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| This set of tubes link the TRZ anti-roll bar to the rear end housing. One set of links is mounted on each end of the housing. TRZ includes chrome moly rod ends and grade 8 fasteners with the kit. Don’t be afraid to use them. Unless you make a chassis ride height or four-link change, the stabilizer bar should require only occasional inspection. From time to time, check for neutral adjustment by rotating the links and feeling for tension. Remember that this must be done on flat, level ground. Every stabilizer bar should be mounted on bushings to prevent binding. Lubricate the moving parts during your routine maintenance procedures (each bushing on the TRZ bar is equipped with a Zerk fitting). | |
Rear End Torque Rotation…
Bickel points out that the rear end gears turn the driveline power 90-degrees to the axles, but create rear end torque rotation in doing so. Why? Simple. The inertia of the car resists rotation of the wheels, axles, spool and ring gear. The resistance causes the pinion gear to impart rotational force to the rear end housing. Confused? Bickel suggests we think of it this way: “Imagine that the driveshaft is connecting to a rear facing airplane propeller. As the driveshaft rotates clockwise (viewed from the front), the propeller rotates in the same direction. Like an airplane propeller, a racecar rear end torque-rotates in the same direction as the driveshaft.”
What this rear end torque rotation does is it tends to increase the traction of the left rear wheel and decreases traction to the right rear wheel. Without a correction, this torque rotation will push the car to the right upon acceleration.
Bickel notes that chassis roll due exclusively to engine torque is equal and opposite that of rear end torque reaction. According to Jerry, a completely rigid chassis allows these two forces to counteract one another, and the car can accelerate straight down the track. The chassis is the connecting “link” that must be as rigid as possible to efficiently transmit these opposing twisting forces. Some racers argue that the chassis must be flexible to absorb some of the force and to comply with track irregularities.
Bickel opposes the flexi-flier approach: “I disagree with the flexible chassis concept because the degree of flex cannot be adjusted. Unless you want to try to build a different car for every track, it is my view that a chassis should be designed for maximum rigidity. Spring and shock rates can be adjusted to tune the chassis and to compensate for track irregularities.”
Controlling The Roll…
One way to control chassis roll is to install extremely stiff coil springs. Another common approach used in the past and still rather common today is to install an air bag or two in the back springs (stock spring applications). This approach may limit roll, but it creates a very rigid suspension system that cannot comply with racetrack irregularities. If you have a high horsepower car with a four-link suspension or with coil rear springs, the chassis builders we polled all recommend the installation of a rear stabilizer bar (sway bar). The bar adds a considerable amount of roll resistance without affecting normal movement of the suspension system.
Solutions For The Little Guy…
So what if you have small tire, stock mounting point suspension arrangement car and you’re trying to make it hook? We were faced with the exact situation on our Buick Regal, and we needed a bar designed for the application. It certainly isn’t a Pro Stock car, but it sure does have plenty of rotation out back. Enter TRZ Motorsports. Todd Braasch and company manufactures such a bar that welds between the stock frame rails.
The TRZ stabilizer bar (shown in the accompanying photos) is a chrome-moly tube that pivots on bronze bushings captured within the end brackets. Like other configurations, it connects to the rear end through attaching levers and links fitted with rod ends. Meanwhile the stabilizer bar itself is bolted to a tubular chrome moly cross brace that welds between the respective frame rails. On straight up and down suspension travel (no chassis roll), the attaching levers move together. The stabilizer bar simply rotates on the bushings and suspension movement is unaffected. Chassis roll, on the other hand, causes the links to pull the attaching levers into different angles, which, in effect, twists the stabilizer bar. The bar resists this twist and chassis-rolling force is delivered directly into the rear end housing.
Now you’ll find the anomalous doubter claim that a stabilizer bar is nothing more than a crutch for a poorly setup suspension system. Opinions from the pros opinions are far different than those of the odd drag strip “rail bird”. According to Bickel, Cathey and Braasch, virtually every high horsepower car to which they’ve added a rear stabilizer bar has demonstrated improved launch characteristics and lower 60-foot times. On a similar note, Pro Designs’ Cathey suggests that all rear axles (stock or modified) be fortified with a simple performance type anti-sway or stabilizer bar. Aside from improving handling, the traditional Detroit-style of sway bar helps to spread and transmit the torque loads more equally. The end result is a rear suspension-rear axle assembly that isn't bending, twisting or breaking. Instead, it maintains rigidity and yes, a corner-carving component can actually help your car go quicker and faster down the straight and narrow. That’s certainly food for thought if you have a high horsepower street, street-strip or all out drag car and it seems to go every which way but straight when you dish out the grunt.
FYI, in our initial look at anti-roll bars, we’ll take a close look at the hardware. Next issue, we’ll examine the installation of a TRZ system at LeJeune Performance. Stay tuned.
Sources |
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Jerry Bickel Race Cars 141 Raceway Park Drive Moscow Mills, MO 63362 PH: 636-356-4727 |
Lejeune Performance & Fabrication 201-1492 ADMIRALS RD. VICTORIA, B.C., V9A 2R1 PH: 250-381-4513 |
Pro Designs Pleasant Grove, AR |
TRZ Motorsports Division of Southside Motorsport Technology Inc 2450 Smith St Kissimmee, FL 34744 PH: 407-933-7385 |