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What's going on here?

Joined
8 March 2006
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Location
Boston
I had my reign of an autoX lot with some cones I set up to practice various things with the car, uninterrupted thanks to the generosity of an autoX director. So I tried a lot of different things and learned a lot of car control without fear of "losing it" as there was nothing to hit within hundreds of yards.

One thing that consistently happened is as I tried to recover from a tail slide going one direction, the tail would often snap back and slide the other direction.... Until the energy was dissipated and speed had slowed to almost nothing.

So my question is, is this a suspension setup thing? Sliding one way was much less nerve racking for me the sudden snap over into the other direction. Is that just what you get with a stiffly sprung car? Is there something I need to take note of while driving that I'm missing?

Any help from the veterans is appreciated.
 
You mean you're experiencing snap oversteer that almost all nsx's encounter?

- - - Updated - - -

It sounds to me if you're correcting it and it's "snapping back" and you're only regaining complete control after you've slowed to almost a complete stop you gotta power through it.
 
The way it was explained to me is that in a hard corner, all rubber bushings in suspension compress and at the first chance [lack of grip] they uncompress, creating the snap and that a mid-engine doesn't help because the car rotates on its center.

I'll be interested in what the big dogs say.
 
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Fwiw, my setup is:

KW competition dampers
1000/600 swift springs
Type R front and OEM rear bar
Ti Dave non compliant beam bushings, toe links, and front clamps
17/18 RSII 215/40/17 AD08 and 255/35/18 AD08

BUT... At the time I was starting to experience this more, I was running NANKANG all season tires rear. Which actually were a decent tire, but I found as they got hot all traction went to hell. Next time I go back I am going to go back to my AD08 rears, but I am not sure the car will behave a lot differently.

My rear camber is at -2.5. I can increase it.

Visual (LOL):

e51008e4d695016da86c447141e6bcad_zps71549fab.jpg
 
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Fwiw, my setup is:
KW competition dampers
1000/600 swift springs
Type R front and OEM rear bar
Ti Dave non compliant beam bushings, toe links, and front clamps
17/18 RSII 215/40/17 AD08 and 255/35/18 AD08
BUT... At the time I was starting to experience this more, I was running NANKANG all season tires rear. Which actually were a decent tire, but I found as they got hot all traction went to hell. Next time I go back I am going to go back to my AD08 rears, but I am not sure the car will behave a lot differently.
My rear camber is at -2.5. I can increase it.
3 things: How do you get to Carnegie Hall?

1) Practice

2) Practice

3) Practice

and... Really work on your technique using quick, subtle inputs and minute corrections. Soft hands. 'be the ball, Danny'.

I think you're running too much neg. camber in the rear. Run -2.5 up front and stand up the rears, -1 to -1.5 max. You need all the contact patch you can get on those puny little 255's.

Your on crap tires which will let go & snap roll without warning, especially when mounted to an uber-stiff go-kart. Try this exercise on R comp DOT's.

I think your over-sprung for your needs & ability. Aside from your small sway bars, your car is more set up for slicks, not tread.

Need some CT Bars?
 
I'm running the alignment settings recommended by billy Johnson, also the spring rates. I know the sway bars are too small, but as you noted with Dali yourself, getting bars is tough. I do realize a lot of what was happening is because of the nankang rears.

I like the added rear camber because my tires tend to wear heavily on the outside with less camber. 2-3 actually seems to get more even track wear...

I'm thinking the tire had a lot to do with it. At first when colder, I had to use generous throttle to get the car to slide and induce oversteer. When they got hot, just a sudden change into a turn would send the car sideways. Needless to say though.... Having the lot totally to myself for 45 minutes was invaluable. Everyone here has always told me seat time on the track, but I'm gaining a lot at autoX and drift events. It makes me much better on the track. Going over the limit is hair raising on the track.

Anyway, getting off subject. I was just wondering if that snap oversteer is somewhat normal.
 
Continue to practice.

The reason the car is snapping the other direction is that your wheel is still turned opposite when the car regains traction thus sending you in the other direction. If your wheel is turned straight when you regain traction you will not snap in the other direction, you will go straight. You need to straighten the wheel before you think you do. The steering should be really stif as you turn the wheel back to straight from counter steer.

Alot easier said than done but if you keep at it you should get it.
 
Continue to practice.

The reason the car is snapping the other direction is that your wheel is still turned opposite when the car regains traction thus sending you in the other direction. If your wheel is turned straight when you regain traction you will not snap in the other direction, you will go straight. You need to straighten the wheel before you think you do. The steering should be really stif as you turn the wheel back to straight from counter steer.

Alot easier said than done but if you keep at it you should get it.

