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Old 02-09-2010, 01:10 PM   #101
littlewhitewagon
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WHAT?!?!? But, that would look horrible! What's that going to do to the street cred of my hellaflush whip?
You're done. You might at as well and turn around to find another way home pizza boy.
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Old 02-09-2010, 01:11 PM   #102
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Just for fun, here's a pic of a BC front strut compared to a Whiteline Group 4. The G4 is similar to TICs current AST setup. You can get an idea of how they compare in overall stroke.



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Old 02-09-2010, 01:18 PM   #103
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Originally Posted by gagliano View Post
My car is not a daily driver anymore. Not sure what 'crap I'm doing to it to make it a daily' you're talking about.



Tony, it was a loaded question. My point was corner balancing with a dual adjustable setup is easier/more effective than changing preloads to accomplish the same thing.
Basically, if you run a fuel level different to what you cornerweighted at you will affect the balance. If you have a passenger, you will affect the balance. If you carrry home a load of groceries, you affect the balance.

More effective? Not at all. Proper coilovers that do not have the dual adjustable bracket use helper springs. There is no preload that is being changed when you adjust the ride height. One argument manufacturers use for the dual bracket setup is that you "maintain full stroke regardless of ride height". That is true, however the majority of these dual adjustable's have so little stroke to begin with that its a moot point.
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Old 02-09-2010, 01:37 PM   #104
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Originally Posted by Arnie View Post
Basically, if you run a fuel level different to what you cornerweighted at you will affect the balance. If you have a passenger, you will affect the balance. If you carrry home a load of groceries, you affect the balance.

More effective? Not at all. Proper coilovers that do not have the dual adjustable bracket use helper springs. There is no preload that is being changed when you adjust the ride height. One argument manufacturers use for the dual bracket setup is that you "maintain full stroke regardless of ride height". That is true, however the majority of these dual adjustable's have so little stroke to begin with that its a moot point.
Again, my car isn't a DD, but I see your point.

I disagree about the preload statement though. Any time you change the height of the lower spring perch you are changing preload. That's why some manufacturers put the helper springs in there. When you lower the perch to lower ride height, the helper spring keeps tension so the main springs don't come out of their seats when the suspension gets unloaded on those bumpy roads everyone mentioned in this thread.
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Old 02-09-2010, 01:41 PM   #105
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Have you ever adjusted the ride height of a coilover with helper springs?
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Old 02-09-2010, 01:42 PM   #106
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No matter what you do to the height you are not changing the preload. The only way you could change the preload would be to swap in a different rate spring or add/subtract weight from the car. It will always be preloaded the same as there is a constant amount of weight being supported by the spring.

Tony
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Old 02-09-2010, 01:48 PM   #107
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Quote:
Originally Posted by gagliano View Post
Again, my car isn't a DD, but I see your point.

I disagree about the preload statement though. Any time you change the height of the lower spring perch you are changing preload. That's why some manufacturers put the helper springs in there. When you lower the perch to lower ride height, the helper spring keeps tension so the main springs don't come out of their seats when the suspension gets unloaded on those bumpy roads everyone mentioned in this thread.
You aren't changing preload on the main spring if you have a helper spring in there. And preload on the helper spring is irrelevant since it's fully compressed at static ride height anyway. In no way does dual height adjustability make corner balancing the car any easier or more effective.
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Old 02-09-2010, 01:53 PM   #108
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Does the G4 not use a bump stop or is it internal.
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Old 02-09-2010, 01:54 PM   #109
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Tony,

So then a dual adjustable coil over doesn't need all the travel of a single adjustable coil over to make ride height adjustments?
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Old 02-09-2010, 02:05 PM   #110
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Quote:
Originally Posted by gagliano View Post
Tony,

So then a dual adjustable coil over doesn't need all the travel of a single adjustable coil over to make ride height adjustments?

The real, actual point is that ride height is not adjustable. You can adjust it a bit, but with a decent suspension design (and i'm talking about the suspension links, here) there is very little room to adjust it in either direction. Therefore, good coilovers simply adjust the length of the strut to match the correct ride height, and give you adjustable spring perches for corner balancing and setting wedge.


Look at the RCE springs for the 08+ cars for an example. High performance lowering spring that drops the car less than half an inch. That's all you can get away with on the new cars.



Dual height adjustability simply means they didn't bother designing a damper for a specific car - they just use one damper for a million applications. It's cheaper for them, and thus they make more money. It's not a performance feature.
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Old 02-09-2010, 02:21 PM   #111
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Does the G4 not use a bump stop or is it internal.
Its uses a bumpstop, just don't have it pictured when I took this pic.
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Old 02-09-2010, 03:32 PM   #112
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correct me if im wrong (noob here), but the bad thing about the coilovers from the first couple of pics is the low distance the wheels drop when the cars lifted? I was looking into getting some decent c/o's for my DD but its looking like its a bad idea if theyre gonna turn out like that (was looking into megan)
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Old 02-09-2010, 03:36 PM   #113
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Easy answer is if you are daily driving you don't need coilovers. However some will still want them and will run them. That is fine. To get ones that will work well on the street though you will be spending at least 2.5x the price of the megans. That's just how it is.

