Need rear spring/suspension advice

[BMR Tech 2]

One more thing I haven't mentioned yet: the adjustable panhard bar will soon get replaced by a BMR Watts Link. It's here, I just haven't had a chance to install it yet.
As far as I know Watts Links don't have any adjustability to raise or lower a vehicle, correct?
Also, if I can't center the axle enough so the tires won't rub with the current set-up, I'm not gonna be able to do it with the Watts Link installed either, right?

The WL will not change your ride height it all. It's also true that you won't be able to get the rear centered any better with a watts over a PHB when the car is static, but the WL will keep the rear centered better throughout your entire range of suspension travel.

Just an FYI, the Koni Yellows are only rebound adjustable. Setting them to full stiff does nothing to prevent your tire rub.

This is kind of janky, but I know a lot of guys in the F-body world do a "heater hose mod" to their springs. They'll get some heater hose and push it over the coils to give themselves a little extra lift. You could always try something like that.

 

[Sky Render]

The Steeda adjustable spring perches you linked to REQUIRE 2.5" COIL-OVER SPRINGS. They WILL NOT WORK WITH YOUR CURRENT SPRINGS.

 

[Norm Peterson]

I've already made it quite clear I think that I'm not changing the wheels.
I love the look and not changing it.

This is a classic case of letting appearance preferences get in the way of doing things technically right (or at least somewhere near right). Not liking either the problem or the proposed solutions is putting you in a little box with no way out.

From what your picture shows, another 1/4" will not eliminate the rubbing, and I really doubt that another 1/2" will either. You'll eventually just drive a little less carefully where bumps and other causes of suspension motion are concerned and the rubbing will come back anyway.

Springs that are MUCH stiffer than Steeda Sports MIGHT help (coilover springs for one of those adjustable perches can be had in some pretty high rates), but you should know that your car's handling balance will shift toward "loose" and you might not be much happier overall considering the possible effect on ride quality.

If you're getting rubbing under heavy acceleration, you may need to run a more aggressive relo bracket setting (you do have those things with all that power, don't you?).

You could get the rear flares reworked, which is probably the best solution from a technical standpoint given that you're refusing to fix this problem at its root cause (wrong wheel offset).

Or you could just resign yourself to driving enough slower and more gently, and with no passengers or trunk load . . . maybe then 1/2" could work more of the time.

Let's just say I've seen your problem, except it was from a swapped axle being a bit too wide instead of the wheels being wrong for the car.


Norm

 

[Speedboosted]

I've already made it quite clear I think that I'm not changing the wheels.
I love the look and not changing it.

Now, as a vendor that offers all kinds of suspension parts, maybe you could give me some ideas and/or links to products you sell that might do what I want, and that being to lower the back of the car 1/4-3/8" LESS than it's lowered now.

He gave you the best advice, but you chose to ignore it because you think your ride looks dope. Mark gave you the same correct advice. You have a poor wheel/tire setup in the back, nothing is wrong with the suspension (other than Koni but we'll continue past that).

It seems like the heater hose mod that Dylan mentioned is more your style. You should give that a try.

 

[modernbeat]

I've already made it quite clear I think that I'm not changing the wheels.
I love the look and not changing it.

Now, as a vendor that offers all kinds of suspension parts, maybe you could give me some ideas and/or links to products you sell that might do what I want, and that being to lower the back of the car 1/4-3/8" LESS than it's lowered now...

In that case (not changing the wheels) I'd narrow the rear axle to accommodate the correct fit of the wheels to the fender. We've done it on other cars when absolutely necessary.

Raising the car to accommodate tire to fender lip clearance is not the right way to do it. You will eventually hit enough of a bump the tire will still contact the body.

 

[Gabe]

I'm definitely not gonna narrow the axle.

I just ordered the Steeda adjustable rear perches along with their coilover rear springs in a 200lb rate.
We'll see.
They say the car will handle fine with the Sport springs in the front and the coilover springs in the rear

 

[Gabe]

The new adjustable perches and new springs showed up yesterday, hope to get them installed today and see what's up.

 

[quiksilver15]

Sweet! Post up how it goes. Hope it's the solution you're after.

 

[Gabe]

Sweet! Post up how it goes. Hope it's the solution you're after.

Thanks.
Got them installed today and so far so good.
Car sits about a half inch higher in the back, it gained a nice stance that makes me drool every time I look at it, and it drives a bit firmer but certainly not annoying, it handles great and so far seems that the rubbing is gone.
I need to do a bit more "testing" and put a couple hundred miles on the new set-up and see how the springs settle before I call it done.

The new stance as of a few minutes after the install:

 

[quiksilver15]

Looks good, nice raked stance.

 

[Pentalab]

The new springs might settle after a month, and it will sit slightly lower, so it may have to be re-tweaked slightly.

