Miata Turbo Forum - Boost cars, acquire cats. - K24Z3 Miata NB2 by ex-BMW snob - "Booger" Story of a Benchwarmer to Starting Line-up

Quote:

Originally Posted by bimmerboy (Post 1626618)

My best effort at Mid-O... critique at will!

https://www.youtube.com/watch?v=1hmwEkui_iU

This is a good start. Just keep in mind that this is a higher hp car and they're running the Pro course.

1("turn 1"): you're turning in far too early and you were drifting inside even before you turned in. Stay out and apex later. You were waiting for an eternity to get back on the gas. You don't have TPS overlayed, so it's kinda hard to know how committed you are other than engine tone. And also you could have carried more speed with your current line, given that you didn't track out all the way to the rumble strip. I try to use every inch of those (in the dry) and just short of putting 2 off to make the turn as wide as possible.

2 (chicane/bus stop): I think fixing turn 1 will allow you to carry more speed into the chicane. Which I was kinda surprised you could turn in without any scrubbing with the K. Like I'm flat through the turn in and I can hear the front left protesting. Once you can carry more speed through 1 and also get back on the gas sooner you may end up needing to lift or brush brake into 2. The turn in point can be adjusted depending on how much curbing your car can run (depending on your spring/damper setup)

3: You need to get all your braking done between turn in for 2 and 3. You were trail braking pretty late into 3, which I couldn't do without spinning. I need to be on maintenance throttle by the time I start transitioning left. So that may be your setup is a bit understeery given that you didn't have to countersteer.

4(keyhole): Pretty decent line. I try to just clip the rubble strip on the right side. Then let the car wash out about 1 car width from the inside edge and try to rotate it. Again it seems like your car is rather understeery, because you have a bunch of steering lock cranked in for quite a while and you wait for quite a while to get back on the throttle. And you could carry more speed, since you used the rumble strip, but that was just because you were straightening the wheel.

6(china beach): Braking waaay early. Based on the geez, I think there's more brake torque available, but it takes cajones. I'm just past the 3 cone, and there's still a bit more left. You have more power, but just know there's at least 1 cone there. Probably 2 tenths in the brake zone.

7(madness). Don't transition out to the right when entering 7. You need to carry as much speed as you can through 6 that you end up on the inside of 7. It's the slowest corner of the track, off camber, and downhill, so there isn't too much to be gained and no reason to sacrifice your speed/line through 6 for it. And you can carry more speed into 7. The entrance is uphill so you can scrub speed quickly, downshift, then maintenance throttle and let it washout to about mid track over the crest. You don't want to run all the way right over the crest, because that compromises your line into 8, which for us is basically the start of a long straight to 11.

8(esses): You had a decent line through 8. You only want to run just over the middle line on track out, so that you don't compromise your drive through 9. You can use all of that yellow curbing on the inside of 9 to straighten your line.

11(thunder valley): Turn in was a bit early. I try to get parallel with the curbing on the left and then do my braking. It seems like you were coasting and then doing somewhere between a brush and medium braking. If you can't stay flat through 10, then you can cheat the line a few feet to the left of the inside curbing to give you a wider arc into 11. You really need to be parallel with the curbing (car pointed straight) when you do your braking, because that can easily cause a spin. And you don't have too much space to brake, so you need to get it done quick (harder brake for shorter) and then get to maintenance throttle to stabilize the car for the turn. You can really carry a bunch of speed over the crest. Again I like to have 2 wheels all up on that inside curb, even 2 in the grass to straighten the corner out. If you turn in a bit later and use the curb, then you can have your wheel straighter and get on the gas sooner.

12: I turn in a couple feet past the 100ft marker. You were already drifting inside before you turned in. You need to stay right on that white line as far right as possible. I know I've turned in too early because I hit the hole right before the inside curbing starts in 13. It looked like the car understeered just after turn in and you were a couple feet off the inside curbing. Again I like to use that whole inside curb, even if I fuck up and hit the hole. It doesn't benefit you to go way out on the yellow curbing on the exit of 13, because that puts you in a bad spot for the carousel, but I do just touch it.

14(carousel): I enter just on that inside white line. You entered wide, which didn't help your line through the corner. You need to brake as late as possible, but get most of your braking done before you suspension unloads over the crest. You'll know when you brake too late because you'll lockup and blow the turn... Then it's similar to the keyhole, get the car to rotate, let it wash out about 1/2-1 car width and then the front straight for us as soon as you can get the car rotated around toward 15. If you're further toward the inside of 14, which you should be, then there is a bump just at the exit which may force you to delay your throttle application (or risk spinning).

I think you may want to adjust your setup. It seems verrrrrry understeery for a Miata. Like the low speed keyhole and carousel a Miata should be getting some natural rotation through those, which you should be able to adjust with just small changes in throttle angle (from maintenance to just a touch of engine braking should allow you to adjust the yaw rate). I really like to carousel for working on low speed balance, since you will need to balance low speed rotation with high speed stability. And there is an awful lot of time in those 2 corners. Since the keyhole leads onto the back straight, and the carousel is just a very long turn.