A Spring of Basic Suspension Education.

“It’s hard to drive at the limit,
but it’s harder to know where the limits are.”
~Sir Stirling Mossⁱ

The mechanical engineer in me has a pretty intuitive grasp of suspensions.

Springs are force dependent. Dampers are velocity dependent. Camber dictates contact patch in the corners when the tire is under lateral load. Caster dictates the steering wheel’s willingness to return to centre exiting a turn. Toe dictates turn-in as well as high speed stability. I kinda get it.

Or at least I’m starting to.

As summer begins and this unusual spring (season) is now behind us, this whole “sit at home and do nothing” schtick turns out of have had the unexpected benefit of allowing me to intellectually tinker with suspension ideas for the last three months, and for the most part, it must be said that they’re coming together rather nicely. But as Sir Stirling alluded to, intentionally or not, episteme ≠ techne! And when it comes to motorsports, the proverbial rubber hits the road only when the literal rubber hits the road.

Thankfully, my barren wasteland of a travel schedule means that I’ve already been out to the track six times this seasonⁱⁱ – three times in cars and three times in spec karts – which has allowed me to confirm, refute, and start to cement my evolving intuitions about motorsports suspensions. To say that this process has been enjoyable would be a gross understatement – it’s been a complete and utter delight – so where have I been, where am I, and where am I going with this education? Let’s take a look at the driver feedback (footnotes contain more technical details for the aspiring race engineer/club driver/jack-of-all-trades):

2013 R35 Nissan GT-R – 600hp

Spring 2019: Premature wear on outsides of front tires, flip-flopping in mid-speed transitions, mild understeer, and nose-diving under heavy braking.ⁱⁱⁱ
Spring 2020: Incredible grip and turn-in responsiveness, essentially no understeer, much better stability in mid-speed transitions, massively improved anti-dive under braking,^iv still premature wear on outsides of front tires,^v still some wallowing in high-speed transitions.^vi
Spring 2021: I don’t think I’m going “full retard” next season, like Nasty Seaweed did,^vii but you never know. TE37 UTEs, a Top Secret body kit, and Tractive DDA dampers wouldn’t be so bad.^viii I don’t currently have plans for more power, nor trans upgrades, but depending how demanding the new SCR expansion^ix is on cooling, the Alpha Performance Street Cooling Kit (radiator+trans+oil cooler), HKS Differential Cooler could be worthwhile.

2006 S2 Lotus Elise – 320hp

Spring 2019: Former co-owner Adam OB^x spun “Dreidel” off the track and into a swamp on her last lap of last season while trying to keep up with me in the GT-R around Turn 5 of SCR-CCW. The suspension set-up was largely to blame for his off.^xi
Spring 2020: Improved road poise, steering still “sticky” and slow to centre, very little feel just off-centre. Track results TBD, we’re still a month from SCR re-opening to cars.^xii
Spring 2021: Improved high-speed stability.^xiii

201? Spec Shifter Kart – 32hp

Spring 2019: N/A^xiv
Spring 2020: Seriously violent driving experience due in no small part to the solid rear axle that bangs across the undulating infield surface at SCR. There’s adjustability in tire pressures but that’s about it for suspension tuning. It’s hard enough just to remember to breathe, keep your eyes up, and keep your hands from choking the fucking steering wheel while you’re holding onto this goddam roller coaster for dear life, but once you get over the initial shock, it’s manageable and moderately enjoyable, if still painfully physical.^xv
Spring 2021: TBD

2019 W463A M-B G550 – 420hp^xvi

Spring 2019: Stock everything, slightly wallowy ride, awkward ingress/egress, best damper feel in Comfort.
Spring 2020: Improved egress, still slightly awkward ingress, slightly diminished “command” driving position, improved body control at high speeds, reduced compliance over parking lot speed bumps at low speeds, best damper feel in Sport.^xvii
Spring 2021: Probably not a whole lot different than this summer, unless I get bored and go the other way with Lift Springs, 35″ tires, and the Brabus Widestar kit. Never say never.

Onwards to summer – the education continues!
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1. 1929-2020. RIP. ↩
2. Compared to twelve times total in the last three years since I plunged headlong into motorsports. ↩
3. R35 Spring 2019 Alignment:
   Front Camber -1.5º
   Rear Camber -1.7º ↩
4. Big props to Ari, who has been helping me dial it in:

   

   Clearly the little man’s endless hours in the g-force simulator are paying off!

