Soarer Central: Archive through July 06, 2009

Soarer Central Suspension Why you shouldnt lower your car too much- For better handling, read on Archive through July 06, 2009

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Gary Rollason
TryHard
Qld
TT 5 speed

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Thursday, April 09, 2009 - 01:51 pm, by: Gary Rollason (Garyr)

Umm... don't recall offhand David. May still have them at home somewhere, but chances are I've chucked out the printout, it was a while back now. I'll have a look.
They assumed that I wanted a specific setup for some track work or some such and so didn't bother to question the figures. I do recall the fitter saying he had trouble getting it set up to those specs though.

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

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Thursday, April 09, 2009 - 02:34 pm, by: Phil Gibson (Sciflyer)

Ben Lipman wrote on Wednesday, April 08, 2009 - 07:07 pm:
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.

Ah i thought that was the only way it could possibly be done but didnt think you could get enough adjustment given that you would effectively be making the lower control arm bushes "squint" in the crossmember

But then i guess as we're talking about only a few degrees it must be enough...

Louis Angelopoulos
TryHard
Vic
Soarer SC250 TT Manual

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Thursday, July 02, 2009 - 11:12 am, by: Louis Angelopoulos (Revolution)

Guys,

just reading through this post, its brought to my attention a problem i have on my car and I'm assuming that its my springs either being too soft or they're sht. (i have replaced my shocks hoping that was the issue but to no avail)

When going over bumps/ditches etc it feels like the rear wheels are bouncing off the road causing the revs to jump for a moment till the tyres hit the road again. Makes for difficult gear shift to say the least.

Am I correct in assuming that the springs are too soft?

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Thursday, July 02, 2009 - 12:39 pm, by: David Vaughan (Davidv)

Sounds like shot shocks, but given you said you had replaced those then unmatched springs and damping should be it. Does the car have stock springs? Did you fit stock shocks? Does the car itself heave and bounce or only the wheels go airborne?

Louis Angelopoulos
TryHard
Vic
Soarer SC250 TT Manual

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Thursday, July 02, 2009 - 12:55 pm, by: Louis Angelopoulos (Revolution)

No, no stock springs David and I don't know what brand... it came with the lower springs when I bought it.

The shocks were replaced with some pedders.
As far as I can tell its the wheels that go airborne.

There is some bounce when going over speed bumps and the like but the wheels being airborne also happens when (attempting) to do standstills. They just hop arround instead of doing a constant spin

Damian Ware
DieHard
Victoria
UZZ32

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Thursday, July 02, 2009 - 01:45 pm, by: Damian Ware (Frozenpod)

Replaced with Pedders shocks.

I would be looking there for a start.

Louis Angelopoulos
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Vic
Soarer SC250 TT Manual

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Thursday, July 02, 2009 - 01:58 pm, by: Louis Angelopoulos (Revolution)

Ok....i'll check out some other shocks...any ideas? are monroes any better??

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Thursday, July 02, 2009 - 02:16 pm, by: David Vaughan (Davidv)

Under-damped, I would say. That is, if the dampers are in good condition then the springs are too stiff for them. You need softer springs, probably meaning not lowering ones, or stiffer dampers.

Now, consult an expert to know because my reference on suspensions warns me that, "It can be difficult to sort out the difference between dampers that are too stiff and springs that are too stiff." I checked up on that after I came to the above view, because under-damped seemed more likely.

Perhaps Pedders did a shock test when you bought the new ones and can explain to you how they matched the new dampers to the springs?
IMHO you do not expect to find experts at Pedders but I may be doing someone a disservice.

Damian Ware
DieHard
Victoria
UZZ32

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Thursday, July 02, 2009 - 02:29 pm, by: Damian Ware (Frozenpod)

Monroes are Pedders shocks, Pedders ones are just painted red.

Somewhat considered one of the worst the money can buy.

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Thursday, July 02, 2009 - 02:42 pm, by: David Vaughan (Davidv)

Given the side conversation on Monroes/Pedders while I was writing, it definitely looks like under-damping unless they are poor quality and very stiff. Adjustable shocks might be useful, given you have unknown stiffer springs. How is the budget?

Dave Cazes
DieHard
SA
tt

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Thursday, July 02, 2009 - 05:06 pm, by: Dave Cazes (Cazman)

Ajustable shocks are a myt in Australia.

If you are haivng real dampening problems, bilstein or Koni mono tubes are the only way to go.

Its a pitty your in Victoria, as I would be able to look at your car for you.

