Soarer Central: Archive through April 09, 2009

Soarer Central Suspension Why you shouldnt lower your car too much- For better handling, read on Archive through April 09, 2009

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David Samuel
Tinkerer
nsw
v8

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Wednesday, April 01, 2009 - 06:45 pm, by: David Samuel (Thenavigator)

ben
hey mate been racing karts for 15 years....my boy when he was 9 years old would put a kart through a 90 degree tight corner at over 110 kph and not come out of the throttle.....poo your pants takes more than that.
just for the record mate !
ps ..how fast were you going when you were nine.

David Samuel
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v8

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Wednesday, April 01, 2009 - 06:47 pm, by: David Samuel (Thenavigator)

ben
sorry about that , i guess i am saying do not make too many assumptions .

David Samuel
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v8

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Wednesday, April 01, 2009 - 08:08 pm, by: David Samuel (Thenavigator)

dave
thank you. it could be the unloaded rear. ill collect together all the data i have and , if its ok , ill get back to you. is dynamic camber similar to "total collect" ? and what is K.P.I ?
i am finding this very interesting....i like to make decisions based on information not supposition, over the years i have found in yields better/repeatable results.
kind regards david.

Ben Lipman
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NSW
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Thursday, April 02, 2009 - 06:51 pm, by: Ben Lipman (Ben12a)

David Samuel wrote on Wednesday, April 01, 2009 - 06:45 pm:
ben
hey mate been racing karts for 15 years....my boy when he was 9 years old would put a kart through a 90 degree tight corner at over 110 kph and not come out of the throttle.....poo your pants takes more than that.
just for the record mate !
ps ..how fast were you going when you were nine.

David Samuel wrote on Wednesday, April 01, 2009 - 06:47 pm:
ben
sorry about that , i guess i am saying do not make too many assumptions .

WTF?

David Samuel
Tinkerer
nsw
v8

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Thursday, April 02, 2009 - 09:18 pm, by: David Samuel (Thenavigator)

ben,
W T F.....am i to draw the conclusion that you don't understand ?

Dave Cazes
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tt

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Friday, April 03, 2009 - 03:43 pm, by: Dave Cazes (Cazman)

KPI would Kingpin Inclination
Or caster, only applies to the front wheels. My advise is to max it out at the front, and youll still only have 3-3.5 degrees.
It will wear your tyres and make you track, but the added turn in is worth it.
It helps your steering wheel center itself too, more noticeable when doing U turns or drifting. Call it auto counter steer almost.

There are many many downsides to caster, but none outway the benifit.
On commodores if you run too much caster you will kill your power steering, In all cars that you push hard I would recommend a power steering cooler, this will help fix the problem with over loading your steering.

most nissan guys that are hill climbing, tracking, or drifting run 6 deg MIN (stockish) to 10 deg.

There are huge debates on this, as caster will wash off mid corner speed, and in lowly powered cup races more caster robs lap times, even though your car handles better.

None of these problems effect the soarer, just tyre wear and tracking. if you CAN put up with that then I would.

As for finding out your problem, its very hard without A. Data logging B. A friend watching C. First hand experience in the car

I would probably try to find out how mucht eh inside shock is extending, My bet is it isnt.

The cheapest way to find out is disconect your swaybar links on the rear bar.
You car will be unstable, be warned, but test it.
Turn tightly and see if the problem is still there. Ease onto the gas to see if the traction is still non existent.

But by the sounds of it its only happening when you hit the gas right?
If it does it in NO other situation, it really has to be inlift, once 1 wheel comes up just a little (doesnt have to come off the ground, just enough for the diff to spin it slightly) then the rear will step out.

Have a mate film you form behind, you will probly notice its only getting about 3 degrees sideways, but enough to unnerve you.

The soarer already has not much anti squat setup into the cradle, you can set it up for more squat, and subframe bushes will help regardless, but this way everytime you floor it, the rear end will try to squat towards the ground, thus giving moe traction.

Other potential problem in that situation, is toe setting front and rear.
Toe out on the front will casue this, I run 4mm total toe out, it gives the best turn in.
And 2mm toe in at the rear, this is still a stable setup.

if your toe settings are not near the factory settings then its not going to help.

Last test is to see if you dampers are bottoming out, put a zip tie on the base of the chrome shaft, and then go for a drive. At 340 CWG you have only about 50mm of suspension travel, I would say if you are this low, or lower when you corner hard you will be bottoming out the shock. Its not a big crash like when you hit a pot hole so you wont notice it, but when it happens the car no longer has ANY suspension, and you are just using fixed suspension (no shocks and springs)
When this happens you will also have alot of camber on teh rear tyre, maybe even 4 degrees, so already its not going to work.

