Adjustable control arms for Miata

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Dan133
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Re: Adjustable control arms for Miata

Post by Dan133 »

Both sways are stock. Good driving might be out of the question--- I might have to do it with hardware.
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Re: Adjustable control arms for Miata

Post by phranquelynn »

i'm thinking wider wheels is a cheaper alternative.

try asking for ideas on miata.net also.
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Re: Adjustable control arms for Miata

Post by milkmandan »

if both sways are stock, you definitely need some thicker bars. a big fat tubular front bar will have you understeering in no time. a lot cheaper and easier than control arms too.
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kyle.bowker
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Re: Adjustable control arms for Miata

Post by kyle.bowker »

eage8 wrote:
kyle.bowker wrote:and more camber definitely won't hurt.
More is not always better. -10°will likely hurt grip both in the corners and accelerating down straights. It's all about the choosing the right static camber setting for your particular setup (ride height, roll stiffness, roll center, etc.) I don't ever see people needing more than -4° or -5° in the rear on a Miata and that is sometimes doable with the stock eccentrics. Last I heard Dan was already running a decent (albeit street biased) performance alignment - Icehawk or Lanny or whatever. I don't believe he is going to get the gains he's looking for by adding a degree or two of additional camber.
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Re: Adjustable control arms for Miata

Post by kyle.bowker »

Dan133 wrote:Both sways are stock. Good driving might be out of the question--- I might have to do it with hardware.
Which coil/spring setup did you go with? I remember trying to persuade you towards the FCM valved Bilsteins or the Tein Flex as good choices for a dd Miata. Both of those setups are often tuned for a mild front sway bar upgrade (think Flyin' Miata) and NO rear sway bar at all. If you're running on a relatively mild coil/spring setup (KYB AGX or Koni Yellow & some lowering springs) then you might get some gain with a matched set of beefier sway bars.
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Re: Adjustable control arms for Miata

Post by eage8 »

kyle.bowker wrote:More is not always better. -10°will likely hurt grip both in the corners and accelerating down straights. It's all about the choosing the right static camber setting for your particular setup (ride height, roll stiffness, roll center, etc.) I don't ever see people needing more than -4° or -5° in the rear on a Miata and that is sometimes doable with the stock eccentrics. Last I heard Dan was already running a decent (albeit street biased) performance alignment - Icehawk or Lanny or whatever. I don't believe he is going to get the gains he's looking for by adding a degree or two of additional camber.
I realize that more isn't always better. I didn't realize you could get -4 or -5* of camber out of stock components. I was thinking he was running -1-2*.

he's also running tokico illuminas with ground control coilovers if I'm not mistaken.

If you're running stock sway bars, I would definitely at least upgrade the front sway bar and see how you like that. it's a lot cheaper than new control arms.
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moxnix
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Re: Adjustable control arms for Miata

Post by moxnix »

Without full details of the current setup (Spring rates, Ride heights(fender lip to wheel center), tire pressures, Alignment, Shock settings(If adjustable), Tire model, Number of runs on tires, Other suspension mods) it is hard to give anything besides general advice.

Having said that. In general these are some other things besides camber that can cause oversteer in a miata.
If the rear is to low for your spring rates you can get into the bump stop or even hit the control arm on the frame and increase the rear rate and cause oversteer.
If you trail brake going into the corner you can cause oversteer.
Old heat cycled tires can cause oversteer.
Rear toe settings can cause oversteer.
Tire pressures (to much or to little) can cause oversteer.

