| MIATA BUILD |
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 | |  | August 12, 2007 - A number of little things were done today in order to prep the car for the track day on Friday.
This little filter is on the valve cover to feed the PCV system. That's a pretty misunderstood system, and in most cases a filter on the cover would be a bad idea. In my case, I have an engine management system that uses manifold vacuum to determine load, so there's no problem if some air comes through the valve cover first.
The car also got the first oil change and is now running full synthetic. The transmission and diff were drained and refilled with the correct fluids this time (whoops), and judging by the condition of the stuff coming out of the diff it's not a bad thing that I "flushed" it. I spent a bit of time working on exhaust system alignment, I'm afraid I'll have a bit of a rattle on hard cornering.
On the less mechanical side of things, I put some small rubber bumpers under the trunklid to ensure it doesn't rattle at all. Windshield wipers are in place (and functioning) and I added Grassroots Motorsports and SSR decals to the side of the car in front of the door. This is partly to acknowledge the support from GRM (go pick up a copy of the October 2007 Grassroots, you'll find my Seven in there) and to give SSR a bit of credit for originally supplying the wheels being used on the car. It's also partly a test of how to arrange sponsor decals on the car. Oh, and there's a big black FLYIN' MIATA on the nose of the car now to match the rear bumper. Pictures will come.
entry 289 - tags: drivetrain, exhaust, decals | | | August 13, 2007 - Car gallery added to the website.
After being innundated with a request, I've put up a gallery of the car from a bunch of angles. Yes, it's completely self-indulgent. But I don't mind at all.
So, if you'd like a Targa Miata wallpaper or just want the chance to critique the stripes carefully yourself, check it out: Targa Miata gallery.
Meanwhile, the car got aligned today. A bit of tuning on the computer and it's ready for the track. I've been driving it around for the last few days. I'll post some driving impressions soon.
entry 290 - tags: alignment | | | August 14, 2007 - So, how does it drive?
The engine isn't fully tuned yet so the car doesn't have full power, nor does it like to idle much. But ignoring those little foibles, it's a blast. The car is conspicuously light. It's surprising just how much difference an extra 300 lbs can make to a car, but it will happily surge forward on even just a tickle of the throttle. Even in the semi-tuned state there's a real snap to the throttle response. The car wants to run, and the short gearing exaggerates this.
The power steering is very light. A bit too light, perhaps. I'll try disabling it to see how that feels and if I'd want to deal with hundreds of kilometers of shattered roads without it.
The car is very rigid, with absolutely no flex - even compared to a modified Miata with a butterfly brace, structural foam in the frame rails and a rollbar. Amazingly, there are no rattles although there's a fair bit of noise and vibration through the uninsulated chassis and competition motor mounts. It's also rather warm inside as the engine and exhaust heat gets nicely transmitted. I'll have to do something about that.
The springs are stiff, but the Öhlins shocks control them very well. It'll be interesting to see how well that works on the track even without sway bars.
In short, the car is a ball to drive. It's a reminder that it's not just a Miata with a cool paint job.
entry 291 - tags: testing, stiffness, suspension | | | August 14, 2007 - Ready for the track day.
Three years ago, my Seven made its public debut at the Flyin' Miata Open House as well as its first serious track testing. This year, it's the Targa Miata's turn. There's a lot of interest in the car so it's going to be fun.
For final preparation, Brandon and I bolted on a new right rear caliper to solve a problem with the handbrake sticking on. Hopefully the rotor will be okay, a coworker drove the car about 1/2 a mile today with the old caliper siezed tight in place. Stinky!
The engine tuning was given a bit of a tweak today as well. The engine isn't putting out full power, that's fairly obvious even if we didn't put the car on the dyno. Still, it should be safe to run on track and the engine is very eager and flexible. At least it will idle happily now!
And voila. A bit of cleanup for the interior and I'm ready. Just in time, too!
entry 292 - tags: testing, brakes, tuning | | |  | August 19, 2007 - Time for the kids to come out to play.
I managed to get both the Targa Miata and my Seven out to the track together - and since I was running the day, I got to schedule myself into two run groups so I could run both cars. Ah, it's a tough life.