I will do. Trying to get as much time as I can. I can get the car to drift now a little. I'm already better than my instructors with the car. I'm feeling much more confident and relaxed when sliding. I mean I slid for 45 minutes... Right, left, slow, fast, I was trying everything. The car will drift at high speeds much easier. It does not like slow tight turns. Right now I can hop in a BRZ and hold a drift long enough to make a phone call. If you can do the NSX you can do anything.
 
On hard compound treaded tires? Yes, perfectly normal.

Also, what works for a professional NASCAR champion with cat-like reflexes, may not work for you or I. Like you, I have always taken counsel & advise from a lot of different drivers with different styles and then translate that input into what works best for my style of driving and car spec.. Kip Olson likes a super stiff go-cart set-up on his 2300lb. 600hp NSX. Thats input does not transfer directly to my 2850lb. 400hp NSX. YMMV.
 
Dave, CL65 taught me a ton on my first track event with him. One of those things was not over-reacting to slide. Turn 7 at putnam is 90 degree hard right and rear end stepped out on me once. Immediately I wanted to counter-steer but remembered what he said and rode it out to a perfect exit line into turn 8a. It was awesome. So what I learned was not to freak and counter-steer. Maybe train yourself to use some of that rear end slide and throttle out instead. My track rookie .02
 
More practice and better rear tires will go a long way towards helping this problem.
Also, I think 275/35/18's would yield a better balanced setup (that's what we run on both our NSX's paired with 215/40/17 fronts).

YMMV,
Brian
 
Just wondering if that's correct. I remember reading somewhere by a very respected individual that the further away the tire width generally from the front to rear the more drawbacks it has. Like a 225 paired with a 275 would be better than a 215/275 given the SAME amount of tire stretch on each and contact points.

More practice and better rear tires will go a long way towards helping this problem.
Also, I think 275/35/18's would yield a better balanced setup (that's what we run on both our NSX's paired with 215/40/17 fronts).

YMMV,
Brian
 
slow speed autox slides are a little tough to gracefuly drift through because the momentum is scrubbed quickly...that said as others have noted a loose or oversteering car needs fast hands but calm and relaxed at the same time.
 
Just wondering if that's correct. I remember reading somewhere by a very respected individual that the further away the tire width generally from the front to rear the more drawbacks it has. Like a 225 paired with a 275 would be better than a 215/275 given the SAME amount of tire stretch on each and contact points.

There is no majic setup, you have to do what works for you, 90% of the car is almost always there for any driver to use, getting the last 10% is the hardest part no matter the setup. Every driver has his/her own style and/or mistakes. Confidence is the key to a faster driver. If the car is setup to give you the confidence you need you will learn to be fast. I used to run 205/275 stagger, mainly because the front end of my can never pushed and the car always felt loose to me. Now I run a 235/275 tire setup and have made changes to the spring rates and bar settings to get the car more neutral. I am changing my driving style as for years I have driven and setup my NSX with a slight tendancy to oversteer, this was leftover from my AutoX days. After working with a chassis guy at several HPDE days on my friends Viper and Vette I am learning to tune the car to the style of driving that makes me most comfortable. None of this mattered if I only used the first 90% of the cars potential, once I was pushing harder and was finding the limits I began to realize what I needed to change about the car and my driving style. You can get a lot more out of a stock NSX than most people would think possible, start making changes and you can get more or sometimes less, keep making changes and you could soon be lost. You have to be able to drive to the first 90% constistantly then start making changes to the driver and car to take advantage of the last 10% the car has to give. Some things you change are suttle and only effect the car in a very minor way, some things like tires or HP make more dramatic changes to the car.

The best thing anyone can do is pratice, learn to break a track down into specific corner types and learn how to drive each type of corner, learn to do that and you can drive any track as they are just corners you already know how to drive. This is something I wish I learned a long time ago. AutoX is different as you just do not get enough time to learn things as fast as you can at a HPDE.

Dave
 
Dave I agree completely. I get into some advanced driving classes and I honestly feel I am better than the instructors there, but I do them anyway because I learn more car control. People laughed at me when I said I was going to do drift clinics. But I learned more about the NSX's behavior over the limit there than probably 50 DE days. I have started to do more autoX not because I like autoX, but because I can PUSH to that last 10% without fear of hitting a wall. Hell I am even going Karting when I can't go to the track at all.

I already know that I am going to be MUCH faster because of all that I have done OFF the track. I think those off track practices are really important in giving you confidence and making you faster on the track.
 
