Project 240SX – Part 3 – Track Ready Suspension Setup

With Project 240SX’s stiffer chassis now highlighting the suspension’s movements, we became more and more dissatisfied with the car’s current “drift” setup. Our Nissan arrived at our doorstep equipped with generations old TEIN Type HE Drift Spec Winding Master coilovers (yup, that’s really the name – Ed.). Although we want to be winding masters as much as anyone else, the suspension was built with drifting in mind. This meant that lots of compression valving was the name of the game, which is useful for quick weight transfer and Scandinavian Flick-type feint moves to initiate drifts.

But Project 240SX rockets over the undulating pavement and curbing of Buttonwillow Raceway, meaning that a damper resistant to compressing will shock the chassis over rough surfaces and cause the tires to lose contact with the ground.

After pulling the coilovers and making a trip over to TEIN USA for a damper rebuild and revalve, we were told that the Type HE’s twin-tube damper design was nearly a decade old. TEIN’s internal damper piston and shim designs have changed dramatically since and the Type HEs could be rebuilt, but not with the modern internals. We ended up leaving with a lighter wallet and a set of TEIN’s latest Mono Flex coilovers.

The MonoFlex system is based around TEIN’s newest 16-position adjustable monotube design. The monotube damper features a larger piston than TEIN’s twin-tube designs, displacing more shock oil per stroke and thus giving finer damping control as well as greater heat dissipation. TEIN also inverts the front strut monotube for a decrease in unsprung weight. During installation, we maxed out the front upper spherical bearing camber plate by shoving the strut all the way in. To our surprise, the front lower strut mounting bolts were 14mm in size, while the Mono Flex lower mounting bracket had 12mm holes. We guessed that Project 240SX was equipped with S14 front spindles but didn’t think much else of it and drilled out the brackets to fit the bolts.

New Energy Suspension urethane bushings on top and rotting, dead stock bushings on the bottom. We used the entire Energy Hyper Flex Master Kit to cover all the bushings

Megan racing S13 front roll center kit (L) and S14 front balljoint (R). Notice how the tapers on the shank are different? We didn’t, not right away, and almost paid the price with a non-seated spindle

After driving on the new Mono Flex suspension, we couldn’t believe that the Type HEs came from the same company, regardless of the difference in production date. The Mono Flex exhibited a much more smooth and controlled ride, even on full stiff, with more precision than the HEs and better traction due to the tires actually being able to stay in contact with the ground at all times.

Looking for a more precise alignment, we sourced a set of adjustable rear arms from SPC Performance. Manufactured out of steel tube with full adjustability, the SPC arms are vastly stronger and more flex-resistant when compared to the cheap stamped steel stock arms. The arms also come fit with new rubber bushings, which are a higher durometer than stock. SPC sells three links for the rear, a camber link, toe link, and traction link, of which the latter can be used to adjust for bumpsteer. To start, we set all the arms to stock length and then adjusted them for our alignment settings.

To go fast, and we’re talking Corvette/Porsche ass kicking fast, Project 240SX would need a lot of camber. Strut-type front suspensions like to have large amounts of static camber on account of their horrible camber curves. Thanks to the SPC arms, Project 240SX wound up with nearly 3-degrees of negative camber and 1/16-inch total toe-in in the rear. In the front, we got a measly 2-degrees of negative camber. Not good enough. With our non-refundable registration fees already on the line for a Buttonwillow test day, we headed over to M1 Fabrication & Development with just two days to spare.

Tatsu Tsuchida at Tokyo Auto Repair in Placentia, CA helps us with our urethane bushing swap. First, the rubber is broken up

Next, the inner sleeve and rubber is pressed out

A grinding tool is used to take out the remaining rubber, leaving a bare control arm to receive an Energy urethane bushing

When’s he not working on 250cc Superkarts from the likes of Wayne Rainey (three time 500cc World Championship motorcycle champ) and Eddie Lawson (four time 500cc World Championship champ), M1’s Mack Sunthonlap applies his sizeable fabrication knowledge to work on nine year-old derelict projects from the OR team. Yeah, we’re not sure how we pulled that one off either.

Project 240SX’s camber limitations were being caused by contact between the strut tower’s support ring and the heads of the camber plates’ inner bolts. Mack machined out the TEIN upper camber plates to allow more adjustment range and then drilled a set of holes in the top of each tower to provide clearance for the camber plates’ bolts. A pair of chromoly rings were then cut and welded into each tower to provide structural support and our “Mickey Mouse” strut tower tops were done. 3.5-degrees negative camber each side without breaking a sweat.

