Based on extensive study of the geometry of the 90-99 SW20 MR2 suspension, the Wilhelm Raceworks Suspension Geometry Kit is designed to correct the negative effects of lowering, and to improve on the stock geometry by reducing dynamic toe (aka bump steer) and adjusting the roll axis of the chassis. The result is significant improvements to turn-in and front end grip, while also reducing the oversteer tendency that the SW20 is so known for. The kit also makes it much easier to catch or control oversteer once it starts.
Made in the USA!
Package deal: Purchase a geometry kit and a full set of coilover top mounts and save $80!
Description of Options:
Short tie rods are typical for US market '91-'92 cars, '90-'91 in the rest of the world. Long tie rods for US '93+ cars, '92+ elsewhere. Please double check your cross member before ordering, a previous owner may have changed it!
High misalignment rod ends highly recommended for stock struts due to large droop travel. With most aftermarket coilovers either front rod end may be used. See instructions here for how to measure droop to verify which rod end you need.
The included bump steer spacers should be close enough for most users, but if you wish to fine tune a little you will need some additional spacers. This kit includes 2 each of .030", .060", .100", and .200" aluminum bump steer spacers. You will need to remove the spring, and jack the suspension through it's range of motion using a bump steer gauge to properly adjust bump steer.
Replacement Rod Ends
Eventually, it is possible that the original rod ends supplied with the kit will need replacement. A full replacement set of six premium quality FK rod ends is $220 with the high misalignment front option, $150 without. Please contact me to purchase.
This kit improves the MR2's suspension geometry in several ways. First, it corrects the negative effects of lowering. As discussed in my suspension geometry analysis, lowering the MR2 (or any McPherson Strut based vehicle) has negative effects on the suspension geometry. In particular, lowering degrades the camber curves and excessively lowers the roll centers, resulting in more body roll. The kit is designed to fully compensate for 1.25" of lowering. However, lowering further than that will not negate the effects of the kit. If anything, the lower your car is the more you can benefit from geometry correction.
Second, the front RCAs are thicker than the rears. This raises the front roll center above the rear resulting in improved turn in AND improved rear end grip.
Third, significantly reduced rear toe change on a Rev1 (91/92) MR2. I have found this to have a significant positive affect on stability at the limit, making the car much easier to drive fast, and consistently. With this adjustment I run my 91 at 1/8" total toe in with no loss of stability, leading to greatly improved rear tire wear. On the Rev2+ cars the kit restores the stock toe curve, which is otherwise significantly altered by lowering the car.
This kit is designed to be bolt-on, and completely reversible. A little work with a press is required on the rear knuckle.
All kits use 3-piece, USA made FK rod ends.
Geometry kit installed on my car:
Front tie rods use a custom made tapered stud, aluminum spacer matched to the roll center adjuster (RCA), aluminum tie rod adapter, and FK rod end.
For the rear tie rod the spherical bearing is removed from the knuckle and a steel slug is pressed in its place. The tie rod drop bracket is a welded steel assembly that simply clamps onto the knuckle. In addition to shifting the pivot point down to match the RCA, this also shifts the pivot point rearward, which reduces the natural toe changes of the rear suspension, aka bump steer. The stock rear tie rod is completely replaced by an aluminum hex tube with 3-piece FK rod ends at both ends, and custom bushings to adapt the rod end to the chassis at the inner end.
Roll center adjusters are machined from 6061-T6 aluminum, and designed to fix and improve the suspension geometry. All aluminum parts are anodized black, the steel front tie rod studs are yellow zinc coated, and the rear tie rod brackets are powder coated in black. All hardware is grade 8 standard / grade 10.9 metric.
This kit requires at least 16" wheels. The rear may require 17's, depending on the exact shape of the wheel. The stock brake dust shields will need to be modified (bent) or removed to clear the front ball joint / RCA.
So, what does this all do for you? Better camber curves, reduced bump steer, improved tire wear, improved roll center location (reduces body roll), and reduced roll center movement for more stable cornering.