Most of the STS miata's are in the 2-3 degree camber range but they are running 350-450 springs in the rear.
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Re: Adjustable control arms for Miata

Post by Dan133 »

Running Illumina's and ground control's from Flyin' Miata. With the stock eccentrics maxed out I am getting approx -1.5 front and -1.8 rear. Ride height approx 12.5'"center of hub to lip.Toe is set at OEM both front and rear. Tires------ I have those fairly worn A6's but will have to do something else this year as well. I don't see the advantage of a bigger front sway as (if I understand correctly) that would just cure my oversteer by creating some push. Push always feels slow. I want to increase the overall cornering G's. And I really do appreciate everybody's input. This is a great learning experience.
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Re: Adjustable control arms for Miata

Post by david.valeri »

Dan133 wrote:Running Illumina's and ground control's from Flyin' Miata. With the stock eccentrics maxed out I am getting approx -1.5 front and -1.8 rear. Ride height approx 12.5'"center of hub to lip.Toe is set at OEM both front and rear. Tires------ I have those fairly worn A6's but will have to do something else this year as well. I don't see the advantage of a bigger front sway as (if I understand correctly) that would just cure my oversteer by creating some push. Push always feels slow. I want to increase the overall cornering G's. And I really do appreciate everybody's input. This is a great learning experience.
It is curing your oversteer by changing the weight transfer characteristics of the car, not by losing overall grip. If you were to cure your oversteer by over inflating the front tires to reduce their maximum grip level, you would be sacrificing grip at one end to balance out what you have at the other. You would effectively have degraded the front grip to match the apparent lack of rear grip. But what if your rear grip potential is the same as that in the front, but you are asking the rear of the car to carry too much load through the corner. If you alter the weight transfer characteristics of the car, you can ask the front end to pick up more of the load, which consequently reduces the load on the rear and can bring the car back towards neutral or understeer.

Think of it as making the front work to its full potential rather than reducing the front's potential to that of a possibly overtaxed rear.

Your front/rear spring rate bias and your roll axis inclination (think rake of the car as the roll center at the front and rear of the car are not at the same height and you also lowered your car as well so you may have moved the front/rear relationship here as well) also contribute to TLLTD.

Unlike weight transfer items, your alignment and tire pressures contribute to the grip available at each end of the car independently.

See:
1) http://grassrootsmotorsports.com/articles/lean-less/ - section on TLLTD and anti-sway bars
2) http://buildafastercar.com/tech/Roll-Centers
3) There are a ton of books with good diagrams out there as well. Try Amazon and ask for some recommendations on here.
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Dan133
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Re: Adjustable control arms for Miata

Post by Dan133 »

Verrrrry interesting. (the second article--for some reason Grassroots is a bad gateway this morning-Damn Chinese Gov't)

thanks,Dave. Lots more to think about.
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Re: Adjustable control arms for Miata

Post by moxnix »

Dan133 wrote:Running Illumina's and ground control's from Flyin' Miata. With the stock eccentrics maxed out I am getting approx -1.5 front and -1.8 rear. Ride height approx 12.5'"center of hub to lip.Toe is set at OEM both front and rear. Tires------ I have those fairly worn A6's but will have to do something else this year as well. I don't see the advantage of a bigger front sway as (if I understand correctly) that would just cure my oversteer by creating some push. Push always feels slow. I want to increase the overall cornering G's. And I really do appreciate everybody's input. This is a great learning experience.
Are you giving up caster in the front to max camber?

Stock GC spring rates are 375F, 250R is that what yours are? IMO they are lightly biased toward oversteer with stock bars but they seem well matched with a big front bar.
Stock alignment specs for toe are.
Front
Toe out 1/8" +/- 1/8
Rear
Toe in 1/8" +/- 1/8"
So stock toe is a range not a setting and can be anywhere from 0 to 1/8" (A big difference in feel in high performance driving).

If you are on old tires I would get fresh tires on the car before you start trying to fix any handling problems because your car will be completely different on fresh tires.
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Re: Adjustable control arms for Miata

Post by edfooliu »

moxnix wrote:If you are on old tires I would get fresh tires on the car before you start trying to fix any handling problems because your car will be completely different on fresh tires.
Amen. Everything begins and ends with tire; tune the suspension for the tire. Don't know if rcomps are any different, but at least with street tires, my entire setup changed _dramatically_ with tire choice... the alignment settings, springrates, etc that worked with one tire didn't work with another (and changed as they wore since I started with full treads instead of shaving).
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