Stein

iTrader: (46)

For my upcoming track day I'm looking for initial tire pressures and shock settings. We are running four hours on the road course and four hours on a prepped drag strip.

306 V8/Tx/8.8 with 3.73 gears
NB Miata, probably 2500 lbs (I suspect I gained 150 lbs)
Tein Flex, standard springs that they come with
Hard Dog HCHT bar, Stein frame rails
Stock NB front bar, no rear bar
new RS3's on 15x8 6ULs
FM performance street alignment, nothing extreme

Best guess for tire pressures and shock settings for both road course and drag strip.

I have a new set of 205/50/15 Mickey Thompson ET Street Drag Radials on another pair or 6ULs for the drags. Also, I've never been to the drags - haven't even ever launched this car.

Stein

iTrader: (46)

No love.

mx5-kiwi

Hi Stein, I suspect problem is question is to broad and very directly relates to your driving style and specific setup.

Without knowing spring rates etc it is very hard.

My first thought for the road course is have you bled your brakes and put in hi temp fluid and pads and/or bigger brake setup?

My friend with an LS1 (?) has terrible brake issues on our road courses. Brakes catching fire, fading to nothing etc and this is WITH a 6 pot willwood and 11.5 - 12" rotor and the correct pads (well race pads, correct is still questionable...). A V8 Mx5 is a VERY fast car on the track.....think close to Porsche GT3 speeds (maybe one with an average driver... )

Tyre pressures we end up running are anywhere from 23 - 30 psi on dunlop 03g/toyo r888 type tyres but varies tremendousley on track type, ambient and track temp, type of tyre (no experience with RS3's) and how long each session is......I can get my tyres close from looking at them after a session but I spent years road racing motorcycles....where tyres are your life!

You want a slight amount of rubber rolling off the outside of the tyre, and the surface looks a bit like 200 grit sandpaper but ****, hard to explain....(gonna get nailed for that descriptpion I suspect)

Try and talk to someone who is religousley measuring tyre pressure/temps at the beginning of the day and after each session. They will most likely point you in the right direction...people who just show up and drive...not so much.

As far as suspension goes I would imagine full stiff at both ends and reduce at either end from thereon for balance (pointy, tail'y....). I would think Teins with standard rates are TOTALLY unsuitable for a v8 Mx5 on the track (still to soft) but you will still have fun (while you have brakes at least....)

You might also want to lower the car (but don't go crazy), this might help reduce roll and pitch making braking and cornering a bit more pleasant.....of course this needs a new wheel alignment (See 949racing.com for suggestions on wheel alignment for track cars).

For the strip probably reduce rear to full soft for weight transfer at launch..? Could even raise the car a little to promote further weight transfer...?

Very vague but hopefully helps or initiates someone with more experience than me to chip in and correct my errors

Most of all have fun, take it easy on the car and it should be an awesome day.

Stein

iTrader: (46)

Thanks for the input, I understood your description of tire wear just fine.

I do have a Corrado front big brake kit with XP8 pads and stock NB rears with XP10's and a willwood prop valve that I have set as close as I can on the street, will adjust at the track. Brake system was flushed with Willwood 570* brake fluid.

Car height is lowered some with 1/2" rake at the pinch welds. IIRC it was set to 12" and 12.5" at the fender-to-hub.