How should i set up my car?

[CheyneX5]

Hi All,

Over the past year, i have spent some time modifying my car. I have focused on suspension rather than power. Now that i have everything that i wanted together, the car feels good, but not amazing. I'll explain...

- First things first. I have read a lot about alignment over the past year. I have also had a couple of alignments. Everything felt great until the new wheels were put on. The steering now has little feel, delayed turn in and has a small dead spot when centred. Ill write the specs of my current set up down a little further. I understand that after putting on wider and lower offset wheels that the cars handling will change, but not this much.

- The car seems to have quite a bit of scuttle and shake when going over anything less than smooth, this can be quite unnerving mid corner, It almost feels like the suspension towers are doing a little dance, possibly somewhat corrected by a strut brace...? I would expect a little of this from a car that has been stiffened so much, maybe i have made it a little too stiff?

- It loves wide open corners and grips till the cows come home, however i have noticed that it does not like groups of tight corners as much (I'm using a tight sector of a road near port campbell near the GOR as an example). It has a tendency to understeer, it also feels a little delayed and quite unsettled when changing directions quickly. Don't get me wrong, it still turns well, but not as well as it should.

My alignment specs are:
Front:
5 Degrees of Castor
2.4 Degrees Neg Camber
1.6mm Total Toe In

Rear:
2.2 Degrees Neg Camber
2mm Total Toe In

I have a 1990 NA6. It has done 209,000kms and has the following mods:
- Koni Yellow Adjustable Shocks, If 1 is Softest and 10 is Hardest, Front is on 7.5 and rear is on 7.
- King Springs
- Flyin Miata Adjustable Sway Bars (23mm Front and 16mm Rear) Front is set to Hardest and rear is set to Medium
- Racing Beat Length Adjustable Sway Bar End Links
- Cusco 4 Point Front Subframe Brace
- Cusco 2 Point Rear Subframe Brace
- 949 Racing 6UL 15x8 +36
- 205/50/15 Bridgestone Potenza RE002 Running at 36psi
- Brown Davis Steel Roll Bar

I can provide more info if needed, i know that some of you are running similar set ups to me and i would be curious to know what works? I drive the car daily but like to have fun with it within reason. The occasional track day will be considered as well.

Thanks a lot for reading and i look forward to some suggestions

[sailaholic]

the rims are not "low" offset, so shouldn't make a big difference.
Reducing the front toe will give better turn in, some where just under 0.

I'd probably try softening front and rear swaybars to mid and full soft respectively.

Also try the koni on full hard front, 8? Rear. Do each step one at a time then test drive out decently before changing the next. If it is worse change it back, but be properties to try it again once you change something else.

Sent from my GT-I9100 using Tapatalk

[manga_blue]

Cheyne, I'd set the toe to zero, both front and rear. That alone should make the car feel.livelier and turn in faster. You can do that yourself with just stringlines or a tape.

If there's too much scuttle then it might be the result of stiff springs AND stiff sways. Going back to stock sways couldfix it.

[NitroDann]

Zero toe front and rear, soften the front swaybar. Lower tyre pressures, try 32.

Dann

[93_Clubman]

Cheyne, does your NA6 have PS?

[CheyneX5]

Cheyne, does your NA6 have PS?

It has Manual Steering

Zero toe front and rear, soften the front swaybar. Lower tyre pressures, try 32.

Dann

Cheyne, I'd set the toe to zero, both front and rear. That alone should make the car feel.livelier and turn in faster. You can do that yourself with just stringlines or a tape.

If there's too much scuttle then it might be the result of stiff springs AND stiff sways. Going back to stock sways couldfix it.

I have read that having Toe in on the rear will be a benefit, i have always had this. How will zero toe help the rear? Also, should i leave the rear sway bar on medium when changing the front to soft?

Phil, I have never heard of Koni and Kings having issues with Scuttle and shake, i'm thinking sway bars need to be adjusted first as you mentioned.

the rims are not "low" offset, so shouldn't make a big difference.
Reducing the front toe will give better turn in, some where just under 0.

I'd probably try softening front and rear swaybars to mid and full soft respectively.

Also try the koni on full hard front, 8? Rear. Do each step one at a time then test drive out decently before changing the next. If it is worse change it back, but be properties to try it again once you change something else.

Sent from my GT-I9100 using Tapatalk

I don't think stiffening the shocks will help much, it already crashes around. I will try the sway bars first.

[manga_blue]

The 16mm rear bar is pretty massive. You've almost converted the rear suspension to a beam axle and, with the assistance from stiff springs, it sounds like it's handling like one.