I drifted and tracked a bunch in other cars before I got my NSX I found that its a bit different in that it'll do everything you tell it and it'll do it quickly, especially the bad stuff. For example, Typically in a FR car with a longer wheel base you'll feel the momentum build up as it initiates a slide (either weight transfer left to right, front to back or power-over) right when you feel it you have about 1/4 a second to let the car settle then another 1/2 to decide what to do- Get on throttle, get off throttle, turn in, do nothing... In the NSX it seems that that time you have to figure out what you need to do is much, much shorter. Its almost like you need a deliberate anticipation before something happens and if you zig when you should zagged, you'll loop it. Since my car is SUPER tail happy (sway bar debacle as mentioned in another thread) ive gotten rather good at straddling all above options to feel what the car needs. Unintentionally as it may have started this characteristic of my NSX has refined my driving inputs to be much more subtle and deliberate. I'll watch video of myself driving and get to points where i remember feeling on the razors edge of catastrophe but the footage the moment looks nothing more than a quick steering motion. I always get the comment from non NSX driving friends that say "look how easy it is to go fast in that thing, your hardly doing anything, its driving itself" : / The reality is im using all my brain and body to feel what small corrections are needed. The NSX rewards finesse, restraint and deft inputs with unbelievable car to driver communication if you'll listen to its whispers it'll tell you how to drive it faster than you think itll go. Thats the most cheesy but the best way to articulate how different it is and why i find it so rewarding.


As far as crack back, its not the same as 'snap oversteer' that people talk about, crackback is what happens after the car has already gotten sideways- If you're already in that situation you can avoid crack back by not letting off the gas too quickly, rather stay on it and squeeze it off as your reducing your steering angle. The crack back is just pent up polar inertia that reacts on the car when as regains grip when not in a straight line, all that energy gets channeled into the suspension and releases its self as a rebound frequency from one side to the other until its dissipated. To put it another way you want to maintain reduced traction (keep on throttle) until your more inline with the direction of travel so when you regain traction the energy that was trying to pendulum the tail around is now just manageable forward moving inertia.

As far as car set up to get rid of crack back its more of a roundabout answer. At the risk of over simplification the idea behind pretty much all race parts is to get as much energy from the chassis/motor/aero into the contact patch of the tires, then stickier tires will increase ability to go faster.
That being said all deleting the rubber bushings and getting stiffer springs and bars is meant to do get the energy through the chassis to the tires in a more linear path. Instead of slowing the path to the ground with bushing deflection, compliance and unwanted compression the forces are now channeled directly into your tires which now struggle to cope. Fitting race rubber basically increases the bandwidth threshold of energy from car to ground. Things like corner balance, alignment, weight distribution are adjustments affect the sharing of this energy through as much bandwidth as possible on all available outlets (tires). This can be further tuned with spring rates and swaybars. Mind you now, this is a theoretical model dealing with a 100% flat surface, things get much more complicated when you add bumps etc, but you get the point. With your set up, crappy NANKINGS will give up faster (slide) because your asking more outta them in a shorter period of time. Now that we've been down the garden path; All tires produce grip, all sliding takes energy. If you have a situation with both there will always be potential for crack back. Set the car up to avoid sliding sideways and by transitive nature you'll avoiding crack back too.


A good thing i learned years ago was to look at steering angle and throttle as connected- the more steering angle you have the less throttle you can use at the same time. Less steering angle, more throttle.

My old ae86 had no power steering and a quaife quick ratio steering rack, crack back was down right dangerous. I sprained my thumb more than a few times figuring out what i was doing. I learned out of self preservation that if the slide is too far gone just gas the shit outta it and loop it into a 360 instead of letting it crack back. it was much easier on all components of the car (and driver) :] Ill try and find a video of what im talking about.
 
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Thanks for the thoughtful reply. I am pretty comfortable with the car doing a pirouette now. Although it looks dramatic, it does just spin and come to a stop pretty quickly. And I just know the point if no recovery. There is a point at which there is NOTHING you can do. It is just going to spin. What I don't like, is that change of direction which is much more out of control. Like this:

<iframe width="420" height="315" src="http://www.youtube.com/embed/88QT5JD46NE" frameborder="0" allowfullscreen></iframe>
 
Thanks for the thoughtful reply. I am pretty comfortable with the car doing a pirouette now. Although it looks dramatic, it does just spin and come to a stop pretty quickly. And I just know the point if no recovery. There is a point at which there is NOTHING you can do. It is just going to spin. What I don't like, is that change of direction which is much more out of control. Like this:

<iframe width="420" height="315" src="http://www.youtube.com/embed/88QT5JD46NE" frameborder="0" allowfullscreen=""></iframe>
Key word: 1st Lap

Cold tires, Cold brains = recipe for disaster.

Sucks for that guy.
 
Key word: 1st Lap

Cold tires, Cold brains = recipe for disaster.

Sucks for that guy.

