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Discussion Starter · #1 ·
Anyone have real world experience driving an SW20 with cheapo coilovers up front and stock suspension in back? Someone I know, he's an older gent, is threatening to do that as he's sick of the tire selection and wants to go taller up front. He also wants rain/snow tires and the like (he lives in a weather treacherous mountain area) and wants to get away from UHP tires.

I can't advise him as I can't recall ever driving that sort of setup long term. My speculation is if he doesn't track the car or perform any 'spirited' driving it will be OK. But I don't know if there's any adjustment needed as he doesn't want to end up doing a 180 on a snow driven pass because the two ends of his car may be at odds. I'm thinking if the spring rates are similar and the shocks can be somewhat matched, it should work.
 

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This is going to take some explaining, I hope I can draw this in your mind's eye like its drawn in mine

Do you remember Ground Control? I do not know if they are still around- but basically they are/were a weld on perch to be able to run 2" or 2.5" springs on OEM strut housings

Since we have cartridge struts, its really easy for us to modify the housing. If you or he know a good fab guy, it might be a really easy way to 1) get a smaller spring 2) gain clearance 3) run camber plates 4) keep the same rate and damping as currently on the car

Something will need to be done with the upper hat to adapt to the smaller spring, but that might not be utterly hard to do

I explored this before because I want/need more front camber. Then I discovered Alex builds exactly what I need, so after I dry sump my C5, I will just go shopping with him <3
 

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Discussion Starter · #3 ·
I had forgot about Ground Control, I know they're used by the MK1 crowd. If I recall, you can ask them for an SW20 config even though they may not advertise it (much).
 

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I don’t see why a stock length Koni with some sort of 2.5” linear spring setup wouldn’t work well at pretty close to stock height. I’d probably say at minimum a stiffer rear sway bar might bring the balance back given it’d be tough to make a linear 2.5” spring of the same rate as stock work up front.

Something like 175-200 lb/in would probably be doable up front with some preload. But that would be quite a bit stiffer than stock, so I imagine the suspension balance would shift.

The slightly stiffer rear sway would help balance some of that, but you have to drop the rear subframe to install it for some odd reason on the SW20. Not the easiest install, but probably the easiest avenue to get some more rear axle roll stiffness.
 

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Discussion Starter · #5 ·
That's very useful. That's exactly the spring rate I was thinking about for front. I hope to have him avoid any twisting of the frame. A stiffer rear sway might help. He's planning on a almost square setup: 225/45-17 front, 235/45-17 rear. There are 50 to 100 tire models in those sizes, I'm jealous.

I think I created a monster though... Way down the list of my suggestions, dead last, was pressing in the spring perch. He wants to do that now. No surprise, there's no cost and it's fast - but there are risks.
 

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Also, preloaded suspension tuning is a bit more difficult than non-preloaded springs, as you end up operating in a narrow range of spring stiffness/length. When your spring isn’t preloaded you can adjust car height 1:1 and only have to worry about running out of suspension travel on bumps.
 

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225/45-17 doesn’t work at all on the front of these cars. It’s what I currently have. It’s entirely too tall. Even a 215/40-17 is borderline too tall, but it’s at least somewhat usable.

225/45-17 has huge reductions in steering angle and suspension travel.
 

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Discussion Starter · #9 ·
Well, he's going to try the spring perch 'adjustment', I had a feeling. Certainly not as fun as building a hybrid suspension setup, a pity as I was looking forward to that. He's got some old replacement struts he's had for years in case things go sideways. He's already shopping for all season/snow tires.
 

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The problem is I think you will have a hard time achieving any sort of ride / handling balance doing this. Even if you replaced the front coilover springs with something as soft (or nearly as soft) as the stock springs, they will then probably be quite over damped, assuming the valving on the cheap coilovers was even close to correct for the springs they originally came with.

What is the ultimate goal here? Just to get more tire selection? I know it's bad in the stock sizes, but is it really that bad when going slightly larger, while still sticking with sizes that fit under the stock spring perch? Or is this the guy who wanted to try 70 series tires to raise the car higher? If it's the later, he may also run into issues where the cheap coilovers were designed to lower the car, and at max height may or may not be able to even achieve stock ride height. So the small rise he could get from the tire size increase might well be lost if the car sits lower on the suspension. On the other hand, MAYBE the coilovers allow a ride higher than stock? Really depends on the coilover.
 
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Discussion Starter · #11 ·
Yes, balance is what I warned him about and that there may be some adjustment involved but I wasn't sure what exactly. It's not the 70 series guy, though this dude may be just as much a senior.

His goal is 45 series w/ mud & snow or snow only in 17", and just more sidewall. There's not a whole lot in 15" or 16" He's tired of compromising tire brands when there are so many 45 aspect ratio 17" brands/models available I can't blame him as this has always been a sticking point for the SW20. Still hasn't pressed in his spring perch yet, soon though. But considering the complications (and expense) of a hybrid suspension setup, I can't really dissuade him from the idea of altering his spring perch.
 

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205/45-17 shouldn't be too hard, and I would think would have good availability. Shouldn't even need to modify the perch, unless you want to run lots of camber. Paired with a 235/40-17, there should be lots of tire options as well.

It's smaller than a 235/40-17 (slightly), and that fit for me back in the day, I only had to modify the perch to allow autocross levels of camber.
 

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Discussion Starter · #14 ·
Yes, I thought of that, but the 235/40-17 is the stickler - not much there either for snow/M&S.

On the other hand, 225.45-17 is an option for the rear here and still maintains a nice 20mm stagger. Might have him look for tires in those 2 sizes.
 
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