In the same way that moving weight off the inside wheel onto the outside wheel reduces total grip for cornering, wouldn't that also affect total grip for acceleration? The trac-loc may keep the inside from spinning, but is the total ability of both rear tires to put power down reduced? Again, I'm not sure how bar vs stiffer springs actually makes a difference there, but people who know more than me seem to think it does...
bravenrace wrote: One behavior I have noticed is that sometimes the rear will hop in a corner, and not because of a bump. It seems to do it most when powering out of a corner. It almost seems like it should be breaking loose,but instead hops and then grips again.
If you can replicate this easily, remove the rear bar then try it again. I've seen several Autox cars do this with "too much" rear bar, but otherwise feel fine.
in OP case... you would adjust on the rear....
bravenrace said: can you think of a reason that on a car that exhibits understeer in stock form and has a front anti-sway bar,
As hungry bill stated... if the springs are too soft, the front bar will "stiffen" the front end.
sway bars... are just part of the total package (nothing new here) and used properly... help fine tune the balance.
In reply to oldeskewltoy:
Except 650 lb/in springs on this car are not even close to being soft.
bravenrace wrote: In reply to oldeskewltoy: Except 650 lb/in springs on this car are not even close to being soft.
I saw that... what I was doing is responding to what you initially wrote....
650#/in isn't that extreme... I know of a few Corollas(2000# or less) that use spring rates in that area(around 12kg/mm).... many of these Corollas will run rear rates of 490#s(9kg/mm) or greater.
What are your rear rates???
Having owned a few Mustangs myself (LOOOONG time ago)....... It is a challenge to get then to handle well.
I know what you mean, as I have 500's on the rear of my CRX, but for vintage mustangs driven on the street it's about as stiff as you can get. They may even be a little more than that since they were trim to fit springs and I cut better than a coil off them. Most guys run 450-500 on these cars with small blocks. Its too stiff for me actually. But I'm working on designing a coil over setup for the front, so I'm not inclined to change the rate until I'm done with that. The rears are 5 leaf, 180lb/in. Again, most guys run 120-150 in the rear.
What prompted my question in the first place was that I always wondered why vintage mustang guys tend to shun rear bars when mine handles pretty well for an old car, and that I may need to remove it to do some other things.
I'm inclined to disconnect it and see what effect it has. But I'm also inclined to at some point start from scratch and go with a complete Cobra Automotive suspension, since they've been racing these things for years and I've seen how fast their cars are. And they do it all without totally re-engineering the suspension with high dollar bits and a coil over rear.
I'm confused by the comparison of spring rates across different cars...
What's the motion ratio on the Mustang, Corolla, or CRX? Isn't the Corolla mac strut? That's the only one where spring rate ~= wheel rate... 650 lb/in springs mounted halfway out the arm is 162.5 lb/in wheel rate, while 3/4 of the way out (from inboard pivot to ball joint) is ~366 lb/in...
I don't know off the top of my head, but I do know that even for track use, almost nobody uses spring rates as high as mine on a vintage mustang with a stock configuration suspension. When I bought it it wallowed all over the place, and I went a little overboard on trying to tighten it up. I've known this all along, but just haven't taken the time, effort or money to change it. It does handle well though, and corners as flat as a new Mustang GT.
TL;DR
I skimmed through, but with every car it can be different variables as to why it is under/oversteering. You need to identify exactly what is creating the inherent loss of traction and counter act that. So here are a few questions to ask then identify the answers...
Understeer:
What is the cars weight balance? Is it front heavy?
After considering all of those things, then start looking at the rear of the car. Every car needs to turn right? So make sure the front is setup properly from the beginning then look at keeping traction out back. and apply most of the same questions to oversteering issues.
Most likely if your car is oversteering You don't want to take away front grip to equal it out, so you are going to fix it with either softer springs, sway bars, adjusting camber, more toe in, wider tires (or skinnier front tire if class restrictions limit you) adjusting weight, adjust ride height to keep off the bumpstops and or add rear aero!
That's my 2 cents anyway!
I replied to your post first with a short answer. Now that I have seen what others have posted I would have to say that you should use alignment settings and spring rates to get close to the kind of handling you desire then use sway bars to fine tune it or change it as desired or needed.
The 1st gen Mustangs can be made to handle, most of the mods you may already have done such as relocation of the front upper control arm mounting points.
A rear sway bar allows quicker response to direction changes without having to resort to stiff springs that could result in a rough ride or poor handling on rough roads.
Any suspension set up is a compromise, very high spring rates will work great in a smooth race track but suck on the street.
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