With the car buttoned up, we headed out to Buttonwillow Raceway for Project 240SX’s first real shakedown test. We knew something was wrong the instant we got onto the highway. A massive dead center appeared in the steering response and the car felt unstable at highway speeds. Once on track, Project 240SX violently and quickly snap oversteered the instant it touched its first bit of curbing. The car became nervous, wandering over any surface that wasn’t as smooth as glass and lacked any and all feedback during cornering.

TEIN’s latest S13 240SX Mono Flex coilovers use monotube dampers (inverted in the front), spherical upper mounts, separate adjustable ride height and 16-position combined rebound and compression dampening adjustment

Despite having more rear spring rate (7kg/mm versus 6kg/mm), the TEIN MonoFlex are more compliant than the old TEIN Type HE drift coilovers

Z32 Nissan 300ZX rear lower shock brackets (R) are required to fit 300ZX rear aluminum spindles. These brackets are nearly impossible to buy separately, stock shock brackets are on the left

When we returned, we discovered play between the front lower control arm and spindle. We had the wrong balljoints installed. Doh. Project 240SX’s previous owner had recollected that the five-lug hub conversion was done using conversion hubs only. Wrong. We discovered earlier during the coilover install that we had S14 front spindles but neglected to follow up on it. We soon discovered that Project 240SX used S14 front spindles, hubs, balljoints, and S13 lower control arms for the five-lug conversion. Stupid us.

We had earlier sourced an S13-application Megan Racing roll center kit, which has a different taper on the balljoint than the S14 kit and won’t seat correctly. We’ve since swapped the front for a Megan Racing S14 application roll center kit. If you’re carrying out a five-lug hub conversion, do not attempt to use S14 spindles and S13 balljoints. Learn from our mistakes. First lesson - keeping control arms attached to a car is a good thing.


Sources

DRIVETRAIN   
Nismo Super Coppermix clutch, pressure plate, flywheel, reinforced 6-speed transmission
JDM Power
(949) 855-9174
www.jdm-power.com

SUSPENSION
Mono Flex coilover suspension
TEIN
(562) 861-9161
www.tein.com

Adjustable rear camber, toe, traction links
SPC Performance
(303) 772-2103
www.spcperformance.com

Urethane control arm, rear spindle, swaybar, endlink bushings
Energy Suspension
(949) 361-3935
www.energysuspension.com

Clutch, pressure plate, flywheel install
SR Motorcars
(310) 516-1003
www.srmotorcars.com

Urethane bushings, roll center kit install
Tokyo Auto Repair
(714) 993-7300

Continue to Project 240SX - Part 2 - Chassis Stiffening >>>

Continue to Project 240SX - Part 4 - Nismo 6-speed Transmission >>>

The reason that you’ll need new rear lower shock brackets when switching to rear aluminum spindles is the bushing-type 300ZX lower shock mounting point. This bushing is also not included with the Energy 240SX kit. All 300ZX models, turbo or non-turbo, use the same aluminum rear spindle

SPC Performance’s rear control arm set swaps out three links to adjust toe (top), camber (middle) and bumpsteer (bottom). Stiffer than stock rubber bushings are pre-pressed into the arms and there’s no deformation like with the stamped steel stock arms

Be sure your SPC arms are the same length as stock before installation, this will make for a better baseline from which to begin alignment adjustments

Even with the older Type HE’s camber plates, the limiting factor for the front camber adjustment is contact between the strut tower’s support ring and the inner adjustment bolt heads. We didn’t feel safe sliding the plate all the way in and only running two adjustment bolts

Adding more camber adjustment range to the front upper plates, M1 Fabrication & Development machined the slots to allow the struts to slide further in

Notice the small pocket that has also been machined into the lower bearing plate. This is done to provide clearance for the inner mounting stud’s head, which protrudes out the backside of the green plate

Two chromoly rings, per side, were cut to reinforce the main strut tower support ring

After drilling two holes for camber plate clearance, the chromoly rings are welded into place and ground down to fit

The end result is now 3.5-degrees of negative camber up front with clearance for the camber adjustment bolts. Now the limiting factor is the strut’s upper mounting nut