Ok... What did I do wrong?

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Caboose302

Caboose302

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I've been seeing them on the top and bottom. You would think it would be easier for the spring to hold up the bearing plate rather than the plate AND the spring. Suspension stuff fascinates me lol.
 

mcglsr2

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Yah, not seeing it. Normally the helper spring is compressed, so it's not an active part of the suspension. Why does it matter whether it's on the top or bottom?
 

mcglsr2

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Alright, I took some pics and measured my current ride height.

I'm sitting at 27" right now, measured from the floor to the top of the front fender:

IMG_4013.jpg



(I will drop it down to about 26.5" to 26" after I install my bumpsteer kit.)

I also snapped a pic of the front struts and where the collar is at:

IMG_4014.jpg


IMG_4016.jpg



As you can see, I have pretty much the entire sleeve-worth of adjustment. It's currently at the top of the sleeve. I suspect I can easily get the car down an inch.
 
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Caboose302

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Alright, I took some pics and measured my current ride height.

I'm sitting at 27" right now, measured from the floor to the top of the front fender:

IMG_4013.jpg



(I will drop it down to about 26.5" to 26" after I install my bumpsteer kit.)

I also snapped a pic of the front struts and where the collar is at:

IMG_4014.jpg


IMG_4016.jpg



As you can see, I have pretty much the entire sleeve-worth of adjustment. It's currently at the top of the sleeve. I suspect I can easily get the car down an inch.
And that's with the helper Springs correct? I would be happy with 26". Tonight I'm going to try and preload the spring enough to drive it while I wait on the helpers
 

mcglsr2

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And that's with the helper Springs correct? I would be happy with 26". Tonight I'm going to try and preload the spring enough to drive it while I wait on the helpers

No, no helper springs on the front. Just the 10" springs. The helper springs are on my rears.
 

mcglsr2

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less chance of the coupler between the two to shift when its down around the strut. More of a "just incase" kind of thing.

Oh, I see, because of the thicker diameter of the sleeve there's less "wiggle room" for the coupler. That makes sense, it certainly couldn't hurt. Next time I'm back there I'll swap it around. Thanks for the suggestion!
 

Addermk2

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Talked to Strange about it and they said 10" 350lbs was too much unless I have a big block (has he seen the size of a mod motor?) , and that he recommended a 12 or 14 at 175lbs. That sounds waaaay too soft for me. This isn't a drag car...

I'll try to loosen everything back up and retighten it tonight. I still have stock A arms and didn't loosen them up, but maybe something in the CC plate is binding?

Why is a 350 way too much? What are the disadvantages other than a rough ride? Are you saying that could be part of my issue?


I'm not about to read the whole thread... ADD is way too bad tonight. What spring rate are you running in the rear? If you've got stock location springs back there, they better be damn near 500lb/in.
 
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Caboose302

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I'm not about to read the whole thread... ADD is way too bad tonight. What spring rate are you running in the rear? If you've got stock location springs back there, they better be damn near 500lb/in.
They're H&R supersports in the back, but they're getting replaced with coilovers when I find a kit I'm happy with. I've been looking at around the 425-475 lb range. I said in another thread, this coilover stuff is confusing just based on the number of different accounts. Even different manufacturers and tuners will say conflicting things. Strange says they're too stiff and MM said they shouldn't be an issue. I have no problem taking these back apart and throwing regular Springs back on it if I have to order the right spring rate and length.
 

Addermk2

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They're H&R supersports in the back, but they're getting replaced with coilovers when I find a kit I'm happy with. I've been looking at around the 425-475 lb range. I said in another thread, this coilover stuff is confusing just based on the number of different accounts. Even different manufacturers and tuners will say conflicting things. Strange says they're too stiff and MM said they shouldn't be an issue. I have no problem taking these back apart and throwing regular Springs back on it if I have to order the right spring rate and length.

What is it exactly that you are going for? The rates you have are up near racecar levels. I run 175 front and rear, and when I tell you it's far from soft... I mean it.


Right off the MM website, they give approximate conversions for spring rates based on location, to wheel rates.

When you make the conversions and look at the factory 96-98 Cobra WHEEL RATES, you see that the front is about 100-126lb/in, and the rear is 82.5-132.5lb/in (progressive springs). When you compare these to the 94-95 Cobra (mine) the rates are similar, but linear, with a 100lb/in front wheel rate and 82lb/in rear wheel rate.

You state that you have H&R SS springs, which have a spring rate of 275-300. This ends up being a wheel rate of 137.5-150 lb/in, which is obviously slightly stiffer than stock.

HOWEVER, and this is where the craziness starts...

Your 350 lb/in coilovers springs have a wheel rate of 315 lb/in. This means that you have more than twice as much spring in the front, than you have in the rear. This is going to create a handling problem. Your car is going to have an overwhelming desire to understeer, which defeats the purpose of your suspension work. If you were to keep the H&R springs in the rear, my recommendation would be to run a 175 lb/in spring. This will bring the car back into better balance, while also giving a nice ride and a moderate improvement in handling. I personally run 14" 175lb springs.
 