 

[Epic510]

Now I'm freaking out! I just bought some 20x10.5's. The 305-35 NT 555r's were shipped today. I am also on Steeda springs. The wheels I bought have a 45et so I'm hoping like hell thats gonna be the difference...

 

[Gabe]

Looks good, nice raked stance.

Thanks, I'm honestly surprised how much I like the new rake ... can't take my eyes off of it!

The new springs might settle after a month, and it will sit slightly lower, so it may have to be re-tweaked slightly.

Yes, I'm actually hoping to drive it again very soon, looking to put a couple/few hundred miles on it and then re-check and see what adjustments are needed

Now I'm freaking out! I just bought some 20x10.5's. The 305-35 NT 555r's were shipped today. I am also on Steeda springs. The wheels I bought have a 45et so I'm hoping like hell thats gonna be the difference...

You might end up being in the same boat.
The 10.5's are a half-inch (12.7mm) wider but that 45 offset only tucks the wheels inward 5mm more than mine, so they actually stick out ~7mm more than mine overall.
I was never a fan of 10.5"-width/45mm-offset set-ups ... the outside of the wheel ends up outside the fender, makes me wonder what the F are wheel manufacturers thinking?

 

[Gabe]

Some pics from the install of the perches and new springs.

The new springs are a must-have if doing these perches since they're quite a bit shorter allowing room for the perch:

Something good to know is that the new coilover springs are the same diameter as the Sport springs, so the Sport springs should certainly fit just fine on the adjustable perches, but they would most likely lift the car a bunch, even with the lower spring rate of 175 lbs VS the shorter spring's 200 lbs:

As far as the install itself, I removed the rubber lower spring seat, cleaned it up, and installed the perch and tightened it as much as I could (I set the torque wrench to 85 ft-lbs and it never got there, it just went from turning to a stop point - Steeda doesn't specify a torque spec).
Steeda says to grease the threads, I used anti-seize, and also applied anti-seize on the inside and bottom of the rubber spring seat to keep any rust from forming, then re-installed the round plastic cap from the stock perch to the top of the Steeda perch:

And how the new set-up looks once installed and set to the current setting that lifted the car a half-inch over where it sat with the Steeda Sport springs installed:

One slight issue I had was the driver side LCA relo bracket (CHE unit) gets in the way of the lower shock bolt, so I couldn't remove that bolt, I ended up removing the top nut and letting the axle droop down that way, with the shock still attached to it, then just had to be more careful when lifting the axle back into place, making sure that the shock shaft was going into its hole.


.

 

[KonaBlueBryar]

Thanks, I'm honestly surprised how much I like the new rake ... can't take my eyes off of it!




Yes, I'm actually hoping to drive it again very soon, looking to put a couple/few hundred miles on it and then re-check and see what adjustments are needed




You might end up being in the same boat.
The 10.5's are a half-inch (12.7mm) wider but that 45 offset only tucks the wheels inward 5mm more than mine, so they actually stick out ~7mm more than mine overall.
I was never a fan of 10.5"-width/45mm-offset set-ups ... the outside of the wheel ends up outside the fender, makes me wonder what the F are wheel manufacturers thinking?

Some people (me) like how that looks, with the right tire it seems absolutely flush and looks great. I'm not a fan of tucked wheels what so ever.

 

[oldVOR]

.

FYI, the adjustment collar is installed up-side-down (see image 9 of the install sheet). The shoulder on the collar is designed to keep the base of the spring from rubbing against the threaded shaft and ruining the threads. Also, you don't really need the rubber spring base gasket with the setup and you won't be able to install it with the collar facing the correct way.

 

[Gabe]

FYI, the adjustment collar is installed up-side-down (see image 9 of the install sheet). The shoulder on the collar is designed to keep the base of the spring from rubbing against the threaded shaft and ruining the threads. Also, you don't really need the rubber spring base gasket with the setup and you won't be able to install it with the collar facing the correct way.

Thanks for catching that.
What sucks is that they ship you the perches with the collar on them exactly the way I have them installed, in their picture on their web site they show them the same way, and one other picture you have to click on to actually see shows the collar installed with the shoulder upward and the spring around it, the spring kinda hiding that shoulder in the pic.

So I guess I'll be taking it apart, removing those rubber seats and flipping those collars upside down. yayyy ...

 

[Norm Peterson]

Dimensionally the rubber seats wouldn't be necessary, but I think I'd still keep them. Mostly for the NVH isolation (hearing gear noise better gets old after a while).


Norm

 

[Stetler17]

How does the adjustment sleeve attach to the reared perch?

 

[oldVOR]

There is a blind fastener that inserts into the rear-end perch and the threaded sleeve is tightened down to that blind fastener. Doesn't take much since weight on the spring will keep it all together and the shocks keep it from over extension so that nothing falls out.