Mission: Max front end grip for doridori fun.

[ravingrichie]

1990 NA6
Koni coilovers with 26.60 N/mm front, 25.09N/mm rear
Running lowish
Stock swaybars
185 60 14 front + rear (due for replacement)
Manual rack
VLSD grenade that works
FM butterfly brace
B6 with a little bit of work but basically stock power.

TLDR;
Oversteer good, Understeer bad.
Help me slide with less of the latter.

Now that's out of the way let's talk goals.

For my lifestyle an MX5 is the perfect daily. It even likes to get its tail out and keep it there with some encouragement. ie. Oversteer is a good thing IMO. A very good thing.
It's great having the rear out, so long as the front has enough grip to keep things tidy & keep translating steering corrections into fun. Undeesteer induced by mid-dori surface changes or just poor execution is terrifying. This is where the mission comes in.

Theory goes a soft front and hard rear is the way to go. Is this theory solid?

I have reason to rebuild the front subframe (after a minor off) and access to a near complete spare. What shall I do to give it a refresh & dial out the understeer while at it?

Bushes: I'm prepared to put in tuffboi bushes in selective places but not everywhere. Are there any select spots or shall I keep things oem? Will bushes help reduce understeer anyway, soft front theory and all?

Swaybars: being lowish they have some preload on them. Am thinking to put adjustible end links on the front to dial out the preload. Will keep the rear as is, maybe a stiffer bar in the rear after front end optimisations are done.

Rack spacers?: I've heard that us lowbois can get rid of bumpsteer with rack spacers. Would this make any difference to the mission?

Alignment: Is there an optimum front end alignment for reduced understeer? So far it's dialled for even tread wear and that's about it. The rear has a little toe in it to help it slide just a bit.

Tires: Running 14s does limit tire choices. Am pretty set on the idea of a performance pair on the front and econos on the rear. Any suggestions on tires? 185 60s aren't a must but some sidewall is required for daily duties and a little stretch for fitment.

Springs: I work next door to a spring shop. Would softer front springs help too? Perhaps after front swaybar adjustment.

And then...: I'm probably overlooking some other point or even a silver bullet. What else can help this mission? Cartalk search tool is full of Evo blah for some reason.

[Magpie]

Alignment?

Tyre pressures?

When is the understeer? Corner entry, mid, exit?

The car is almost 30 years old. When was the bushes changed? Alignment bolts? If you have to rebuild the front, damage to control arms? No point band-aiding the understeer. Get everything fixed up, aligned and decent tyres then try again.

Understeer is caused by overpowering the front available grip of the tyres. So slow down or get better tyres or take it to the track/skidpan and learn how to control/prevent.

[ravingrichie]

When does it undrsteer eh, depends. Sure I can induce it by reefing on the steering. I'm not really talking about that. Moreso losing front end grip when flicking back preslide or getting unsettled midslide and losing effective steering correction. The point is, with only 100hp on tap, steering is the most effective way to initiate and control a slide. Power clearly secondary, hence the mission.

I've got a much younger set of alignment bolts at the ready.

Nothing (majorly) bent in the subframe. It was only the LCA that copped bendage but it is truely old and the stack wouldn't have been kind to old bushings, ball joints, end links etc. Spare subframe to be rebuilt, see OP

Alignment see OP

Tires, 34psi all around.

Slowing down isn't really an option when you want to lose grip. I just want the front to reliably hang on far longer than the rear can.

[Magpie]

are you drifting on public roads or track/skid pan?

Alignment as is actual settings.

34 psi hot or cold?

[ravingrichie]

Private roads. Sealed.

I can't remember alignment figures but it's tame.

Cold pressure.
Curiously high interest in tire pressure.

[ManiacLachy]

Magpie is track oriented, alignment and tyre (not tire) pressure are important and significant to him. You're lucky he didn't ask what temps you're running at!

You want max camber up front for grip, you'll probably end up about -2* on stock components. You could get extended lower ball joints to get more front camber if you were keen. Rears would be a little less for optimum grip, maybe -1.8*, but you don't want grip back there, so maybe dial it out to around -1.2* or even -1*.

Your springs seem oddly close in weight, usually the rear is lighter than the front by a bit more. But that might just be me being unfamiliar with N/mm as a measurement, I'm more used to seeing kg/mm or lb/inch. Don't know if there's much in it for what you're looking for anyway, just an observation.

I don't know about rack spacers. There are some r-package tie-rod ends that are OEM and designed to dial out some bumpsteer though. Google will help you find them.

Adjustable endlinks aren't a bad idea, but not sure if they'll help your oversteer.

Gripy fronts and eccono rears will help like you say. Not sure on brands, sorry. Keep them even in spec though, don't get wider or taller rubber at one end than the other.

Do tyres, and alignment and see how things feel. You don't want to go too far with it too quickly.

[Magpie]

You're lucky he didn't ask what temps you're running at!

Was never going to ask:)

However... at 34psi cold and then punishing them you may fine that the front's are failing to grip because of exceeding the heat tolerances of the rubber.

Contact this company https://www.destroyordie.com/product/mx5-angle-kit if serious about drifting.

Do you have permission to use the private roads for drifting?

[ravingrichie]

It's tolerated more than permitted.

Good call about getting more front camber with the right ball joints. I'll look them up for sure. Likewise bumpsteer.

Is there a basis for not running different tyre sizes front to rear. The new wheels are staggered and awaiting tyres. Did I do a bad thang?