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Caboose302

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What is it exactly that you are going for? The rates you have are up near racecar levels. I run 175 front and rear, and when I tell you it's far from soft... I mean it.


Right off the MM website, they give approximate conversions for spring rates based on location, to wheel rates.

When you make the conversions and look at the factory 96-98 Cobra WHEEL RATES, you see that the front is about 100-126lb/in, and the rear is 82.5-132.5lb/in (progressive springs). When you compare these to the 94-95 Cobra (mine) the rates are similar, but linear, with a 100lb/in front wheel rate and 82lb/in rear wheel rate.

You state that you have H&R SS springs, which have a spring rate of 275-300. This ends up being a wheel rate of 137.5-150 lb/in, which is obviously slightly stiffer than stock.

HOWEVER, and this is where the craziness starts...

Your 350 lb/in coilovers springs have a wheel rate of 315 lb/in. This means that you have more than twice as much spring in the front, than you have in the rear. This is going to create a handling problem. Your car is going to have an overwhelming desire to understeer, which defeats the purpose of your suspension work. If you were to keep the H&R springs in the rear, my recommendation would be to run a 175 lb/in spring. This will bring the car back into better balance, while also giving a nice ride and a moderate improvement in handling. I personally run 14" 175lb springs.

Damn I should have talked to you first, lol. I'm going to see if Summit will exchange them out. Is there a disadvantage to running a 12" vs a 14"? I'm still looking for a lowest setting of around 3" under stock.
 

mcglsr2

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Something important to keep in mind here regarding stock wheel rates: they were designed for a mass market comfortable ride. Because of the spring geometry, moving to stiffer and stiffer springs has an increasingly adverse effect on ride quality (and to an extent handling).

The point most important from Addermk2 is that your balance between front and rear is way off. If you intend to run coil-overs for the rear, than you can restore that balance. It all depends on what you want to do. Yes, 350 lbs is race car territory. However, 175 lbs is still soft. My recommendation is to target around 250 lbs or so for the front, even if you plan on DD'ing your car. There are a couple important points here: it's not just about spring rate. The spring rate *has* to be matched to your dampers (struts/shocks). They work together. For an example of springs rates for given dampers, look at this page at MM. Specifically, pay attention to the Bilstein HD coil-over rates (front: 250 - 325 lbs; rear SA: 175 - 250 lbs), or the Tokico Illumina (front: 250 - 325 lbs), or the Koni Yellows (front: 275 - 375 lbs). As you can see, they are all above 175 lbs for the front, and aren't necessarily "race setups." The race setups are in the 400 lbs range, for the fronts.

Are people using 175 lbs for the front? Sure. But why. The whole point, the *whole point* of coil-overs is to correct the suspension geometry, to put the springs out by the wheels, and fix the shitty wheel rates the stock geometry gives us. By doing this, it allows us to run a stiffer spring *without* the adverse effects of the stock setup. Why in the world would you want to switch to coil-overs just to run the equivalent of stock rates? You might as well not convert. Maybe you are just looking for more low, that's fine, but you can eat your cake too. Get more low *and* better handling.

Coil-overs provide a better ride than stock geometry - you can (and should) run a higher rate over stock. Some info from MM's website:

Q. Why does a coil-over spring with a higher wheel rate ride better than a conventional spring with a lower wheel rate?
A. Although the front coil-over spring in the above example increases the wheel rate by over 60%, the ride quality will actually improve. A conventional spring located on the Mustang's front control arm contributes to ride harshness because of friction in the control arm bushings and ball joints. A Mustang front coil-over kit eliminates this friction by applying the spring force directly to the spindle and upper strut mount. Coil-over springs are also much lighter than a conventional Mustang spring. The resulting reduction in unsprung weight allows the suspension to more easily follow bumps in the road. Rear coil-over conversions provide a similar improvement in ride quality, although it's not as dramatic of a difference as the front kits.


So, to Addermk2's point, balance out the front and rear. 350 lbs up front is fine if you plan on running 225 lbs coil-overs in the rear (or about 450 to 500 lbs regular springs). I don't even know if stock springs are made in that rate, so for 350 lbs up front, you would have to eventually run coil-overs in the rear. However, for about ~250 lbs up front, you can easily get away with ~300 or so in the rear. If you don't plan on going to coil-overs in the rear, then you are more limited up front with what spring rates you can run (meaning you can't run the higher spring rates).