The event was the Flyin' Miata Open House, and the track is actually a large kart track. We've found that if you run it backwards it is a more challenging track, with a larger variety of corners including one downhill sweeper into a tight braking zone that is pretty tough. In a fast car, you have to make the choice between braking before a little kink or waiting until afterwards, in which case you don't have a lot of room for error. A number of other corners conspire to catch you up and it's a very fun challenge.
entry 293 - tags: testing | | |  | August 19, 2007 - The first session took place in a light rain.
Great, just the way I like to test out a car for the first time. Other than about 200 road miles, the car was completely fresh.
On this first session, the car was a handful. It would understeer on corner entry then light up the rear wheels and oversteer on the exit. It didn't help that I had brand new RA-1s on the car that hadn't been heat-cycled yet and I never got around to installing sway bars! It was a bit of a challenge.
The one thing that did stand out, however, was the engine. It's a hero. Sharp throttle response, lots of torque from deep down and a killer top end. I thought there was something wrong with the tach - I use that to judge my speeds on this track because I know it so well. And in a couple of places, I was pulling almost as many rpm as I do in the Seven - a car that weighs 1300 lbs!
It's cool seeing the action shots of the car, partly to see how the stripes work. This picture was taken in light rain, but the blinding white and the orange-red colors jump out just the way they're supposed to. Excellent. The headlights are up because I forgot to put them down, no other reason.
entry 294 - tags: testing, Martini | | |  | August 19, 2007 - After that first session, everything dried up and I got faster.
My best lap on the first session had been a 1:12.049. I was concerned that the wheelspin on exiting hard right corners and a banging noise was due to a possibly bad shock, so I bumped up the damping a little to see what would happen.
The results? No real change in the behavior of the car, but then again the track conditions were quite a bit different. The tires were biting now on turn-in, and the combination of excellent initial grip and no sway bars made for a car that required a fairly light touch. I let Bill Cardell from Flyin' Miata take the car out as well and we agreed that the lack of traction on corner exit was probably a wheel lifting. The Torsen differential used in the car is nice when both wheels are on the ground, but once one lifts it acts like an open diff. The lack of sway bars and resulting body roll meant I was getting a lot of droop on the inside rear wheel, and the short Ohlins shocks didn't have a lot of droop to provide. This is something that could be solved by lowering the car - not good for the Targa - or by limiting the roll a bit more. I did test, and the car dealt very well with big bumps such as driving over the kerbs in the chicane.
My time dropped to 1:08.527, mostly due to the dry pavement. This picture was taken on the most difficult part of the track, as I'm accelerating hard downhill towards a braking zone that has the car up on its toes. On my first hard lap, I didn't have the car properly settled before nailing the brakes, and I was rewarded with a spin. Right, no sways and 2050 lbs instead of 1300. After reminding myself of that, I was able to take the late, gutsy option without drama. This corner is an excellent one for dialing in brake balance.
entry 295 - tags: testing, brakes, suspension | | |  | August 19, 2007 - Turn one was a bit of a fast one.
As the day went on, I was starting to figure out how to drive the car better. The biggest trick was getting a good drive out of corners, and it led to me taking some different lines than I usually do in the little lightweight weapon. The Seven has a huge amount of traction, but in the Targa car I was taking wider lines to settle the rear down first. It was paying off, my fastest lap dropped to 1:07.977.
I've found a satellite picture of the track here . We were running counter-clockwise, and the big sweeper is the fun part. My goal is to start braking when my left front wheel hits the kerbing before the hairpin.
entry 296 - tags: testing | | |  | August 19, 2007 - It wouldn't be a track day for me without an oversteer shot!
I was able to throw the car around a bit. By this point, I'd figured out that my banging noise was probably the exhaust hitting the differential. I knew that clearance was tight there, I'll have to get back underneath and take a peek.
The 1:07.977 was my fastest time of the day, and it was a pretty good one. By comparison, a turbo Miata with 225/45-15 Toyos (well scrubbed in) and the JIC shocks turned a 1:07.119. Another turbo Miata was close behind with a 1:07.337, both driven by coworkers of mine. And the Targa Miata was third, ahead of another 45or so Miatas. It was an excellent first day out. The fastest car on the track (1:03.733) was my little Seven, to my satisfaction.
