So the shocks are really hard, and the springs really soft.. Why?

[Deer Killer]

I noticed this a while ago and some people thought I was crazy for saying the GT suspension is too hard. Well with more data and more driving, it's obvious the springs are very soft, but when you hit a sharp bump it gets you good. Compared to riding around in my friend's STI, it is rough and noisy all the time, but a bump just doesn't feel as bad, infact I thought when I was about to cross a particularly bad part of a highway that we'd get some air time with his hard suspension, but surprisingly it was way more absorbant/planted than the GT. So what's the deal? What type of performance were they trying to accomplish?

[gtguy]

Generally, if an automaker is going to err, it will be on the side of underspringing. This usually yields a softer ride quality, and on most roads, isn't a liability because the dampers aren't doing very much when the car is just rolling along. But, as you and others have noticed, when you hit a bump, the liability of a mismatched spring/shock combo is that the damper does more work than it is supposed to. In the ideal world, the spring and damper work in unison. In an undersprung car, the damper does more of the work. But if the damper is firm, as the GT's dampers are, you get the thud. The STi is closer to right, but even STi people, with the stiffer springs, are complaining about the car's being jittery. Subarus have traditionally had an overdamped condition. This was true of the WRX, as well, as was even true to a certain extent of the SPT suspension kit that was sold for the WRX. The ride of an undersprung car is smooth and compliant, until you hit a bump. The ride of an oversprung car is jittery and harsh, all the time. If an automaker goes for that perfect combo of strut damping and spring rate, it gets spendy. If you've ever ridden in a Porsche 911, that suspension is dang near perfect. It's a blend of smooth compliance and excellent bump performance. It's also on an $80,000 car. When an automaker sins, it is better to do so, from a ride comfort standpoint, on the side of underspringing, because that will yield a more consistently comfortable ride (there aren't that many bumps on most roads) than other options. Notice that you mention that your friend's STi is "rough and noisy." That's a consequence of that car's higher spring rate and firmer dampers, coupled with its lower price point. At lower price points, an automaker has to pick their poison, so to speak. Kevin

[devobuzz]

Do you know what the stock spring rates are (in lbs/inch) for the GT?

[Xenonk]

Another way to look at it: If the springs are hard but wound so far apart, you will osciallate more the harder you drive it.. (like going into a dip and then up over a hill, the car will fly off the ground cuz the spring is going to fight from being compressed). The car will feel like a boat in big waves. This is incredibly scary when you are doing 50 mph off a top of the hill. It's going to land with a few hops too. That is why road track race cars will go with super hard springs and even harder shocks to keep the car planted (not to mention the giant front and rear wings to keep the car planted). For rally cars, it will be different, the springs will be soft and long (suspension travel) while the shocks are super beefed up for the constant banging it will go through. Keefe

[B4GT]

I've also noticed that the stock shocks are rather harsh in terms of absorbing small bumps and seams on the road. I can feel almost every little bump on the road, coming from a car with higher profile tires, this takes some getting used to. I don't mind the slightly more bumpy ride, given the low profile tires, but the stiff shocks transfers more shock to the cabin, which vibrates every time you go through a bump. That's what I don't like. So If I understand correctly, really good suspension setups should be able to absorb bumps well and still have little body lean when cornering, correct? It seems our stock setups are the reverse of that? What can we do to improve that? Get better dampers and stiffer springs to help the cornering? Which shocks would you recommend to better absorb the bumps? Thanks! Sorry for the newbie questions. I've never modded suspension on my cars before.

[Xenonk]

That's going to be a tough one to modify if you want to increase the floating boat feeling and not feel the bumps on the road.. that's pretty much taking out the "sport" feeling and going to the more "luxury glide" feeling. Is that what you want?? Keefe

[gtguy]

