build diary

February 22, 2009:
I started off my Seven journey five years ago (wow!
) with a model of a Caterham. That's what pushed me over the edge to build the car. Well, things have come full circle. Russ DaCosta - that's him in the middle - is a friend of mine who's very quick in his STi and has a collection of the nicest kids you've ever met. They're involved in Cub Scouts, and it's pinewood derby season.
On the left is Christian, who won both the design and speed contests with his 1938 Auto Union. On the right is Scotty, holding his entry. Yup, that's what you think it is.
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I was blown away when Russ sent me these pictures.
They were a surprise, and I'm incredibly flattered. The kids have seen the Seven at full tilt boogie a number of times as they come out to the track to cheer on their dad. But I had no idea. Isn't it amazing?
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Not only is that my license plate, even the little Nuerburgring sticker under the left taillight is there.
The instruments are in the middle of the dash, the harnesses are red, there are louvers in the hood - everything is so good. I think the quality of the welding on the rollbar is accurately modeled as well!
Scotty won the design class (I'm assuming there are age groups involved, as his brother also took first in Design), but came in third in the speed contest. I could have warned him about this - the pinewood derby track is straight and the Seven's aerodynamics undoubtedly cost him. If he'd managed to find a venue with a few more corners, I'm confident he would have taken the checkered flag.
Amazing.
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March 6, 2009:
I knew this would happen eventually.
I was at the track today testing the Targa Miata, and Bill came along with his Westfield. Brandon had his bike-engined car as well. We didn't have any transponders on the car but I was playing with a Traqmate data acquisition system that will do lap timing and datalogging. After playing with the Miata for a while, I stuck the setup in the Westfield. Bill came back in with a 1:00.3 showing on the screen. Yes, 1.5 seconds faster than my existing lap record. After reviewing the logs, I think it's actually a 1:00.8 or so - but regardless. Consider the record well and truly smashed. This was on a day when the track was pretty slow, too, with low temperatures and a lot of dust blown on.
Yowza. Nice work, Bill. Since the Open House, the Westfield has received a new intercooler, a sway bar and a set of Nitto NT-01 tires in a 225/45-15 size on 15x8 wheels. Those tires seemed to be the key, as the car was glued to the ground and Bill could make use of the car's ridiculous power/weight ratio.

Brandon's car was looking pretty good too. Other than a fire when leaking fuel on top of the gas tank lit up. No harm done, but his to-do list now seems to center around sealing the leaking filler neck on the tank. Good plan.

Watching the two cars play on the track made me wish I'd brought the little orange beast. Sure, it would have been slower. But still, it would have been so much fun to play.
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May 12, 2009:
Well, it's official.
Bill has the lap record. We had a track day last weekend and while I'd originally planned to bring the Seven, I ended up driving a V8 Miata instead. It was good - I took it around the track faster than any other Miata has ever managed with a 1:02.889 - but Bill was there with the Westfield and a transponder.

The times didn't quite match up to those coming out of the datalogger which was a bit odd, but an official 1:01.546 was enough to take my crown. That's still close enough that I could probably steal it back again with a bit more practice.

Brandon brought his car and failed to catch on fire, so that's good. In fact, it was the most uneventful day for him yet. His time was a 1:02.210 which is still pretty darn fast, but he seemed disappointed. Oh, how our standards have changed in the past year!

Remember my first visit to this track? I did a 1:09.6. Really.
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July 30, 2009:
While procrastinating on the latest book, I found myself flipping back through this build diary.
The Flyin' Miata Open House is coming up soon and I just realized that it will mark the 5th anniversary of the Seven's track and public debut. 5 years! It's hard to believe. It's also hard to believe that for the last two of those five years, the car has really only come out of the garage for the Open House. It's a real shame. So I took it for a short blat to make sure everything's working properly (answer: yes) and then proceeded to prep it for a track day.
It's shameful. I've been distracted by the Targa Miata and V8 Miatas. It's time to get back to first principles.

Now, we've agreed not to chase lap records at the Open House this year so we can concentrate on giving rides, so I'll probably leave the Seven in the garage that day. But Saturday - Saturday is different. It's a full-on track day. Brandon will be there with his little lightweight, complete with a new airbox. He hasn't been able to touch the lap record quite yet, but he's within sniffing distance. Bill should be there with the monstrous Westfield, but running narrower 205 tires due to a small interference problem between his spring perches and his oversized wheels. So it might turn out to be an epic day.

Again, there have been no changes to the car in the past two years, but I've been spending a lot of time on the track. Is there room for a little more to be shaved off? Bill's only 0.3 seconds ahead. This is going to be good.
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August 1, 2009:
Is it bad when you can't even finish two laps of the track without two things going wrong with your car? At the track day today, I had the hood come almost completely free.
Three of the four latches undid themselves, and the hood started to fly once I got over 60 mph or so. Quite eye-opening. Because of this, I aborted my first session in order. When I came into the pits, it became obvious that my quickie repair to the front fender stay (remember that from the Open House last year?) had come undone. Whoops.
So, off came the otherwise-undamaged fender and stay. No problem, it's two bolts. I'll fix that at home. A bit of tape over the latches solved that. So it was back out.