So, what did I learn about the car? I'd like to try a nicely sized front sway bar to cut down the roll, and maybe a bit more front camber. That will make the car easier to throw around, something I'll need to be able to do on the Targa surfaces. Unlike the track, I'll be reacting a bit more instead of anticipating.
The braking is very light, almost to the point of being overassisted. It's the first time I've tried these brakes with the larger booster and master from the late Miatas, and that could be the reason. It could also be the street-only pads I was running (you could smell them at the end of the day) and the fact that I was jumping out of the Seven which has a very firm unassisted pedal. After the first lap, it wasn't really a problem so it may have been acclimatisation. Still, I'll get some proper pads in there and see.
The shocks are the big question. They do an excellent job of damping surface imperfections. But can I run the car high enough to get the ground clearance I need for the Targa? I'll have to drop the rear down a bit and see how it works. There's another set of shocks sitting at work that have 5" of travel and I want to try them next.
entry 297 - tags: testing, other cars, brakes, suspension | | |  | August 19, 2007 - All the kids were available for rides at the Open House.
Orange is my Seven, yellow is the FM Westfield I helped to build and set up, white you know and blue is my wife Janel's little turbo Miata. The Targa car was pretty popular, both amongst people who had never heard of it and a bunch of regular readers who were exited to see it in the metal. Turns out I'm not the only person who thinks the stripes look good. It's obvious from the pictures at the track that the black FLYIN' MIATA on the nose and tail really stands out as well.
One thing I discovered on the test drives - I was leading my coworker Brandon in his turbo Miata that makes approximately 230 hp at the wheels and weighs around 2350 lb or so. When I put the throttle down, he could keep up. But he didn't seem to be gaining ground. Wow, maybe the engine is working better than I thought. It sure feels great, and it has just the flexible nature I'll need.
entry 298 - tags: other cars, Martini | | |  | August 19, 2007 - Interior shot.
It was pointed out to me that I haven't shown the final result. With the hardtop on, it's hard to get much of a picture, but here it is. It's a spartan interior that needs a bit of heat insulation, but it's a start.
After the recent push to get the car ready for the track, I'll be taking a bit of time at a slower pace. It's time to catch up with everything else in my life, but the Targa Miata is only at the beginning of its development...
entry 299 | | |  | August 20, 2007 - So much for taking a break!
I convinced Bill at Flyin' Miata that the best car for testing this new shock setup would be the Targa Miata, in large part because of the travel available. You can see how much longer they are fully extended than the gold Ohlins shocks are. My only concern is that they'll have too much! We may have to play with the length of the upper mounts to get the wheel to move within a useable range.
Other than size and stroke, the shocks have an aluminum body and are adjustable for both bump and rebound separately. They're not yet on the market, but if they live up to their specifications it should be a nice setup.
entry 300 - tags: suspension | | |  | August 20, 2007 - Well, the droop problem is certainly solved.
The measurement from the hub to the fender lip is 16.5" in the rear and 14.5" in the front - that's a full extra inch in front and a lot more in the rear.
The shocks have SAE spherical joints in them, so they need SAE bolts. In the front I can drill out a 12mm hole to clear the 1/2" bolt, but in the rear the shock bolt goes into a captive nut in the control arm. I'll talk to the shock engineers - they're very responsive - to see what they have to say.
entry 301 - tags: suspension | | |  | August 20, 2007 - I installed the shocks with no springs so I could check maximum travel - and holy cow.
There's 6.75" of travel in the rear, then the suspension starts to hit itself. That's a bit too much bump travel, really - I'd end up with the chassis close to the ground. Maybe I could run very long bumpstops.
entry 302 - tags: suspension | | |  | August 20, 2007 - If you thought the rear had some bump travel, check out the front.
After 5" of compression, the wheel is firmly planted into the fender and the suspension is bound up - and there's still at least 2" of travel left in the shock. That's ridiculous.