To calculate wheel rates:

Front:
Stock setup (spring in stock location): Spring Rate * 0.25 = Front Wheel Rate
Coil-over: Spring Rate * 0.90 = Front Wheel Rate

Rear (solid axle):
Stock setup (spring in stock location): Spring Rate * 0.50 = Rear Wheel Rate
Coil-Over: Spring Rate * 1.10 = Rear Wheel Rate

Remember the front and rear need to be balanced, *not* equal. The front should always have a higher spring rate. For reference, on my set up I am running this (which I worked with MM to determine): Front Wheel Rate = 337.5; Rear Wheel Rate = 247.5. Understand that this is for a track car, and I am softer in the rear because I run a panhard bar. However, for the street, the ratio of front to rear is still relevant, just with less wheel rate.

So yes, 175 lbs will work for you. But why go that soft when you don't have to?
 

mcglsr2

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So, to summarize, a 175 lbs coil-over up front is equivalent to about 157 Wheel Rate, which can be had by using 630 lb springs in the stock location. So. If you buy front springs that have a spring rate of 600 - 700 lbs, that's roughly equivalent to a 175 lbs coil-over. HOWEVER. Because coil-overs can provide a better ride due to the relocation of the geometry, you can get away with running a stiffer Wheel Rate than you could with a stock location spring. You get cake, and you can eat it.

A 250 lbs coil-over, which will still give you an excellent street ride, has a Wheel Rate of 225, which would require a stock location spring with a rate of 900. Which is like H&R Race Spring territory. So you get the stiffness from a coil-over, but with a better ride than equivalently stiff stock location springs. There's your cake.

And because your Wheel Rate is now stiffer up front, your car will handle better. With no adverse effects. You are eating your cake.

The rear works the same way regarding stock springs and coil-overs. But because the stock geometry isn't as effed up as the front, it's not as much of a noticeable improvement. Thus, you can run coil-overs up front and stock location springs in the rear without too much difficulty. Though you would still benefit from coil-overs back there.
 

mcglsr2

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Lastly, as I mentioned in a previous post, it's not just about spring rates. It's all about spring rates *and* the damper you are running. Dampers are different, and are valved to handle different loads. Some dampers will let you run stiffer coil-over springs, while others will not.

If you have a damper that is rated for 250 - 325 lbs (the Bilstein HD's for example), and you run a 175 lbs spring, you will be over-dampened, and your ride will suck. You will start to see the civic bounce. If you run a spring of 400 lbs with these struts, you will be under-dampened, and your ride will suck. You will bounce more, and possibly blow out the strut. The spring rate has to match the strut. Which may be why you are hearing conflicting stories. On top of that, everyone feels things subjectively different. A stiff ride to me may not be a stiff ride to you, or vice versa. Your best bet is to find a spring rate that works within the range of the damper and go with that. Strange says 175 is fine because it probably is. It will work with the strut. MM says you can go higher, probably because you can. Both may work - will you notice a difference? Probably not. Maybe if you start throwing the car into corners a lot you might start to notice a difference. But maybe you do notice. I can't say.

All I know is that if I have the opportunity to run a stiffer spring with very little adverse effects, I will run the stiffer spring. If my top priority is a butter smooth Cadillac ride then I would probably go with the softer springs. It all depends on what you want to do with the car.
 
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Caboose302

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Damn the information in this thread should be a sticky...
I called Strange again to find out what their struts are rated for. This guy I talked to said 150-275 so for a car that is Street driven with a little track use, he would recommend a 200-250. Summit also said I can send the 350s back and exchange them so when I get back in town the regular springs are going back on and I'm shipping the hypercoils back. That gives me some time to decide. Admittedly I rushed into this without doing enough research. Now I know where to start off. Thank you guys for helping me with my screw up.
 

mcglsr2

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Damn the information in this thread should be a sticky...
I called Strange again to find out what their struts are rated for. This guy I talked to said 150-275 so for a car that is Street driven with a little track use, he would recommend a 200-250. Summit also said I can send the 350s back and exchange them so when I get back in town the regular springs are going back on and I'm shipping the hypercoils back. That gives me some time to decide. Admittedly I rushed into this without doing enough research. Now I know where to start off. Thank you guys for helping me with my screw up.

No worries dude. We all start not knowing things. It's all part of the process. Don't sweat it and good luck :)

And 200 to 250 sounds about right to me. You can match that in the rear with stock location springs without too much difficulty.

Edit: Also, based on what Strange said, you could also run the 175's if you wanted to. It's in the range of the strut.
 

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Edit: Also, based on what Strange said, you could also run the 175's if you wanted to. It's in the range of the strut.


I recommended the 175's because they would be a good match for the springs he's got in the rear. If a stiffer rear spring would be installed, then the 225-250 in front would be a good choice.
 

mcglsr2

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I recommended the 175's because they would be a good match for the springs he's got in the rear. If a stiffer rear spring would be installed, then the 225-250 in front would be a good choice.

Oh gotcha. Agreed, that would match with his current setup. I think he mentioned that he might be swapping to coil-overs in the rear or something. Not sure.
 

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