Also I know I hark on about it, but please measure your CWG, I had a customer whos CWG was 325mm with reset stock springs. Needless to say it bottomed out everywhere and destroyed his nice new shocks.

Unless you know the height and spring rate or your new springs please dont go installing them.

If people are bottoming out, I have a solution, with raised top hots you can gain 1.5-2inchs of travel back from lowering the car.

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Thursday, July 02, 2009 - 06:00 pm, by: David Vaughan (Davidv)

Dave Cazes wrote on Thursday, July 02, 2009 - 05:06 pm:
Ajustable shocks are a myth in Australia

Possibly true. My Koni Sport are imported but I understood you could buy them here at the time (about three years ago).

Louis Angelopoulos
TryHard
Vic
Soarer SC250 TT Manual

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Friday, July 03, 2009 - 07:42 am, by: Louis Angelopoulos (Revolution)

David, budget aint on the ball at the moment. I just bought a set of tyres and that set me back a bit.

The shocks were installed by my mechanic at S&L so definately didn't get any tests of any sort. Just a direct swap out.

I never would have guessed that the set up would be too hard. My theory was that the springs were too soft and bounced arround.

So David if I understood correctly if I buy a pair of stiffer shocks or softer springs that should reduce the problem somewhat??

Dave, mate it would have been fantastic if you could check the car out as I'm sure if i take it to a dealer they are going to tell me I need to spend thousands and I just dont have the money

Damian Ware
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Friday, July 03, 2009 - 08:57 am, by: Damian Ware (Frozenpod)

KYB is also a good cheap shock.

In theory you aim for a dampening coefficient of 0.5 which is called critcially damped.

In the real world you want your new shocks to be overdamped as with age they deteriate and being slightly over damped often can make the car a little more stable.

Given your budget I would be considering KYB's pending your current spring size and rates are acceptable.

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Friday, July 03, 2009 - 09:09 am, by: David Vaughan (Davidv)

Yes, that is what I think, Louis, with the caveat that this is general advice. I have never seen or driven your car so I can never know as much as a suspension mechanic who can check it themselves, so you must ultimately rely on them.

If your springs were soft and damping hard then, yes, the suspension could bounce around because the springs would not push the wheels back on to the road. Effectively your dampers take some of the springing action and do it badly. However, if the springs are hard and the damping soft then the car will clear off the road because the dampers can not stop the bounce or chatter in the springs.

If you have lowering springs, they should be harder, and springs do not wear out that easily

. We know also that you have a cheaper range of shocks rather than known high quality ones. This adds up to hard springs/soft shocks being the most likely problem.

Please also take Dave's advice before you take the car anywhere. He knows what he is talking about. CWG or "eyebrow height" is easy for you to measure, as described in Dave's first post here: About CWG

By the way Dave, I think the springs are on already.

Spencer Cameron
Tinkerer
NSW
JZZ30 (converted Manual)

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Friday, July 03, 2009 - 07:54 pm, by: Spencer Cameron (Switchio)

Louis Angelopoulos wrote on Thursday, July 02, 2009 - 12:55 pm:
There is some bounce when going over speed bumps and the like but the wheels being airborne also happens when (attempting) to do standstills. They just hop arround instead of doing a constant spin

Umm.. I might be off the mark here, but the last part of that quote sounds like axle tramp. Maybe the craddle bushes are totally gone and they've developed travel. If they're floating around enough it could do what your talking about on big bumps and ricer filters. This would explain why the change of shock did nothing for the problem too..

David Vaughan
Goo Roo
NSW
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Friday, July 03, 2009 - 08:26 pm, by: David Vaughan (Davidv)

Could be. It depends exactly what is happening, which is hard to tell in posts, without the car to hand.

Louis Angelopoulos
TryHard
Vic
Soarer SC250 TT Manual

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Monday, July 06, 2009 - 07:47 am, by: Louis Angelopoulos (Revolution)

Spencer, mate whats this axle tramp and how do I check it?

I dont know if this is related, but I do hear some knocking around happening in the rear end which I assumed was the upper and lower bushes needing to be changed - the knocking happens when reversing then going forward and reversing again.

I'm already looking for some better shocks but if i can cross off some more possibilities its a bonus!

David i checked the CWG on the rear and its safe to say that the tyres are pretty much level with the guard. The front however has about 1 - 2 cm b/t the wheel and the arch.