Given that there are only 7" springs on these shocks, there's no way I'd be able to use this much travel anyhow. It looks like the car could run 8" springs for my ride height front and rear, but something needs to be done to control that travel a bit. If the upper shock mounts were more like the Ohlins design with the bumpstop flush with the top of the mount - instead of embedded in that big tube - it might be about right.
entry 303 - tags: suspension | | | August 22, 2007 - More suspension testing.
I spent some time on the phone with the shock company yesterday, discussing options. Some of my concerns - such as the SAE vs metric bolt sizes - are due to the fact that this set of shocks is for development testing only. Last night, I measured a number of aspects of the new shocks to determine what would work best and I think I've come up with a good set of dimensions. We'll get those working and then I'll be able to test the new shocks to see how they work. This company has a long race history on rough surfaces so I have high hopes for the end product.
entry 304 - tags: suspension | | |  | August 29, 2007 - A bevy of bumpstops.
I sent my "wish list" of dimensions to the engineers at the shock company. They responded with their recommended shock and shaft combinations. I can't believe how helpful these guys are being. Of course, part of what I'm doing is helping to set up the specification for a potential future Flyin' Miata product, so it's a possible they wouldn't be quite this responsive to an individual racer. But it's great being able to go right to the guys who actually build the parts to ask questions. I'm keeping the name of the company quiet for now to avoid all the detailed questions that FM is expected to answer as soon as a rumor of a product shows up. Let's see if I can get something to work first. There's another set of revalved Miata shocks coming this way for comparison, it'll be very interesting to test the two back to back.
They've asked me to get the car on the road so I can get some rough compression and rebound settings. These development shocks have a wider than usual range of adjustment, and they want me to close in a bit on a more ideal setup. In the front, that meant cutting out about 2.5" of compression travel to keep the wheels out of the fenders. The big bumpstop is crude, but it will do the job for now. That's not full extension, by the way!
I put the car on its wheels this morning and drove it in to work. This is going to be interesting, I've never started with a blank slate before. Initial reactions are a good, a smooth ride with all the hard edges taken off small impacts. Of course, there's only so much I can test driving to work in traffic, so more adjusting and testing will follow. I suspect I'll need a bit more compression damping, but with 7" of rear travel and nearly the same amount in the front, I should be able to absorb just about anything.
entry 305 - tags: suspension | | |  | August 30, 2007 - Quite possibly the coolest course maps ever.
The Targa Newfoundland website has loads of detailed information on all the stages of the rally, including gas stations on the transit legs, road closure information, start times and the like. But the coolest thing is that it's also bundled up into a Google Earth file so you can lay it out on your own pet planet. Select what you want to see, spin it around, do a fly-through or just marvel at the wind-swept ocean. Amazing. I'm going to spend a lot of time "driving" the rally now. It's science fiction come to life.
This is the "Upper Island Cove" stage on the last day.
entry 306 | | | September 1, 2007 - Suspension tuning continues.
It's a fascinating process. I know intellectually what adding more compression or rebound damping will do, but it's something completely different to start with a blank slate and make the car work. My initial settings had too much compression and not enough rebound, and I'm gradually sorting that out. The car's working better and better, and will be on track again next Friday. It'll be interesting to see what a difference the extra droop travel makes.
entry 307 - tags: suspension | | | September 6, 2007 - Lots of time spent working on cars, but not much on the Targa car.
I've been waist-deep in changing the engine on my old Toyota pickup. It makes me appreciate the amount of room and relative simplicity of the Miata engine bay, that's for sure.
I have been driving my "baseline" Miata around to help recalibrate my butt for the suspension tuning. The baseline setup is a set of Flyin' Miata springs with Tokico Illumina shocks and Flyin' Miata upper shock mounts. Despite using 17" wheels, the ride/handling compromise is an excellent one. The spring rates (318 F/233 R) are what I'd like to use for the Targa. The current suspension setup I'm working on uses 450/300 so my goal is to get the same compliance despite the higher spring rate. I think I'm on the right track. There's a short window for some track testing tomorrow and I'll see how the new long travel setup compares to the previous short travel Ohlins. The big question - should I install swaybars for the trackday?
entry 308 - tags: suspension, other cars | | |
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THE DIARY