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Discussion Starter #1
My main complaint with my Z (2005 Touring) is that it seems to bee really fussy about how it wants to go around a turn. When I'm driving hard, I can plant the nose with the brakes, roll into the turn, and it sticks like mad. Wonderfull in the twisties on summer days.

However, when I'm just commuting to work, over the same twisties, it REALLY likes to push the nose out in turns, especially when going uphill. I figure this is partly my driving technique, and partly the suspension setup on the car (bone stock).

It just seems like the front wants to wash out in the turns unless I'm driving really hard, and have put a ton of weight on the front-end to keep in planted in place. It doesn't help that when driving lazily, I often coast into a turn, and lightly accelerate through it. Which transfers the weight back, lifts the nose, and it starts to push to the outside of the turn. If I let off on the throttle, the nose comes down, grips more, and turns in nicely, but I don't want to decelerate my way through the turns.

I'd really like something that carved in more on the turns. Both my wife and I have noticed this with the car (we split the driving time 50/50). The other car (2004 WRX) is much easier to toss through a turn at low speeds, although it rolls like mad).

My thoughts are that for problems that show up during spirited driving, I should try to fix me first, and then the car, but this shows up mainly when driving much further back from the edge.

Anyway. I've thought that what I needed to do was swap out the sways for a set like the Hotchkis that stiffen the rear up more than the front, to induce more oversteer. Also, I know that the staggered tire size setup also increases the understeer. I'm not looking to change up wheels/tires right now, though (running stock wheels, and KDW2's).

However, it looks like all the coil-over setups shift the roll stiffness to the front, which seems to me that they'll make it understeer more?

Also, how much of this can be tuned out with a different alignment. I'm going to realign the front to ensure that the toe isn't eating up my tires (starting to feather a touch at 25K miles on the car, 8K on the tires), and was thinking I could bump up the rear camber at the time, if that will help.

Thoughts?
 

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My basic drivers' ed class taught me that you should start to accelerate halfway through the curve (I assume long curve). It helps carry the car through better. If one brakes into a turn, doesn't that lose control? I would think so. I think a driver has to find the medium or point of balance between throttling and slowing down to take corners well.

I have been told that the Hotchkis setup does improve handling. That's why I bought the kit. I haven't installed it yet (**** winters), but I can't wait until I do get them on and start driving like it was meant to be driven.
 

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Discussion Starter #3
If one brakes into a turn, doesn't that lose control?
No, or at least not in anything I've driven. I do my breaking in the straight, or as part of the transition of an S, and then try to smoothly go from the brakes into the steering (go from full braking and no steering to no braking and full steering), and hold that to the apex and start rolling on the throttle. On a longer turn, especially if off-camber at the start, I roll more on the throttle early, which seems to "plant" the outside rear tire, and it just rips through the turn. But on an uphill turn, that will push the front-end out.

It's just so wierd feeling the front-end pushing out like that.
 

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:rolf2: It's been so 'long' since I drove my Z that I've forgotten what it's like. I do feel like the front end gets a little squirrely when taking a long sweeping curve too fast or not correctly. Maybe an upgrade in wheels and tires would also help. :dunno:

I hear you about braking early and then applying the throttle going into the long turn/curve. At least that's how I do it (if I even brake).

Anyhow, people with the Hotchkis setup say that it feels like they are riding on rails. Might be something to think about.
 

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Discussion Starter #5
:rolf2: It's been so 'long' since I drove my Z that I've forgotten what it's like.
Nice thing about Cali, I can drive it year round without too much worry. Although I've had to drive twice on ice. Not fun at all with a Max Summer type tire...

Anyhow, people with the Hotchkis setup say that it feels like they are riding on rails. Might be something to think about.
I'd been leaning towards the Hotchkis sways... But figured I'd rule out other stuff before making modifications.
 

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Thoughts?
  1. Better Tires. This will make the biggest difference in overall grip. The OEM tires suck with re to dry grip.
  2. Hotchkis TVS Stage 1. This is where you can really dial out the understeer since the Hotchkis bars are adjustable. I set my front sway bar to the softest setting and the rear to the stiffest. I LOVE the way the car handles now.
 

