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Arkhaeon

Gktech R32 Gtr/z32 Front Upper Control Arms

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On 8/11/2017 at 7:50 PM, GUWOP said:

I'm at the put-it-back-together stage and finally got to install mine. They're pretty sweet! 

 

 

 

 

IMG_7561.JPG

Mine arrived while I was on a recent OS trip.  Have ripped them apart with glee today!

Question is....there's a pair of washers in a small bag.  Should it be obvious to me where they go?

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Following up on this for posterity.

I finally got back into the country & found enough time to fit the GKTech front upper control arms.  These replaced factory arms that had polyurethane bushes @ inner end and polyurethane bushes with eccentric adjusters at the outer ends - the standard Whiteline/Superpro setup. These had been replaced several times over the last 15 years or so since originally installed, but not looked at too closely in the last few years.  They were comprehensively f**ked.  Bush distortion at each end was so severe that the inner end bolt and outer end bolt were at least 10mm out of parallel!

I put the new FUCAs on, set to factory length (~180mm between bolt centres) as my best guess.  Did not and have not yet gotten a wheel alignment to see where everything is.  Will come back to that point.

So, the car clearly had a compromised front end, not stock, not better than stock.  The GKTech FUCAs are a massive improvement.

  • The first thing I noticed is that at very low speeds under certain turning conditions (such as driving forwards out of my driveway), a scrubbing noise/feeling that I was getting for the longest time was now gone.  So long term suspected suspension geometry wrongness confirmed, and now banished.
  • The next thing I noticed is that there is a substantial increase in front end grip.  Years of nagging wonder about why the car has a basic understeer characteristic, despite having lots of good money spent on many parts of the suspension, completely explained by replacing twisted crap with straight good stuff.
  • No noticeable increase in NVH.  Probably should have expected this, at least until some wear turns up in the rod ends & bearings on these arms.  And especially compared to the creaky/squeaky nature of the urethane bushes, even with grease nipples added.
  • Suspension compliance seems at least as good as before.  Placebo effect makes me think it feels better than before, but there's not really a lot to suggest that the old bushes put up any additional resistance over the 5+kg front springs.

On the subject of alignment - my guess of putting them in at stock length seems fine for the moment.  I appear to have >1° -ve camber, but not a lot more than that.  It seems even both sides.  The toe might have been altered from what it was before, because the top end of the upright is now in a completely different place (fore-aft) than it was before with the rooted poly bushes.  Nevertheless, the car drives straight and the steering wheel is straight.  My tyres are >75% worn, so I will watch how they wear before deciding what to do about alignment going forwards.

I probably should mention that I have adjustable caster rods on the front that put a lot of tension into the upper arm's bushes and probably contribute to their getting stuffed.  This same tension is what I think makes the suspension less compliant than it should be (with normal upper arms, not the twisty GKTech ones), and what leads me to expect the suspension to work better now.

Cliff's notes: 2 thumbs up.

Edited by GTSBoy
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Put mine in back in Jan. 

Was already running -2.5ish negative with hardrace arms which have a bearing instead of a bushing and are length adjustable instead of offset bushings, which probably is a better option. That being said the bearings seemed worse for wear (grease coming out) Also would have weird steering feedback at limits of travel, hitting bumps etc on lower speed corner.

New arms in Seem just as good, was a pain to tighten them without having the right sized large spanners but got it to an alignment shop, similar alignment and they seem just as good on the track as the GKtech and much less unpredictable on the bumpy roads. 
Not as much of a noticeable improvement as above but that's probably because the existing arms were serviceable.

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Following up on this AGAIN for more posterity.

After 6 months and not very many road kilometers, the "self-lubricating" teflon lined bearings started talking.  And they rapidly got a lot worse.  Over a distance of probably only 500km a little squawk turned into a major cacophony.

The weather has been almost exclusively dry too, so it's not as if they got all wet every day and rusted.

Took them apart and found that the outer rod end on the strong arm part was very tight and marked where it had been galling the outer race.  The other two rod ends on the other part of the arm were also a little tight and a little marked, but not as bad.  The bearings installed in the inner end of the strong arm appear to be COM10T press in rod ends (2 off) with an ally crush tube in between.  A reasonable enough idea, except that these are rods ends just like the others, but don't get any weather/dust protection.  So while the other rods ends have boots that do at least something, the COM10Ts are exposed.  These bearings were all much harder to rotate than they were when new.  I'm thinking that maybe some sort of rolling element bearing with grease seals might be worth considering on these.

So I cleaned everything as well as I could, sprayed teflon spray into the COM10Ts, whacked a lot of lithium grease into the other rod ends and they're silent again.  This may not be the right thing to do, but we'll find out, won't we.

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I had to grease all the rod ends on both sides.  This is explicitly against their advice...but we all know that people who really use rod ends on race cars keep them lubed.  The sphericals in the main body on the other side of the car are still moving freely enough at this stage.

It's about 8 months now, but when the bearings got tight enough to upset me was a couple months ago.  Only about 4000km of use up to that point, I think.  I can't fault their service.

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And  one more follow up.

I still had a lot of noise in the front LHS.  This had previously only ever occurred when the old poly bushes were dry and when the rod ends in the GKTechs were buggered (as described above).  I bought a bunch of new rod ends and changed them all out.  Still noisy.  So many rod ends on a single arm that it is hard to be 100% sure about where the noise is coming from, so I bit the bullet and bought a set of the UAS arms (the old centre pivot ones that they came up with >10 years ago), on a group buy advertised on here to get a batch made up.

Still noisy.  The noise must be coming from somewhere else in the LHS suspension.  Could be the upright's upper bearing, as that is a likely candidate.  But really it could also be in the rod end on the front of the caster rod, or in the lower control arm bush, ball joint, ARB link (which are sufficiently new that it shouldn't be them) or even somewhere unexpected like the crossmember attachment to the chassis.  May have to do a little extra swappsies and maybe invest in some chassis ears.

Anyway, the moral of the story is that I still think the GKTech arms are a good thing and they don't have as much trouble with generating clinking noises as I had thought they did.  Subject to my greasing efforts, anyway.

Edited by GTSBoy
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