Adjustable Suspension Arms

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zossy1
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Re: Adjustable Suspension Arms

Postby zossy1 » Wed Jun 29, 2011 7:04 pm

NitroDann wrote:1.5 degrees is EASY both ends even with stock ride height.

Of course, as you adjust camber castor will be affected this is normal.

You want something like 2 degrees front and 2.5 rear with absolutely maximum camber for a mild weekend warrior on street tyres. And zero toe whatsoever front and rear.

Or just go to spinning wheel.

Dann


Opinions are like... well you know, ND...

But you really need at least *some* toe in front and rear on a street setup. That's MY opinion. Happily, Flyin Miata happen to agree with me :)

I agree that, unless something is bent up there, Bob Jane need to be kicked up the arse. If your car is lowered at the front, it should be easy as anything to dial in -1 camber... Heck, my aligner just told me that the LEAST camber he could give me was -1.5 degrees on the front (mine's lowered to align the top of the tyre tread to the lip of the guard front and rear - running 15's and 50 profile tyres).

Rear camber is more of a problem - the minimum camber he could achieve on the rear was -3.5 degrees. I was considering adjustable uppers on the rear until I read what you posted re the just jap wishbones. There are sets available from the US on eBay... or I may just have a set of elliptical upper bushes made for the rear.

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Re: Adjustable Suspension Arms

Postby nicholas787 » Wed Jun 29, 2011 7:11 pm

zossy1 wrote: I agree that, unless something is bent up there, Bob Jane need to be kicked up the arse. If your car is lowered at the front, it should be easy as anything to dial in -1 camber... Heck, my aligner just told me that the LEAST camber he could give me was -1.5 degrees on the front (mine's lowered to align the top of the tyre tread to the lip of the guard front and rear - running 15's and 50 profile tyres).

Rear camber is more of a problem - the minimum camber he could achieve on the rear was -3.5 degrees. I was considering adjustable uppers on the rear until I read what you posted re the just jap wishbones. There are sets available from the US on eBay... or I may just have a set of elliptical upper bushes made for the rear.



I will lower the front, as you said it should give me more camber, it also happens to not be as low as i'd like.
Sounds like the rear is still significantly lower than mine if you're minimum camber is 3.5Neg

Just Jap sell bright red ones with the threaded adjusters as shown on their website.
Same set as i saw on ebay just after i returned mine to just jap.
Short of importing some Flyin Miata ones from the States, the elliptical bushes sound like the way to go.

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Re: Adjustable Suspension Arms

Postby NitroDann » Wed Jun 29, 2011 7:36 pm

No hes got 2 degrees rear, and thinks he cant get what he wants cos the aligner was a useless halfwit and told him so.

As for the toe and general alignment setting, those were just a start to get him on his way with his setup, Its by no means exactly what he needs or wants. As he will never get what suits him first go anyway.

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Re: Adjustable Suspension Arms

Postby zossy1 » Wed Jun 29, 2011 7:41 pm

nicholas787 wrote:Sounds like the rear is still significantly lower than mine if you're minimum camber is 3.5Neg


Well it isn't slammed... but yeah, she's low :)

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Re: Adjustable Suspension Arms

Postby manga_blue » Wed Jun 29, 2011 10:25 pm

NitroDann wrote:Everyone is tiptoeing around it. Im going to be blunt.

Mx5s go best with about 1 deg more in the rear than front. So your issue with more in the rear is right.

Also if you truly have gone so low you have crazy amounts of camber the handlings ruined anyway.

Also get it away from bob jane. Cant adjust the front camber !!! Bullshit.

2.5 degrees front and 3.something rear is heaps for anything less than big semislicks that you dont have.

Dann

I'll be even blunter, Dann. Nothing personal against you but I reckon what you said here is all just bullshit. Here's Emilio's basic layout:
Emilio at 949Racing wrote:Since everyone seems to have widely varying opinions on optimum alignments settings for the 90-05 Miata, I thought I'd add mine to the mix just to confuse things.

THESE ARE NOT STOCK TIRE, SUSPENSION, STREET OR TIRE WEAR FRIENDLY SETTINGS!

These are the maximum performance settings I use to set up a Miata to generate the best balance of turn in, steady state lateral grip, braking grip/stability and power application in competitive type driving environments The bias is towards steady state lateral grip as that is what makes a Miata fast more than the other facets of it's performance envelope.

These settings assume:

* Either factory sport package Bilsteins, Koni's or high performance aftermarket dampers
* At least a slight increase in static spring rate front and rear
* True high performance tires, not bargain all season rim protectors
* You are comfortable with potentially less high speed directional stability than the Mazda factory alignment settings may provide

Notes:

These settings work best with a torque sensing helical diff like the factory Torsen. Clutch type diffs may require -1/16" total front toe to help the front turn in off throttle in autocross situations. Ideally you will change the front to rear spring rate and anti-roll bar differential (FRC) biased towards the front. The OE FRC is only slightly front biased but the lower front camber serves to keep the car more or less neutral. I have found that setting the front camber from equal to -4* more than the rear provide best grip and lowest lap times. Doing this on an otherwise stone stock Miata will result in an excessively loose, tail happy car so don't!