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Discussion Starter #7
  1. Better Tires. This will make the biggest difference in overall grip. The OEM tires suck with re to dry grip.
  2. Hotchkis TVS Stage 1. This is where you can really dial out the understeer since the Hotchkis bars are adjustable. I set my front sway bar to the softest setting and the rear to the stiffest. I LOVE the way the car handles now.
Well, I'm already on the better tires. The KDW2s blow the stockers out of the water. Is the TVS just the sways or the whole spring/strut/sways combo? Lowering the car is not an option (hit enough stuff with the underside of the nose as it is).
 

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Well, I'm already on the better tires. The KDW2s blow the stockers out of the water. Is the TVS just the sways or the whole spring/strut/sways combo? Lowering the car is not an option (hit enough stuff with the underside of the nose as it is).
The TVS kit is springs and sways. It does lower the car, but very little -- less than an inch. I believe it's advertised as dropping 15 mm in the front and 19 mm in the rear. I don't currently have any issues hitting stuff with the OEM chin spoiler, however I can see it happening if you have some aftermarket bumper or spoiler.

While the hotchkis springs give a net increase in spring rate, it's pretty small so you don't notice it. However, what you do notice is an improved overall ride since they change the balance by increasing the rate up front and decreasing it in the back. It got rid of that annoying highway bounce. Of course, they also helped increase the overall handling, too. :cheers:
 

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Hotchkis back springs are stiffer than 2003/4 Zs and lighter than stock 2004.5-on Zs. Most aftermarket springs follow the rates of the 03 springs (the ones with the bounce) and when the new 04.5s came out nobody went back to the drawing board to see if there were improvements to be made.

It seems as if most will drop the car but finding springs that are also of an increased rate is difficult. Nismo, Eibach KG/mm and Espelir have higher rates out back, RSR is similar to stock. Other than that it's coilovers.

Chris
 

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Discussion Starter #11
The TVS kit is springs and sways. It does lower the car, but very little -- less than an inch. I believe it's advertised as dropping 15 mm in the front and 19 mm in the rear. I don't currently have any issues hitting stuff with the OEM chin spoiler, however I can see it happening if you have some aftermarket bumper or spoiler.

While the hotchkis springs give a net increase in spring rate, it's pretty small so you don't notice it. However, what you do notice is an improved overall ride since they change the balance by increasing the rate up front and decreasing it in the back. It got rid of that annoying highway bounce. Of course, they also helped increase the overall handling, too. :cheers:

Unfortunately, there are enough driveways and lots around here with steep approaches that at stock height, we've scraped the underside of the stock chin fairly often. It's down where it can't really be seen, but it's aggravating doing it as often as it happens now, let alone if we go lower.
 

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Discussion Starter #12
stiffer in front, softer in rear
By stiffening the front, and softening the rear, does that effect the under/oversteer issues at all? Seems like that would also increase the tendency to oversteer, unless they expect you to match it with the hotchkis sways on the agressive settings, where it's MUCH stiffer in the rear than the front (dialing back out the understeering)?
 

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By stiffening the front, and softening the rear, does that effect the under/oversteer issues at all? Seems like that would also increase the tendency to oversteer, unless they expect you to match it with the hotchkis sways on the agressive settings, where it's MUCH stiffer in the rear than the front (dialing back out the understeering)?
All things being equal, yes, stiffer front and softer rear will add a little oversteer, theoretically. However, by lowering the car a bit, you get more camber. And as you mentioned, the sways can work that so it's more balanced.

I felt that overall the whole package was a huge improvement over stock.
 

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Discussion Starter #14
All things being equal, yes, stiffer front and softer rear will add a little oversteer, theoretically. However, by lowering the car a bit, you get more camber. And as you mentioned, the sways can work that so it's more balanced.