[quote name='B4GT']I've also noticed that the stock shocks are rather harsh in terms of absorbing small bumps and seams on the road. I can feel almost every little bump on the road, coming from a car with higher profile tires, this takes some getting used to. I don't mind the slightly more bumpy ride, given the low profile tires, but the stiff shocks transfers more shock to the cabin, which vibrates every time you go through a bump. That's what I don't like. So If I understand correctly, really good suspension setups should be able to absorb bumps well and still have little body lean when cornering, correct? It seems our stock setups are the reverse of that? What can we do to improve that? Get better dampers and stiffer springs to help the cornering? Which shocks would you recommend to better absorb the bumps? Thanks! Sorry for the newbie questions. I've never modded suspension on my cars before.[/QUOTE] Keep in mind that body roll is a function of suspension compliance, which EVERY car needs. Anybody who says they want no body roll is out of their minds, and I hope I'm not on the roads with them on a rainy day. :lol: The ideal suspension is a combination of compliance and firmness, and the GT is almost there, something that is remarkable, given its price point. To improve the GT's handling, you can mod a number of things: 1. The driver. The GT, more than any other Subaru to date, demands smoothness. It almost editorializes, by being difficult in the hands of the heavy-handed. If you are smooth, the car just carves corners, with very little body roll. If you pitch, or muscle the car around, it rolls and understeers all over the place. Driving school, SCCA programs or track days with an instructor are some places to learn smoothness. 2. Springs. The STi pink springs are certainly a nice compromise. They don't mess up the smooth ride quality of the GT, according to reviews, while taking out a bit of body roll and adding some improved turn-in. 3. Struts/springs. Usually, people go with coilovers here. To my knowledge, only two people on the board have these, Another B4 and XenonK. Both like their setups a lot, and have posted much about them. 4. Little things. Camber and tire pressures are often-overlooked when it comes to altering a car's handling dynamics. The vagaries of camber (front...rear isn't adjustable), caster and toe can affect a car's dynamic behavior in many ways. They won't affect body roll, but they can definitely affect turn-in and other handling parameters. The problem you're noticing with the GT isn't that the shocks are stiff. They are. But with a bit more spring, there's better compliance, and the shock (theoretically) does less work, which transmits less of that damper thud into the cabin. But if the spring gets too stiff, you run into an oversprung condition, which makes the car all jittery. I suspect that for most drivers, based on the reviews (we'll know more when more people are running them) the pink STi springs are the best thing for most drivers wanting a little more, while still retaining the stock car's smoothness. Kevin

[B4GT]

Thanks for your inputs guys. I've seen people talk about Zeals and Bilstein upgrades on this board. What are the advantages of these upgrades compared to the stock suspension setup? What do they do for the car? Thanks.

[DAP]

[quote name='gtguy']Keep in mind that body roll is a function of suspension compliance, which EVERY car needs. Kevin[/QUOTE] This is only true for passive suspensions. Active suspensions can remove body roll, or even lean into a turn like a bicycle without affecting other parameters. A full active suspension is very expensive, and very power hungry, but I'm rather surprised that noone has attempted a simple anti sway bar preloader that hydrolicly preloads the sway bar based on speed and stearing wheel position to remove the body roll. I would think it would be rather easy to implement as part of the power stearing system.

[gtguy]

[quote name='DAP']This is only true for passive suspensions. Active suspensions can remove body roll, or even lean into a turn like a bicycle without affecting other parameters. A full active suspension is very expensive, and very power hungry, but I'm rather surprised that noone has attempted a simple anti sway bar preloader that hydrolicly preloads the sway bar based on speed and stearing wheel position to remove the body roll. I would think it would be rather easy to implement as part of the power stearing system.[/QUOTE] But the suspension still has compliance, irrespective of how active or passive it is. And yes, the better suspensions get, the more expensive they get, which almost goes without saying. But if you don't have compliance, the car beats the heck out of you. There are setups such as the Bose Active Suspension which claim all sorts of wonders, but who knows? Kevin

[gtguy]

[quote name='B4GT']Thanks for your inputs guys. I've seen people talk about Zeals and Bilstein upgrades on this board. What are the advantages of these upgrades compared to the stock suspension setup? What do they do for the car? Thanks.[/QUOTE] Search, wee hopper. The existing threads contain far more information than anyone could impart in a single post. Kevin

[tsyGT]

[quote name='gtguy']But the suspension still has compliance, irrespective of how active or passive it is. And yes, the better suspensions get, the more expensive they get, which almost goes without saying. But if you don't have compliance, the car beats the heck out of you. There are setups such as the Bose Active Suspension which claim all sorts of wonders, but who knows? Kevin[/QUOTE]I recently drove a new Jaguar with their C.A.T.S. (basically computer controlled active suspension) and was impressed by how well it works. I tried to upset the balance of the car, taking quick jerking turns, but the suspension kept the car very even and controlled (very big car too). Of course, once again, you get what you pay for! But hopefully 5-10 years from now we'll be programming suspensions instead of changing out springs and shocks and sway bars! (ok, wishful thinking :D ) But I'm sure we'll get some trickle down eventually. Sorry to go a little off topic. :) tom

[gtguy]

I know, Tom. I keep bringing up the Porsche 911, because that car's suspension is, as near as I can tell, perfect. Compliance, body control, confidence-inspiring adhesion, everything a little enthusiast could want. Kevin

[tsyGT]

[quote name='gtguy']I know, Tom. I keep bringing up the Porsche 911, because that car's suspension is, as near as I can tell, perfect. Compliance, body control, confidence-inspiring adhesion, everything a little enthusiast could want. Kevin[/QUOTE] Apparently the 997 is even better than the 996! Well, $80K has to pay for something. :) tom

[Xenonk]

that's why you can get a used Porsche for about $30k for a 996 (1999 non turbo).. shop around.. :D Keefe