G-Body Steering Upgrade – How to Fix Bump Steer
How To Fix The Steering and Bump Steer On Your G-Body
After Car Craft upgraded the suspension on their G-Body Wagon project dubbed MalibuST, they wanted to upgrade the steering as well. The suspension and steering work hand in hand to make a great handling car and both should be upgraded to achieve the max performance out of either system. UMI Performance make a bump steer kit for the G-Body that virtually eliminates any bump steer in the steering. Read along below for the full install!
Malibu G-body Steering Upgrade for the Street and Track by Jesse Kiser
Steering is usually an afterthought when building a project car. In our last MalibuST installment we assembled the UMI Performance Stage 3.5 handling kit and Wilwood brakes. If we left the 38-year-old steering alone, it would significantly limit the car’s potential. A performance handling car requires precise steering, and in this installment, we upgrade the G-body steering system for $1,600 and zero fabrication.
Our combination of parts includes a Turn One Steering Saginaw 600 steering box (PN: T12BASE; $799.00), Turn One Steering C5/C6 Power Steering Pump with billet pulley and upgraded AN fitting (PN: T40Y, TUR7, TUR12; $470.00), Classic Performance Products inner tie rods and center link (PN: DS909, ES2034L; $148.00), Red Line Oil power steering fluid (PN: 30404; $11.95), and UMI Performance Bump Steer Kit (PN: 3060; $179.99). This combination of parts results in improved adjustability, overall better performance, and a total of $1,607.94.
A basic G-body rack-and-pinion conversion retails for as little as $1,600 and requires some fabrication skills. Instead, we opted to retain the OE front-steer steering-box layout for its ease of installation and the ability to build a more performance-oriented steering system for the same dollar amount. The G-body never featured a rack-and-pinion, so some steering experts stress the difficulty in matching the perfect rack for the car.
“You can do it, but you’re stuck with whatever the rack-and-pinion is,” says Jeff ‘Junior’ Roethlisberger, VP of operations at Turn One Steering. “You only have a small window to adjust, but with a steering box you can adjust the feel and ratio without spending thousands.”
Our new Vortech LS-Swap supercharger system requires a Corvette C5/C6 front accessory drive and matching power steering pump. Rather than sourcing an OEM pump for a rebuild ($160 new, plus $150 rebuild service), we opted for a new Turn One Steering C5/C6 pump, which comes custom built to match our needs.
Fixing Bump Steer
The UMI Performance bump-steer kit includes everything we need to adjust bump steer on the stock G-body steering system. The science behind bump steer can be complicated. When you hit a bump, and the wheels turn without your input, that’s bump steer, and it’s bad. Bump steer is a change in toe during wheel travel. “For manufacturers, packaging is a priority, not optimizing bump steer,” said UMI Performance’s performance engineer, Ramey Womer. Bump steer often becomes worse when you lower ride height or increase caster, two things we did in our last installment.
Bump steer geometry is illustrated in the following way: if you face the front of the car and draw invisible lines through each individual suspension pivot point, they meet at the car’s instant center. This complex theory is reserved for chassis builders. Ideally, your steering arm should move on the same plane/angle as the suspension’s instant center, during wheel travel. What a bump-steer kit does is allows you to adjust the steering rod-end height to best match the lower control arm’s originally geometry, making this complex theory simple for you and me. It’s the best method of fixing most of the bump steer trouble, next to redesigning the chassis. You can read more on the science of bump steer here.
