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Author Topic:   stock trailing ams on a modified
posted February 11, 2001 07:05 PM
The car you saw Ron Jones running with stock trailing arms was almost certainly a Wissota car. Until 1996, the Wissota cars had to run rear ends mounted in thier stock locations, either with leafs or coils. If it was a coil car, that meant stock length arms and chassis mounting locations. Back then, Ron was running almost exclusively Wissota shows, going to USMS the following year. Since Wissota opened up the rules for rear suspensions, a few guys have tried to run their old stock 4-links only to have thier a$$es handed to them, so now anyone who's even remotely competitive has something else back there.
Quite frankly, the biggest reason Ron Jones was fast with that car was that he's just that much better a driver then most everyone else. There was an article in Circle Track magazine about him 3 or 4 years ago that said, at that time, that he'd won over 50% of the races he'd ever entered. That's gotta say something, and anyone who's ever shared a track with him would probably agree.


posted February 15, 2001 06:45 PM
Well, as in most instances, there are a few exceptions to the rule. You have to admit that most of the guys who tried to run the old 4-links didn't have the same success as the likes of Nelson and Boyce, which only goes to support the point of my earlier post; that it takes a real driver to make a winning car out of something so inherently handicapped as the GM 4-link.
Granted, it's a simple design, which in itself has it's merits, but there are other designs just as simple that would perform much better for the weekend warrior-type driver, ie: 3-link pullbar/liftbar set-ups.
The basic downfall of the 4-link has to do with it's inherent bind of the upper links. They're mounted at 45 degrees to the axle tube and perpendicular to each other, which, when swung through thier arcs will have the trailing ends of them moving away from one another. So we mount them in rubber.. but they're's a limit to how much the deflection of the rubber will allow. Some of the bind is gone, but for the most part it's still there. This bind, cushioned through rubber will change the spring rate of the rear end of the car as it moves through travel, but it won't be a linear change, it will be a very inconsistent change as the rubber wears. Even in the most ideal conditions, this rate change will be goemetrically disproportionate to the actions of the springs themselves, bringing about erratic handling characteristics that are not easily remedied by what most of us would consider conventional measures.
I think the real key is seat time. Jones, Nelson, and Boyce have all been racing nearly since the advent of internal combustion. They already know a wealth of tricks that most of the rest of us would take years to figure out for ourselves. Further, unless you were to have one of these guys build you a car themselves, I'd think finding chassis builder support to help anyone running a 4-link car would be virtually impossible because I'd bet my own car that no builder could confidently advise anyone on how to beat the likes of Jones, Nelson, etc. with one of them. That's why my best advice would definitely be to run something else...there are a lot of simple ideas out there, and they're winning a lot more races than the 4-links.


posted March 22, 2001 11:06 PM           
Originally posted by ss11:
I was wondering if anyone had ran stock trailing arms on a modified and what you think about it. I know Ron Jones ran them a few years ago and done quite well.

The Limited Modifieds in the Houston Area are required to run this factory Metric setup, I am curious to any advice for this rear susp set-up. I know there are lots of Limited Modified drivers who would jump at anything to help these car handle and hook better.


posted March 23, 2001 09:05 AM
If you have to run them, that's a different story. Look hard at your rules, and see if they specify what angles your arms have to be, and if you're allowed to switch rear end housings. Our rules for street stocks back in the day used to state that the mounts had to be in the stock locations, but that we could change rear end housings. If we changed housings we had to build new mounts on it so we'd build them such that would allow for correcting the angles.

We always ran the lowers level, for purposes of keeping rear steer to a minimum, but since then I've decided that there might be a little more to be gained by running 2 or 3 degrees upward angle in them. We used to cut the stock mounts off the old rear ends and use those for the new ones, keeping the ride hieghts the same and saving a lot of fabrication time.

We had to run the stock upper arms, so when it came to the mounts we'd build them out of 1/2" plate and make a big hole in which to tack weld a stock trailing arm bushing. If you're not required to run the stock arms but have to run the stock lengths, by all means run tube arms with hiems on them, but you'll need rubber at one end of them (preferrably the chassis end) to allow for the bind I mentioned in the earlier post. Build your mounts off the rear end accordingly for the use of hiem ends.
The upper mounts at the rear end were built to mount the bars at 15 degrees downward. There were also a lot of guys who'd mount the left side at 20 degrees to give them a little more left side bite, but I never tried it myself. The reason for the increased angle in the uppers was because as the rear end wraps under acceleration load, the upper bars will try and straighten themselves which will increase the downward thrust of the axle. With the lower arms level we could never actually make the car lift under throttle, but it didn't squat half as much as it used to before we could change the uppers. This is why I'd consider adding some angle to the lowers. If you can get the rear end to lift the car, you're going to drive the tires into the track harder on initial acceleration; and also raise the rear CG, allowing for more wieght transfer to the rear.

Hope it helps,

posted March 23, 2001 10:47 AM
Matt is right about his angles, I run one of these cars right now as a limited mod. He is also right about angling the lowers up. Make the mounts on the rearend as low as they can go before they will hit the ground in the event of a flat tire. That in our experiences is the best. We have tried to even more in by raising the mount on the chassis but it was not as effective. I raced all last year against cars that are brand new and once we got dialed in we could compete with anybody. The place where these cars have troubles especially in the big motored class compared to the open cars is when you get on the tighter tracks where it is much tougher to keep the corner speed. Just my two cents.