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Old 02-09-2010, 06:46 PM   #114
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Originally Posted by Turn in Concepts View Post
No matter what you do to the height you are not changing the preload. The only way you could change the preload would be to swap in a different rate spring or add/subtract weight from the car. It will always be preloaded the same as there is a constant amount of weight being supported by the spring.

Tony
I don't see how you can say that. Mono adjustable coilovers require you to make height adjustments by changing the preload setting of the lower perch. If I add zero preload to the coil, the unit will sag thus lowering ride height. If I add more preload by moving the lower perch higher up the shock body, the vehicle will sag less and the ride height will be taller. The differing spring rates you mention will determine how much pressure is exerted against the perch as I increase preload.

Quote:
Originally Posted by boost junkie View Post
In no way does dual height adjustability make corner balancing the car any easier or more effective.
Then let me say it this way, dual adjustables make the changes by shifting CG to attain balance without making any changes to spring preload and sag; is this not better?

Quote:
Originally Posted by sniper1rfa View Post
Dual height adjustability simply means they didn't bother designing a damper for a specific car - they just use one damper for a million applications. It's cheaper for them, and thus they make more money. It's not a performance feature.
And how is this bad? Ohlins makes dual adjustable coil overs for our cars; can we agree that they make a quality product?
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Old 02-09-2010, 06:48 PM   #115
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I don't see any numbers crunched. I would certainly hope that someone took the time to calculate the required stroke for the car.

Otherwise this thread will quickly turn into: "my (coilover) stroke is longer than your's"
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Old 02-09-2010, 07:05 PM   #116
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Quote:
Originally Posted by gagliano View Post
I don't see how you can say that. Mono adjustable coilovers require you to make height adjustments by changing the preload setting of the lower perch. If I add zero preload to the coil, the unit will sag thus lowering ride height. If I add more preload by moving the lower perch higher up the shock body, the vehicle will sag less and the ride height will be taller. The differing spring rates you mention will determine how much pressure is exerted against the perch as I increase preload.

Then let me say it this way, dual adjustables make the changes by shifting CG to attain balance without making any changes to spring preload and sag; is this not better?
You aren't getting it. If you use a helper spring, you can raise and lower the spring perch WITHOUT preloading the main spring. What you're saying would be true if you used a single height adjustable body with only a main spring, but the helper eliminates the need to change preload on the main spring.
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Old 02-09-2010, 07:11 PM   #117
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Originally Posted by gagliano View Post
I don't see how you can say that. Mono adjustable coilovers require you to make height adjustments by changing the preload setting of the lower perch. If I add zero preload to the coil, the unit will sag thus lowering ride height. If I add more preload by moving the lower perch higher up the shock body, the vehicle will sag less and the ride height will be taller. The differing spring rates you mention will determine how much pressure is exerted against the perch as I increase preload.
Wrong.

With a single-adjustable coil-over, the main spring should be fully extended at full droop. On top of that, the helper spring should be mostly extended. This causes the springs to remain firmly seated. Due to the tiny spring rate of the helper spring compared to main spring, the main spring is compressed infinitesimally so long as the helper spring hasn't reached coil bind. As your raise and lower the lower spring perch, you are moving the main coil up and down without compressing it. The change in the distance between the upper and lower perches is being entirely accommodated by the helper spring compressing and expanding. Because of the helper spring, the preload on the main spring isn't changing at all. As soon as you set the car on its feet, the helper spring collapses and becomes solid. The main spring compresses slightly and the car settles to its final ride height. Because the main spring always compresses the same amount for a given car weight on it, moving the lower spring perch up and down results in the overall ride height changing.



Quote:
Then let me say it this way, dual adjustables make the changes by shifting CG to attain balance without making any changes to spring preload and sag; is this not better?
Neither singles or doubles change the preload. They're making the same adjustments to suspension geometry, CoG height, etc.

Quote:
Ohlins makes dual adjustable coil overs for our cars; can we agree that they make a quality product?
There is one advantage to dual-adjustable. If you're stroke limited, that is to say if the damper bottoms out before the coil binds, a DA setup can offer you slightly more height adjustability without sacrificing damper stroke. However, if you already have more travel in your damper than you do in your spring (which is easy to do if you use cheap springs), then there's no difference between DAs and SAs.
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Old 02-09-2010, 07:14 PM   #118
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I don't see any numbers crunched. I would certainly hope that someone took the time to calculate the required stroke for the car.
That's a somewhat deceptive statement. Required for what? No matter how much travel you have, you'll always be able to go faster (requires more movement for a given bump) or find a bigger bump. In a very real sense, you can never have enough travel. You can, perhaps, design around the 80th percentile bump and speed, which is where a lot of goal come from. There's also inherent limits on stroke created by the overall suspension geometry of the car.
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Old 02-09-2010, 07:37 PM   #119
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That's a somewhat deceptive statement. Required for what? No matter how much travel you have, you'll always be able to go faster (requires more movement for a given bump) or find a bigger bump. In a very real sense, you can never have enough travel. You can, perhaps, design around the 80th percentile bump and speed, which is where a lot of goal come from. There's also inherent limits on stroke created by the overall suspension geometry of the car.
I am not going to argue w/ you that BC's are stroke limited. But its also important not to get ahead of yourself with this stroke business. I mean you do agree that stiffer springs require less stroke, right?
Cars w/ lower motion ratios will require significantly LESS stroke.
You only need enough stroke to be not fully compressed on corners and have enough travel to soak up the bumps.

