build diary

September 29, 2005:
I cleaned the Seven off last night.
Cloth seats are not a good idea in a car with no weather protection. Yuk.
entry 1033

September 30, 2005:
I installed new brake pads and rotors last night.
The good thing about Miata rotors is that they're only about $10 each! Starting with new rotors prevented any material transfer from the kevlar-metallic pads I'd used before. The pads are Carbotech Panther XP8s that I've mentioned before. The pads proved to be just a hair too fat on the front to fit the anti-squeal plates on one of the two pads, but that's no great problem. The rotors were given a splash of black paint to keep them from rusting. The front rotors I took off the carI headed out (now in the dark) to bed them in.

Now that was some childish fun! The first couple of stops felt normal. On the third, it was like the Seven had grown little claws and sunk them into the pavement! Holy cow, there was certainly something wrong with the previous setup. I realise now that the other pads were probably never bedded properly as they were installed very early in the car's build and I was paying too much attention to everything else once the car started moving. I'll scuff them up and put them on Janel's Miata instead. Breaking in the Carbotechs was very entertaining, though - there were sparks coming off the front wheels as the exhaust blew fireballs on overrun. Quite a show!
entry 1034

October 3, 2005:
Another track day.
This one was "Octoberkross", a two-day event put on by the same guys who ran the autocross a few months ago. They're still new at this and it did show on the first day. The event was aimed at the "sport compact" crowd, so it was a younger group and there were a lot of FWD cars. Most of the drivers were complete track novices. It's good to see them out on a real track, learning performance driving. In many cases, their exposure to high performance driving has come from watching showy videos - that's good and bad. The format of the weekend was a practice/qualifying/tech day on Saturday and the actual race on Sunday. I'll go chronologically.

After some confusion and some frustration on my part, I was allowed on to the track at around 5 pm on Saturday. They had saved the big guns for last, the Fiat (remember him?), myself and a collection of Subaru STis and an EVO8. My own driving wasn't good. The new brake pads apparently have much greater front bias and I had to make massive changes to my bias setting. It didn't help that there is little weight on the right front wheel and that my hardest braking took place on a slight right turn where it was unloaded. I'm tempted to install a proportioning valve in the front lines to help balance this. I also had bad understeer on a couple of right corners while the balance felt pretty good going left. Probably has something to do with the location of the driver! Elsewhere on the track was mayhem. A number of self-styled "drift specialists" were going off the track (usually nose first) all over and the EVO8 was a total loose cannon. I suspect that if he'd tried to go 5 seconds slower, he'd have gone 5 seconds faster. I finished the day with a time in the 1:05.99 range with an STi hot on my tail at 1:06.06. Too close for comfort and 0.4 seconds slower than my best. It is good for your confidence when the starter recognises you, shakes your hand and says "You still own this track!". Janel did well, taking nearly two seconds off her previous best. She's a smooth driver who takes care of her car. She was appalled at how much some people beat up on their cars. Rick Weldon showed her how it's possible to be smooth, gentle and extremely fast when we were at Thunderhill and she took it to heart.

That night, I added a touch of camber to the understeering left front and gave it a turn on the spring perch, hoping to add a bit of weight. I also dropped the tire pressures a touch. This track is a weird one for tires, being a bit too fast for autocross but not as demanding as a real track.

Sunday worked like clockwork in stark contrast to the day before. Being on "pole", I was the first one out. I shaved a tenth off but still had some balance problems. The STi was a bit off yesterday's pace. A turbo Civic turned a 1:06 and made it quite clear who the target was. The Fiat was struggling a bit. Even the out-of-control cars from yesterday were behaving themselves a bit more.