I was back up to speed pretty quickly. Remember, last August I turned a 1:01.893. Well, today I managed a 1:01.960. And if I'm reading the time sheets correctly, I managed to do it twice! Weird. So a year ago, that would have been a new lap record. But it's not a year ago. I was playing with some higher tire pressures and it's possible that improved grip was masking some rustiness on my part.

Bill didn't show up with the turbo Westie, so it wasn't a concern. Brandon, on the other hand, had been building a nice fibreglass airbox for his lightweight beast. Between that and a more aggressive driving style that was apparently modeled after mine (his girlfriend, being used for ballast, called it "terrifying") he was going faster than he'd ever gone. Not quite enough to beat the lap record, but very close. His 1:01.652 is only a tenth behind, and there's still more left in the car.
I got a chance to tuck in behind him on one session after he did a little half-spin. It was very interesting. There certainly isn't much between us. A small mistake in braking into turn 4 and he picked up a car length, but overall it was a close match. Until, while screaming down the back straight, the back of the Seven stepped out. The next braking zone - the hairiest part of the track in any lap - was quite exciting. And it wasn't a one-time thing, it was as if the right rear tire had deflated or got covered in oil. There was just no grip back there. The left rear wasn't feeling so good either.
Since it was the last timed lap, I was on my way in anyhow. I cooled the car and then pitted. Tire pressure was good. I think I simply overheated it. Hard to believe with such a light car, but I do get a fair bit of wheelspin at times. Everyone was complaining about their tires getting greasy.
Unfortunately, I never got a chance to find out if that was the case, as the photographer reported that my car appeared to have thrown a belt. It was still running cool, but a peek underhood revealed that this was true. It had thrown the alternator/water pump belt again! That's the second time, and I'd just tensioned it the day before. The pulley setup is stock Miata, and they don't usually throw belts. They don't usually turn over 8000 rpm regularly either, but still. The car never did it before. An eyeball alignment check showed that the front crank pulley seemed a bit cockeyed. Starting the engine up confirmed it - fairly serious pulley wobble.

Uhoh. If you know Miata engines, you know the 1990-91 models had a crank nose that could break. Has the Seven fallen prey to the dreaded crank nose problem? Or is it something else, like a heavily abused 20-year-old harmonic damper that's failed internally? I don't know yet, but some disassembly will tell. The belt was retrieved undamaged, but I parked the car for the rest of the day. With the belt back on, it drove home happily enough. Even if it is the crankshaft, one of the other Miata drivers at the event happens to have a spare 1992 bottom end at his house. I could probably replace it in an evening. So it's not a big problem overall.

So that's it for a while. Time to do some real work on the car before it comes out of hibernation again.
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So what was it like driving the car after such a long vacation? Awesome.
Oh man, I'd forgotten just how good the car is. Places where I was expecting to have to baby the car through a corner, it simply tore through. It talks and talks, it slides around beautifully, it just does what it's told. There's one spot on the track between turns 1 and 2 where I can get a good burst of full throttle in the Seven. In other cars, those two corners are linked. They simply make more of a fuss getting around the corner.

The big thing was the engine, though. It's almost operatic. It howls and crackles and has a number of different voices depending on where you are in the rev range. It's got so much character and slugs you back in the seat coming out of a corner. I found myself goofing around on the cooldown laps just to make the engine talk. What a great sports car engine.

It's not perfect, though. I need to do a bit more work on the rear suspension to improve droop travel. I'd also like to run slightly less spring rate in the rear to cut down the oversteer just a bit. A quicker steering rack would be handy. Relatively small detail things, but things that would help the car out a bit.

But oh, that engine!
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August 9, 2009:
The Seven is showing signs of neglect.
It's been used so hard with so little TLC over the last few years that it's getting a bit rough. Tom Heath from Grassroots Motorsports was in town for the Open House and took the car for a short drive. The car was missing a fender (that didn't get fixed from last week), the throttle bodies are a bit sticky at slow, light throttle openings (such as driving in traffic), the rear suspension was "direct" (he was being very kind) and there was a weird noise coming from underhood that may or may not have been related to the crank problem. On top of that, the differential didn't seal into the housing the last time I installed it so it's dripping a bit.

It's time to go through the whole car, stem to stern. If I end up pulling the engine for a new crank, I'll make sure to sort everything out. I've learned so much since building the car, it's time to put some of that knowledge to good use.
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I had a Traqmate datalogger in the Targa car this weekend when I was at the track.
I reviewed the logs and saw some interesting things. In that car, at least, I'm not anywhere near the limits on the back straight. That used to be the strongest part of my lap, but you can see that I'm neither cornering at maximum effort or accelerating hard - at least, not in the Miata. I'm wussing out. I also need to review my old videos to find out just what my line was there, as we were discussing options and I managed to confuse myself!

So, even with me being a bit of a wimp, I was still almost on my pace from last year - less than a tenth slower than my all-time best. Why? Because there's a new concrete patch on the outside of the last two corners, and it means a much better drive on to the front straight. Some of the lap record action in the 2009 may be due to this faster line. Now all I have to do is fix my car, get myself back into shape and go hunting cars with more horsepower and less weight!
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