How does lowering affect suspension geometry and handling
12-08-2011, 09:57 AM
#1
Staging Lane
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How does lowering affect suspension geometry and handling Ive had a set of lowering springs for a while now and haven't wanted to put them on since this was my dd, and my car already doesn't like speed bumps but now I have a second car. As far as the current suspension goes, I have a matched set of umi sway bars, and kyb agx shocks installed. I also have the lca relocation brackets sitting in the garage. How will installing the lowering springs affect my handling? Do I need to install the lca brackets? The reason I havent yet is I worry about lift throttle oversteer in mid corner, would that be an issue? Also how necessary is an adjustable panhard bar? The springs are bmr 1" drop. I guess my main question is installing just the parts I have, would it help or hurt handling
12-08-2011, 11:00 AM
#2
Lowering springs achieve, well I should say should achieve, several things: Primarily lowering your center of gravity and altering the springs rates to be more aggressive. The looks part is just an added bonus.
If those are our old 1-inch drop springs, they are 550 progressive and 150 linear rears. We have since increased the drop to 1.2-inch with our new springs and moved to a linear front and a 160 linear rear.
As for you concern with lift throttle oversteer, we haven't experienced it nor have customers reported back to me any incidents where it has occurred. It's always best to be accelerating through mid corner at the apex and continuing on your track out. But, should you need to lift off the throttle, there won't be any erratic behavior as a result of our springs.
To do everything right and by the book, yes, an adjustable panhard bar should be installed. The factory bar was cut to the length to work best with the factory ride height. Altering this ride height means you need to alter the length of the panhard, which locates the rearend. Will you need it? Well, our 1-inch lowering springs aren't overly dramatic so the visual alteration of the rearend location won't be as noticeable as say a 1.5-inch lowering spring. You can get away without using one, but if you're looking to really get it perfect, you should.
As for the lower control arm relocations, if you're drag racing, you will probably enjoy them greatly as they can limit wheel hop and will improve your lower control arm angle, which will change when you lower your car. However, using these for handling can sometimes cause the rearend to bind - which I personally didn't experience on my daily-driven 2001 SS for over 6 years. The best thing about them is that you can install them and still run the factory control arm position and change to the lower setting for track duty.
Hope this helps.
Kevin
If those are our old 1-inch drop springs, they are 550 progressive and 150 linear rears. We have since increased the drop to 1.2-inch with our new springs and moved to a linear front and a 160 linear rear.
As for you concern with lift throttle oversteer, we haven't experienced it nor have customers reported back to me any incidents where it has occurred. It's always best to be accelerating through mid corner at the apex and continuing on your track out. But, should you need to lift off the throttle, there won't be any erratic behavior as a result of our springs.
To do everything right and by the book, yes, an adjustable panhard bar should be installed. The factory bar was cut to the length to work best with the factory ride height. Altering this ride height means you need to alter the length of the panhard, which locates the rearend. Will you need it? Well, our 1-inch lowering springs aren't overly dramatic so the visual alteration of the rearend location won't be as noticeable as say a 1.5-inch lowering spring. You can get away without using one, but if you're looking to really get it perfect, you should.
As for the lower control arm relocations, if you're drag racing, you will probably enjoy them greatly as they can limit wheel hop and will improve your lower control arm angle, which will change when you lower your car. However, using these for handling can sometimes cause the rearend to bind - which I personally didn't experience on my daily-driven 2001 SS for over 6 years. The best thing about them is that you can install them and still run the factory control arm position and change to the lower setting for track duty.
Hope this helps.
Kevin
12-09-2011, 08:14 AM
#3
Staging Lane
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Thanks a bunch, that definately helps clear it up a bit. The main reason I worry about lift throttle oversteer is if I have to slow or brake abruptly mid corner. What kind of a difference do your new sprints make, with the linear front spring rate?
12-09-2011, 01:13 PM
#4
Well you're dealing with physics, honestly. So depending on corner speed, the line your took, the surface/angle, power levels, suspension, tires, and the a whole bunch of other variables will be dependent on if you will encounter "throttle oversteer" as you have a concern for. You need to know your vehicle and learn its behavior in a variety of scenarios. I will say that our springs won't create this problem or enhance it, but having the increased spring rates will help add more control to your vehicle.
Back when we first came out with our springs, progressives were all the rage because they road comfortably on the street and would offer the performance rates when getting pushed. Since the early days, however, things have changed, and people want linear springs. Linear springs are more predictable since they are already at the more aggressive 550 rate as you enter a corner, rather than the progressive which would start off at a lower range and move up.
Side-by-side, they actually ride around the same. Our new linear springs aren't harsh, and are really a good compromise of performance/comfort.
- Kevin
12-09-2011, 02:45 PM
#5
Lift throttle oversteer can happen a lot of ways. Brackets won't help it. Shocks matter, spring rates matter, bars matter, tires, and a lot of other things. The UMI bars you have match my bars in size, and my springs work extremely well with them. The weak link you have are those AGX's. They don't deal with stutter bumps and short sharp movements well and that can upset the back of the car. I wouldn't call it lift throttle oversteer at all. Oversteer and lift throttle oversteer are not the same things. And frankly only cars with a rear weight bias tend to lift throttle oversteer much at all.
