Handling Setup - Oversteer vs. Understeer

[ildylan]

Originally Posted by Racecomp Engineering

IMO it can both understeer and oversteer depending on how you drive the car. Stickier tires changes things too.

- Andrew

Originally Posted by solidONE

This. I think that why a lot of us newbs will get understeer entering the turn then oversteer exiting on the FR-S suspension. What's the solution? slow steering input at turn in?

We recently did a test and tune at Grissom AFB and I had a ES national champ drive my car and sure as sh#@ he was having to control slip everywhere while I was busy plowing into turns - same exact car.

The problem: Me.

I was late on braking, and turn in and it wasn't unwinding the wheel as soon as I should have been so I was putting down throttle with the front tires like this \\ or an even steeper angle. Next event I took his advice and started getting quite a bit faster.

As @Element Tuning said - work with an instructor.

[zdr93523]

Originally Posted by ildylan

We recently did a test and tune at Grissom AFB and I had a ES national champ drive my car and sure as sh#@ he was having to control slip everywhere while I was busy plowing into turns - same exact car.

The problem: Me.

I was late on braking, and turn in and it wasn't unwinding the wheel as soon as I should have been so I was putting down throttle with the front tires like this \\ or an even steeper angle. Next event I took his advice and started getting quite a bit faster.

As @Element Tuning said - work with an instructor.

This is correct and what most people fail to realize.

@solidONE This is much more likely the issue than a spring rate change. Spring rates get you 1/10ths, not massive handling differences. The odds are that your technique was better during the improved sessions and not the car.

[CSG Mike]

Originally Posted by solidONE

I don't doubt technique has everything to do with it, but there was nothing I was doing different in terms of "technique" that can attribute to the faster laps aside from being more confident in the balance of the car from the spring change. Matter fact, I was running slightly narrower tires as well. Meh..

How many more track days have you attended in the past few years?

[CSG Mike]

Originally Posted by solidONE

6 last year. Once this year so far with one upcoming this weekend. Hoping to do at least one a month beginning this month.

Sounds to me experience is a larger factor than your parts.

[wparsons]

Originally Posted by solidONE

Possibly... Though as long as I'm getting faster who give a shit, right? lol Hopefully I can convince one of the better instructors to ride with me this weekend.

If you're really chasing tenths, you need data logging. An instructor can give pointers, but until you see isolated data on different approaches to a specific section of track (without making other changes in previous sections) it's really just a crapshoot.

[CSG David]

Originally Posted by solidONE

True that. lol Though I honestly believe the confidence from the changed balance allowed me cut 4 entire seconds from my PB even with one size narrower tires than previous. Same track, same direction with only one other track day between them on a different track. It's got to have contributed at least partially, that's my feeling.

Pretty sure you can lap very similar times with the FRS vs. BRZ at the same track. This is a confidence and skill issue rather than the parts.

[zdr93523]

Originally Posted by solidONE

Not all of us have as much seat time or feel like you or Mike has.

You said it. Seat time > parts... every time.

We have a couple of guys starting to track and they will be running basically stock cars with upgraded brake fluid and oil coolers. They will probably stay that way until they're ready for their Time Trial licenses. Then, they will mildly mod for tenths within their class.

These cars are awesome in stock form.

[CSG David]

Originally Posted by solidONE

That's my point. Confidence in and connection to the machine. The setup that lead to more confidence that led to a driving style that lead to faster lap times. Therefore, the hardware change did directly (or indirectly) led to better performance from driver. Not talking about the "potential" of the machine but the potential of the guy controlling it. Make sense?

I think Mike remembers when I had him take me for a few laps in my car when I just bought it. The way he was driving I had no idea what the rear end was doing besides sliding. My exact words "feels like the rear end is floating" the entire time. I felt no connection to the rear end of the car at all. lol That is definitely a driver issue which was remedied by adjustment in the setup. Yes?

Honestly, I think Mike can drive a car with 3 blown shocks and alignment that pulls to one side and still drive the way he does. Not all of us have as much seat time or feel like you or Mike has.

