The Reverend

One more thing...
as for laying the power down while exiting a corner, I have found my Kaaz LSD solves that problem. I haven't taken it to the track with the Kaaz yet (I've had so much sh!t break on this car that I'm afraid to track it now), but from driving it on the street, I can already tell it will make a world of difference.

ultimate lurker

heh, 6/5 is too stiff? I'm running 10/14 on a 2100 lbs car that I drive almost everyday. I can jump on the door sill and all that compresses are the tires :-). Sounds like you and I are both in the 99th percentile for street insanity.

On teh rear, I find it to be mushy even on the stock tires (of course, back to back with my other car anything feels mushy). I'm also a big fan of using swaybars rather than springs to control balance. For a road course I want the softest springs I can tolerate for pitch and the stiffest swaybars to allow me to soak up bumps while controlling roll.

Also, remember that the Comptech bar is designed to give auto-x folks on stock springs the balance they want. If you add more front spring too, the car may understeer too much (if the Comptech is adjustable then you won't have a problem).

One more thing, for those who have the Comptech bar. Have you tried it on street tires? I'm a big fan of doing my road course lapping on street tires (especially since I can't carry a spare set of wheels in the S2K). I wonder if the Comptech bar might cause understeer on the OEM S02s?

UL

cdelena

I want to thank all of you for sharing your experience and commenting on my situation and proposals.. it is very valuable. I have had an opportunity to share this with an experienced driver / tuner so let me summarize some of the discussion.

spring rates and ride

More than one of you commented on how a compromise setup may be a disappointment in all environments, and this was echoed in the talk. It was suggested to me that the answer is very little stiffening and a very minor shift in balance from the stock, 3.5/5 kg to maybe a 6/6 setup. Since I have already installed a bigger front bar, the equal front and rear rates should get me a step closer to a neutral balance.

ride height

Total agreement with your comments. Lower can help on the track but there is a penalty to pay on the street. It was suggested to me that 20

GTRPower

Hey all-

The key to the S2000 stock suspension is...

***digressive shock valving***

At least, that's what I think it is. In stock form, the stocks are overdamped on small hits, and underdamped on the big hits. Underdamped on the quick hits, and overdamped on the long, drawn out hits.

Another car company uses this shock valving to great effect- Mercedes Benz on their SLK. This digressive tuning is more suited for the boulevard cruisers like the SLK, and not out and out race cars which the S2000 is trying to emulate. This is the single biggest flaw in the S2000 overall- and it is VERY apparent on tracks with small undulations and big berms. There's nothing quite like feeling the rear end oscillating up and down from a medium turn with a bump, or a quick drop at speed that completely upsets the suspension for over five or six full shock extensions...

I would pick oversteer in a sports car anyday over understeer. The last thing I want at 100mph is to turn the steering wheel and... still go straight! More responsive handling is almost always better than less responsive, in my book.

Is there a good, medium cost suspension on the market for the S2000? Not until Mugen assembles a Lowdown kit @$1500 for the S2000. The TEIN stuff is not really as good as what some people are making it out to be, although they produce perfectly adequate road setups. My thoughts on that are, if you're going to spend $2K on a strut/spring set, shouldn't it be good enough for weekend track warriors too? The price of the N-0 kit is a good compromise between the cheap and dirty kits and the full on race setups, but with the ability to hang with the racekits on a limited basis, and provide a superior street setup.

cdelena

Nick, Thanks for your comments. I am not at all sure I understand

ultimate lurker

Nick, your description of the shock characteristics sounds pretty accurate.

On the understeer thing, are you really sure you'd rather have steady state oversteer vs. understeer at high speeds? We're not talking about tail out or terminal push, but with a little understeer, all you do is turn the wheel a little more or ease off. It's safe and easy to correct.

With oversteer you're faced with the task of either easing the throttle and potentially getting more oversteer with lift off, or countersteering and widening your line. No doubt that a neutral to loose car is quicker in skilled hands, but for the average weekend warrior, a net of mild understeer is a safe path to choose. I think we all love a little oversteer, but the speed at which it becomes uncomfortable is directly proportional to driver skill.

