An E30 M-Tech 1 steering wheel.
One of the biggest weaknesses of the E30 3-series is its steering. Needing 4 full turns lock-to-lock, and a far too leisurely 36.5mm per turn (the amount of wheel movement per 360 degrees of steering input), the car can be incredibly cumbersome on a track.
My E30 tackling the now-defunct Subic International Raceway
I’ve taken the car to the sadly-departed Subic International Raceway, and in the more technical areas, I would need to shuffle the steering wheel just to make the turns! The stock 325i chassis was great and power was adequate, but the steering feel and change of direction was very much lacking.
Fortunately, there is a popular fix for this – swap steering racks! There are several options for this:
Car—————mm/ per. turn——–BMW Part #
E30————–36.5 mm—————32 13 1 092 335
E30 M3———38 mm——————32 13 2 225 556
E36 M3 ’95—–39 mm——————32 13 2 227 191
E36————–45.5 mm—————32 13 1 096 280
E36 M3 96+—-45.5 mm—————32 13 1 096 280
E36 Z3 M——–45.5 mm————–32 13 1 096 280
E46 Std———-50 mm—————-32 13 6 755 065
E85 Z4 M———51 mm—————32 13 7 836 844
E36 Z3 non-M—53.5 mm————-32 13 1 095 575
(source: http://forums.bimmerforums.com/forum/showthread.php?1654735-330i-ZHP-rack-installed)
The Z3 non-M rack is universally acknowledged as the best steering rack to have, but it’s not without its drawbacks. For starters, it’s the priciest of the lot (nearly double that of the standard E36 rack), especially since demand is pretty high. But just as important, it’s the twitchiest rack of all, owing to the quickest mm/turn and the fact that it’s a linear rack, as opposed to a progressive one. The difference: a linear rack has the same turning rate at any position, while a progressive rack slows down towards the middle and quickens up as you approach full lock. The reason for this is to provide more stability at highway speeds, but better response when you need it for tighter corners on the track or going up and down your favorite twisty road.
An E36 non-M steering rack. 3.2 turns lock-to-lock and a massive upgrade from the E30’s standard 4 turns lock-to-lock
After weighing the pros and cons, I decided to go with the standard E36 rack. The difference between the two upgrades is significant – 24.6% quicker for the E36 non-M and a whopping 46.6% faster with the Z3 non-M. The difference in rack sensitivity seems to be proportionate to the price, but still the price difference was too much to ignore. The car is meant to be streetable, as well, and the less twitchy rack will be a benefit during highway cruises where you want that progressiveness at high speed.
The install was done at ARC Automotive. You can actually buy used steering racks for this to save a few more bucks, but it’s best to buy at least a remanufactured part from a reputable supplier. The installation required some modification to the steering knuckle, but was a fairly straightforward operation otherwise. For detailed DIY instructions, check out this very helpful thread on R3vlimited:
About to install the E36 rack in ARC Automotive
Shiny new E36 rack installed, old E30 rack below
The result was mind-blowing. I’ve done a lot of mods to the car, but this has changed the E30’s character overnight. Steering feel is a huge part of the experience of the car, and the new rack allowed me to more fully explore the 325i’s chassis dynamics. The only drawback is a very noticeable increase in steering effort need to drive the car around town, though not so much as to detract from the car’s enjoyability. On the track, the improvement is remarkable. During the last DTM Ph race, the E30 was much easier to toss into corners and gave me more confidence to get the tail out a bit and ride it out with a flick of opposite lock.
My E30 with the E36 rack responds much better on the track, this time in the DTM Ph Cup Leg 1 at the Clark International Speedway
I highly recommend this modification to anyone who takes their E30 out to the track, or even for some spirited driving. Hope you tune in for the next episode, and as always, drive safe!