| MIATA BUILD |
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 | |  | March 11, 2007 - Driver development time!
Most of my track time is spent in the Seven, but it's time to start paying more attention to Miatas. So this weekend I was at the track with a big blue car instead of the usual little orange one. The Miata is supercharged (about 155 hp at the wheels, I'd estimate) and has an off-the-shelf suspension from Flyin' Miata that works very well - FM springs, Tokico Illumina shocks, FM rear shock mounts and FM sway bars. There's one of Flyin' Miata's "butterfly braces" underneath so it's a good solid chassis. I was also running a set of Toyo RA-1s that were nicely broken in and some autocross brakes. Overall, it's a pretty good test bed for the rally car as it's running the same ride height and spring rates we expect to use.
After all the time spent in the lightweight car, it's good to see how well a sorted Miata works. It's forgiving, it's controllable and it sticks like crazy. There's obviously more weight transfer going on (and this car is heavier than the Targa car will be) but it's easy to use this as part of your driving technique. The autocross brake pads weren't up to sustained hard braking, so this meant I had to carry in higher entry speeds and worked as an excellent training tool. We'll be running better brakes in the Targa.
I spent some time driving "off line" at the track, pretending I didn't know where I was going and trying to deal with very different situations than the usual ideal line. I also tried to avoid using all of the track to give myself some extra room like we'll have to do in Newfoundland. It's tricky to pretend you don't know a track that's quite familiar to you, but it's also quite eye-opening how a well-known corner changes when you enter it from a different angle! Not only did this help me improve my skills, it also illustrated quite dramatically how much of a difference it makes in speed around the track.
Luckily, there were very few cars on the track so nobody thought I was crazy.
A good day overall. Time to get back to work though!
entry 90 - tags: testing, other cars, skills | | |  | March 16, 2007 - Our Corbeau seats are here.
They're the FX1 Pro, a nicely fitted fibreglass seat that fits in small cars. We also have a set of Corbeau harnesses for each occupant of the car.
entry 91 - tags: sponsors, seats, ergonomics, safety | | |  | March 16, 2007 - As we've found with some other Corbeaus, the padding is a bit on the thick and firm side.
This puts the driver too high in the air while not providing the comfort you might expect. We've ordered some memory foam to fill this cushion. Well, what I really did after calling upholstery shops was order a mattress topper from Amazon. For about the price of 4 square feet, I can get a whole bed's worth of the stuff!
There's some experimentation ahead.
entry 92 - tags: ergonomics, seats | | |  | March 20, 2007 - In order to make the seat sit as low as possible, the rear factory seat mounts were removed.
So much for having the interior of the car nicely painted! I'll have to get some more of the paint in an aerosol can for this sort of fix. Then again, it'll be under the seat so nobody will see it.
entry 93 - tags: ergonomics, seats | | |  | March 20, 2007 - The next obstacle in the battle against seat height?
These nice little feet. The seats have both side and base mounting options, so we'll use the sides.
entry 94 - tags: ergonomics, seats | | |  | March 20, 2007 - The risers at the back of the seat are no longer.
They were actually wooden pegs inside, that was a bit of a surprise. This seems a terrible thing to do to a brand new set of race seats, but Miatas aren't that big and I have a tall torso.
entry 95 - tags: ergonomics, seats | | |  | March 20, 2007 - The result of all the seat abuse.
The driver's seat is well placed and ready to be bolted down. The codriver's seat is unmodified. There's a drastic height difference.
entry 96 - tags: ergonomics, seats | | |  | March 20, 2007 - Along with seats, Corbeau supplied these 3" harnesses and pads.
While the pads might be overkill, I know how bruised my collarbones get after a track day. Perhaps this will help with comfort a bit.
entry 97 - tags: sponsors, safety | | |  | March 20, 2007 - The end result, being tested with the hardtop on the car.
It's a snug fit, but everything goes nicely in place. I always like to get the ergonomics sorted out early in a build, as an awkward driving position causes all sorts of problems down the road. All that's left to do is build the side brackets for the seats and mount the sub belt.
entry 98 - tags: seats, ergonomics | | |  | March 22, 2007 - The memory foam for the seats is here.
It's really odd stuff to work with, in a constant state of slow melt. It's easy enough to cut with a good set of scissors though.
How does it feel? Good. A single 1.5" layer in the bottom cushion to replace the stock hard foam (shown here on top of the memory foam sheet) lets me sink much further into the seat, while giving better comfort than either the stock foam or nothing at all. I'll call that a win.
The co-driver's seat has also been modified to sit a bit lower, so I'm almost done with them. I'm going to trim a little bit of 'glass off the side of the seats to allow them to sit inboard a touch, but first I have to figure out how to disassemble them far enough to do that without hurting the cover.
entry 99 - tags: ergonomics, seats | | |  | March 23, 2007 - One last bit of seat modification.
