psreynol

from 4.2 front and 4.5 rear, non corner weighted and no driver weight. to about 4.5 all around. it made me a few tenths slower. I want to try 4.1 on all corners perhaps 4.35 driver side front. going in for a corner balance and alignment next week seeking a little more speed.. should I get bushings or perhaps upper rear control arms for the rear to aid alignment? sad to say I don't dedicate the time I would like to the hobby so ideas are appreciated.I recall pole miatas are qualifying in the high 2.48s and I'm only doing low 2.47s. now I know on track the car is not very fast but for now I want to focus on suspension setup. i;ve never had an alignment or corner balance before so it cant hurt. any pro tips for set up? the other possibility is the maxiss rc-1 are falling off. after 5 days. good tires but it seems they will heat cycle out well before the rubber is gone...

z31maniac

It's going to be difficult for anyone to give you advice without tires, alignment, tire temps, add in never having had the car corner balanced, etc.

flier129

iTrader: (7)

Ok, I'll be that guy..... are you sure those few tenths going slower isn't just your driving? If pole miata(Spec Miatas?) are qualifying at a 2:48 at the same event and you're only ~1 sec faster on a turbo setup...... I'd chalk it up to inconsistent driving. Plus different ambient temps, track temps, heat cycles on the tires, head wind, tail wind, humidity, amount of gas in the car(weight), etc.

Set your height to where your suspension isn't bottoming out, get an alignment, and go drive. Not to mention, a few tenths on a damn near 3min track is like a fart in the wind difference for a HPDE car. Also keep in mind one set(alignment,corner weights, height, etc) could work for this track, but would need to be vastly different at another track.


TL;DR - Don't put the carriage before the horse.

dc2696

iTrader: (2)

http://949racing.com/miata-race-alignment-info.aspx

This gets you 98% of the way there setup wise. After that its a matter of being consistent enough to know what the car is doing right and what its lacking and fine tuning things, not; I need to go faster so I'm going to change this stuff.

You have any data/video to help people with your setup?

psreynol

So I believe the tires are toast.. got the car corner balanced and aligned and the car was undriveable. swapped the slightly older rear tires to the front and it was better but still pushed at turn in and over steered on track out. over all I was about 4 seconds off my previous fast times. I guess this is a starting point for next year. do these settings look reasonable? they took the caster pretty low due to no power steering. The car gets pretty hot and I think it is killing my power. my fast laps are pretty much always the second or 3rd lap if I get a clean one. I'm going to see about perhaps buying a camera for next year. I've been slow to do so because Harrys laptimer has been unreliable for me so dont want to buy a camera if i end up going with another system.


Alignment specs:
Ride height: LF 4"1/8 RF 4" 1/8 LR 4" 1/8 RR 4" 1/16
Corner Weight: LF 696 RF 665 LR 577 RR 546 TOTAL 2484 with 210 driver 3/8 fuel
Percentages Cross:50.0% Left 51.0% Front 54.7%
Front Camber: 3.8'
Rear Camber LR -2.8 RR -3.0
Toe: Front 0.0" Rear 1/8" Total
Front caster 2.0

themonkeyman

That is a lot of camber for a streetable car. What spring rates and front/rear bars are you running? Are you checking tire temps with a probe-type pyrometer? Whats tread wear look like? You say tires are shot, how many track hours or heat cycles are in them? Also which tires are you running and what size? Your sig mentions NT01s but you mention in the first post RC-1 Maxxis... Still gonna need lots more info to help point you in the right direction.

Savington

iTrader: (31)

Car is half an inch too low

mx5-kiwi

We found that much rear camber to be slower but we run a 15mm (equiv) rear bar. We ended up finding 2 - 2.5 was about right with 1600cc 260 Hp atw and 200 ft /bs.

Also, if your doing this naval gazing on worn / used tires your probably wasting your time.

