| MIATA BUILD |
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 | |  | August 18, 2012 - The uprights are attached to the car with rivnuts.
I chose this location for the mounting points for several reasons. The usual trunk lid mounted setup wasn't compatible with my stripped-out trunk lid, and I'm not completely convinced that this is the ideal place to put 100+ lbs of load anyhow. I also couldn't attach to the trunk lid even if I wanted to because of the pins.
This vertical lip is a great option. It's very strong, and my 1/8" thick aluminum uprights fit nicely in between the trunk lid and the body. They're also more watertight than having holes in the trunk lid, and if I remove the uprights there's no visible sign of the wing. I'm pretty happy with it.
entry 1057 - tags: aero, wing | | |  | August 18, 2012 - Here's one of the finished uprights in place.
I'll put up some more pictures of them in the daylight later. You can see all the holes for the adjustment system as well as the double bend that moves the mounting points inboard and also twists the upright. Did you ever notice that the trunk opening for the Miata doesn't have parallel sides? I hadn't.
You can see the specific shape of the mount between the holes - that's copied right off the steel NASCAR mount, and is needed to allow the maximum angle position. It appears there's about 16 degrees of adjustment in this wing, by the way.
Once I was done with all the shaping, I threw the uprights in the bead blaster to give them a nice finish.
entry 1058 - tags: aero, wing | | |  | August 18, 2012 - I didn't use any special tools to build these uprights.
Well, other than the bead blaster at the end. The aluminum was cut with a battery-powered jig saw and final shaping was done with a hand file and a belt sander. Holes were all hand-drilled, and you've already seen the exotic brake setup. Three of the most useful tools are shown here.
The transfer punches allow you to transfer the center point of a hole to a new piece of metal. You simply put the appropriately sized punch in the hole and whack it with a hammer. Voila. I got these from Harbor Freight, although you can spend a lot of money elsewhere if you want.
The gold punch is spring loaded. I used it to emphasize the dimples from the transfer punches. There were something like 60 holes involved in this project, and every single one of them lined up. Also Harbor Freight.
The blue stick is wax. Spreading this on the blade of the jig saw kept it from loading up with aluminum and helped it cut smoothly. I'd read about this somewhere, but never tried it. It works really well. I used ski wax because that's what I have in my garage.
entry 1059 - tags: aero, wing, tools | | |  | August 18, 2012 - An interesting touch on the wing.
The left end plate had this cute little Gurney flap on it. The NASCAR cars are always turning left, of course. I suspect the airflow was a bit sideways in the middle of those long corners, and the flap made everything just a tiny bit more efficient with a bit of side force. Some of the end plates available for these wings are actually little aerofoils.
The flap along the back of the wing wasn't there when I got the wing. There was a slot for it, though, and a piece of Home Depot aluminum angle slipped right in. It's locked in to place with the end plates.
entry 1060 - tags: aero, wing | | |  | August 21, 2012 - First road test with the wing.
Not really much of a test, but I can confirm that the wing is properly anchored and stable at 80 mph with no movement of the assembly. That's about all I can do on the road, really. But this is also the first time I've seen the car out of the garage with the wing on it. With the front splitter, it looks as if it was supposed to be this way from the start. What a mean looking car.
entry 1061 - tags: wing, aero | | |  | August 21, 2012 - Gratuitously dramatic wing photo.
I'm really happy with how the mounts turned out. They won't work with a normally hinged trunk, but otherwise they're just what I wanted. The placement of the wing is not based on lots of aero testing, but is simply hung up in the air. I'll do some further testing later to check air turbulence and direction. The mounts will make that easier.
entry 1062 - tags: aero, wing | | |  | August 22, 2012 - A view of the wing and splitter together.
The splitter used to look big, now it's a bit subtle! It's 3" at the moment. I'll test it out at the next track day in a few weeks and see what the balance of the car is like in a 70 mph sweeper. I suspect it'll start to understeer, but I have to admit that light understeer in a quick sweeper sounds like a reasonable idea. I'll play around a bit with the wing settings to see how it feels.
entry 1063 - tags: aero, wing | | |  | August 22, 2012 - Pikes Peak!
