Whether for on-track duty or simply improved street performance, the E30 series cars have proven to respond to well-chosen upgrades. The CarTech BMW 3-Series Performance Guide offers current and future owners a wealth of important information, including a buyer's guide, year-by-year upgrades and changes, and more. This book is a valuable addition to every BMW owner's library, and Pelican is proud to present you with the excerpt below.
The E30 steering system is like that of most cars from its era, a light, efficient steering rack with socket type inner tie-rod ends and standard outer tie-rod ends. All US-sold E30s came with power steering (in Europe and other markets the car was available with a manual steering rack). The stock steering is a rather slow 20.5:1 ratio, with more than four turns lock-to-lock. By modern standards (and for any competition use) that is too slow. However, it so happens that the E30 rack is interchangeable with many later BMW steering racks from the E36 and E46 cars.
The fastest of these, depending on source, is the Z4M coupe rack, at 12.8:1. The Z3 1.9-liter rack is also very fast and has a linear ratio (the ratio does not change as you turn the wheel, as the early E36 M3 rack does). The E46 330i rack is another popular choice, with a fast ratio and less than three turns lock-to-lock. The E36 rack is almost a direct replacement for the E30 rack (as is the E46 rack, although it needs to have E36 tie-rod ends to work properly). The rack-mounting tabs are a little thinner than the E36 tabs; the input shaft on the rack is longer than the E30 shaft. The Z4M rack is longer yet. Each case requires you to shorten the factory steering shaft with its two U-joints.
The lower U-joint likely has to be clearanced to allow more articulation because of the greater angle between the new longer steering rack input shaft and the factory steering shaft. Otherwise the U-joint may bind.
There are two ways to remove an E30 steering rack: the right way and the "cheater" way. The problem with removing the steering rack is the clearance between the oil pan, and the rack is too tight to simply un-bolt the rack and pull it out. The right way is to un-bolt the left engine mount and use a jack with a block of wood between the jack pad and the oil pan to lift the engine an inch or two. Check very carefully for any wires that get pulled when you do this and make sure that the exhaust is not being stressed.
The cheater way is to simply bend down the two lower mounting tabs on the subframe to pull the rack out. The tabs are steel and rather flimsy (the rack is located by the upper tabs and these serve only to reinforce the mounting). When the new rack is in place, bend the tabs back into place with a block of wood or a rubber mallet. The downside of this method is that it introduces the risk of damage to the tabs, which can crack or tear. This is not likely, however, and many people have successfully changed their steering rack this way.
Although all E30s were shipped to the United States with power steering, some people prefer the lighter weight, simplicity, and better feel of manual-steering setups. The factory power rack can be disconnected from power and works just the same as a manual rack. You simply loop together the power steering inlet and outlet lines and fill them with fluid to keep the power part of the rack lubricated.
The easiest way to fit an E36 rack is by removing the two collapsible rivets, adding spacers, and replacing them with bolts. This does eliminate the collapsible function of the factory shaft (the shaft shown here is connected to a stock E30 rack). (Photo Courtesy Ryan Gangemi)
An alternative to the stock E30 steering shaft and its two rubber bushings is to buy two 17-mm x 54 spline U-joints with one 3/4 DD end (available from Flaming River) and a short length of 3/4 DD steering shaft. (Photo Courtesy Vorshlag Motorsports)
Vorshlag's E30 shaft has a collapsible feature similar to the stock steering shaft and eliminates the rubber couplings. (Photo Courtesy Vorshlag Motorsports)