| MIATA BUILD |
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 | |  | 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 | | | September 7, 2007 - Track test for the new suspension.
This was an informal and short window of opportunity, but it was enough to take the car out with the new setup. I spent some time on the phone with the suspension engineers and learned about bit more about how my valving worked.
On the track, the car felt pretty good. It took a few laps to discover where the difference lay. The first hint was the chicane area. There are some big berms here and the car is usually dancing around due to the kerbs throwing the car around and the nature of the entrance to the turn. Not today. The car was just swallowing any bumps, including ones where it was off balance before hitting the kerb. Coming down the hill into the tough braking zone, I discovered that it was impossible to upset the car. I started provoking it, coming in off-line and hitting berms when the car should have been vulnerable. Nothing. It just stopped. I think the endless rear travel kept the rear wheels on the ground no matter what, adding greatly to the car's stability.
A bit of experimentation with compression damping helped balance the car a bit better and gave it more composure in the corners. At the end of the day, the car was forgiving and able to deal with just about any imperfections I could find on the track. Imperfections like dropping off the outside of kerbs on corner exits, or cutting corners so that I'd drop inside the kerbs, or hitting kerbs under hard braking. It isn't quite the super-playful Miata yet but I have some ideas for extracting the last bit of fun.Maybe a little more front camber and a front bar to encourage faster turn-in and a slightly flatter stance. I don't want too much of a wayward tail for the Targa, though. On the street, the car feels good.
There's a set of 8" 350/275 lb springs on the way along with some rubber snubs to limit the travel a bit better than my rough-and-ready bumpstop arrangements. The spring rates are closer to what I'd like to run on the Targa, although the way things are working right now I'm not sure how critical that will be! They're also an inch longer than my current setup so I can get a little more ride height, and throw some relatively soft sways in there as well.
Tomorrow, Targa 2007 starts. Good luck to everyone!
entry 309 - tags: testing, suspension | | | September 12, 2007 - Whoops.
The instrument lights haven't been working in the car and I've been driving it at night more than I ever expected. So I pulled the instrument cover off to see if someone might have cut the wires - and the 16-year-old plastic snapped. It's a common problem, the cover is held in place with three very strong clips. But all three of them went at once. I just threw out another one with the same problem. I guess I'll have to spring for a functioning cover, or find another fastening technique. Hmm.
I also started working on the VICS system. This controls a quartet of butterflies in the intake manifold, changing the volume of the manifold to improve low-end torque. It works amazingly well. But of course, the VICS actuator has a broken vacuum fitting. I could either try to glue it in, or modify a later VTCS actuator by shortening the shaft. And that's what I'm going to do, because I'd rather use a welder than glue!
entry 310 - tags: engine | | | September 14, 2007 - Martini paint codes.
Someone asked me via email for the paint codes for the Martini paint job, and I realized I'd never really spelled out the final mix. So here it is. I used NAPA Martin-Senour paint in the "Gold 5.0 urethane" single stage mix for the stripes and was very happy with how it laid down. The white was PPG Omni.
Dark blue. VW Marine Blue from a 1988 Golf. VW LA5B, M-S code 23427
Cyan. Mercedes DB5508, apparently. I used M-S 59392
Red. Opel Flame Red from a 1968 GT. Opel L512, M-S 20934
White. Mazda Crystal White from a 1990-93 Miata. Mazda UC, M-S 39783
entry 311 - tags: paint, Martini | | |  | September 14, 2007 - Some more suspension parts to try out.
This is a set of 8" long springs (1" longer than my current ones) with a 300/225 split. It's closer to the rates I was planning to run on the Targa and I'll be able to lift the car a touch. The rubber bumpers are to control travel a bit on these prototype shocks, although I thought they were going to be longer.
entry 312 - tags: suspension | | |  | September 15, 2007 - Whoops!
The last time I was at the track, the car was pinging above 6500 rpm. We pulled out some timing, but it persisted. I think I might have found out why. Two of the bolts holding the cam gear in alignment slipped, and the intake was at full retard.
A walk down to the hardware store at the end of the street yielded some replacement bolts and the problem was fixed for just a few cents. The car should hit the dyno soon so I can get an idea of the correct timing (they were set at the equivalent of stock to start), and then I'll loctite them in place. These particular gears have spent a lot of time spinning fast on several cars and this is the first time we've lost a bolt, so hopefully it's an isolated incident. It's a good thing I have the cam cover cut, or this would have been hard to spot.
entry 313 - tags: engine | | |  | September 20, 2007 - Spring time!
The (chrome) 450/300 lb springs have come out and the (yellow) 300/225 springs have gone in. The new springs are an inch longer as well. This is the spring set I've been expecting will work out best for the Targa.