One of the world's best known races, and it's in our backyard. So Janel, Brandon and I headed for the 2012 running to check it out. It's been in the back of my mind as a "possible", but I've never thought I would have the nerve. It's one thing to run a rally and balance risk vs reward, but on a "known" course like this it's a flat-out time trial. With some big penalties for mistakes.
Dave Kern used to run with me at track days years ago and always made me feel timid and slow - he has set records on the mountain. But watching the event, the most obvious thing was the number of amateurs in the event. We could usually identify the ones that wouldn't make it to the top, either due to a lack of talent or an over-abundance of enthusiasm. Still, it did get me thinking about the possibility. The event is within the range of mere mortals, and the Time Attack division is essentially for rally cars complete with navigators. One thing that was kind of cool is that Andrew Comrie-Picard was running, and he's a Targa mainstay. I've also met winner Rhys Millen in the past.
If you've been reading the motorsport news, you know that there were a couple of extreme accidents this year. One was a 1400 hp car that got a stuck throttle almost immediately and went spearing off into the trees at well over 100 mph. That's a bit frightening and I do wonder what happened mechanically. More frightening and closer to my imagination was an Evo that took a dive off a cliff and rolled a long, long way down the mountain.
That latter one has me looking at the cage in the Targa Miata. There are a few things I'd like to change after living with it for so long, and looking at the shattered remains of the Evo has put that a little higher up the priority list. We'll see what comes about.
Very few of the Unlimited monsters did well this year. Only two finished - a Ford RS200 Group B rally car and the Palatov D4 shown here, which took first place. The D4 is an interesting little car technically, but more interesting to me is how they got to the event. They took a similar crowdsourced approach to our own, although it was significantly more successful in terms of money raised. There's no scale on their fundraising thermometer, but the top is $175,000. I'm going to be spending some time trying to figure out exactly what they did that worked so well, although some differences are fairly apparent - the Palatov site is a very popular one and the cars they build are quite a bit more expensive than our little Miatas. Also, Pike's Peak is a higher profile event than the Targa Newfoundland.
One interesting difference is that the team blog was restricted to sponsors only until after the race. It's a great way to make your sponsors part of the team and treat them like insiders, but I would also expect it to cut down on a certain level of sponsorship. I'm going to keep looking through their blog to see what I can learn from the approach.
Overall, an interesting weekend for a bunch of different reasons. I have looked at the rules, and thanks to our engine swap we'd probably have to run in Open class against a number of purpose-built vehicles like the D4. Well, we wouldn't expect to win anyhow!
Photo by Ben Padolsky. It's not the best one he took all weekend, but it illustrated my point nicely.
entry 1064 - tags: sponsorship, racing | | |  | September 8, 2012 - Time to test the wing!
Other than add the wing and splitter, I hadn't touched any other settings on the car since the Summer Camp a month ago. This was to give me a reasonable before/after picture of the effects of the wing. The short version? My first timed session popped out a 1:01.344. My previous best time in the car was 1:03.388. Yes, that's almost exactly two seconds faster. Two seconds! It may also be the lap record for cars with doors, although I need to do some digging around to be sure. It's certainly the fastest Miata time. Now, conditions were pretty much perfect and everyone was going quickly, but that's still a pretty spectacular difference. Not long ago, that would have been the overall record for cars.
I could feel the difference in the balance of the car as well. Where I'd previously had a bit of oversteer down the fast sweeper, I now had a bit of understeer. According to the rally computer, my peak speed was also something like 6-7 kmh faster than I'd seen before. That peak speed occurs as you're balanced on the limit of grip on the fast sweeper, and is limited (in this car) by the amount of lateral acceleration you can produce. So it's a quick and easy way to get a feel for actual grip. On that fast lap, it translates to sustained cornering of 1.1g or so, with a peak of 1.3.
