Author Topic: leaf spring traction  (Read 104 times)

Offline lightning boy

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leaf spring traction
« on: May 09, 2024, 05:16:30 AM »
Since my Qjet is so awesome, nailing it with the big blades in the back is kinda like a nitrous shot. Seriously though, I'm tired of spinning the tires. Does anyone have any tips on making a leaf spring car hook? 69 Camaro with 255/60/15 tires. Any recommendations, shocks, slapper bars, cal-track bars? looking for something that doesn't hang down too low, I don't want to get hung on my driveway!

Offline Mudsport96

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Re: leaf spring traction
« Reply #1 on: May 09, 2024, 06:44:25 AM »
I run Lakewood slappers on my Nova and they work great. Granted it is like 300hp so your results may be different. 
Guy I work with has a set of bars that bolt on like slappers, but the front clamp to the leafs behind the front spring eye and he has zero traction issues..... here is a picture of his Z
All motor goes 8s in the 1/4.

Offline Mudsport96

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Re: leaf spring traction
« Reply #2 on: May 09, 2024, 06:49:59 AM »
You could also look into the "factory" radius rod traction bars

http://www.camaros.org/radiusrod.shtml#problem

Offline Cliff Ruggles

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Re: leaf spring traction
« Reply #3 on: May 10, 2024, 05:03:54 AM »
You do NOT need bars of any kind, most look like chit anyhow.

I won the Pontiac Nat's 5 times with two trips to the King of the Hill Race (last man standing) without any kind of traction bars.

First order of business is to weld the axle tubes to the carrier. 

Get some good tires.

Install sub-frame connectors and box/weld them in place instead of bolting them in.

Fabricate an adjustable pinion snubber to control the upward travel of the differential with good traction.  I simply modified mine by making a bracket and shims for it.

I would also recommend having a good driveshaft made with 1350 Brute Force U joints in it.  Billet yoke on the diff and slip joint for the drive shaft even better.

I like and use Chrysler SS leaf springs on my GM cars but you can get away with making clamps to stiffen up the front sections of stock springs if they are in good shape.  It's also a good idea to drill thru the stack of springs and replace the whimpy little bolts with 7/16 or even 1/2 grade 8 bolts that hold the stack of springs together.  Double check the welds on you leaf spring perches.  I've yanked them off the tubes a few times so just make it a habit of reinforcing those welds while I'm setting up the diff.

Replace the factory posi unit with a good clutch type. The Eaton unit is excellent.  The factory "S" and other type posi units are weak and spider gear breakage is going to happen, IF you are making any kind of power at all and find good traction.

Mosier axles are also a nice upgrade.  I prefer the bolt in variety vs the "C" clip versions.

I know all of this sounds like "over-kill", but at the end of the day you will be able to "hit" the suspension with full power, hook hard and lift the front of the vehicle without twisting the chit out of the chassis or breaking something.

WAY back in the late 1990's I starting taking steps to make my 73 Ventura faster at the track.  I broke EVERYTHING behind the engine a couple of times before doing what is described above. 

Once all that was up to par I went another 25 years and broke nothing, even hitting it with over 600ft lbs torque and running 1.5 60' times. 

The best part about all of it is that there are no visible traction devices.  Bars look like chit on those leaf spring cars and not nearly effective at controlling diff "wind-up" as simply stopping the upper travel of the diff at the source instead of trying to do it out on the axle tubes........hope this helps some......

Offline lightning boy

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Re: leaf spring traction
« Reply #4 on: May 14, 2024, 04:39:30 AM »
Really excellent points. Thanks for the advice. Do you happen to have a pic of the pinion snubber you made?