How does it feel? After a quick run around the block (the block in question is not your average city block, but includes some low speed turns with bumpy exits, some mild crests and is probably 6 miles around) it's pretty good. It's time for a sway bar of some sort though, and I need to do a back-to-back comparison with the control car. The most obvious thing is that I could probably use another inch of spring length on the front to get the nose up to my desired ride height, but it's very functional right now and I have piles of travel. So maybe I don't need to raise the nose after all.
entry 314 - tags: suspension | | | September 20, 2007 - Susquehanna MotorSports has joined the Targa Miata team!
They will be providing some of their signature rally products, such as a first aid kit, map light for Eric, mudflaps and other bits and pieces. On top of that, they'll be helping out with advice and information thanks to their long experience in the sport. They're best known for their lighting parts, and if we didn't already have a good stash of Hella lights we would have been in touch for those.
You can visit Susquehanna MotorSports at rallylights.com.
entry 315 - tags: announcements, sponsors | | | September 24, 2007 - The 2007 Targa ended a bit over a week ago.
It sounds like it was a good event, but there was one stage with a wet wooden bridge that brought tears to a lot of eyes. It's spooky, because it's the sort of conditions I can't really test or practice very well. Here's some good video of the spot.
entry 316 | | | September 25, 2007 - I drove the car in to work today with the new springs.
It's gained a fluidity that I really like. I haven't had the chance to stretch its legs yet but I'm hoping to do that tonight. I'll put on a front sway bar soon and see if I can arrange a bit of track time to test the setup.
entry 317 - tags: suspension | | |  | September 28, 2007 - Sway bar time!
I have a good selection on hand. For the front, a 23mm front bar from a Mazdaspeed MX-5, a 7/8" adjustable aftermarket bar and a 1" adjustable. The rear will be served with a 14mm Mazdaspeed bar or a 5/8" adjustable. I'm trying a different setup than I usually use to ensure the rear wheels stay hooked up on rough surfaces. We'll see how this works out. I might see if my local alignment shop is willing to work with me on this, I expect it'll be spending a lot of time on the rack.
entry 318 - tags: suspension, alignment | | |  | September 29, 2007 - I have quite a collection of end links for sway bars.
From the left, we have 1999-05 stock, a set of adjustable ones with rod ends, a pair of Racing Beat ones with bushings and stock 1990-97. I'm using the rod end style because I have a full set of four and they will allow me to adjust the length and avoid any preload. These particular ones were made with inexpensive rod ends, and thus make a slight rattling noise. It's not a problem, just a little disconcerting when driving through a parking lot.
entry 319 - tags: suspension | | | September 29, 2007 - The sways are installed.
There's a 7/8" bar on the softest setting up front and a 5/8" bar on the softest setting in the rear. I considered using the 14mm Mazdaspeed bar in the rear, but the aftermarket version has longer arms so I suspect they're about the same in the current setting - and this gives me more options. This current setup is slightly more biased towards front stiffness than I usually run. Typically I'd have that rear bar on the middle setting. I also have a factory 12mm rear that I can throw on if required. One nice thing about the Targa Miata is that I can install the rear sway bar without even jacking up the car, thanks to the cutaway rear bumper!
I headed out for a run to test the bars. To make things more exciting, the wind was howling and rain was splattering down. It's the best imitation I've seen of Newfoundland weather here in the Colorado desert. I'm assuming I won't have to dodge tumbleweeds in the rain in Newfoundland, though.
The car feels great. It's got a very nimble feel and it just glides over imperfections in the road over 20 mph. Below that speed there's more impact felt through the body but the car just deals with it. One 2nd gear corner with a very corrugated exit caused the rear end to lose traction, but it had more to do with the cool tires, wet road and too much power than with the damaged pavement. The Torsen diff let the loose wheel just spin up, an indication of how little traction there was. It was a smooth breakaway and I just rode it out. The car is very eager to turn in and feels a bit darty, but that could also be the strong cross winds. I'll see how it feels over the next few days. The next track session is scheduled for November 3rd, but I might be autocrossing the car next week. We'll see.
entry 320 - tags: suspension, drivetrain, testing | | |  | October 1, 2007 - Hard Dog Fabrication sent along this trick dual-durometer rollbar padding.
The problem is that rollbars are hard. The SFI-compliant padding at right is hard enough to protect a helmeted head from the bar, but it's not soft enough to protect an unhelmeted head very well. Since I want to be able to drive the Targa Miata without a helmet, this isn't ideal. The solution is a softer outer shell, with a firmer SFI padding inside. It's obviously quite a bit thicker overall than just an SFI pad so I can't use it in a couple of locations, but it'll fit nicely around my head.
entry 321 - tags: sponsors, safety | | |
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