I used to bottom my tein flexs out everywhere, literrally every hils drive, every 3rd corner.
I was still fast, but the car was so far from optimum it wasnt funny. It wasnt stable and stepped out everywhere.

Anyway, Im going to get back to some "work"

Damian Ware
DieHard
Victoria
UZZ32

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Sunday, April 05, 2009 - 12:26 am, by: Damian Ware (Frozenpod)

Dave, some of that post seemed to not agree with previous information if I am understanding it correctly.

Caster as you say aids the wheels to self center which aids straight line stability at high speed.

It stops the car tracking and makes it continue in a straight line even over bumps.

Factory soarer settings are nearly 3deg of caster and I believe it is possible to achieve in excess of 6 deg with other reasonable geometry settings.

Increased caster leads to a slight delay in turn in a less direct feel but as it adds camber to the front wheels it can provide more mid corner grip pending the camber settings (almost certain on a stock soarer suspension).

With increased caster you will also loose exit steering though which can help tame corner exit oversteer.

Normally on low grip tracks you will want to add as much caster as possible as it will make the car more stable. With high grip tracks you will want to reduce caster to a point as you can use the faster turn in reaction and exit steering without loosing the rear end.

Again this is all assuming ideal conditions and all other suspension settings being optimal.

David Goldthorpe
TryHard
NSW
UZZ31 GT-L

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Sunday, April 05, 2009 - 01:28 pm, by: David Goldthorpe (Sprocket82)

Hey Dave, just looking at one of the pictures in your original post. What do you call the black spring that sits on top of your main spring? I'm thinking I might need a set of these, as my car is sitting at least an inch too low. Where can you buy them and roughly what cost?

Thanks.
Dave G.

Dave Cazes
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Tuesday, April 07, 2009 - 02:31 pm, by: Dave Cazes (Cazman)

Caster seems to make the car track more, I know people on here hate tracking too.

If you can get 6 degrees out of your stock soarer ill give you $100 and a beer. Its impossible. There is NO chance of getting more than 4 degrees, and you would need to sacrifice camber to even get 4 deg.

With increased caster you lose speed full stop.
Its negligible in our cars as we all make over 160rwkw. on lowly powered civics etc this becomes a problem.

Where you said "Increased caster leads to a slight delay in turn in a less direct feel"
I realy beg to differ. The main reason people do a caster adjustment is to increase turn in. This is the main reason for doing it.

Damian Ware
DieHard
Victoria
UZZ32

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Tuesday, April 07, 2009 - 03:14 pm, by: Damian Ware (Frozenpod)

Dave I was suppirsed to see how easily it was set to a high caster setting, (this was a while ago but from memory it was 6 deg). I have heard people cant even get to the factory setting of 2.85.

I can only assume perfect bushes makes it easily combine with factory ride height and minimal negative camber.

More caster in theory should make a car track less as it aids self centering and increases high speed straight line stability. Problem is with too much caster you end up fighting the car to turn into a corner. I have actually reduced the caster back to 3.5deg as 6 deg lost way too much initial turn in.

I am not aware or I haven't experienced caster causing any loss of high speed but given it increases high speed stability I can believe there is a down side ie probably more drag. Can you explain how does caster effect high speed does it increase drag??

Tracking is caused by many factors and I think sometimes they are often mis diagnosed. I didn't notice any issues with increased caster and tracking in my soarer that doesn't mean other people that have had this issue had worn bushes, steering rack bushes ect and more caster just made the situation worse.

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Tuesday, April 07, 2009 - 04:31 pm, by: David Vaughan (Davidv)

My recollection is that higher caster should improve turn-in but especially so on tight turns, less apparently on fast turns requiring low steering where one might notice the alignment (trail) effects as resistance. A mix of high caster and low static camber might well offer poor turn-in on all but tight corners.

Price: 2c
Value: TBA

Damian Ware
DieHard
Victoria
UZZ32

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Tuesday, April 07, 2009 - 08:31 pm, by: Damian Ware (Frozenpod)

There is possibly a miss understanding as to which direction of caster adjustment is being referred to.

When I am referring to increased caster this is done by moving the top arm relative to the lower arm towards the center of the car ie increasing the positive angle. Or the lower arm away from the center of the car as in a soarer the upper arms are in a fixed position.

Caster can also be expressed as high caster which the arms are very close together which results in a low angle; or as lay back, which there is a much larger distance between the arms and then increased angle.

Phil Gibson
Goo Roo
WA
'91 UZZ31 track bunky, '94 blk/blk UZZ31

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Wednesday, April 08, 2009 - 11:42 am, by: Phil Gibson (Sciflyer)

so how is it possible to get *any* castor adjustment given that you cant move either arms forward or backward?