To maximize the performance you need to test, test, test. That means, same tires, same driver, same conditions, change on thing at a time. Record tire temps with a probe type pyrometer (no lasers!), lap times, tire wear patterns, tire pressures and most importantly, driver impressions immediately after run. There is no optimum alignment for every condition. The more you are trying to squeeze out of the car, the more you have to test, record adjust, repeat.

Most DOT R compound race tires will develop their peak steady state lateral (cornering) grip at camber, toe and pressure settings that won't necessarily show even tread temps or wear. Generally when temps are even you are either very close or spot on, but don't assume anything. Clocks don't lie

Please don't ask me how your tires will wear because: A) I don't know. B) You shouldn't care if you are considering using these settings as a starting point. In practice, when the suspension is right, my race tires wear absolutely perfector, run a tad hotter inside, only need about 30psi hot and the car is fast.

Miatas between 13 - 12" front ride height

Front camber: -2* (or as close as you can get to it)
Caster: +3.75 to +4.25*
Front total toe: 0

Rear camber : -1.8*
Front total toe: 0

Miatas below 12.0"

Front camber: -2.8* (or as close as you can get to it)
Caster: +2.75 to +3.5*
Front total toe: 0

Rear camber : -2.5*
Front total toe: 0

Miatas over 180whp or so can add +1/16" total toe in at the rear to attenuate corner exit power oversteer.

http://forum.miata.net/vb/showthread.php?t=245058
’95 NA8

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Re: Adjustable Suspension Arms

Postby NitroDann » Wed Jun 29, 2011 10:38 pm

Theres a lot of opinion around. Sav runs more rear camber and I trust him. I dont know if hes faster than emelio. But anyways the main point here i think is dont ever go to a tyre joint for a wheel alignment. I always run more rear camber than front, and max castor. The castor evens up the dynamic camber when cornering. This is all preferrence though isnt it.

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Re: Adjustable Suspension Arms

Postby manga_blue » Wed Jun 29, 2011 10:59 pm

Yh, I'd go along with you there. I figure there are about 3 or 4 shops capable of doing it well in Melbourne, probably a similar number in Sydney (and places beginining with K or BJ are definitiely not among them).

F/R camber balance is not a strict rule. It depends on your spring, wheel, tyre choices as well as how you like to drive. My setup has been evolving for years but it has just happened to have turned out to be identical to Emilio's.
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Re: Adjustable Suspension Arms

Postby manga_blue » Wed Jun 29, 2011 11:04 pm

BTW, if you're trying to work out the effect of lowering on camber then Shaikh did a really good camber curve reckoner for that.
http://www.virkki.com/jyri/miata/camber/
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Re: Adjustable Suspension Arms

Postby zossy1 » Wed Jun 29, 2011 11:49 pm

More relevantly to the OP's original post (and to my own issues)...

http://forum.miata.net/vb/showpost.php? ... ostcount=7

Looks like offset upper bushes are in my future.

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Re: Adjustable Suspension Arms

Postby Guran » Thu Jun 30, 2011 12:15 am

Even stock suspension will allow up to 1.25-1.5 degrees of negative camber on the front. You need a wheel alignment at a competent workshop not a tyre store!
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Re: Adjustable Suspension Arms

Postby NitroDann » Thu Jun 30, 2011 8:07 am

I think its worth adding is that guran means stock height, lower than stock much more can be achieved.

Dann
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Re: Adjustable Suspension Arms

Postby jerrah » Thu Jun 30, 2011 8:54 am

I have Koni Yellows (maximum height setting) and Kings lowering springs.

With this the minimum rear camber I could achieve was -2.1 but at this height I have -2.0 front at 4 caster. 0 toe.

If your car is set up evenly I would assume you should be able to achieve at least -2 in the front if you have -2 in the rear or perhaps the car needs to be lowered at the front and raised at the rear slightly?

Can you measure the height of your car at each corner?
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Re: Adjustable Suspension Arms

Postby Charlie Brown » Thu Jun 30, 2011 10:18 am

Can I just pitch in here with a little more information for you?

There are a couple of points that have been missed by the others that are quite important.

You were after 1 degree negative camber front and 1.5 negative camber in the rear to obtain maximum grip. These are great figures when you are running the standard height in an NA or NB. As soon as you lower the car you need to increase the negative camber, by how much depends on how far the car is lowered.

On the NC a rule of thumb is for every 10mm lower you need to increase the negative camber by around 20 seconds. So with a 30mm drop increase the negative camber by a degree. You’ll need to check what it is for the NB, though Stu at Spinning Wheel will know straight away. I’d forget taking the car to your friend’s aligner especially if he normally does Nissans. You need to go to an aligner that specialises in MX5’s.

Another point, before you get an alignment, make sure that the rake of the car when measured on level ground, is between parallel and 10mm higher at the rear than the front. Do not have it dragging its arse.
Also ensure that the height side to side is the same. In other words measure from the centre of the hub vertically to the lip of the guard. The height should match both sides for the fronts and both sides for the rears though front to rear can be different depending on the rake.

Once you have done all this you are ready for an alignment, otherwise you are just throwing money away.
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