I felt that overall the whole package was a huge improvement over stock.
So stiffer front springs or stiffer rear sways increases oversteer, stiffer rear springs or stiffer front ways increase understeer?

I think that makes sense, in a hard turn, the front outside tire won't compress as much, although it's got a lot of weight on it. Then the rear will try to pivot around that point? vs. with stiffer rear springs, the rear outside corner is more of the pivot point for the car's tendency to yaw? And if you get it just right, you get a perfect neutral 4-wheel drift?
 

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If one brakes into a turn, doesn't that lose control? I would think so. I think a driver has to find the medium or point of balance between throttling and slowing down to take corners well.
Only if you do it wrong.

Its a technique called "trail braking". You carry a bit of brakes into the corner to keep the front end loaded so you get more pressure over the front tyres. As long as you're not braking too hard to cause the fronts to exceed their grip threshold and plough understeer, it can also get the car to turn in a bit more sharply as the rear unloads and gets a little light. Of course, that also means you're liable to spin if you fail to control the brakes properly.

It also allows for "supa-laate boraiking technique des'ka!" (to borrow a BMI term) since you can brake a little later, and turn in a little better, than someone who does the traditional "brake only in a straight line" technique and take them up the inside.

With the stock setup as understeery as it is, trail braking is the best way to get the Z to turn in smoothly. Your biggest issue is progressively easing off the brakes and onto the throttle to not have it oversteer. Trail braking is not an easy skill, and the cost of failure can be quite high if you haven't got decent runoff. Just practice somewhere with plenty of runoff.

I used to be able to do it quite well (and the Z is quite easy to steer on brakes as well as throttle, I discovered) but I've stopped driving in anger as much as I used to, so I've lost it.


As for the original question, I think swaybars are the first upgrade if you want a bit more handling without a loss of ride.
 

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Only if you do it wrong.

Its a technique called "trail braking". You carry a bit of brakes into the corner to keep the front end loaded so you get more pressure over the front tyres. As long as you're not braking too hard to cause the fronts to exceed their grip threshold and plough understeer, it can also get the car to turn in a bit more sharply as the rear unloads and gets a little light. Of course, that also means you're liable to spin if you fail to control the brakes properly.

It also allows for "supa-laate boraiking technique des'ka!" (to borrow a BMI term) since you can brake a little later, and turn in a little better, than someone who does the traditional "brake only in a straight line" technique and take them up the inside.


If you brake too hard in a corner, it's not the front exceeding too much grip that you have to worry about.. It's the transfer of weight and unloading of the rear end. Trail braking is used as you say to out brake your opponent who is just braking in a straight line.

Braking in the right spot before the turn does in fact load up the front end with weight. No problem. However, there are only a few turns I would even worry about trail braking into. Otherwise, I'd rather be on the throttle, not the brakes. It's all about exit speed.

Good discussion.
 

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If you brake too hard in a corner, it's not the front exceeding too much grip that you have to worry about.. It's the transfer of weight and unloading of the rear end. Trail braking is used as you say to out brake your opponent who is just braking in a straight line.
Depends on how hard you're working the brakes. If you're braking really hard, then most of your front tyres' total grip threshold will go towards decelleration in the fore/aft plane. If you try to turn in, then there's not enough grip to do so and the nose ploughs wide. I've done it enough times on the track, and on the street a few times :( Overshot my braking point, and can't come off the brakes because I'm going too quick. Had to rely on ABS to get me around the corner, badly.

Braking in the right spot before the turn does in fact load up the front end with weight. No problem. However, there are only a few turns I would even worry about trail braking into. Otherwise, I'd rather be on the throttle, not the brakes. It's all about exit speed.
It can also be used to drive around a car's inherent turn-in understeer. As you say, it does unload the rear and make it swing around a bit.

I know of a couple of pro drivers in Australia that use it in Porsches. They'll left foot trail brake into corners to help load the front up on a very rear heavy car, and keep the right foot on the throttle to keep the engine load up for more power once they come off the brakes.

