Time for an update! I've put almost 2300 km's on the car so far and it's been quite reliable. The clutch master cylinder started leaking so I had to replace that, but it was over 20 years old so it was inevitable. The weather has been pretty good and at times even warm enough to drive in shorts and a t shirt. The car gets tons of attention and people give you thumbs up everywhere you go. Driving it is kind of a strange mix of embarrassment and pride. I managed to snap a few pics outside my work just as the cherry trees were blossoming.
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As for the Performance of the car I'll break it down by sections.
Brakes:
At first I found the braking to be very poor. The pedal effort was quite high, and the fronts would lock up at only moderate deceleration levels. Now that the pads are bedded in and I'm used to positioning my foot on the proper part of the pedal the effort is totally reasonable. I've also adjusted the balance bar for a lot more rear brake and removed a lot of camber which helped immensely (I might be adding some back but I'll get to that later).
Cooling:
In cooler ambient temperatures the cooling system seems to be fine. I did have it get quite warm on me one time though. It was the hottest day so far this year (28*C) and my wife and I decided to go out for a 4 hour loop. The car was fine in city conditions or even slower country road cruising. It was only when we hit the highway with sustained higher speed and traffic that the rad could not keep up. It could maintain a reasonable temperature if I kept the speed to ~90km/h but with increasing speed the temp would start to rise. To be honest i'm not surprised at this since there is no radiator ducting at all. I think the shape of the car and lack of body work allows air to enter in and hit the firewall behind the radiator causing a high pressure area that stalls any airflow through the rad. I'm going to add some ducting to better connect the rad to the opening in the front. I'd also like to add ducting behind the rad but i'm not sure if I should duct it to the low pressure area underneath the car or up through the hood GT40 style. Any thoughts?
Power:
The car is quick, but not nearly as fast as I was imagining. I love the N/A power and instant throttle response so I won't be going turbo, but maybe it'll get a set of cams at some point. The Vtec hits pretty hard. I think substantial mid range gains could be had if the engagement rpm was lowered. I did do a 0-60 mph test, actually it was 0-100 km/h (62.5mph) and it ended up at 4.9s. This was on a bit of an incline and since the car does exactly 60mph in 2nd there was a 2-3 shift and an extra 2.5mph in there. I think it would probably do a true 0-60 in 4s but I'll have to change the settings in my Koso dash to find out. Fuel mileage has been great at ~28mpg. The exhaust sounds great but it is a little loud so there may be a redesign in the future if it causes problems at the autocross events.
Handling:
I've been making lots of suspension tweaks to try and get some of the understeer out of it and I think I'm on the right track. As it sits now the rear is 15mm higher and the front is 15mm lower. I tried the caster at 5*, 7.5*, and 3.5*. I found the higher caster to have too heavy of steering, and the weight jacking really accentuated the fact that I have an open diff. I found I liked the lowest the best for lighter, more precise steering, and less weight jacking. I changed the front springs out for 300lb/in from 200lb/in because I found the turn it was fine but it was washing out a little after that. Kind of like it was great while on the compression of the shock but once settled on the spring it was too soft. I read that lack of roll stiffness in the front could cause that and also that the roll stiffness distribution, as a rule of thumb, should be about 5% higher in the front than the static weight distribution. With the 200lb springs the roll stiffness was 30% front with a 35% weight, while the 300lb springs put the front roll stiffness spot on at 40%. Right now I'm running -0.25* camber in the front and -0.75* in the rear with 20 and 30psi tire pressures respectively. After this weekends autocross I found that the car could use a little more camber than that. Perhaps I'll bump it up to -1 and -1.5 or so for the next event.
Autocross (Putting it all together):
This weekend the car made it's debut autocross. I went into the event with pretty low expectations. My old turbo Miata pretty much FTD'd every event I attended so the new car was following in some pretty big footsteps. With the amount of understeer that I felt was plaguing me on the street I didn't think there was a hope in hell the car would be composed on the track. I was pleasantly surprised. While it still had some understeer on corner exit, the car handles beautifully on transitions, steady state, and corner entry. I had a blast and ended up 2nd overall. I was .5s behind 1st which was a hyabusa powered 7 on Hoosier A7's (I'm on Rival-S street tires).
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http://www.youtube.com/watch?v=_8Qp9yRHqr0http://www.youtube.com/watch?v=LZAcVNg8Bsw
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