FWIW, the claimed rates are different than what was claimed before. As I recall the old BMR springs were 170, and the "new" 160, not 160/150.
Shocks add control, they are what make are tied down. Springs effect balance, roll and pitch stiffness, ride, and camber control. There is reason I don't run high rate rear springs and that's simply for the most compliance I can get without shooting the balance to hell. The rear has no camber curve to control like the front, etc.
FWIW, the claimed rates are different than what was claimed before. As I recall the old BMR springs were 170, and the "new" 160, not 160/150.
Shocks add control, they are what make are tied down. Springs effect balance, roll and pitch stiffness, ride, and camber control. There is reason I don't run high rate rear springs and that's simply for the most compliance I can get without shooting the balance to hell. The rear has no camber curve to control like the front, etc.
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12-09-2011, 03:37 PM
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Thanks a bunch for the replies guys. Definitely hitting some good ground for me. I really like the way my car rides and handles now with the agx's at stock ride height, contrary to what everyone says about them, though I came from factory shocks and I have them set very stiff. Does anyone know how they do on a lowered car vs stock height, or is it about the same between the two? Also, I dont want to beat this to death, but to clear it up for bmr, its not the springs but more the brackets im worried about causing lift throttle oversteer. If I understand correctly, when they are installed on the setting for the best hookup, they basically push the rear tires into the pavement when on the gas to give better traction, so say im powering through a corner and see a car or something on the road, and let of the gas therefore reducing the traction to the rear. Is that theoritcally something to worry about? I do lots of spirited driving on the streets and tight mountain roads (spirited, not reckless) and dont want to set myself up for a wreck or worse
Sorry for the long paragraph and thanks a bunch for the great info guys!
Sorry for the long paragraph and thanks a bunch for the great info guys!
12-09-2011, 03:47 PM
#7
Your choices are to go with either the guy who designed, tested, and wins with his suspension components... or the big name company that ripped him off.
Save yourself a lot of time and headache and call Sam Strano directly. He wont steer you wrong (no pun intended)
Save yourself a lot of time and headache and call Sam Strano directly. He wont steer you wrong (no pun intended)
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12-10-2011, 12:29 AM
#8
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I agree with the techs above, they offer quality products that will really enhance the cars handling under all driving situations.
I highly doubt any companies are "ripping someone off" all their products are copy righted. Don't throw accusations out there.
I highly doubt any companies are "ripping someone off" all their products are copy righted. Don't throw accusations out there.
12-14-2011, 11:08 AM
#12
Hey Sam, quick driving question. Do you find lift throttle oversteer (trailing throttle oversteer?) is oft due to the front understeering then suddenly sticking when power is reduced? Lift throttle oversteer would be a front suspension problem while "standard" oversteer is due to the rear not sticking?
ramey
ramey
12-14-2011, 01:40 PM
#13
Hey Sam, quick driving question. Do you find lift throttle oversteer (trailing throttle oversteer?) is oft due to the front understeering then suddenly sticking when power is reduced? Lift throttle oversteer would be a front suspension problem while "standard" oversteer is due to the rear not sticking?
ramey
ramey
The basic definition of Trailing Throttle oversteer is oversteer that shows up off throttle. How or why you jumped off the throttle is kind another matter.
NASCAR drivers call what you are describing as "push/loose". The front slides then finally bites and snaps the tail around. This can happen with any throttle position. On power when you finally bust the rear tires loose, if you can. Off power by unloading the rear suddenly, or neutral throttle again as something changes and makes the rear tires spin up (off camber, slick patch, etc).
This whole thing shows why the details of a suspension setup matters. With a given set of springs and bars, you can greatly effect the response and attitude of the car with the shock damping if you can adjust it. The shocks effect how fast something happens. Balance itself comes from the other parts, tires, alignment, etc. Shocks aren't a balance tool in steady state terms. They are a tool to smooth out the reactions of things. If you can calm the car down from snap oversteer to normal oversteer--that's a lot better... not that oversteer is ever the ideal. Balance is the ideal, but balance means that both oversteer and understeer are within the car's behavior depending on what you are up to.
I do my stuff to be balanced to very slight understeer... that's how you make a fast car. Oversteering cars feel fast because they are edgy and the rear grip is lower than the front. When the tail takes off you feel like you are going right to edge (and you are, of the rear tires only). And it's dangerous on the road because oversteer is a lot harder correct than understeer is.
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www.stranoparts.com --814-849-3450
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Check out our KONI prices, our Master Cylinder Brace, and new Xtracker Hub/wheel bearing upgrade kits!
12-14-2011, 02:32 PM
#15
Oh, that's a murky subject.
The basic definition of Trailing Throttle oversteer is oversteer that shows up off throttle. How or why you jumped off the throttle is kind another matter.
NASCAR drivers call what you are describing as "push/loose". The front slides then finally bites and snaps the tail around. This can happen with any throttle position. On power when you finally bust the rear tires loose, if you can. Off power by unloading the rear suddenly, or neutral throttle again as something changes and makes the rear tires spin up (off camber, slick patch, etc).