UL

GTRPower

cdelena-

Don't get hung up on the big words... An easier way to understand the suspension is-

Regular, progressive valving rates increase proportionally to the forces. Most, if not all shocks have a limit to when the entire shim stack "blows through"- when the force of the motion collapses the entire shim stack. The S2000 shocks seem to exhibit this characteristic pretty quickly relative to other "sporty" shocks, although the handling before the shim stack is overpowered is quite reasonable. Unfortunately, when the stack is overpowered, there is no damping available to the suspension, which produces the familiar "pogoing" effect, and is more pronounced on the rear end because people are generally more comfortable reaching the limits of the rear end of the S2000 than the front end. Both are a problem area...

About getting more time in the car... I actually had the exact same problem with when King Motorsports borrowed my Type R last year- they did a bunch of upgrades to it, and took it to California for testing with the C&D and SCC people... I didn't see that car for months, not that it really mattered since we had *snow*. When it returned, I had extensive track time in the early springtime and came to the conclusion that the TEIN HA kit that was replaced with the Mugen kit was completely inferior under all conditions, street and track. I was given the choice of keeping whatever was on the car or reverting to my older parts, but I chose to keep the Mugen upgrades. Because of this experience, I assume (perhaps incorrectly although I doubt it) the Mugen parts that King installed on my S2000 will perform in a similar fashion. According to King Motorsports, my S2000 will come back very soon, in all probablity by March. I have at least three trackdays in the local area in the month of March alone, scheduled around my business and fun trips (I will be out of town for the Racemark Challenge in Jacksonville with the other car as a One Lap tuneup, and I have an overseas business trip in the middle of March- busy life!). When I have enough tracktime in the car to give good feedback I will post it. FYI- I will be in Dallas in early March with the GT-R to try and test at the Motorsports Ranch before heading out to Jacksonville- do you have any leads on how to get on that track? Buddies who are members, perhaps? It would be VERY helpful...

UL-

A well balanced car should not push. I personally do not want a car that pushes at the limit, even if it is a mild, steady state understeer- I'd rather have a mild, steady state oversteer. Both will require the driver to lift gently to overcome the over/under w/steering correction, but the mild oversteer will point you in the right direction earlier and quicker. Again, this depends upon to what degree the over/understeer problem is. A car that has terminally severe understeer will be fairly useless on the track or street, because you can't turn without going off on a tangent (literally). At the same time, a severely oversteering car is also impossible to drive, because at any throttle imput with directional change, the car will constantly need more correction. But... if we are talking about relative under/oversteer, I prefer the oversteer. Imagine getting into the understeer, getting the pogo going, and trying to turn. That's fairly uncontrollable in my book- and that's not unusual to encounter on the street, let alone on the track. When it starts to pogo, you have poorer braking power, harder throttle modulation, and less steering control (along with the bump steer problem this car has) all due to poor chassis balance.

Besides, don't you think this car, even stock, is not necessarily the best car for a novice? I think it reacts very quickly even when stock, which is not a characteristic you'd want to have in a beginner car- people are generally hamfisted before developing finesse. Yes, under those conditions mild understeer is preferable, just to keep people from driving their new car into walls (or worse yet, into other people!).

To all-

Sorry for the long post, but this seems to be the only forum I've been to that appreciates details...

ultimate lurker

Nick, we agree that the S2K is not for beginners, at least those without discretion when it comes to cornering speeds and throttle application.

However, I'd have to say we disagree on the issue of understeer/oversteer. Let me start by describing my ideal setup (for my current skill level).

At low speeds I want the car neutral to slightly oversteering at steady state. This way I can make it around tight corners and get pointed and back on the gas early.

At higher speeds, I want a bit of understeer at the limit - not a lot, just a bit. This would probably require aerodynamic tuning to coexist with my low speed preferences.

The reason I want this is probably related to my skill level. Despite taking Bondourant and having my fair share of track time, oversteer at triple digit speeds is a bit unsettling. Also, mistakes, and we all make them, are more forgiveable when the car understeers IMO.

Now, I don't set up professional race cars, but I've heard from more than one source that for high speed racing you start with the bias towards understeer and dial it out to the driver's comfort level (usaully less understeer for qualifying). Does that sound like what you've heard?

Also, regarding the example you propose. If the rear end starts pogoing around, do feel that oversteer is preferable? At that point, I think you risk snapping the rear around if you're trying to correct while available rear traction is changing rapidly. With understeer, just slow down :-)

In my case, I also feel that with a bit of understeer, I can always add power to rotate the car (up to a point where you don't have enough thrust to rotate the car, then you increase understeer with throttle application).