Our local journos also bitch and moan about Audi's nanny systems, that throw a hissy fit when the throttle and brake pedals are actuated at the same time. It assumes the driver is in trouble and initiates the stability control, cutting power, when all they want to do is get the damned thing to turn in while keeping the revs / engine load up. Drives them mad.


This might be better off in the Driving Techniques forum. :)
 

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Depends on how hard you're working the brakes. If you're braking really hard, then most of your front tyres' total grip threshold will go towards decelleration in the fore/aft plane. If you try to turn in, then there's not enough grip to do so and the nose ploughs wide. I've done it enough times on the track, and on the street a few times :( Overshot my braking point, and can't come off the brakes because I'm going too quick. Had to rely on ABS to get me around the corner, badly.
If you are using 100% of your traction for braking, than you have nothing left to ask for. If you turn in, and the nose ploughs wide, the car is understeering. Putting all the weight forward is helping them grip more, yes. But, to me it's more a problem of what happened before that. If the nose end is plowing, there was a mistake prior to that happening. So, I understand what you are saying 100%. I teach vehicle dynamics. :) What I was saying, is I'd rather not have to be on the brakes. But on the throttle increasing my exit speed. Tit for tot.




It can also be used to drive around a car's inherent turn-in understeer. As you say, it does unload the rear and make it swing around a bit.
Braking while turning is a great way to create over steer. Which is a great way for an inexperienced driver to get hurt. :( I completely understand where you are coming from.


I know of a couple of pro drivers in Australia that use it in Porsches. They'll left foot trail brake into corners to help load the front up on a very rear heavy car, and keep the right foot on the throttle to keep the engine load up for more power once they come off the brakes.

Another reason why certain people like to trail brake and left foot brake, etc.. is to keep the turbo spooled up so when they are on corner exit, it's ready to go. Driving is technique. What's great is that everyone is different just like cars are different.


Our local journos also bitch and moan about Audi's nanny systems, that throw a hissy fit when the throttle and brake pedals are actuated at the same time. It assumes the driver is in trouble and initiates the stability control, cutting power, when all they want to do is get the damned thing to turn in while keeping the revs / engine load up. Drives them mad.
This might be better off in the Driving Techniques forum. :)

Yes. I don't like the elec. gizmos unless I'm not driving. :biggrin: Those systems save more people that don't know, than stop more people that do.

Again, I have taught several SAE Vehicle Dynamics classes and have gone down this path of discussion over and over.. Over zealous drivers complaining about systems that can stop better than them. Yet, they complain that it is "messing them up".. When it's actually trying to cover up poor driving technique, 90% of the time. It's the other 10% that bugs me. So, I normally shut them off.

Fortunately, I've had the chance to test and plot data with and without electronic systems and ABS in place. Most of the time, they operate within their means. Certain scenarios can provide interesting results though.

This probably would be better off in the "driving forum" but at least it's being talked about at all. :wink:

Have a good evening. :cheers:
 

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At Skip Barber, they tought trail braking as an advanced driving tecnique and remarked on how incredibly hard it is to use correctly and efficiently. They said we can feel free to practice it, but that we would probably have better results if we just focused on braking in a straight line.

Basically, trail braking is a great way to maximize your entry speed, but it's really easy to mess up. If you do mess up, at best you hurt your exit speed, or at worst, you lose control. So unless you are a seasoned driver, I don't recommend trail braking. Wait till you have mastered the more basic stuff first. If you can effectively trail brake, more power to you! :cheers:
 

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All things being equal, yes, stiffer front and softer rear will add a little oversteer, theoretically. However, by lowering the car a bit, you get more camber. And as you mentioned, the sways can work that so it's more balanced.

I felt that overall the whole package was a huge improvement over stock.
Actually, just the opposite happens. Stiffer in front adds understeer. A stiffer front end means that, when cornering, most of the lateral load transfer is absorbed by the outside front tire, since the front end resists roll more. The extra load on the outside front tire causes it to slip more, hence the understeer. You can stiffen the front with springs, or with a larger anti-sway bar.
 
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