July 24, 2011 - Track day test!
The car isn't quite in the final Targa spec, but it's pretty close. Specifically, this is the first time I've taken it on track on the Toyo R1R tires. I was also interested in the effect of the springs. The engine is healthy but not fully tuned up yet.
The current spring setup: 550 front and 450 rear. I'm homing in on my desired rates, using what I have for testing before I order in a set that's a different rate. The rears are the question here, that's a lot of rear rate for those front springs. I may end up running a 375 or 400 back there. But this car has always preferred more rear spring rate than other Miatas. The alignment was also low on front camber, and the solution for that is back at Flyin' Miata. It'll be installed on Tuesday. Still, some testing is better than none!
On the first session, the car was very, very loose. All over the place. I pulled in to check the rear sway bar after about 2 laps and discovered I'd left it on the stiffest setting. Oops. So I removed it and headed out again.
Better. The balance of the car was improved on the long sweeper. It was pretty obvious that the tires were having a real problem putting the power down, and I could easily light them up coming out of corners. Overall, I found I had a little bit of turn-in understeer followed by as much oversteer as I ordered. Coming in under braking, the car was also moving the back end around nicely. But that corner exit oversteer was pretty wild.
Now, this track is tighter than any stage on the event, and trying to transfer all that power in second gear coming off a tight corner is asking a lot. I spent some time working on just how much power I could lay down, and it's easy to modulate. But I do need to try and get a bit more traction. It's possible that the high ambient temperatures and very hot track surface were overheating the tires, and I'm going to have to go back and play with tire pressures once I've got the last couple of pieces in place.
On a couple of sessions, I did rather forget myself and left quite a bit of rubber on the track. I won't be able to drive like that through the race or I'll have no tires left after three days! Still, it's good to know that the car is just as forgiving and easy to toss around as before. The suspension feels good over the road at low and high speed and deals well with berms on the track. I was able to control the oversteer well - when I hung the tail out, I could easily keep it there and just modulate the slide. So the platform is pretty good. Still, I'll try it again with some small changes to alignment and spring rates and play with pressures a bit more.
Janel did come out for a few laps. From the navigator's seat, she asked why the tires felt so squishy - there's definitely more of a slip angle on these R1Rs than there was on the RA1. After she'd been behind the wheel, she felt a lot more comfortable with the car's behavior and she trusts it again. She hasn't been in the car since driving it at Laguna Seca last April, and she just wanted reassurance that she could put her faith in it as she had before.
Other than the tires, the car did pretty well. It was very hot inside, so I'm going to spend a bit more time on heat shielding. Granted, it was 100F outside as well so hot was to be expected. No cooling problems at all, unlike some of the other cars there. I'm still sorting out the brakes, the rears don't seem to be working fully although braking into corners had the rear dancing. Based on the amount of brake dust accumulating on the wheels, the fronts are doing all the work. I'll start working on that this week.
tags: testing, suspension |
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