This whole thing shows why the details of a suspension setup matters. With a given set of springs and bars, you can greatly effect the response and attitude of the car with the shock damping if you can adjust it. The shocks effect how fast something happens. Balance itself comes from the other parts, tires, alignment, etc. Shocks aren't a balance tool in steady state terms. They are a tool to smooth out the reactions of things. If you can calm the car down from snap oversteer to normal oversteer--that's a lot better... not that oversteer is ever the ideal. Balance is the ideal, but balance means that both oversteer and understeer are within the car's behavior depending on what you are up to.
I do my stuff to be balanced to very slight understeer... that's how you make a fast car. Oversteering cars feel fast because they are edgy and the rear grip is lower than the front. When the tail takes off you feel like you are going right to edge (and you are, of the rear tires only). And it's dangerous on the road because oversteer is a lot harder correct than understeer is.
The basic definition of Trailing Throttle oversteer is oversteer that shows up off throttle. How or why you jumped off the throttle is kind another matter.
NASCAR drivers call what you are describing as "push/loose". The front slides then finally bites and snaps the tail around. This can happen with any throttle position. On power when you finally bust the rear tires loose, if you can. Off power by unloading the rear suddenly, or neutral throttle again as something changes and makes the rear tires spin up (off camber, slick patch, etc).
This whole thing shows why the details of a suspension setup matters. With a given set of springs and bars, you can greatly effect the response and attitude of the car with the shock damping if you can adjust it. The shocks effect how fast something happens. Balance itself comes from the other parts, tires, alignment, etc. Shocks aren't a balance tool in steady state terms. They are a tool to smooth out the reactions of things. If you can calm the car down from snap oversteer to normal oversteer--that's a lot better... not that oversteer is ever the ideal. Balance is the ideal, but balance means that both oversteer and understeer are within the car's behavior depending on what you are up to.
I do my stuff to be balanced to very slight understeer... that's how you make a fast car. Oversteering cars feel fast because they are edgy and the rear grip is lower than the front. When the tail takes off you feel like you are going right to edge (and you are, of the rear tires only). And it's dangerous on the road because oversteer is a lot harder correct than understeer is.
ramey
12-14-2011, 06:40 PM
#17
Famous quote: "Oversteer is when you hit the wall tail first, understeer is when you hit it nose first".
I think Harry Hyde also finished his statement with "..... and on the edge of out of control".
Things were different back in the days of bias-ply tires too. It was sometime in 1990 that NASCAR went to radials, and that movie was made in 1989 and debuted in 1990. So, it actually had some truth to it... Bias tires were much easier and tolerant (and somewhat faster) driven sideways to a degree. But we don't run bias-ply tires 
I think Harry Hyde also finished his statement with "..... and on the edge of out of control".
Things were different back in the days of bias-ply tires too. It was sometime in 1990 that NASCAR went to radials, and that movie was made in 1989 and debuted in 1990. So, it actually had some truth to it... Bias tires were much easier and tolerant (and somewhat faster) driven sideways to a degree. But we don't run bias-ply tires
__________________
www.stranoparts.com --814-849-3450
18 SCCA National Championships in house, many more for our customers prove we know our stuff.Talk is cheap, results matter.
Check out our KONI prices, our Master Cylinder Brace, and new Xtracker Hub/wheel bearing upgrade kits!
www.stranoparts.com --814-849-3450
18 SCCA National Championships in house, many more for our customers prove we know our stuff.Talk is cheap, results matter.
Check out our KONI prices, our Master Cylinder Brace, and new Xtracker Hub/wheel bearing upgrade kits!
12-15-2011, 07:21 AM
#19
It would appear the typical lowering amount on this forum is around 1-1.25 inches. Sometimes less and sometimes much more. I haven't done the math on a 4th Gen Camaro, yet, but my feeling is the effect of the slight roll center height change is minimal as compared to say going up 200 lbs/in on a front spring rate.
My background is asphalt oval track and a good example is spring rate vs panhard bar height. We would consider a +25lb RR spring rate change as huge while 1/2 inch PHB height change would be considered fine tuning at the track. It was a big deal to change a spring while each night we messed with the PHB due to changing track conditions.
The bump steer is a similar situation. Since we're not moving pickup point or ball joint locations at all, usually, the bump steer is practically the same as it is from the factory since everything is still traveling in the same arc. If we get crazy with caster or get to messing with the lower ball joint then of course we have to address bumpsteer.
ramey
My background is asphalt oval track and a good example is spring rate vs panhard bar height. We would consider a +25lb RR spring rate change as huge while 1/2 inch PHB height change would be considered fine tuning at the track. It was a big deal to change a spring while each night we messed with the PHB due to changing track conditions.
The bump steer is a similar situation. Since we're not moving pickup point or ball joint locations at all, usually, the bump steer is practically the same as it is from the factory since everything is still traveling in the same arc. If we get crazy with caster or get to messing with the lower ball joint then of course we have to address bumpsteer.
ramey
