Suspension Wallow Blues

Porpoising! There's the term I needed all along! The cyclical loading and unloading is exactly what I think is happening. I just didn't want to believe that the brand new GR2s that many on the forums seem to love could offer so little suspension control.

I considered trying a couple of used tires on the front to see what happens, but the selection of used 14"s is limited, to put it mildly. Also, inflating from 35 to 50+psi didn't really change anything. On the other hand, it would just be my luck and poor judgement to spend $375 to replace new shocks only to find that tire are the culprit.
 
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Porpoising! There's the term I needed all along! The cyclical loading and unloading is exactly what I think is happening. I just didn't want to believe that the brand new GR2s that many on the forums seem to love could offer so little suspension control.

I considered trying a couple of used tires on the front to see what happens, but the selection of used 14"s is limited, to put it mildly. Also, inflating from 35 to 50+psi didn't really change anything. On the other hand, it would just be my luck and poor judgement to spend $375 to replace new shocks only to find that tire are the culprit.
 
I just realized you are using a 260# spring. That's a really, really, really soft spring. I think you should step up to something ~#500 and used the Bilstiens. It won't be harsh at all. Maier Racing can set you up with both (if you are on the west coast or Street or Track for the east coast).
 
My "GT" springs are the Grab-a-Trak branded coils sold by Mustangs Plus as GT/GT 350 springs and by Mustangs Unlimited as Grab-a-Trak 480lb. MU says they are a 480 lb spring, but since I got 'em I see that M+ calls it a replacement for GT/Shelby springs. OpenTracker Racing recommended them as a match for 4-1/2 leaf rears, though I went for 4-leafs in silly fear of ride harshness. I dunno. I probably should have gotten out of the resto parts catalogs and went with Eaton or Maier or some such company.

For now, ride comfort is still a bigger concern than handling for me and I'm choking when it comes to spending money to replace new parts. That, and I cringe at the thought of going through another front spring change/ride height adjust/alignment episode! I believe I should be able to make this thing handle satisfactorily without going stiffer. I do regret not going 4-1/2 leaf in the rear, though.
 
Not sure why this could/would be true. The rear axle is heavy, it's unsprung, and it's not geometrically constrained to minimize movement laterally or to rotate around a specific location. Adding a sway bar does not solve this problem. If the rear springs are old and the rear has more lateral motion when cornering, it's a magnified demonstration of the design issue. Tightening up the front suspension can also magnify this issue. Anyone that's stuck a watts under their car has talked it up and down as to the improvements. The Panhard does something very similar but is a little less expensive and leaves more room for exhaust, etc...

I might be taking this too a little too much of an extreme for what the OP is looking for in improvements, but my car is destined for a watts, sooner than later I hope.

a panhard bar is not going to be that effective with the early style leaf spring suspensions, unless the leafs have some serious side flexing, and then you have other issues. a rear anti roll bar will do most of what a panhard bar will do in the rear, as well as limiting rear body roll.
 
a watts linkage will stop any side flexing .but it will not stop body lift in a corner
and thats what usualy causes body roll and even porpoising,wallowing in a turn ,especialy if the shocks are to soft to keep the body under an even load ,the sway bar takes care of that ,along with the shocks.
 
The Watts allows you to adjust the roll center and and since the roll center and lateral motion are now fully controlled you don't need a sway bar in the rear, nor do you need high spring rates and heavy duty shocks to get the car to handle well on the street. I'd use a rear sway bar as a last resort.

a watts linkage will stop any side flexing .but it will not stop body lift in a corner
and thats what usualy causes body roll and even porpoising,wallowing in a turn ,especialy if the shocks are to soft to keep the body under an even load ,the sway bar takes care of that ,along with the shocks.
 
480# is cool. My mistake. I thought you were using the GT springs M+ lists on their site. 260#
http://www.mustangsplus.com/catalog/suspension_10.pdf

Not sure what to make of it now. The MU catalog list the same part number at 480lb. I got 'em through OpenTracker and I don't remember where they shipped from (not that it matters, since they appear to be the same part).
http://www.mustangsunlimited.com/itemdy00.asp?T1=GT2670 01

Anyhow, they seemed pretty stiff when I was fighting them onto the car! At least a *lot* stiffer than the saggy junk I took off. I haven't installed new springs in anything in a long time and don't really have a frame of reference. I have a Stang-restoring uncle nearby who probably has a car or two around with new standard V8 springs. Maybe I'll go over and bounce on his fenders for comparisons sake.

Does anyone know who actually makes the Grab-a-Trak branded springs? I can't find anything online.
 
You can't really tell by pushing on the fender, because the shocks low speed valving comes into play. I guess you could unbolt the top of the shocks and leave the hood open. When you hit the brakes, does your car take a nose dive?
 
