What To Spend My Suspension $$$ On

[bunna]

Bush material choice for all companies is a fight between the vehicle dynamics team, the NVH team, and durability. The end result is a compromise (of course).

For an FG XR6 at roughly standard height, the specs are as follows (all in decimal degrees):

Front camber

(individual) -0.56

(cross) 0 +/- 0.5

Front castor

(individual) 6.53

(cross) 0 +/- 0.7

Toe

(individual) -0.06

(total) 0.1 +/- 0.1

[Smoke them tyres]

The "jig".....you crack me up.

Never said that a toe adjustment would be a cure all for unwanted direction change.

Obviously some common sense must come into it......what rational wheel aligner and owner would have it with absolutely no shims and wildly different settings on each side. Give people some more credit.

I prefer mine to be symmetrical on both sides but that's me. Even the factory set them up with camber and caster mildly non-symmetrical on each side.

Bush material is also a choice when considering customer satisfaction, durability and the minimising of recalls to fix flogged out (diff etc) bushes.

With all the technology in plastics these days, there are better and cost effective materials. It just that the industry can get away with fitting rubber.

A 1700kg car generating >0.5g hanging off a few rubber bushes a couple of inches round is not conducive to predictable handling, even tyre wear or durability. Then they go and void them, introducing tear points in the rubber.

The video shows that this kind of movement under dynamic loads will actually contribute to dud handling of the car. What's the point of doing a schmick static wheel alignment when it changes so much under reasonable applications of dynamic load?

Brembo six pot (temp?) cure for for the crap std bushes....why don't they just fix it properly and put some different material in it. To load the bush up with the washer is an admission that there is too much movement there and a vain attempt to increase the durometer of the bushing. Accountants have a lot to answer for.

Edited 05/07/10 11:13 AM by Smoke them tyres

[senna_T]

Hey Bunna, I'm sure we can all agree with Smoke's last sentence - its all the Bean Counters fault!

Have you been getting feedback from service departments regarding XR6 (n/a) tyre life? We've seen at least 5 in our workshop alone that have destroyed the front tyres in less than 20,000k's

Plus we are seeing some hard to find squeaks in the FG's - seems to be coming from the lower control arms but we can't seem to isolate it with lubrication (had two cars stripped down and re-built).

[Smoke them tyres]

Pat,

This is exactly what concerns me about these bushes. Great for business though. Tyres will not last long. Soggy chassis.

Where has the lubrication been applied to find the potential source?

[senna_T]

First car we went around with iNox and gave a quick spray one area at a time - swaybar d's, LCA bushes, ball joints, UCA'a, caster rod bushes, coil wrap on springs etc

Its very frustrating because we can't chase it with a stethoscope (spelling) as its not a "grinding" squeak, rather a high pitched one.

The second car we thought we found it in the UCA bushes so we replaced those - came back....

I swear I've lost hair and gained some greys trying to find these squeaks....

[Smoke them tyres]

Do you have an apprentice you could lodge in there and go for a drive????

I'm still happy just to have hair!

Yeah, those annoying sqeeks can really a person.

This may be of help.....

Now that I have fitted poly in all the front end on my BF, I can hear the occasional sound you describe on sudden suspension movements...ruts, dips etc. I lubricated all bushes with the Fulcrum grease on fitment.

I know that it is coming from where the front and rear faces of the UCA bushes meet the mount faces. Rubber would also have the same tendency against these steel mounts.

I found this by going over some bumps with the brakes applied to move the UCA's with axial load on them.

I could pull them and grease them, but I suspect that it would not take long for them to start squeeking again. Might need a thin plastic or teflon washer on the rear faces at least? Grease does not seem to last long in this area.

The FG LCA is axially restrained by the strut rod. The upper has no help to locate itself other than it's own bushes. Might be worth a closer look???

Don't fully know how much the FG bushes contact their mounts though

Edited 05/07/10 12:45 PM by Smoke them tyres

[senna_T]

Well that's the thing, the FG UCA bushes have voids in them (gawd) and one car we had was fitted with pedders (nolathane) void fillers - still squeaking...

We'll keep trying to find it, and thanks for the tips - same old same old "I've got a noise in my car..."

[Smoke them tyres]

Hi senna_T,

Any success on finding the noise?

[senna_T]

So far so good, no other cars coming through with the same issue, only problem is we don't know why its stopped!

[JP300]

Great job Pat... my guess is that the Inox took a bit longer to seep into the creak(s). Should have used WD-40!! (only )

Interesting thread ... I'm no suspension expert but I love hearing peoples perception and feedback of what is "better handling".

My interpretation of handling is how the suspension keeps the tyres on the ground and what the car does after it looses traction on the road.

In most cases when stiffer springs and shocks are installed in a car (with no other changes) the car might feel like it handles better because it does not lean over as much. This is in most cases interpreted as better handling but has this actually made the car better and safer?

Installing the wrong combination of shocks and springs (and heights) can lead to producing a dangerous outcome at high speed and wet conditions.

The BA and BFs had a very unbalanced and wobbly feel I could not wait to modify the suspension, I originally had Kings springs and Bilsteins but the car did not feel comfortable around fast sweeping corners, it was too hard and the rear end jiggled around and lost traction. I changed then to the Teins and the difference in the car was very noticable, a bit softer ride but the car still held on and was well balanced around the faster corners.

The FG was a big step up in standard form. I have done a lot of country driving in various conditions and the standard suspension is pretty good. Recently, I once again forked out the $$$$ for the Teins but have not had a chance to put them through their paces.

My 2 cents !!