David Vaughan
Goo Roo
NSW
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Monday, July 06, 2009 - 08:57 am, by: David Vaughan (Davidv)

Measure wheel centreline to bottom edge of the guard, assuming you have no added tupperware. That is the number for which we have a specific reference and it should be 370 or a little over. However, from your description then your back end is too low, probably around 330-350 CWG. Have a look at the first photograph in the first post on this page and compare it with your car low cwg

It is looking like a change of springs will be the right start, then see once again how your shocks are holding up. If your bushes are old and shot then replacing them will improve the car markedly but good ones (VFT) cost a bit.

My earlier suggestions that you change shocks were predicated on retaining lower stiffer springs but I think from what you are saying that they should not be retained. Measure the actual CWG as described, compare your car with that photo I mentioned, and let us know the results.

Spencer Cameron
Tinkerer
NSW
JZZ30 (converted Manual)

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Monday, July 06, 2009 - 09:59 am, by: Spencer Cameron (Switchio)

Louis, axle tramp is pretty common for these cars, especially manuals. Its basically a violent shuddering that occurs when you break traction while accelerating hard. Its caused by the rear suspension deforming under load because the bushes (or components themselves) have lost their rigidity.

The thread below has some diagrams showing the bushes in question:
http://soarercentral.com/sc-forum/messages/30604/287611.html?1244703465

All that aside, in a 15 year old car theres bound to be more than one problem (unfortunately

). Personally, i'd try to deal with the springs first. Some Pedders springs to go with those shocks will balance things out for starters.

This should clear up the whole CWG thing. The car in this pick is as low as i could get it without taking a backwards step in handling. That said, its still pretty bad on rough roads. Yours will need be be higher than this.

Upload

Matt Newman
TryHard
QLD
soarer tt

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Monday, July 06, 2009 - 12:33 pm, by: Matt Newman (Soarersrock)

just out of interest does anyone know the standard CWG? as i think my stock suspension has gone to pot
thanx matt

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Monday, July 06, 2009 - 12:46 pm, by: David Vaughan (Davidv)

Matt, see the post to which I referred in my last post.

Axle tramp can be caused by any undamped compliance in the suspension, not only shot bushes, even though I expect that problem exists.

Matt Newman
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soarer tt

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Monday, July 06, 2009 - 02:54 pm, by: Matt Newman (Soarersrock)

sorry David i didn't explane myself well i meant it looks like my shocks have dropped in height I've got some pics and took some quick measurements
front 370 rear 350 (edit to the corect measurements)

you'll have to excuse the carport post in the rear lol, by the way the suspension is stock and has not been lowered
thanx matt

Dave Cazes
DieHard
SA
tt

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Monday, July 06, 2009 - 03:55 pm, by: Dave Cazes (Cazman)

Damian Ware wrote on Friday, July 03, 2009 - 08:57 am:
KYB is also a good cheap shock.

In theory you aim for a dampening coefficient of 0.5 which is called critcially damped.

In the real world you want your new shocks to be overdamped as with age they deteriate and being slightly over damped often can make the car a little more stable.

Given your budget I would be considering KYB's pending your current spring size and rates are acceptable.

KYB are the standard shock, i would bet $100 that the aftermarket KYBs are indeed actually OE shocks inside.
These are brilliant for a weekend car, or a daily. No need to get anything else. Fantastic for daily use.

Matt Newman:
The OE CWG should be 390 front and 370 Rear.
It is measured from center of the wheel to the gaurd, just like spencer wrote.
It is the most universal measurement that works for every car. If you are running bigger 20 inch wheels then you need to compensate with springs though.

king springs drop your car to 360 front and 360 rear.
This is bang on legal in SA (about 5 mm higher actualy, but this •••••••• for heavier cars etc, sag)
Spring rates are, by memory 7.x and 3.4kg/mm

These rates are perfect for stock stock mounts/shocks.

Never have i had them bump out, crash badly, or even heard of a complaint from them from other people. They still ride well (unlike my race setup)

Tein springs are a bit higher, and are 13 and 6.7kg/mm
So they are alot stiffer, but being progressive rate, you couldnt tell. Very nice IMO and about $400 a set on special atm by memory.

As for pedders, I have seen 2 cases on this very forum of them bottoming out, They didnt do theyre research when they designed them, whereas King/tein did. My customers have said the same with lovels in SCs.

David Vaughan
Goo Roo
NSW
V8 Ltd manual

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Monday, July 06, 2009 - 04:00 pm, by: David Vaughan (Davidv)

Dave has answered your question, Matt, to which I would add that shocks may lose damping but they don't drop. It is the springs that hold you up. Statically, dampers do not support a thing.

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