I have been watching "South Eastern Gasser Drags" on U-Tube. Most cars I see don't show much clearance between rear fender/quarter panel & rear wheel/tire sitting static. When you watch the "launch" there's not much movement between the two. Why invest buko bucks into a rear suspension, weather it be Leafs, coils, ladders, slappers, etc. if the rear isn't showing any range of motion? Why not just welder up solid, I don't see a bunch of weight transfer to the rear?
Well here's my rear tire clearance: The '39 is leaf springs with ladder bars, and the Austin is coilovers with ladder bars. On both cars I have urethane adjustable bump stops so it limits travel before tires can contact the fenders. I really dislike seeing huge gaps above rear tires, but also don't want to not have enough travel to make the ride harsh. So this allows enough for most small bumps, yet stops damage from big bumps also. At the drags it limits travel at launch and helps let the tires hook up having some travel, but not so much as to get into wheel hop. But even solid mounted axles can have wheel hop on cars with lots of power, so that's why they have some suspension to help it.
A properly set up 4 link or ladder bar set up helps push the slicks to the pavement at launch so the tire gap to fender would increase at launch, bumps are another problem I'm reading the SEGA gasser rules while building mine, they do have rules limiting rear suspension set ups, note: one says the car has to have 4 working shocks, if you plan on running with them it's worth taking time to read them before you weld
Your assessment is correct. Most nostalgia gassers are set up with too stiff suspension. To look "period correct" the tires need to stick out beyond the fenders, with wheel well openings near the tire tread. If it is sprung stiffly it will cover up some of those period correct suspension shortcomings. Like too high and too short of an instant center. To function at it's best, you can make a modern Pro Mod style of suspension, with rear tires tucked in, an adjustable 4-link suspension with anti-roll control, coil-over adjustable shocks, and a softer spring rate. And wheelie bars. So then it becomes a choice between the best (read: modern) suspension to win the most rounds, or a period correct suspension to accurately recreate the Golden Age of the gasser wars. Some folks want to win races. Others want to capture the true essence of nostalgia cars. Giving careful consideration to what you want to achieve with your build will guide you as to how to make the rear suspension. Even as I am writing this there are probably six guys responding, saying they have true nostalgic old school rear suspensions and they win a lot of races. Maybe so if you are racing other period correct cars. But a nostalgic looking car with a modern Super/Gas suspension will prevail more often. If you're in a dogfight in a biplane against other biplanes sure, the best pilot will usually prevail. But stack your biplane up against a WW II warbird and you be in a heap o' trouble. Do you catch my drift?
I be one of the six. The wheel opening clearance [gap] doesn't mean anything; as long as the tire is compressed into the pavement to gain traction is what matters. Plus the new tires do bite way better than the old so the suspension may not have to do that awful much?
Many old school gassers with stiff suspension have installed ladder bars while keeping axle pads and U bolts in place, the suspension binds with stiff limited travel, but it works Replaced the spring pads with Jegs sliders, to allow the ladder bar to go through its ark.
A torsion bar (swaybar) is just that. It eliminates sway and not just for cornering. At high speeds should a car get a little squirrelly the swaybar helps to stabilize the body so it doesn't start rolling back and forth and helps control the body roll. It is used more on very fast cars at the drags, and might not be needed as much for slower cars. For the street it's just like any car that uses or needs a swaybar to help handling on twisty roads.
It also helps distribute the weight on both rear slicks evenly on launch, minimizing axle twist and keeping the car straight, much to the dismay of some fans in the stands who like seeing the right front tire near the asphalt and the left front a foot higher in the air. Its another choice that boils down to showmanship-vs-sixty foot repeatability. With a ladder bar equipped car that has securely welded on ladder bar mounting points a sway bar is largely redundant, since the entire rear axle housing becomes in effect, a sway bar, unlike with a 4-link where the rear axle is free to rotate about the chassis centerline axis unless it is constrained by a sway bar.
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