Anyways, it sounds like we agree that it is a fine line, whatever the preference. There is a passage in Skip Barber's "Going Faster" book that talks about preferred setups, saying that the fastest drivers set up their cars close to neutral. Those that prefer understeer might overutilize the front tires by 1% while those that prefer oversteer might overutilize the rears by 1%. Whereas an inexperienced driver might overutilize one or the other by 70%. I think we're probably spliting those 2%

For the another thread, I'd like to talk about how driver input affects the balance. I find I have to consciously load the fronts to avoid slow speed understeer on tight corners with the stock suspension. But that's another thread for the racing forum.

UL

GTRPower

Hey UL-

Although we are getting significantly off topic, here's some things I thought I should address in your last post-

1. We are definitely splitting up the 2%...

2. In the example we used (mid corner bump resulting in poorly modulated suspension undulation) smoothly lifting off the throttle (maintenance throttle) will accomplish the same goal whether over or understeer, which is to regain control of the car. Steering input should be used to direct the car. In a sense, using additional throttle to redirect the car would be described as power oversteer, a characteristic this car doesn't have at speed (higher than street legal mph) or I have yet to encounter. When the throttle is applied, the weight shifts back, putting less pressure on the front tires, which in turn lessens the front grip. On an understeering car, you generally apply the brake smoothly to regain directional control. Also, power oversteer is not necessarily the best solution, especially when tire wear is an issue (endurance races, cheapskate weekend warriors, etc), or when the shock valving is relatively unpredictable (I would call the stock S2000 setup as that). Braking is less effective- you lose momentum, use more fuel, and generally make a bad situation worse. Snap oversteer is something different, I think. In my experience, the snap oversteer happens when poorly modulated throttle/brake is applied during any part of the corner, overcoming the grip of the rear tires either momentarily or for good. The above example, coupled with poor throttle input, will result in snap oversteer in the S2000 whether the car is an inherent understeerer or oversteerer. The traction circle limit of the rear tires has been surpassed.

3. In your opinion, you would prefer slight to mild understeer at high speed, with low speed oversteer ability. I prefer the car to steer fairly constant (neutral, or slight oversteer) whether at high or low speed. It's one less variable I have to deal with, and hopefully it will allow me to better predict how the car will react to the various inputs. This is a difference in driving style, which is actually an interesting discussion altogether. A recent article of "Racecar Technology" or "Racecar Engineering" discusses modern telemetry, and how two different racers with different setups can achieve the same times. The engineer describes the problem- only one setup is the fastest, and there should be a set driving "style" that will push the car to the maximum at all times. This style should be refined through telemetry, according to the article. The different setups merely masks the deficiencies of the drivers involved, and to better their skills they need to find the thresholds in their problem areas and enhance them in order to make the most out of the "best" setup. Although the theory is sound, I don't know how practical it is. At least, until they replace the driver with a computer too!

4. Race cars are set up to understeer at first to allow the driver to get used to the car. As you pointed out, the setup changes once the driver is familiar with the handling and wants to eliminate push- gradually getting closer to neutral handling. On low torque cars racers almost never like a car that pushes- it won't allow them to power oversteer. Racers generally do not want momentum to dictate what direction the car is heading, especially if they can't control it. If I'm racing a car I don't want to have to brake continuously to regain control of the steering- talk about slower times! Mild oversteer will be preferable in this case- when racecars are at the limit all the time. Obviously, the faster they go, the quicker they have to react. That's why the fast guys are fast.

5. In any case, we've described the basic reason why a modern front wheel drive car is easier to drive close to the limit than a car like the S2000. Front wheel drive cars tend to understeer (pretty much everywhere unless it's engineered not to like the Type R), are usually not as responsive, handling wise, to throttle input as a front engined rear drive car, and usually allow the driver to power out of trouble in corners (apply throttle, point wheels in the right direction, and wait...). A modern FF car will pretty much stay planted no matter what you do, under normal conditions. However, I think a properly set up FF car will perform exactly the same as a FR car- the Type R vs. the S2000 is an example.

Although I've made several generalisations here, and I haven't elaborated on other statements I've thrown around I think you get the gist of what I'm saying.

Geeze, do you think anyone is actually reading this drivel? I have no idea how much sense it makes since it's 3.40am here...

CoralDoc

You guys are too much! Thanks for the interesting dissection of S2K handling characteristics. Now I'm really looking forward to our next track outing at Homestead on the 17th of March. I'm a novice with only 3 days on the track, but some of this is starting to make sense. Thanks!