Lowering Springs....?

[Jay.Blanket]

So i have tried to look back and search though the forum because I am certain this question would have been asked before.....

At what point of lowering a Standard AU Falcon (AUII in my case) would you recommend replacing the shocks and springs?

I have just picked up a set of SSL rear king springs cheap and want to know what would be the best height for the front? should i just find some SSL fronts to go with it? also should i replace the shocks?

[nstg8a]

SSL fronts and replace the shocks with good short shocks.

[mcfly94]

Any lowering imo will need new shocks, generally original shocks die after the increased spring rate.
Youll want ssl to match for the front, youll need monroe gt sport shocks, (there for superlow or lower, just to prevent bottoming out etc) kyb/gabriel etc dont make shortened shocks, dont know about bilstein or koni however.
Replace shocks all round.
And make sure you have good ball joints aswell as theyll die quickly because of your increased spring rate, only took mine 5000km before completely dieing after king spring install.
Hope that helps.

[Spurious]

When lowering the front you will most likely need a camber/castor adjuster kit.



The camber is preset in the factory & when you lower the AU's it changes the camber angle.
The idea is, by fitting the bracket & shims pictured above,(to the base of the upper control arm) it allows you to bring that control arm out & away from the chassis so as to keep the camber correct.
Photo shows brackets for one side.

[jpblue1000]

Half the time you wont need the kit as you can get enough shims under the existing nuts to reduce camber enough. Assuming you are lowering the car for handling reasons additional front camber is a good thing.
I lowered mine 50-60mm up front and have 1.5 negative camber with no shims. On mine The standard upper arm bracket could accommodate about 8mm of shims reducing camber if I wanted to.

JP

[Sox]

Originally Posted by mcfly94

Any lowering imo will need new shocks,

Not really.
'Low' Springs work fine with standard shocks.
'Superlow' and lower work better with shortened shocks, although even superlow springs can sometimes be ok with standard shocks.

generally original shocks die after the increased spring rate.

Spring rate has virtually no effect on shock longevity, it just causes an underdamped situation.

Youll want ssl to match for the front, youll need monroe gt sport shocks, (there for superlow or lower, just to prevent bottoming out etc) kyb/gabriel etc dont make shortened shocks, dont know about bilstein or koni however.

The Monroe GT sport are a good choice. Koni and Bilstein make shortened shocks.

Originally Posted by FlivverFord

When lowering the front you will most likely need a camber/castor adjuster kit.

Actually, it's more likely you won't need a 'camber kit'.
Camber kits are mostly sold by suspension mobs to pocket a bit extra money because they're too lazy to simply to throw a handful of shims behind the standard brackets.

Originally Posted by jpblue1000

Half the time you wont need the kit as you can get enough shims under the existing nuts to reduce camber enough. Assuming you are lowering the car for handling reasons additional front camber is a good thing.
I lowered mine 50-60mm up front and have 1.5 negative camber with no shims. On mine The standard upper arm bracket could accommodate about 8mm of shims reducing camber if I wanted to. JP

This is spot on.

[nstg8a]

Yeah mine didn't need a camber kit, they managed to get the specs pretty good with shims.

[mcfly94]

Originally Posted by Sox

Not really.
'Low' Springs work fine with standard shocks.
'Superlow' and lower work better with shortened shocks, although even superlow springs can sometimes be ok with standard shocks.

Spring rate has virtually no effect on shock longevity, it just causes an underdamped situation.

The Monroe GT sport are a good choice. Koni and Bilstein make shortened shocks.

Actually, it's more likely you won't need a 'camber kit'.
Camber kits are mostly sold by suspension mobs to pocket a bit extra money because they're too lazy to simply to throw a handful of shims behind the standard brackets.

This is spot on.

Just from experience thats what i believe, mates have destroyed shocks after lowering them because they didnt get lowered shocks.

Also thought if the increased spring rate having a huge affect on the rest of the suspension it would have one on the shocks too.

I know low works with low shocks, but i meant just replace to new standard.

[jpblue1000]

short shock bodies are beneficial but not absolutely necessary...sort of, depending on how low you go

When you lower a car by using reduced length springs the standard shock absorber lower valve (bottom of piston) is operating in the cylinder lower than it does at standard height, effectively increasing droop but reducing bump travel. This is not a problem until you hit a big enough bump that required the shock absorber to absorb travel greater than it has available and compressing the bump stop. With OEM height the shock absorber might have the travel but lowered car and standard length shocks with the lower piston operating in the lower third of the cylinder will likely smash piston and foot valves together ultimately shortening life of the unit.
The shorter shock has less travel but the piston is higher in the cylinder resulting in less valve crushing blows.

Furthermore lowering the car for handling and ignoring the biggest component to good handling is counter productive

JP

[Sox]

Originally Posted by mcfly94

Just from experience thats what i believe, mates have destroyed shocks after lowering them because they didnt get lowered shocks.

I've done it myself more times than I can poke a finger at and haven't lost a shock because of it yet.
Even my current AU Xr8 has King superlow springs with the standard shocks.
It doesn't feel as nice as my P250 with the same springs and Monroe GT sport, however there's no sign of premature failure.

Shocks can fail prematurely with lowered springs if they bottom out constantly, but that's a different matter and will cause other problems too.

Also thought if the increased spring rate having a huge affect on the rest of the suspension it would have one on the shocks too.

Well, I don't think increased spring has a huge effect on the rest of the suspension. It has a small effect, but again, that will have bugger all effect on the shocks longevity.

I know low works with low shocks, but i meant just replace to new standard.

Fair enough.

[Spurious]

Originally Posted by nstg8a

Yeah mine didn't need a camber kit, they managed to get the specs pretty good with shims.

That's basically all the kit is, just shims! Negative camber chews tyres.

[jpblue1000]

Originally Posted by FlivverFord

That's basically all the kit is, just shims! Negative camber chews tyres.

Negative camber benefits cornering grip. A consequence of Negative camber is increased wear of the inside edges oft he tyres. Chewing is caused by incorrect or aggressive toe settings in conjunction with other issues.

As with most things, Performance is a compromise between longevity and ware rates. You want to play you pay.
If lowering the car is an aesthetic only thing adjust the camber back to standard and use standard dampers but don't expect performance gains to match the looks.

JP

[mcfly94]

i set mine up not far from factory spec, just on the boderline actually for camber, very good grip without sacrificing the tyre wear
Run about -0.5' on driver and about -1.20' on the passenger
and then caster is up at 8.30' passenger and about 8' driver, then 2mm total toe.
Huge increase in grip over the factory alignment, but the new michelin ps3's 235's also help with that.
You can easily get those settings camber settings without a camber kit, dunno about caster though, thats a fair way up from factory.