You could rig up shocks like these if you think longer (stroke) is better:
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Old 02-09-2010, 07:55 PM   #120
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I mean you do agree that stiffer springs require less stroke, right?
No, I don't.

Or at least, it's nowhere near that simple. A stiffer spring will result in less damper displacement for a given magnitude of impulse. The problem is that there's basically no upper bound on the magnitude of impulses. If you drive faster, the impulses get bigger. If you hit a higher bump, the impulses get bigger. If you hit a steeper bump, the impulses get bigger. Really, no matter how much travel you have, at least occasionally, you're going to use it.

Then you have to consider the flip-side. The stiffer spring (and the stiffer the damping to go along with it) the greater the force applied to upsetting the chassis as the suspension attempts to absorb the impulse. Upsetting the chassis over every bump is also a bad thing. So in trying to patch the travel issue, you created another problem for yourself.

The thing to take away from this is that you want the minimum spring rate that makes your tires happy and then you want enough travel to prevent reaching a mechanical limit over the majority of your use.



Quote:
Cars w/ lower motion ratios will require significantly LESS stroke.
No.

Or, again, at least not that simple. Because of the change in motion ratio, you need less travel in the damper. However, you still need the same travel at the wheel. So you're not coming up with less suspension travel overall.


Quote:
You only need enough stroke to be not fully compressed on corners and have enough travel to soak up the bumps.
Correct. It's just that the amount of travel required to do this is way more than you think it is.

Quote:
You could rig up shocks like these if you think longer (stroke) is better:
And that's fine, except you can't do that in an Impreza chassis without massively altering the suspension geometry. If I could have 22" of suspension travel and a ramp index that would make a rock crawler cry and yet not alter the suspension geometry, I'd do it in a heartbeat.
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Old 02-09-2010, 08:09 PM   #121
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Quote:
Originally Posted by antonch View Post
Cars w/ lower motion ratios will require significantly LESS stroke.
Quote:
Originally Posted by williaty View Post

No.

Or, again, at least not that simple. Because of the change in motion ratio, you need less travel in the damper. However, you still need the same travel at the wheel. So you're not coming up with less suspension travel overall.
That is no my exact point. It's pretty simple actually. With motion ratio <1 the wheel has much more displacement than the shock does. Lower motion ratios require a damper with less stroke.
We don't have to agree on everything, and I am not here to argue but I wanted to clear that up.
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Old 02-09-2010, 08:20 PM   #122
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The way you phrased it made it sound like you were saying motion ratio changes changed the amount of travel necessary at the wheel, which just isn't true.
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Old 02-09-2010, 08:28 PM   #123
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Originally Posted by antonch View Post
That is no my exact point. It's pretty simple actually. With motion ratio <1 the wheel has much more displacement than the shock does. Lower motion ratios require a damper with less stroke.
We don't have to agree on everything, and I am not here to argue but I wanted to clear that up.
Why is this relevant when we are talking about the GD chassis which has a motion ratio of essentially 1:1? In theory you would need less damper stroke in the rear of a GR/GH chassis but because of the suspension design they are also very travel limited.
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Old 02-09-2010, 08:52 PM   #124
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Originally Posted by antonch View Post
I am not going to argue w/ you that BC's are stroke limited. But its also important not to get ahead of yourself with this stroke business. I mean you do agree that stiffer springs require less stroke, right?
Cars w/ lower motion ratios will require significantly LESS stroke.
You only need enough stroke to be not fully compressed on corners and have enough travel to soak up the bumps.

You could rig up shocks like these if you think longer (stroke) is better:
Hell ya I would take shocks with that much stroke!!

Peep this pic:


As others have said...you are wrong about stiffer springs needing less stroke. That car has double height adj Zeal coilovers with pretty stiff springs (600lb all around) and street tires. It has droop travel numbers similar to the values mentioned on the first page by TiC. As you can see...its lifting a front wheel when tryin to power out of curve. Dont know if you race but you can def feel when this happens and it effects the car everywhere. Meaning power application is delayed and steering feel goes numb. Then once the tire lands it upsets the car.
This is where as much travel as you can get no matter how stiff your springs are is need!

Here is a pic of what good droop travel will do for you:


This is a hard breaking left turn and as you can see the inside rear is firmly planted on the ground allowing the driver to get the power down early. I wish I could find other cars going around the same corners for reference but I hope this helps.
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Old 02-09-2010, 09:11 PM   #125
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^^^^but a really stiff front sway bar could do that (lift inside front tire) even with a lot of droop travel.
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