The Watts allows you to adjust the roll center and and since the roll center and lateral motion are now fully controlled you don't need a sway bar in the rear, nor do you need high spring rates and heavy duty shocks to get the car to handle well on the street. I'd use a rear sway bar as a last resort.

a watts link does not allow you adjust the roll center, it sets the roll center. and it does NOT control body roll either, it merely centers the rear axle under the body and keeps it there. panhard bars and watts links are not needed on a leaf spring car unless the leafs are in very bad shape. panhard bars and watts links are used on four link and three link suspensions because those suspensions do not control the side to side movement of the rear end like a leaf spring does.
 
Roll centers have a pretty strong relation to body roll. As a matter of fact, when they equal cg height, you don't get any. Can't get much more roll control than that(not that you'd want it that way).

And a watts link defines the Roll Center, so if you can move the watts link, other things move as well...
 
Greatly simplified, there are two schools of thought on suspensions (ignoring the more exotic options): Lots of spring, less shock and less sway-bar vs less spring, more shock and more sway bar. For our old-school rears, this would be:

1. 5-leaf springs, poly or Del-alum bushings, HD shackles, softer valved shocks, or
2. 4-leaf (or 4 1/2) springs, traction bar, 3/4" sway-bar, poly or Del-alum bushings, HD shackles, stiff valved shocks
Note: the Bilstein progressive shocks sound nice for either on the street.

Both control body roll, but "2" yields a softer ride. Sometimes you can see the two in action in a Nextel Cup race. The softer spring set-ups will cause the car's chin to dip down and scrape the track surface with relatively small track elevation changes. The stiffer set-ups will resist that. BTW, teams win with both set-ups and controversy remains about which is superior.

The fronts follow a similar theme - softer springs, more shock, more sway bar vs. more spring, less shock, less sway bar.

Upper control arm lowering is good for both up front.

Here's the real takeaway message: If you mix stiff springs with stiff shocks and lots of sway bar, you will by very unhappy on the street. Since you are starting with softer springs, then you should be looking at more shock and sway bar. If you make enough power to generate wheel hop, then traction bars on the rear will help - they also help reduce body roll some.

Tires considerations have been covered. Less sidewall will help with that wallering.

FYI, I run -1/2 degree camber, as much caster as I can get, and 1/16 toe-in with 1" lowered A-arm. Your alignment sounded similar. I agree that caster is tough to get. I have double-adjustable upper A-arm and adjustable strut rods to achieve as much as feasible.

Good luck figuring out what to do. You surely have enough advice in this thread ....
 
If you look at the Fays2, you'll see it's adjustable. As far as body roll, someone else responded to that.

These devices were probably developed for leaf spring cars.

a watts link does not allow you adjust the roll center, it sets the roll center. and it does NOT control body roll either, it merely centers the rear axle under the body and keeps it there. panhard bars and watts links are not needed on a leaf spring car unless the leafs are in very bad shape. panhard bars and watts links are used on four link and three link suspensions because those suspensions do not control the side to side movement of the rear end like a leaf spring does.
 
The GR2s are closer to a stock shock than they want you to believe. If you want a cheap shock that is stiffer and a little more responsive, try the Gas-A-Justs. They are a high pressure shock vs the low pressure GR2. I put them up front (along with a couple other things) and they greatly helped reduce the body roll and understeer I was getting. I'm sure the nicer adjustable shocks from Koni and the like are great choices. But since I'm building a daily driver, I just didn't want to spend that kind of money on just shocks. I need that money elsewhere. So I put the Gas-A-Justs up front and the GR2s in the back and I'm more than happy.
 
I hear a lot of talk about the harshness of the Gas-a-Justs. Did you replace another shock with them? What do you think about the ride quality? I've been thinking about trying a pair up front as an attempt at a temporary fix while I spend money on other ongoing projects.
 
I hear a lot of talk about the harshness of the Gas-a-Justs. Did you replace another shock with them? What do you think about the ride quality? I've been thinking about trying a pair up front as an attempt at a temporary fix while I spend money on other ongoing projects.
I first replaced the broken shocks that were on it with some cheapo Monroe ones from Advance. But it was like they weren't even there. If I took a corner more than 25mph the front end would plow through it. And so much body roll I thought I was going to fall out of the door. So I junked em and put on the Gas-A-Justs. I thought they might be too stiff for the back, so I put the GR2s back there. But they are excellent for the front. There's so much weight up there you really need something stiff. (either shocks or springs) I have stock springs so these really helped stiffen it up. I also put on a monte carlo bar at the same time and now I can hug corners until the tires loose grip without worrying about the body roll. They're not too stiff for everyday driving either. When I go over speed bumps the car still has enough travel to absorb the bump. I don't think you can beat these shocks for the money. I got Advance to price match Rockauto and paid about half price for them.
 
i have used the gas-adjust shocks on all four corners on a fairmont, and they were not too stiff at all. in fact the ride was just as good, if not slightly better than the factory shocks and struts.