In order to move the seats inboard a little more, I had to cut a chunk of the corner off. Once I had the covers off it was easy enough, although I think the end result will look a little nicer once I get some glue under the upholstery.
With that done, I was able to sort out the final seat location and give myself an excellent driving position. The floor has now been drilled for the mounting points - I was able to use the rear mounts on the seat after all, as the threaded portion is embedded in the fibreglass and not the little leg I cut off. The co-driver's seat will be finished up later.
entry 100 - tags: ergonomics, seats | | |  | March 23, 2007 - It's time to start putting some of the wiring in more permanent positions.
This will at least let me sort out some of the more critical bits such as where to mount the Hydra Nemesis ECU and the Coralba C-Giant rally computer. I'll leave it mostly unwrapped until it's all sorted out though.
entry 101 - tags: wiring | | |  | March 23, 2007 - One tip for doing work like this.
Having a vacuum cleaner in easy reach keeps everything cleaner. Maybe not any tidier, but at least when you've been cutting fibreglass with a angle grinder, drilling holes though floorboards or breaking turn indicator bulbs on the floor (whoops) it's a quick and easy cleanup. The end result is that I don't have to put my greasy clothes on to work on the car!
entry 102 - tags: tips | | |  | March 27, 2007 - More driver development.
I've been autocrossing my little Seven for the past few years. But it's time to start concentrating on Miatas again for a while, so I bolted some race tires and a race seat into my girlfriend's supercharged Miata and went hunting.
The event was a Corvette autocross, always a fun group to run with. My coworker Brandon - driving a turbocharged Miata with another 60-80 hp over mine - and I were the only two non-Corvettes at the race.
It took me a few runs to get used to the slower reflexes and lower grip levels of the Miata instead of the Seven, but it started to come back. Lower grip levels not just because of the different car, but also due to cold weather and a dusty parking lot - a good indication of what we can expect in Newfoundland.
It was a good battle between Brandon, myself and a supercharged 2006 Z-06 running on massive V710s. On my last run, I left the braking a millisecond too late on the last corner and understeered badly to the finish line. Brandon didn't make any mistakes and took the fastest time of the day, while the Z-06 ended up just ahead of me.
Lessons for the Targa? The adjustable brake proportioning will be quite useful and of course I'll have to leave some extra room to stop in adverse conditions. I don't have any trouble controlling the car in big slides (after the first run, I did most of my steering with the rear wheels) but sliding off the outside of a corner in the Targa with locked-up brakes is something to avoid.
entry 103 - tags: testing, other cars | | |  | March 27, 2007 - A mystery solved.
For some reason, the brake master cylinder only had two outlets instead of the usual three - one for the rear and one for each front. It was driving me crazy until a coworker remembered the donor car had ABS. The ABS module took care of the distribution between each side, of course!
Now that's sorted out, I needed a junction to feed both front wheels. Voila! This picture sure makes that lower line look crinkly - I'll smooth that out for aesthetics. The ziptie is to help anchor the lines and cut down on vibration.
It's possible to see what a little dribble of brake fluid, left to sit for a couple of days, did to my fresh white paint. Oh well...
entry 104 - tags: brakes, interchange | | |  | March 27, 2007 - It's time to install the suspension.
Why? Mostly because I keep tripping over the parts in the garage! But also because that lets me install the uprights and brakes, giving me the chance to bleed the brake system and check for leaks in the new joints.
I considered seam-welding the subframes, but no.
entry 105 - tags: suspension | | |  | March 27, 2007 - The control arms are fitted with polyurethane bushings.
This gives finer control over wheel movement than the stock rubber bushings. They need to be well lubricated though, so I'm using this really disgusting sticky grease.
entry 106 - tags: suspension | | |  | March 31, 2007 - After assembling one corner of the car, I found there was far more friction in the suspension than I wanted.
Closer inspection showed that the crush tubes in the bushings were not as long as the bushings themselves - not a low-friction situation. Measuring the bushing with the crush tube removed was fine, but the deformation of the polyurethane with the sleeve inserted was enough to cause a problem. So I shaved down the bushings slightly so they were flush with the tubes. I only did a couple by hand, the others were done much more rapidly on the belt sander at work. Why did I do two by hand? Because I forgot the control arm at home.
entry 107 - tags: suspension | | |  | March 31, 2007 - The really disgusting sticky grease had questionable lubrication properties but excellent gluing properties.
So I decided to use some marine grease instead. Much better!
entry 108 - tags: suspension | | |  | March 31, 2007 - Some people make fun of me for using a lot of grease.
I don't know why. But I do know this thing is well lubricated!
entry 109 | | |
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