   

   ↩

5. Once I finish destroying the half-dozen PS4S “street performance” tires I already have in my possession, the Nitto NT01 are next on the list, though the Michelin Cup 2 Connect tires are apparently now available in the requisite 285/35/20, so that’s an option too, even if the whole “Connect” dealio is most likely just an overly complicated and expensive way of doing exactly what Samir will teach you quickly and for free. Ok, so the Nittos it is then. Or should I go out on a limb and try Nankang’s AR-1? ↩
6. R35 Spring 2020 New Parts (So Far): Top Secret Front Upper Control Arms, Top Secret Rear Camber Arms, Top Secret Rear Tension Arms, Top Secret Rear Toe Control Arms, DSC Sport Controller, Eibach Sway Bars, Sabelt 4-Point Harness, AP Racing CP9668 Radi-CAL Pro5000R Front Calipers (5 lbs lighter per caliper than OEM Brembos), AP Racing J-Hook Rotors Front & Rear, Ferodo DS3.12 Pads Front & Rear.

   R35 Spring 2020 Alignment:
   Front Camber -3.5º
   Rear Camber -2.5º
   Front Toe -3mm total
   Rear Toe 0
   Caster 6º

   R35 Summer 2020 New Parts (Coming Soon): Top Secret Super Spring Kit*, SPL Sway Bar End Links, SPL Eccentric Lockout Kit, SPL Front Lower Control Arm Bushings, SPL rear Knuckle Monoball Bushings.
   ___ ___
   *Essentially a high-end Japanese version of the more popular KW Sleeve Kit, which is just a set of springs, top mounts, and threading for adjustable ride height using stock dampers. ↩

7. Not that I’m hating on Nasty! Hell, I wish I’d been in the market for a beautifully built machine like his last season. USD $99k is a bloody steal of a deal for a machine like that. ↩
8. Next season might not be easy on the wallet, but it’ll be cheaper than the new CAD$300k NISMO. ↩
9. Within a month, my home track, Strawberry Creek Raceway, will go from ~2km to ~4km! Yippee!! ↩
10. I recently bought out the other half of Dreidel because my good man Adam OB doesn’t have quite as much time to indulge his passion for motorsports this summer, partly because he now has three little ones, but mostly because his company Bitcoin Solutions is about to list on the TSX this fall, becoming the first Bitcoin ATM Operator to do so. Keep an eye out for this kid! ↩
11. S2 Spring 2019 Alignment (I shit thee not):

    Front Camber -0.1º(L), -0.3(R)º
    Rear Camber -1.7º(L), -1.8º(R)
    Front Toe -0.2º(L), 0.0º(R)
    Rear Toe 0.3º(L), -0.3º(R)
    Caster 3.7º(L), 3.9º(R)

    As you can see, the alignment settings were an absolute fucking train wreck last season, which almost certainly played a part in causing Dreidel’s snap-oversteer issues rather than simply resulting from them, at least initially, though we can also imagine that a dozen spin-offs over the course of three seasons didn’t do the alignment any favours, even if the car never hit anything more solid than a grass lawn. ↩

12. S2 Spring 2020 New Parts: EliseParts Lightweight Steering Arms, InoKinetic Suspension Refresh Kit with MONOball Spherical Bushings, Goodridge Brake Lines, Pagid RS14 Pads Front & Rear, V-Force Harness Bar, Schroth 4-Point Harness.

    S2 Spring 2020 Alignment:
    Front Camber -1.2º
    Rear Camber -2.0º
    Front Toe 0
    Rear Toe 3mm total
    Caster 4.4º ↩

13. Next season, I’m gonna learn about aerodynamics so help me Hashem! While not quite as intuitive as suspension design, being so invisible and intangible, and also being a bit of a “cheat” in some ways, particularly for novice drivers, if next spring/summer is as home-bound as this one, whether voluntarily or not, tinkering with aero will definitely be on the menu.

    To start with, I’m looking at GRP Race Style Side Skirts, S2 Cup-R Front Splitter, Difflow Rear Diffuser (5-Element Rounded), and GFWilliams Side Mirrors. Canards and humongous rear wings just fuck up the Lotus’ svelte lines for me, but at a certain point may be inevitable in my development all the same. In general with the Elise/Exige platform, going “full retard” looks something like Eric from Corner Balanced. Again, not hating, just showing you what the high watermark looks like.

    Then again, we’ll see if I even keep the Elise. It’s never really pulled at my heart strings, to be honest, and if this season’s fettling doesn’t change that, then to the auction block she’s headed. ↩

14. Before this month, I’d never been in a go-kart more powerful than the amusement park ones in Palm Springs. The jump from 2hp to 32hp is not inconsiderable! ↩

15. 

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16. Can’t neglect the DD! ↩
17. W463A Spring 2020 New Parts: H&R Lowering Springs (-1.5″), 463 Industries CG-01 20″ Wheels, Nitto Grappler 285/50/20 Tires, more murdering out. ↩