I then proceeded to spend some time experimenting with wing angles. The next two sessions I cranked the wing down to a fairly steep angle. My fastest time dropped to 1:01.5, but the peak speed went up by 1 kmh. The understeer on the straight got stronger, and it actually became a bit more difficult to drive the car as the balance was changing so much based on speed. I continued to play with various angles, but it became apparent that the rising temperatures were affecting everyone's grip level and times gradually went up as the day went on. Still, it wasn't until the very last (hot!) session of the day that my times finally slipped above my previous best. So that's a big, big thumbs up to the wing, even on our fairly slow track - the average speed on my fastest lap was just a hair over 50 mph. It's also obvious that I need to do more to balance the front out. A lower ride height would help there, but I was leaving everything other than wing angle alone in my experiments today. I'm going to put on the stiff track springs and drop the car down a bit to get ready for an upcoming trip to Willow Springs.
As you can see from the picture, I added some labels to the holes so I can easily keep notes. For those who are interested, I tried C4, A1, B2, C1 and A3 today. It wasn't all perfect, though. It feels as if I lost a coil. I'm still letting the car cool down, but based on a quick test of header tube temperatures, it's the same #1 that has failed twice before.
Brandon also had a good day in his bike-engined Locost. After I was faster than him on the first session, he put his fast pants on and turned a 1:00.355. I believe that's the overall lap record for cars on this track, and so close to the elusive one minute mark!
entry 1065 - tags: aero, testing, personal best | | |  | November 30, 2012 - There's been a bit of interest in copies of the wing mounts for the COT wing.
Brandon made a 3D model of them, and Mark at Paco Motorsports will see what it might cost. Drop me a line at keith@flyinmiata.com if you're interested.
entry 1066 - tags: aero, wing | | |  | January 9, 2013 - The Targa Miata is confined to the garage by snow at the moment, but I'm using the time to work on a number of aspects.
First, I'm installing the track suspension and doing some maintenance on the AFCOs. I'm also changing out the hood pins for Aerocatches so it's easier to open and close, and a pair of hydraulic rams have taken the place of the hood prop to improve access underhood.
I've also got some electrical parts to install. The big one? Two big burly relays to replace the factory one that cost us the lead at Targa last year. They'll be installed in parallel so I have some redundancy in case one goes out, and I might add some warning lights so I know if one has failed. I'm seriously considering the wiring on the car, it's showing the signs of the car's gradual evolution and it might be time for a complete rethink. There are also a few areas where I've been relying on Miata reliability to keep me out of trouble, perhaps more redundancy would be smarter. Twin fuel pumps and filters, maybe? Given the Newfoundland gas, that's not a terrible idea.
I've also got some power windows to install. Way back in the original build, I decided the manual windows were a good way to save one pound per door. But with the current cage configuration, we can't actually adjust them with the doors closed. Janel and I both became fairly blasé about popping the door open on the highway to wind the windows up and down, but it sure would be a lot easier to simply hit a switch. It would definitely attract less attention.
entry 1067 - tags: wiring, suspension, plans | | |  | January 14, 2013 - I spent part of the weekend setting up the car.
Cornerweighting, ride height and alignment. The ride height has changed considerably since the last time it was on the alignment rack, but the new hub stands from FM made this pretty easy to put right. It was pretty revealing how off the alignment was!
I didn't really want to give the stands back, maybe I can find a way to justify a set of my own someday. Springs are now 750 lb front and 450 lb rear, with a pretty low ride height. It should be quicker around our track now - can I duplicate my numbers from last time? Too bad I have to wait a few more months to find out.
entry 1068 - tags: setup, suspension | | |  | January 15, 2013 - I finally replaced the hood pins with Aerocatches.
Much nicer - it's easier to open and close the hood, more aerodynamic and easier to tell if they've been left open. This involved drilling and cutting my poor hood even more - it's been pretty heavily worked over by this point! I've also learned that white Aerocatches get dirty really quickly.
entry 1069 - tags: hood, aero | | |  | January 17, 2013 - A couple of unlikely cousins.
These two cars have a lot more in common than you think. They're both running similar engines (5.3 for the race car, 5.7 for the MG), T56 6-speed transmissions, AFCO suspension, FM radiators and fans, FM fuel plumbing, etc. The MG actually runs Miata brakes, steering and a number of other bits as well. Heck, they even weigh the same. Most importantly, they both perform well beyond their original manufacturer's intentions and put a big stupid grin on the driver's face.
entry 1070 - tags: other cars | | |  | February 16, 2013 - Time for a bit of shock maintenance.