While spending some time flagging, I thought about what was going on. I realised that it all came back to braking. I had been relying on trailbraking to rotate the car on these tight corners and it just wasn't working all that well. I still had too much front bias. I turned it back fairly aggressively and lined up for my next session. The car immediately felt much better, turning in harder and being easier to toss around. My biggest problem was coming from the turn on to the front straight, as the understeer there was costing me a lot of speed. There was a short, fast left just before this 180 degree right, so I used this as a "scandinavian flick" to get the tail out. On the second and third laps, I got the tail out a bit too far and ended up going around the last corner on full opposite lock. I'm comfortable driving sideways and the Seven really takes care of you in this situation, so it was easy to control the slide and smoothly exit on to the front straight. It wasn't any slower than the understeering method judging by where I had to shift on the straight and the crowd seemed to enjoy it. I knew it was a quicker lap - not my lap record, but fast enough and consistent over all three timed laps. The end result was a 1:05.7 or so. Nobody else dropped below 1:06.

At the end of the day, I got the chance to go out and play. I was mostly driving like a meathead but I did find a few spots where I picked up speed. I was disappointed that my final result - with better brakes and more horsepower - was not faster than my previous best but since I only managed to get about 10 laps in, I wasn't as sharp as I had been at the Open House.

One piece of news from the Se7ens on the USA tour. Two couples got married at the Little White Chapel drive-through in Vegas, one couple in a Caterham and one in a Westfield. That's my kind of people!
entry 1035

October 4, 2005:
Reading over what I did to try and set up the car this weekend, some of it sounds backwards.
The tire pressure changes were based on reading the tread. Given the length of the track (a "session" was only 5 miles!) it's possible they only barely reached full temperature. Lester Seal reports that he is running much higher pressures on his RA1s on his car and I'll start off there when I'm at Aspen in a couple of weeks. The real opportunity for tuning will come at a Pueblo event in a month. Hmm, maybe I should hunt down a pyrometer for this. I really need to get the suspension sorted. Lester reports he is running much less camber than I am.

Naturally, there's work to be done before the next track day. The car ran well - flawlessly, actually - but I still have to sort out the hood. I'll try to get a start on that tonight.
entry 1036

One of these cars is a visitor to town.
Guess which one.
entry 1037
My first hot laps at the Octoberkross event.
Still lots of roll here and I'm having trouble getting the front wheel to stick.
entry 1038
By contrast, the left turns are nicely balanced.
This photo was taken later in the day, after I'd added a touch of front camber to both wheels and removed the windscreen for a bit less wind resistance and a big psychological shot at my opposition. That rear wheel looks questionable.
entry 1039
I managed to sort out the understeer - this is the same corner as the picture taken earlier in the day.
This attitude was no slower than the grinding understeer but it sure was a lot more fun. The black stripes on the corner are from the previous lap.
entry 1040
Gratuitous? Not me.
Never. This is a different lap than the previous picture. The best part is that the tail was still coming out but the next photo in the series didn't turn out.
entry 1041
During the fun runs at the end of the day, I was harassing this Neon.
I figured he'd enjoy the view more if I gave him something to watch. The best part is that the owner of the Neon is riding with me...
entry 1042

October 5, 2005:
Well, no progress on the hood.
However, I did spend some time looking at mufflers. Between seeing all the Se7ens on the tour, running my car for a few hours on the road and again on the track with the Supertrapp tip, I've decided it's time to make the car quieter. All the "real" Se7ens run much larger muffler cans, enough that my little resonator looked pretty funny. So I wandered over to the Summit Racing website and started looking around. I've spent lots of time looking through their print catalog but the site amazed me. I was able to set my requirements (2.50 inlet and outlet, centered, round muffler, etc) and it weeded out all the hundreds of options I didn't need. By the end, I was looking at a list of 7 mufflers with full dimensional diagrams and a size range from 4"x14" to 6"x27". It couldn't have been easier - thank you Summit! I'm assuming that pretty much any 2.5" muffler will be able to flow enough air for my approximately 170 crank hp without noticeable restriction, but I'll see if I can find flow ratings for them. I'll do some measuring tonight to see what will work. It's a real shame that mufflers are sold with such vague descriptions - do I want an "awesome full throttle sound", a "deep aggressive tone", an "old school glasspack sound" or just "excellent sound"? I know I don't want a nasty rasp but none of them say that. It'll be a shame to lose some of the crackles and bangs but right now, wide open throttle hurts without the Supertrapp tip or ear protection.
entry 1043

October 6, 2005:
Ben from Caterham is bringing his SV (the red one in the Moab pictures) to the track day at Aspen.
Oooh, the moment of truth! I think he's running an extra 30 hp or so, but I really want to know how it compares on track. This will be very interesting.

