Targa Miata
MIATA BUILD
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 Íhlins 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
January 2, 2008 - Well, my local shop can't source the 2" radius bends I need.
So it's off to Summit Racing for them.
I've also been chatting with the engineers at AFCO. The shocks are off getting a tweak to the valving, based on shock dyno tests of a few other options that did well on the comparison drives. I feel like such an amateur when talking to them, but every time I learn something and the shocks seem to come back a little bit better. This should be the last iteration.
entry 363 - tags: header, suspension
April 20, 2008 - I put the car back together and took it out for a test drive this morning.
The upper rear control arm bolts are a bit looser to allow for free movement of that arm.
I used a piece of road I haven't used with this car before, but it's perfect for per-Targa testing. Incessantly twisty with a lot of blind corners, covered in gravel in inconvenient places and with completely hammered and badly patched pavement.
The car did quite well. I wasn't at full throttle very often but I never had a lack of traction. Even at inadvisable speeds through the roughest, twistiest sections the car never got upset although it did make some interesting movements. I'll have to go back through there with a more normal car to get a baseline. I'm also going to take Janel for a ride to make sure she's comfortable with it!
entry 451 - tags: testing, suspension
June 1, 2008 - Autocross time!
This was an event put on by the Red Rock Racers, a group I started because we didn't have any autocrosses to go to! Problem solved, now there's one a month. And on the prettiest autocross course in the world.
We had a good bunch of cars out - a couple of modified STis (including one on Toyo R888s), a rotary-powered X1/9, some quick Miatas, an Evo and even a Isuzu I-Mark "Handling By Lotus". Everyone's a lot of fun to run with. However, they did have a little trouble keeping up with the Targa Miata. I took the fastest time of the day by a 0.8 second margin.
The car felt good, moving around nicely and easy to toss into corners and transitions. I was using the brake bias to adjust the handling of the car and it worked well. I didn't adjust anything on the suspension after my recent over-the-road testing otherwise.
The picture was taken on a fast right sweeper, and you can see there's a fair bit of body roll. It didn't seem like it from inside the car and it responds to transitions pretty well. But I was still having traction problems on rights, and looking at that roll makes me wonder if it is simply a matter of unloading the inner wheel completely despite all that droop. I'm going to play with some different sway bar and alignment settings, although having Janel in the car helped and I expect a cornerweighting session would also plant that right rear a bit more.
Another thing that concerned me a bit was my consistency - or lack thereof. I'm usually pretty good for putting down similar times, but today I was all over the place on the timing board. Still at the pointy end of the pack, of course, and I posted not only the fastest time but also the second-fastest and (I think) fourth and fifth-fastest. But there was a bigger range than usual. I'm not sure exactly why. I did manage to stay clear of cones all day though.
The car was burping coolant out of the overflow tank, but not showing signs of running hot. I think I might have a bad radiator cap that's venting early. Easy enough to check. Otherwise, the car ran flawlessly.
entry 462 - tags: testing, suspension, brakes