for the adjuster. It ended up being taller than it needed, but that's better than too short!
entry 476 - tags: suspension | | |  | June 17, 2008 - After our sore butts following the 12-hour MG rally, I ordered some new padding for the bottom of the seats.
The blue pad is a "backsaver" pad from Pegasus Racing. It's another type of memory foam, but very different to play with. It's firmer than the original cheap bedtopper I was using before, and almost feels like a gel pad when you try to push it sideways. Weird stuff.
entry 477 - tags: ergonomics | | | June 17, 2008 - I had the car aligned today.
I had a 9 am appointment and the car went on to the (empty) rack at 10. Sigh. Still, by 11:30 it was all lined up and looks to be a decent job. The right front wheel wouldn't give any more than 1.4 degrees of negative camber, which is a bit of a shame. I was hoping for about 0.5 degrees more. It could very well be my ride height, of course. According to the Spec Miata Constructor's Manual, I should be able to do a bit better. But I know from hanging out with certain Spec racers that it's not unusual for the upper control arm to be accidentally and carefully bent a bit, giving more camber. Good book, by the way.
So, how does it work? I took the car out for a run on my local Targa Simulation Road (assuming the Targa has pinon tree, red rocks and 95F temperatures) and it feels pretty good. The front end sticks beautifully and it puts power down well. Of course, I'll have to take it to the track to see if the low speed, tight radius wheelspin is gone but fast road work is not a concern. I still want to spend a little more time fine-tuning the shocks but I feel the car would be quite competitive at the Targa as it sits.
The new padding for the seats seems to work quite nicely. It wasn't a 2+ hour test, but so far it's an improvement.
I also spent a bit of time tuning the engine with the new cams. They don't like to idle much, but I'm starting to get that under control. The car feels pretty strong and it's adding a whole pile of fuel at 4500 rpm or so - right where the previous cams had a big dip in power, and right where I need a big slug of torque. So far they're promising.
entry 478 - tags: suspension, testing, ergonomics, tuning | | |  | June 17, 2008 - I've been trying to figure out how to mount a rear tow hook to the car.
I cleverly took the frame extensions that hold the tie-down hooks off over a year ago, and this made things a little more difficult for me. I can't just bolt on a normal tow loop.
The MX-5 Cup racers use a loop made out of webbing, so I figured I'd give that a try. It took some searching, but I finally found one at I/O Port. It's light and with a bit of creativity I can mount it to the chassis nicely.
entry 479 - tags: safety | | |
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