LOL... I know I shook my head as soon as I read "first lap" he was coming in waaaay too hot. It looks like he almost could recover but then the sudden shift in direction and it's all over then. That is exactly what I never want to do. It's why I am spending time on airfields and parking lots.
 
Dave as others have said this is more of a car control issue than hardware setup. All NSX's have a tendency to snap oversteer due to the suspension geometry and weight distribution. In the factory car, Honda became aware of the problem during prototype track testing and introduced 6 mm of rear toe-in to help manage the unloading and flex of the rubber bushings on corner exit (which cause unstable toe change). Owners complained about tire wear (and even filed a class action lawsuit), so they reduced it to 4 mm, which is not optimal, but still enough to protect from most street oversteer situations. Therefore, one hardware method to reduce snap oversteer is to run more rear toe-in. I know some track guys who run 8 mm. I run 6, since it is the original spec and I am on street rubber with OEM bushings.

Still, while it can be somewhat managed, snap oversteer is just a characteristic of our cars. Car control and practice are the best tools to fight it. John is right- AutoX is tough to practice because the momentum is too slow to really experience the entire correction properly. If you had a wet skidpad, it would be easier. For me, Turn 10 at my local track is where I "practice" snap oversteer lol. It is a relatively high speed, off camber turn where, with just slightly too much steering input or too early throttle, the rear starts to come around. The correction is hard to describe in words, but I think of it as "fast hands, small input, smooth roll out". You need to give it a very quick, but not jerky, countersteer just enough to halt the slide and get the wheels pointing on line before the suspension unloads. If you do it right, you will feel the rear step out with a slide and then snap back in line. It will all happen in a fraction of a second. There is a great example of this in the Senna NSX-R video at 0:57. He puts the right rear tire on the curbing and it starts to slide, but he gives it a quick burst of countersteer and the car settles down. It is effortless for Senna, but a less experienced driver probably would have spun there. Watching this video helped me manage Turn 10 at my track.

The reason your car is coming around is not your tires, or suspension, or bushings. It is because you are over-correcting the slide by turing the wheel to far and/or too hard the other way. When your suspension unloads, your wheels are not on line- they are pointing the other direction, which is exactly where the car goes when it regains traction.
 
.... There is a great example of this in the Senna NSX-R video at 0:57. He puts the right rear tire on the curbing and it starts to slide, but he gives it a quick burst of countersteer and the car settles down. It is effortless for Senna, but a less experienced driver probably would have spun there. Watching this video helped me manage Turn 10 at my track.
...

 
Heres an example from my NSX <object height="315" width="560">


<embed src="http://www.youtube.com/v/LZO9QJ30RCU?hl=en_US&version=3" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="315" width="560"></object>

I was dialing tire pressures after doing a bunch of suspension and aero changes. first incident is at :12. I had too much air in the rear tires and they lost grip much sooner that i was used too. I let it slide while staying on throttle like normal but traction didn't come back, at around 35* degrees I passed the point of no return and had to abort and not huck it off the far side into the berm. The same exact turn and situation starts @ 1:55 but this time i had lowered the rear pressures so when i felt the start to go a quick juggle got it all back in line. It doesn't look like much but I remember that being a particularly hairy situation to be stepping out.

When I got the non compliance rear to fix the dynamic toe change i also reduced the toe to 0. It makes feedback of the tail MUCH more clear and controllable.
 
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I got the non compliance rear to fix the dynamic toe change i also reduced the toe to 0.

So Honcho is at 6mm toe, and you are at zero. Zero sounds very hairy...

Thanks for the video. What is that camera and where are you mounting it? I am surprised of the good audio in that wind and excellent angle.
 
There is a great example of this in the Senna NSX-R video at 0:57. He puts the right rear tire on the curbing and it starts to slide, but he gives it a quick burst of countersteer and the car settles down. It is effortless for Senna, but a less experienced driver probably would have spun there. Watching this video helped me manage Turn 10 at my track.

The reason your car is coming around is not your tires, or suspension, or bushings. It is because you are over-correcting the slide by turing the wheel to far and/or too hard the other way. When your suspension unloads, your wheels are not on line- they are pointing the other direction, which is exactly where the car goes when it regains traction.


I think it's a combination of the countersteer AND the fact that he goes WOT. WOT helps settle the car by transferring the load to the rear, thus adding grip to the rear tires.
Just countersteering alone would have probably left him off track.

2:00 - 2:10 in the video shows great examples of how he modulates the throttle during the slide. It's a common newbie mistake to either lift off the throttle or tap the brakes on the first onset of a slide which makes the load transfer to the front (lessing grip in the rear) making the situation worse. The proper way to control it is to modulate the throttle in a way to get the load back on the rear in a smooth and controlled fashion.
 
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