MP11 / MP11e Spring & Damping Guide

Read this first

Spring vs. oil — what each one does

Spring is positional: it sets how much the chassis moves and where it settles under load. Oil is velocity-based: it sets how fast the suspension moves and recovers. They feel similar in a static squeeze and behave completely differently once the inputs get fast or slow — which is why you can't fix a wrong spring with oil, or a wrong oil with spring.

Pick spring for gripChoose the spring for the support and mechanical grip the surface needs.

Lightest oil that holds itThen run the lightest oil that still controls that spring through your worst landing.

Front heavier than rearIntended balance on this platform — steering support up front, compliance at the rear.

One change at a timeIsolate the variable, run 3–5 laps, read it at one corner and one landing.

Reference

Spring rate chart (in play)

Kyosho / Lutz springs used in these baselines
Spring	Rate	Wire	End	Used for
Red 81	650	1.5	Front / Rear	Low-grip front (or rear). Soft, compliant family.
Red 70	713	1.5	Front	Low-grip nitro front. Loamy / loose.
Navy Blue 72	760	1.6	Front	Softer front — less response, more grip.
Brown 72	805	1.6	Front	Medium front. The "more steering" pair for Black 86.
Dk Blue 70	821	1.5	Front	High grip — more support deep in travel.
Black 72	860	1.6	Front	High-grip front. Stiffest, most responsive.
Lt Purple 81	592	1.5	Rear	Low-grip rear. Bumpy, loamy tracks.
Brown 86	620	1.6	Rear	Medium rear — when Black feels too stiff.
Black 86	645	1.6	Rear	Medium-high rear. Medium-to-higher grip.

Note: the number is spring length (mm); the color is the rate within that family. There is no "Red 72" — 72mm is the MP11 1.6mm front family (Black / Brown / Navy Blue) only.

Platform A

MP11 — Nitro

Nitro buggy

Power through a clutch

Softer mechanical hit, engine braking on release, and a weight that drops and shifts forward as fuel burns — so the damping is a compromise across a changing car, and tends to run heavier than the electric.

How it drives differently

Power delivery is tuned at the needle and clutch, not an ESC. The hit ramps in rather than arriving instantly.
Engine braking settles the car on entry when you lift — you don't add drag brake to get it.
Fuel burn lightens the car through a run and moves the balance, so heavier, steadier damping keeps it consistent tank-to-tank.

Springs & oil

Same spring chart, front heavier than rear. A proven low-grip nitro combo is Red 70 front (713) / Red 81 rear (650) — the soft 1.5mm family for loamy, loose clay. Nitro oils run heavier than the e-buggy, and that's fine here: the clutch's softer hit, engine braking, and changing fuel weight all want more damping to stay settled.

Center / Front / Rear diff: 30k / 20k / 15k
Pistons: 5-hole VRP
Shock oil (F / R): 900 / 800
Sway bar (F / R): 2.5 / 3.0 mm
Rear droop: −3
Ride height (F / R): 24 / 26 mm

Medium-to-high grip nitro baseline. The 900 / 800 oil belongs here — it is a nitro number, not an electric one.

Race plan · Nitro · HARC

HARC Plan 2026

A four-phase race-day plan for a glued, sauced track that climbs to a blue groove. The program opens soft on the 1.5mm Red family (Red 70 / Red 81) for the fresh, loose morning and firms up as the surface comes in — start a click compliant, build from there. Target: a good cornering car with excellent front-end response and a stable rear that squares up on power and drives off.

HARC · Nitro race day

Corner the front, square the rear

Geometry is locked — anti-squat / roll-center pills and every shock mount stay put all day. With anti-squat off the table, the rear is squared up through spring, diff and droop, with one shock hole held in reserve. Front response comes from the 72-family front spring, not from geometry.

Phase 1 — build it like this (red/red soft opening)

Front / Rear spring: Red 70 / Red 81
Pistons: 5-hole VRP
Shock oil (F / R): 750 / 700
Diff (C / F / R): 25k / 15k / 12k
Ride height (F / R): 24 / 27 mm
Rear droop: −3.5

The soft 1.5mm Red pair your guide calls the loamy/loose nitro combo — Red 70 front (713), Red 81 rear (650). Build the car here in the morning; the table below is what firms up as the groove comes in.

The four phases

HARC 2026 — red/red soft opening to blue-groove mains
Parameter	P1 · Red/red	P2 · Medium	P3 · High	P4 · Blue groove
Surface	Fresh glue, loose / soft opening	Glue worked in, line forming	Defined groove, high grip	Polished blue groove, mains
Front spring	Red 70 713	Brown 72 805	Black 72 860	Black 72 860
Rear spring	Red 81 650	Black 86 645	Black 86 645	Black 86 645
Pistons	5-hole VRP	5-hole VRP	5-hole VRP	5-hole VRP
Shock oil F / R	750 / 700	875 / 800	900 / 800	950 / 875
Diff C / F / R	25 / 15 / 12	30 / 20 / 15	35 / 20 / 17	35 / 20 / 18
Ride height F / R	24 / 27	24 / 26	23.5 / 25.5	23 / 25
Rear droop	−3.5	−3	−2	−1.5

Diff oils in thousands (k). The big jump is P1 → P2: off the 1.5mm Red family onto the 1.6mm Brown/Black, oil and diffs stepping up together. Oil and diffs are an AM-build / lunch-change item; springs, ride height and droop are your quick between-round changes. Sway bar holds at the 2.5 / 3.0 baseline — not a moving part in this plan.