Dave Cazes
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Wednesday, April 08, 2009 - 12:58 pm, by: Dave Cazes (Cazman)

Damian Ware wrote on Tuesday, April 07, 2009 - 08:31 pm:
There is possibly a miss understanding as to which direction of caster adjustment is being referred to.

When I am referring to increased caster this is done by moving the top arm relative to the lower arm towards the center of the car ie increasing the positive angle. Or the lower arm away from the center of the car as in a soarer the upper arms are in a fixed position.

Caster can also be expressed as high caster which the arms are very close together which results in a low angle; or as lay back, which there is a much larger distance between the arms and then increased angle.

Nothing you described here is caster. Nothing.

The caster is adjusted by making the lower arm point towards the front of the car more, or point backwards to go the other way

So your arms go like this, imagine these symbols as your ctrl amrs
< left arm
> Right arm
=== crossmember

<===>

What you saying is if you do this
<===>
you get more caster, but that would be camber.
Actually Ill draw a pic, gimme 5 mins

Caster is camber as you turn the wheel, the hub is rotating and pivoting on the lower ball joint, putting it off centre gives you caster.
I could google te definition but im too busy atm.

I am still struggling to work out how you had 6 degrees in your soarer? Something must be broken or bend badly....
A70s can acheive close to this but not z30s

And Phil:
The lower arms are adjustable stock, they use a cam bolt (sort of)
so you can make the arms go forwards and backwards

Damian Ware
DieHard
Victoria
UZZ32

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Wednesday, April 08, 2009 - 01:33 pm, by: Damian Ware (Frozenpod)

Dave, I have describe exactly what caster is. Your diagram is talking about camber not caster as you have pointed out.

When I am referring to the center of the car I am speaking about the center of the car from front to back when you are viewing the car from a side on perspective. This is exactly how you look at a car to take an accurate measurement of caster.

Err nothing is bent or broken badly, I know of at least 1 other uzz32 that can achieve over 6 deg of caster as well.

Perhaps this is a difference between a uzz32 and jzz30, uzz32 do have a slightly greater king pin angle in there specs and they do have different LCA bushes although I thought the bushes were common for uzz32's and uzz31's.

Dave Cazes
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Wednesday, April 08, 2009 - 02:33 pm, by: Dave Cazes (Cazman)

Just eh way you describer caster up above, you were just desricbing camber

"When I am referring to increased caster this is done by moving the top arm relative to the lower arm towards the center of the car ie increasing the positive angle. Or the lower arm away from the center of the car as in a soarer the upper arms are in a fixed position. "

You need to move the front of the arm in the opposite direction of the rear of the same arm.

Have you got a wheelalignment sheet showing 6 degrees? Im now thinking maybe I can swap to a diff soarers arms, maybe the air bag arms more different than just the links. Hmm

A pic to explain caster better, as your description sounds like caster, maybe its just worded incorrectly, thats why i hate forums

Dave Cazes
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Wednesday, April 08, 2009 - 02:35 pm, by: Dave Cazes (Cazman)

I shouldve written in the pic, "by adjusting the bushes in opposite directions to each other gives caster, and in the same direction camber

Damian Ware
DieHard
Victoria
UZZ32

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Wednesday, April 08, 2009 - 05:18 pm, by: Damian Ware (Frozenpod)

Dave we are on the same pages just communicating over a different frequency.

Static measurements for suspension geometry can normally be done in 2D.

As a standard caster is measured as per the above pic by looking at the side of the car. In general terms what I have described is the position of the arms to adjust the caster angle.

As you have pointed out in your pics, that is how caster is physically adjusted on a soarer by only moving the lower arm position.

Damian Ware
DieHard
Victoria
UZZ32

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Wednesday, April 08, 2009 - 05:24 pm, by: Damian Ware (Frozenpod)

For reference IMO even 3.5deg of caster is too much and still leads to lack of and delayed turn in. I am going to try less maybe around 2-2.5deg at some stage in the future.

Ben Lipman
Goo Roo
NSW
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Wednesday, April 08, 2009 - 07:07 pm, by: Ben Lipman (Ben12a)

Phil Gibson wrote on Wednesday, April 08, 2009 - 11:42 am:
so how is it possible to get *any* castor adjustment given that you cant move either arms forward or backward?

Phil-I found it all became obvious once I got under the car and loosened everything off and had a play. I put the wheels on home made "skid plates". You can see the hub move forwards and backwards as you move the rear cam in and out.

Dave- is there a low tech way to measure the caster on the Soarer? I have read some stuff about finding two machined surfaces and measuring the angle from that, but nothing jumped out at me when I had a look. My home made camber gauge works a treat, but I'd like to know what the caster is, and if it is even left to right.