The best way to gain confidence is to continuously apply what you think may work in a safe place and test that hypothesis. If it works, stick to it...if it doesn't, try something new. Start with just the driving skills and go from there. I started with a completely stock Camry and I seemed to do okay. It does have Winmax pads on it, but that's for another day.

The BRZ/FRS is a very safe and conservative car with a long wheelbase (longer than the Miata, S2000, and MR2) which means it's quite stable. Take advantage of it. Go out to 86CUP and drive. We all miss you.

[strat61caster]

I found the balance, thank you camber plates.

I feel like this is the car everyone else has been driving, it just took me ~$2k to unearth it. @DarkSunrise you are right, when it's neutral you decide what to do it happily responds.

I've posted before that I don't love this car, that may actually be changing, rotating the car with throttle is a kind of magic.


Lots of thoughts swirling around, I really need to process them before I shoot my mouth off.

[CSG Mike]

Originally Posted by solidONE

So I had a little coaching session this Saturday and apparently my corner entry under is from too much steering input and a late turn-in (at pretty much every turn). Makes sense since that's how I ride my bike. I got to stop driving this car like I'm riding my bike.

Driving and riding use the same theory. YOu need to change your riding too.

[CSG Mike]

Originally Posted by solidONE

No I don't. I'm quite happy with the way I ride, thanks.

Edit: @CSG Mike, if you've ever ridden a motorcycle at speed you will realize that they way turn in a motorcycle is pretty dramatic compared to what you do with a car. And because of the way you turn in a motorcycle, a late apex (relative to a car line on the same corner) is typically preferred.

Now, I'm sure your not just trolling or trying to be a douche (lol), but I'll start taking advice from you about motorcycle riding when you can drift the tail around every turn with the same amount of slip angle as you did with my car. mmkay?

I can, and it's not drifting. Maintaining a small slip angle is the fastest possible state of cornering. Perhaps this video will better illustrate what is going on; the rear tire is not actually spinning. Note the actual path both the front and rear tires travel; it's exactly what I'm doing in the car, or a bike, or even a bicycle.

[ame="https://www.youtube.com/watch?v=Z4snkUUolJ0"]High speed MotoGP cornering at 1000fps - Casey Stoner - Red Bull Moments - YouTube[/ame]

The theory and science behind turning is identical. You need to stop looking at turning as "turning the steering wheel" and see it as "controlling weight transfers and force vectors". Unfortunately, this will not make sense to someone who is not has the requisite skill level on either a bike OR a car, unless you have a strong grasp of basic (high school/first year college) Newtonian physics. Break everything down into the most basic step you can. To a novice, this will be "turning the steering wheel left turns the car left/leaning left turns the bike left". To someone with a basic level of mastery, this will be "turning the steering wheel left forces a weight shift to the right/ steering right forces leaning to the left". Going another (smaller) step beyond that introduces the torques: "turning the steering wheel left causes a perpendicular torque on the chassis, which causes a weight shift to the right, which makes the car turn left/steering right forces a perpendicular torque which results in the bike leaning left, which ultimately forces the car to turn left (the force acts upon the bike in a direction identical to starting with your left arm pointed straight up toward the sky, and lowering your arm downward toward the ground in a motion that has you pointing straight left when you're halfway down).".

I can continue breaking down what exactly is going on further, but you get the point. Think in force vectors.

[OkieSnuffBox]

Originally Posted by solidONE

@CSG Mike Why don't you bring your bike out and come show me how it's done one of these days? Who knows, maybe you're better than Keith Code or Jason Pridmore. You sure sound like it.

I suspect you are as well?

We have videos of us from back in the day laying huge long black marks coming out of corners on our sport bikes on the street, what does that mean? That I'm suddenly Garry McCoy?

[OkieSnuffBox]

That's why I don't do it anymore.

I haven't ridden since I binned at my last track day really nicely and ended up with Post Concussion Syndrome for about 3 months. By the time I got it put back together I sold it.

[OkieSnuffBox]

Originally Posted by solidONE

Pushing that hard is for the younguns... they heal much faster. lol Though, sometimes the crashing leads to injuries that you will never heal from. Even with the younger guys..

Yep, that was back in 2007 (only 25!). My gait is still a bit off from the way I came down on my hip.