How each target gets met

Excellent front response — Red 70 → Brown 72 → Black 72 up front, climbing to the most responsive 72-family spring on your chart for the groove. Front oil kept from getting too heavy so the front sets quickly, ride height low for bite, and the front spring always leads the rear in rate so the car turns before it drives.
Stable rear that squares up — the rear firms by wire, not rate: Red 81 (650, 1.5mm) and Black 86 (645, 1.6mm) are the same rate, so P1 → P2 swaps the lively rear for the supportive one. From there, center diff up (25 → 35k) for smooth stable power, rear diff up (12 → 18k) so it hooks and drives off the corner, and rear droop coming out (−3.5 → −1.5) so the rear stays flat instead of squatting away. The squaring-up job done without anti-squat.
Good cornering — the rear diff stays lighter than the front the whole way, so the rotation bias never leaves even as the rear firms up for drive.

Your one geometry move: if the blue-groove mains traction-roll, or the rear still won't square up at P4, stand the rear shock up one hole. Per IS2 that keeps the rear flat and stops the outside-rear from collapsing. It is the only mount change in this plan — everything else holds. If it doesn't need it, leave it.

Locked by choice: pills and shock mounts stay put across all four phases. The rear is squared up through spring + diff + droop instead of anti-squat — slower-acting than a pill, but it keeps the car predictable round to round, which is the point on a one-day program.

Platform B

MP11e — Electric

Electric buggy

Instant, tunable torque

No clutch — linear torque from zero, smoothed by punch, drag brake and turbo. Weight is constant the whole run, so you can match the damping precisely to the spring and grip instead of running a heavy compromise. Let the ESC smooth the power; don't tame it with thick oil.

Three-tier baseline — loamy AM to blue groove mains

MP11e shock packages by grip level
Parameter	Low	Medium	High
Surface	Loamy, loose, fresh (AM)	Groove forming, mixed	Polished groove, mains
Front spring	Red 81 650	Brown 72 805	Black 72 860
Rear spring	Lt Purple 81 592	Brown 86 620	Black 86 645
Wire / family	1.5 (MP10)	1.6 (MP11)	1.6 (MP11)
Pistons	8-hole 1.2F / 1.3R	8-hole 1.3	6-hole 1.3
Oil (F / R)	500 / 400	575 / 475	650 / 550
Sway (F / R)	2.3 / 2.6	2.4 / 2.8	2.5 / 2.9

Medium oil and sway are starting interpolations — confirm at the track. Everything moves the same direction with grip: stiffer spring, less piston flow, heavier oil, more bar.

Your current setup: Brown 72 / Black 86 is the "more steering" pairing — a valid medium-high blend. Keep the springs. The only thing off is the oil: 900 / 800 is the nitro number on an electric car. Drop to 650 / 550.

What 650 / 550 feels like vs 900 / 800

Where	900 / 800 (now)	650 / 550
Loamy / rough	Deflects, skates, packs down, harsh	Follows the surface, soaks chop, more grip
Turn-in	Slow to set, lazy to rotate	Quicker transfer, sharper, more rotation
Body movement	Locked down, numb	More roll, squat, dive — feels alive
Landings	Controlled, can feel jarring	Softer; watch a slight rebound kick on big hits
If wrong	Too planted, deflecting = lost grip	If too light on a polished groove: pitchy, slow to settle

Make it one change, same springs, back-to-back. Give it three laps before judging. Same oil brand both ways or the comparison is muddy — cSt scales vary between brands.

ESC — the power levers (do these first)

Low / loose grip: drop punch, no softening — cleaner power on loose clay.
Tight technical: kill turbo. EPA 100% (below 96% disables turbo anyway), drag brake 3–5%.
On the electric car, smooth the power here before reaching for diff or geometry.

Balance levers — one change at a time

Won't rotate / pushes: step the front spring down (860 → 805 → 760), then rear roll center up, then thin the rear diff.
Traction roll / planted on exit: drop punch first, then thin rear diff, then rear roll center — not a spring fix.
Bottoming on landings: shorter / more progressive spring (Dk Blue 70) or lay the shock down — not just heavier oil.

High-grip+ options

Dk Blue 70 front (821): lower initial rate than Black 72 but more support deep in the travel — landing support without a harsher initial feel.
Brown 72 on the rear (805): front spring on the rear for more support and corner speed on the smoothest, highest-grip days.

Spring vs. oil — what each one does

Spring rate chart (in play)

MP11 — Nitro

How it drives differently

Springs & oil

HARC Plan 2026

Phase 1 — build it like this (red/red soft opening)

The four phases

How each target gets met

MP11e — Electric

Three-tier baseline — loamy AM to blue groove mains

What 650 / 550 feels like vs 900 / 800

ESC — the power levers (do these first)

Balance levers — one change at a time

High-grip+ options

When to move tiers