Have a look at Emilio's comments about sways.
http://949racing.com/miata-race-alignment-info.aspx

[CheyneX5]

The 16mm rear bar is pretty massive. You've almost converted the rear suspension to a beam axle and, with the assistance from stiff springs, it sounds like it's handling like one.

Have a look at Emilio's comments about sways.
http://949racing.com/miata-race-alignment-info.aspx

Emilio makes some very good points and is basically echoing what you are all saying.

Instead of getting rid of the rear sway bar, ill try it on full soft first, same with the front. I was always in the mindset that stiffer is better, clearly not

Am i right in saying that i should basically copy the first alignment he lists? for => 12.0" Front Ride Height if i am using Koni & King?

[93_Clubman]

Cheyne, does your NA6 have PS?

It has Manual Steering

ok - if you don't have any luck with other suggestions then it might be worth noting Bwob's observation: "it is woolly at center".

His second post, third para, on this page elaborates:
http://forum.miata.net/vb/showthread.php?t=127316

More info if you need to follow up:
viewtopic.php?f=30&t=47568&p=597451#p597451

[manga_blue]

Just do the easiest things first, Cheyne. 30-32 psi and 0 toe at the front.

[CheyneX5]

Cheyne, does your NA6 have PS?

It has Manual Steering

ok - if you don't have any luck with other suggestions then it might be worth noting Bwob's observation: "it is woolly at center".

His second post, third para, on this page elaborates:
http://forum.miata.net/vb/showthread.php?t=127316

More info if you need to follow up:
viewtopic.php?f=30&t=47568&p=597451#p597451

Spot on, but it feels worse since i changed the wheels and the alignment.

Just do the easiest things first, Cheyne. 30-32 psi and 0 toe at the front.

Will do

[NitroDann]

Rear toe is *really* hard to explain in words so bear with me.

Imagine a few hypotheticals first.

When you are turning HARD, a lot of weight is transfered to the outside tyres. Imagine for a second you are turning so hard that the inside tyres are just 1mm off the road surface. Now the outside tyres are 100% influencing the direction of the car. If the front outside tyre is turned inwards 10*(degrees) and the rear tyres have 10* toe per side, both the front and rear tyres will be pointing the exact same direction. In this case, because only the outside tyres are touching the ground, and they are both turned the same direction the same amount, the car will 'crabwalk' not turn, right? And if the rear was 10* toe out per side the car would turn superfast like a tractor with an articulating centre.

Anyways, when turning, even not hard enough to lift both inside tyres the outside has much more influence on direction change than the inside, so toe in will make the car rotate less and crabwalk more, where toe out will bring the back end around more. Either way, rear toe out makes the rear end far more live, and makes the car turn and change direction agressively. So going from toe in to zero toe will make a huge improvement at the rear.

Dann

[noobee]

greasing front swaybar bushes made a difference to mine,they were locked solid,dry as a bone.I had both links off and could not move the bar.I was told the sways (whiteline adjustable) were fitted about 18 months ago.havent got to the rear yet.
Mick

[CheyneX5]

Rear toe is *really* hard to explain in words so bear with me.

Imagine a few hypotheticals first.

When you are turning HARD, a lot of weight is transfered to the outside tyres. Imagine for a second you are turning so hard that the inside tyres are just 1mm off the road surface. Now the outside tyres are 100% influencing the direction of the car. If the front outside tyre is turned inwards 10*(degrees) and the rear tyres have 10* toe per side, both the front and rear tyres will be pointing the exact same direction. In this case, because only the outside tyres are touching the ground, and they are both turned the same direction the same amount, the car will 'crabwalk' not turn, right? And if the rear was 10* toe out per side the car would turn superfast like a tractor with an articulating centre.

Anyways, when turning, even not hard enough to lift both inside tyres the outside has much more influence on direction change than the inside, so toe in will make the car rotate less and crabwalk more, where toe out will bring the back end around more. Either way, rear toe out makes the rear end far more live, and makes the car turn and change direction agressively. So going from toe in to zero toe will make a huge improvement at the rear.

Dann

You painted quite the picture there Dann. I understand.

Is there any disadvantage to Zero toe then? It sounds quite neutral...

greasing front swaybar bushes made a difference to mine,they were locked solid,dry as a bone.I had both links off and could not move the bar.I was told the sways (whiteline adjustable) were fitted about 18 months ago.havent got to the rear yet.
Mick

Thanks Mick,

The sway bars were heavily greased before installation 9 moths ago. Good point though

[NitroDann]

You probably think your car now is pretty neutral now.

Zero toe eliminates scrubbing, ie the car will have less resistance to roll, which is important in a low powered car like ours. Try it out.

Dann