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track springs/rates

Posted: Mon Mar 07, 2016 5:58 pm
by mx5rally
Hi all

im new to the tarmac although i have been racing my mx5 on dirt for several years, i was wondering if anybody can point me in the right direction with setting up my rally car for track (on a budget of course as this will probibly only be for the 2016 season)

I have done a couple of sprints with NB bilsteins and lowered king springs and i was wondering if changing to some race springs say 6kg rear and 8kg front would work if i got the bilsteins valved to suit.

I have some adjustable spring seats which will suit a 60mm ID spring, does anybody have any springs lying around that i might be able to purchase.

I could change to 65mm ID springs if i had to, and i do have whiteline swaybars installed.

am i going in the right direction with this?

Any advice/help would be appreciated

cheers
Dave

Re: track springs/rates

Posted: Mon Mar 07, 2016 6:33 pm
by project.r.racing
I would just race it in the rally spec you have to begin. If you have super soft gravel/mud tyres, then you'll need to change those. Otherwise they'll be gone in one afternoon on tarmac.

If you need to make suspension changes. Try just lowering it as much as you can and go nuts on the damper setting. From there, make changes if you have to.

Re: track springs/rates

Posted: Mon Mar 07, 2016 7:38 pm
by mx5rally
My rally suspension is at a set height and not adjustable at all, i do however have some bridgestone re55 semi slicks for the tarmac.

Re: track springs/rates

Posted: Tue Mar 08, 2016 4:27 pm
by pepejesus
Tell us more about your car.

NA/NB?
Power level?
RE55S compound?
Wheel/tyre size?
Diff?
Weight?
Assume no aero etc?
Driver skill level?
Particular class requirements or restrictions?
How competitive do you want to be?

Re: track springs/rates

Posted: Tue Mar 08, 2016 4:37 pm
by Magpie
Also alignment settings and condition of bushes/control arms.

Re: track springs/rates

Posted: Tue Mar 08, 2016 4:44 pm
by plohl
Just drive it as dude - you'll figure out which way you want to go with the suspension after a few runs.

Sent from my SM-N9005 using Tapatalk

Re: track springs/rates

Posted: Tue Mar 08, 2016 4:53 pm
by Magpie
Or just follow plohl's and project.r.racing's advice (they have been right in the past).

Re: track springs/rates

Posted: Tue Mar 08, 2016 9:37 pm
by mx5rally
Basicly i can punt the mx around phillip island in 1.59 and sandown 1.35 but i was looking to improve on that a little, i dont think i can push the car any harder the way it is now.
its an na8
16 inch wheels
3.5 neg camber
weight unknown
full cage
4.77 diff lsd (or thereabouts)
hawk blue pads front
trw pads rear
nolathane throughout with offset bushes in lower arms
shortened front upper arms
whiteline sway bars front and rear
front strut brace
no power steering


92kw at the wheels

Re: track springs/rates

Posted: Tue Mar 08, 2016 10:57 pm
by Dan
You can go higher rates for a race car, most race MX5's run 10kg+ at the front.

Here's a good site with alignment tips http://949racing.com/miata-race-alignment-info.aspx (note - It assumes at least 550# springs at the front for a race setup which is 9.8kg)

Re: track springs/rates

Posted: Wed Mar 09, 2016 2:46 am
by pepejesus
mx5rally wrote:Basicly i can punt the mx around phillip island in 1.59 and sandown 1.35 but i was looking to improve on that a little, i dont think i can push the car any harder the way it is now.
its an na8
16 inch wheels
3.5 neg camber
weight unknown
full cage
4.77 diff lsd (or thereabouts)
hawk blue pads front
trw pads rear
nolathane throughout with offset bushes in lower arms
shortened front upper arms
whiteline sway bars front and rear
front strut brace
no power steering



92kw at the wheels

Nice one, with that set up I'd assume you're running an 8 inch or wider wheel and using a 205+ tyre?

You will have a lot of grip and will need much stiffer springs to take advantage of it.

I would suggest:

- get rid of that rear sway and putting the stock one back on
- AT LEAST 10/6 springs (don't run 8/6, not a good combo for track work IMO)
- 12+/7 would be better still
- you'll probably need to revalve the dampers at those rates
- running the stiffer springs will also allow you to run lower (like 100-110mm at the front pinch welds with say 5-10mm rake), softer springs you'll need to run another 10+mm higher
- wheel alignment as per Dan's link above

Running 8/6 springs with the 16mm rear bar and the amount of neg camber you've got at the front will give you a very loose car that also isn't stiff enough to take advantage of the mechanical grip you've got. You'd end up having to run zero rake or less to give you rear grip and you'll lose a lot of rear bump travel in the process.

Or you could just run it in rally set up but the car will be way too high and soft to take advantage of the RE55Ss.

Hope that helps.

Re: track springs/rates

Posted: Wed Mar 09, 2016 8:36 am
by mx5rally
Thanks Guys

That gives me heaps of info to work with.


Cheers

Dave

Re: track springs/rates

Posted: Wed Mar 09, 2016 10:36 am
by project.r.racing
I'm guessing few aren't familiar with your car. I remember once asking whether Murray Coote played with your suspension.

I did take notice of your requirement of being on a budget. A lot of the suggestions and/or options aren't budget friendly. And it isn't like you haven't been on tarmac before. Those not familiar with rallying don't realize not all racing is done on dirt.

I would not touch you current dampers and springs. Have a chat to you normal guys, some shop in Canberra from memory and seek their advice also.

But if you really wanna go budget. I'd buy a set of coilovers for 2016, and then sell used them in 2017. Cheapest why I can think of to get proper large improvements at the cheapest possible dollar value. Or just buy a used set cheap and have fun. And if they are still alive by the end of the year, sell them on also.

Re: track springs/rates

Posted: Wed Mar 09, 2016 10:55 am
by beavis
10kg front
8kg rear

Re: track springs/rates

Posted: Wed Mar 09, 2016 12:39 pm
by manga_blue
I'd say anywhere from 10/7 up to 14/10 with OEM sways. At those rates you may only want different sways to fine tune front/rear balance.

Tein USA stock the springs you want in 65mm ID but you're unlikely to find rates that high in 60mm ID. Because they're wholesalers you'll probably need to buy them through someone like Bill at miataroadster.

http://www.tein.com/products/standard_s ... _list.html

Re: track springs/rates

Posted: Wed Mar 09, 2016 1:14 pm
by mx5rally
I was trying to purchase some second hand coil overs but everybody that seems to be selling them hasn't even taken them out of the car yet. I could just on sell these at the end of the season.
Approx $700 - $1000

Or I can get Baker Brothers in Melbourne to re-valve the NB bilsteins ($250ish) to suit the spring rate I choose, I already have the adjustable spring collars in 60m ID so I would need to change the platform to 65mm ID (no big deal it just a Koni parts $312) and purchase x4 springs ($240)
Approx $802

I think they are my x2 options, if I go the second one I know what I am getting and the Baker Brothers know what they are doing with bilsteins.

I guess I will see what pops up.

Thanks all for your help