To help make the car faster, I've found a care and feeding document for the RA1. Interesting stuff. This will come in handy in Aspen and I promise to do some real setup. The first step will be to dial some real camber into the car because the RA1s like lots of camber. I'll probably also toss in some thicker sways to keep it flat. As for the exhaust, I had a good chat with Chuck at Thermal R&D. He makes the exhausts for Flyin' Miata. I'm going to send him some photos and a list of what I need and he'll come up with something. He does beautiful work and his systems always sound great.

The results are posted for the track event. No surprise that I'm on top - I knew that already - but I was curious about some of the others. The closest competition is a quarter of a second back and there are a fair number in the 1:06 range. I'd better get this sorted out!
entry 1044

October 9, 2005:
I've finally put up some more photos from the track day.
I'm such a sucker for photos of my car although they do provide some interesting analysis. That's my justification.

The Seven did get some attention today (finally!). The Aspen track day is looming in a week so I want to be ready. The first step was to make sure I had enough camber in the wheels. Unexpectedly, I had quite a bit. My memory of my specs wasn't even close. The rears were at 3.4 degrees negative camber and the fronts were about 3.1 (R) and 4.3 (L). The massive amount of camber on the LF is from the recent track day from trying to keep it planted on the rights. A quick check of toe made the cause obvious, though. The RR tire had about 1/8" toe out. That would have rotated the rear nicely (to put it mildly) on the left corners and made up for having too much front roll stiffness, relatively speaking. The right turns were probably illustrating the current balance of the car. I dialed the toe out of that corner, leaving me with about 1/16" toe out in back (I know, that's bad) and put a stiffer sway in the rear. Depending on how the Aspen day goes, I can easily dial out the remaining toe and also use the adjustable bar to add more rear roll stiffness. I'd like to put a stiffer bar on the front as well. I jacked up the LR a bit as it was riding about 1 cm lower than the right side with a driver, then evened out the corner weights. Oh, and the car now weighs 1328 lbs with a mostly-full tank of gas. I've decided the best way to improve performance is to take weight out of the driver. It'll balance the car better, you see...

While I was underneath, I noticed a small gap between the rear upright and the lower rear control arm. The upright was free to bang back and forth under acceleration and braking! I can't explain how I missed this on assembly, but it's been shimmed up now. Yikes, that could have ended badly. That explains a clunk I'd heard a couple of times last track day.

I have noticed that I'm much more sensitive to the car now. Carrying a passenger makes it almost undriveable on the track where I used to find it perfectly acceptable. Even taking a 100 lb girl out for a few laps made a noticeable difference in acceleration and handling.

Next work: the hood then the exhaust.
entry 1045

A front shot from the morning timed session.
I dialed in just a touch more negative camber after this one.
entry 1046
Still a fair bit of body roll, although that front wheel is climbing a berm and I'm hard on the throttle.
entry 1047
Whoops.
Too much front brake bias!
entry 1048
The Seven is starting to look a little mean when parked.
entry 1049
Talking to Janel after one of her sessions.
No, this photo doesn't belong on the Seven site. But she did well at the track!
entry 1050
This is a fun shot.
The car's obviously not going straight...
entry 1051
I think this is one of my favourite action shots of the car ever.

entry 1052
The lower rear control arm where it meets the rear upright.
Why didn't I notice this gap earlier?
entry 1053
A new adjustable rear sway bar and a lot of Moab mud.
entry 1054
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