One of the cool things about AFCOs is that you can work on them at home. In this case, I'm changing out the shock oil. The big syringe is full of the old stuff - it used to be clear! This is the same oil that has seen a couple of seasons of track days plus the 2011 Targa Newfoundland, so it's been worked over pretty hard. This should bring the shock up to full health. Not bad for an hour's work. I'll tackle the other three shortly, maybe even make a how-to video.
entry 1071 - tags: suspension | | |  | March 17, 2013 - Power!
When I first built the car, I was watching every ounce of weight. Manual windows saved me 1 lb per door and were simpler, so I decided to go with them. Now, I've got a bit more power - and with the extra door bar in the roll cage, we can't wind the windows up and down with the doors closed. This can be awkward when you're driving. During the Targa, Janel and I got used to popping the door open on the highway to adjust them, but there's been at least one episode on the track where I had to pit simply to wind down the window.
No longer! Now I've got power windows. I've simplified the wiring quite dramatically by putting the switch in the door, so there's only one wire going in. It's going to feel so luxurious to simply push a button and have the window go up. Aaaah.
entry 1072 | | |  | March 27, 2013 - There's a track day coming up this weekend (weather permitting) so I've been doing a bit of work on the car.
It was pretty obvious at the last test that the wing was increasing grip at the rear more than my little splitter was doing at the front. So I picked up some more aluminum and extended it by about 1.5". Easy enough. I also swapped the rigid turnbuckles for cables, allowing the splitter to move up a bit if it scuffs the ground when I'm loading into the trailer.
entry 1073 - tags: aero | | |  | March 27, 2013 - One of the dirty areas of the car, aerodynamically speaking, is the front tires.
That exposed rubber, spinning at high speed, generates a lot of drag. So I thought I'd be clever and build some canards that would cover them up in front view.
Well, that didn't work out. Somehow I came up with a pretty cool design, but crouching down and looking at the car head-on showed that they only covered about half the tire. Oops. The canards evolved from the original design as I made them.
entry 1074 - tags: aero | | |  | March 27, 2013 - That's a much better way to cover up the wheels.
It seems a bit goofy, but it works. Some computational fluid dynamics run by "plucas", a member of the Miataturbo forum, shows that this setup increases front end grip and cuts down on overall drag fairly impressively. The expected hp to maintain 100 mph drops from 44 to 34 hp, and the car goes from generating lift to generating downforce. Hard to argue with Science, and definitely worth trying out.
I'm going to bring the canards along and give them a try to see if I can feel a difference.
entry 1075 - tags: aero | | |  | April 1, 2013 - Track day test!
I headed over the mountains to High Plains Raceway for an open lapping day. This was a chance to check out the aero at high speed and sharpen up my high-speed skills in preparation for a couple of days at Mazda Raceway Laguna Seca in a few weeks.
It was a nice day with a wide variety of cars in attendance. I was sharing the track with everything from Formula B cars (one step down from Formula Atlantic!) to a McLaren MP4-12c that was still on temporary tags. Cool.
During the first session, I was mostly feeling my way around. The car was understeering, particularly on long lefts. I pulled into the pits and checked tire pressures - oops. Heading back out with about an extra 4 psi, the car felt better but was still pushing more than I liked. I'm on a new spring set that wasn't quite balanced right. I decided to keep the sway bars where they were and see if I could sort it out with other aspects.
Otherwise, the car felt good. Very strong, hitting 4th gear on the back straight pushed me back into my seat and I was topping out at around 126 mph before braking for the end of the straight. A couple of fast Porsches gave me someone to chase and - more importantly - learn from.
On my second session, I was dodging through the quick left-right-light chicane of the "Prairie Corkscrew" and felt a bang through the steering and the wheel went off-center. That's a front alignment cam slipping. So I headed back into the pits to sort that out.
entry 1076 - tags: aero, testing | | |
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