Stick very closely to the 949 recommendations and have faith you are in the ball park is how I run...its worked well so far (thank you 949 once again )

ThePass

iTrader: (3)

Any testing on old tires is meaningless.

psreynol

If I raise the car 1/2 inch in the off season (now) is that enough of a change to justify paying for a new alignment and corner balance? yes I'm sure it is better to have it all done again so let me rephrase the question, should I leave it alone and try my first event with fresh tires on these settings, or just jack the car up 1/2 without a new alignment & corner balance? the spring rates are 800F/500R with the damper adjustment assuming 0-21 clicks for 0-1000lbs spring rate, 17 front and 11 in the rear. the tires have about 40-45 heat cycles but the last 5-10 were very slow. I guess I was pushing the tires too far, they were garbage at the last event but I chalked it up to raising the car to about 4.5 on all corners but clearly I was wrong. 28psi hot tire pressure. as much as it sucks to be slow at times, much can be learned by driving a poorly set up car fast.

with a free nitrogen tank in the garage, I should have more time for tire pyro measurements next year! I stuck to what 949 recommends, the alignment settings are within their recommended spec, some numbers are on the high or low but still within suggested range.

mx5-kiwi

While I am sure the track and race die hard's will be horrified.... I haven't corner weighted the car yet BUT I am fairly stringent about regular wheel alignments. Almost without fail before every race meeting or track day.

A raise in ride height like that would definitely have me at a wheel alignment.

Don't forget that the mx5 alignment bolts and cams do move under load AND stretch / wear out. I don't replace them every season like (i think) Emilio suggests but every 1.5 to 2 seasons otherwise they just dont hold. It's not unusual to have one wheel completely out between race meetings, having moved at some stage. My guess is that cornering and braking at 1.2 - 1.6+ g will do that..? (good race tyres through to good race tyres and aero)

I also disagree with you about driving a badly setup car.......a slow / under powered car can teach you corner speed and momentum but badly setup is just badly setup.....the difference when I get the setup right in our car to not setup is amazing.

Setup right is a pure joy to drive where every thing you do or try comes off (within reason), you get on the gas sooner and sooner in amazement to not setup or balanced just doesn't come off as fun and is an instant self help course in "why do I suck at this today?"

Of course my car to Emilio or Sav is likely badly setup (no corner weight, too big a rear bar etc) but its all degrees of what your used to I guess....

My 5c anyway.

Savington

iTrader: (31)

You are wasting your time. 45 heat cycle tires are trash, any setup data gleaned from test time on those tires is useless. Replace the tires, raise the car 1/2", realign it or just toe-plate it so that all four wheels are pointing straight. You are so far off the mark at this point that cornerweights are a waste of time. Once the car is actually working the way you want it to, you can decide whether cornerweights are worth doing. Cornerweights make sure the car works the same in left/right turns, so if it feels fine in lefts but pushes slightly in rights, it's time to cornerweight. If it feels fine everywhere, save your money.

Your question re: new tires or raise the car is akin to "Which of these two bad ideas should I execute on?" The answer is neither.

k24madness

iTrader: (6)

I'll start by agreeing with the rest of the crowd, you need new tires before ANY further evaluations can be made. I would also reset baseline settings to latest 949 recommendations(height/camber/castor'/toe) and tweak from there.

When you raise the car you loose camber and toe settings change. Sometimes you can't get that camber back without ELBJ or offset bushings. The current mindset with those in the know is to run higher ride heights and ELBJ. This gets you great static camber/castor settings and the added ride height gets you better camber gain so you don't have to run as much static camber. This will help in braking and acceleration.

Savington

iTrader: (31)

Added ride height helps with compliance and roll stiffness, not with camber gain. Low ride heights were a bandaid to get adequate camber, now we have ELBJs which negate the need to run the cars too low.

k24madness

iTrader: (6)

I agree and respectfully disagree....

I understand roll stiffness improves as control arm angles get closer to horizontal. So I agree there

If I use all the available bump travel in a corner (which I do in turns like 1 and 6 at Sonoma) the camber at full bump is now greater than it would have been at 1/2" lower with the same static setting. That's where I get added camber gain from the higher ride height.

Savington

iTrader: (31)

If you use up all the available suspension travel in specific places, and the additional ride height allows for additional travel, then sure, you get extra camber in those specific places. I was specifically referring to this, though:

Raising the ride height will not reduce the required static camber at in every corner on a track. Unless you are actually using the extra suspension travel in high-load corners, the camber requirements are going to be very similar. Perhaps the extra roll stiffness in the front will mean a little less front camber is required, but the rear end is not nearly as compromised.

psreynol

Thanks for the help. mistakes are made. the tires were starting to really fall of the previous day but thought it might be the increased ride. mistakes are made. will try again.