JV and Snyde: NC MX5 handling quirks

[lemming]

i took the little one to work early this morning.

no traffic so all of the roundabouts, onramps and offramps were wide open.

this car is pretty neutral. it's a blast, really. it proves to me time and time again that as long as the chassis is lightweight, you need need all that much power to have fun.

some questions i have about the handling though:

there is some wiggle in the rear end when setting a line on a 270 degree onramp --i would guess it's not enough antiroll dialed in.

but there is other weirdness with the suspension setup too --is it that the springs are too soft? the dampers mis-tuned? once the car bites, it is completely predictable and holds a line. it's just getting there which is interesting to me.

clearly this car out of the box isn't setup for handling sharpness. maybe more for damping out harshness more than body control?

[Nick M3]

Originally Posted by lemming

i took the little one to work early this morning.

no traffic so all of the roundabouts, onramps and offramps were wide open.

this car is pretty neutral. it's a blast, really. it proves to me time and time again that as long as the chassis is lightweight, you need need all that much power to have fun.

some questions i have about the handling though:

there is some wiggle in the rear end when setting a line on a 270 degree onramp --i would guess it's not enough antiroll dialed in.

but there is other weirdness with the suspension setup too --is it that the springs are too soft? the dampers mis-tuned? once the car bites, it is completely predictable and holds a line. it's just getting there which is interesting to me.

clearly this car out of the box isn't setup for handling sharpness. maybe more for damping out harshness more than body control?

A friend of mine describes it as a "wriggly puppy dog" of a car. It's half the point.

[clyde]

Too soft springs with shocks to match. What do you expect?

[lemming]

Originally Posted by clyde

Too soft springs with shocks to match. What do you expect?

i was curious more for the diagnosis from people who spend more time at the limit --i wouldn't change a thing on the car for many, many reasons.

[John V]

IMO, they're sorta not much fun with the stock suspension. Add to the fact that they look dumb like that and ... well, if I bought one I'd be swapping in a different set of springs and shocks pretty fast.

Having driven one with a proper suspension... yeah. Big fun.

[lemming]

Originally Posted by John V

IMO, they're sorta not much fun with the stock suspension. Add to the fact that they look dumb like that and ... well, if I bought one I'd be swapping in a different set of springs and shocks pretty fast.

Having driven one with a proper suspension... yeah. Big fun.

thanks for your input.

i just wasn't sure if it's mostly a sway bar issue or something with the way the car handles compression.

[John V]

It's just softly sprung and poorly damped.

[lemming]

Originally Posted by John V

It's just softly sprung and poorly damped.

i know you have run an NC on an autocross course.

when something comes across as rolley-polley, it's intuitive that it's sway control.

what are the things to point to 'both' soft springs and underdamped? i'm just trying to reason through the mechanics in my mind.

[John V]

You can control body motion with springs and / or bars, and to some degree dampers. IME, bars are more of a fine tuning tool and shouldn't be used to band-aid soft springs

If you keep making the springs stiffer, at some point you don't have enough compliance in pitch so the car loses grip over bumps.

You can go quite a bit stiffer than stock on an NC and not have this problem. So start with springs and shocks to match.

[Pinecone]

Bars control roll stiffness ONLY.

Springs control roll stiffness, overall suspension compliance, and pitch stiffness.

Shocks control the springs to keep them from oscillating.