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Ben280

Aftermarket Front Control Arms

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It's time for a new set of front control arms on the Z. My rotors are flexing enough under load that they are grinding away the corners of the Arizona Z arms, so I need to change to different style. Looking between the Apex Engineered and the Techno Toy Tuning arms, but I'm torn on both so I'm reaching out to y'all! Initial thoughts are that the

 

-Techno arms look to come with better heim joints (3 piece teflon lined) compared to the AE arms

-AE ball joint is a circle track style (re-packable/greasable), Techno arms look to be a spherical bearing? Tough to tell from photos

-AE arms look to be more rigid because of the way the tension rod mount connects to much more of the arm compared to the techno arms. 

 

Can anyone with experience with either of these share some thoughts on their likes/dislikes of these designs? Specifically curious about the heims/balljoints. THANKS!

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Ben, you probably won't get much help as I don't think anyone is using these parts in anger as you are.  The GT2X arms T3 has look to be similar to AE's arms.  To be truthful you'd be better off with a spherical bearing than a ball joint.  This is because you use spacers are much easier to put back in the same position than a tapered shank.  The stock style arms they sell are probably stiffer in bending under breaking then either the GT2X or AE arms.  The other reason I'd say this is because you're at the point where to get to the next step you need to start thinking beyond what's considered normal Z suspension.  My personal preference would be to build a lighter set of arms than what's needed for street.  This will all be custom fabrication to fit your car and wheel/tire requirements.  Search for BTCC or V8 Supercar strut setups for inspiration.

 

In the meantime if you have gusseted the strut tube and you're running a bearing spacer and the disc is hitting the arm you have too much bending.  That means a thicker spindle and larger bearings are needed.  And if you're going to any custom stuff like this then you need to think strongly about NASCAR parts as they are cheap and plentiful.  A custom strut tube built around the 5x5 hub and bearings for instance.  You can source cheap alloy hubs, brake hats, REM or ceramic bearings, etc.  There's a reason all the higher end touring car racers use big bearings spaced farther apart to resist bending loads.

 

Hope that helps,

Cary

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I don't want to derail your thread,  Ben, but have you had issues with pad knockback and soft pedal? I have been, and I haven't isolated what is flexing yet. Could be front spindle, but I have the gusseted strut housings and bearing spacers. Not sure how much of an issue rear spindle flex is. 

 

BTW Wilwood suggested knockback springs instead of residual pressure valves. 

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Thanks @tube80z! I was hoping you'd reply. Good tips on what to look for. I was thinking that the GTX2/AE arms are close enough to what I'd build that it might be worth it to just get them, and then modify as needed. The T3 stock style arms are a good option, and could likely be beefed up to suit my needs with some more structure and weld in sleeves for sphericals. No gussets on my struts yet, or bearing spacers yet, care to enlighten me on the bearings?! Sounds like a  good mod for the off season!

 

I need to do some testing and see where my bending is coming from. I'm using an aluminum hub and custom 2 piece rotors with aluminum hats. These issues became apparent after the most recent event in Canada with a couple almost full lock turns, so I suspect the "bending" is largely steering lock and some goofy interference. Car is in the air at the moment, I need to pull a spring and run the suspension through its range. 

 

@JMortensen I don't have issues with pad knockback, although with the scalloped rotors there is a LOT of feedback through the pedal. I'll keep y'all posted. 

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On 8/31/2019 at 5:44 PM, Ben280 said:

Thanks @tube80z! I was hoping you'd reply. Good tips on what to look for. I was thinking that the GTX2/AE arms are close enough to what I'd build that it might be worth it to just get them, and then modify as needed. The T3 stock style arms are a good option, and could likely be beefed up to suit my needs with some more structure and weld in sleeves for sphericals. No gussets on my struts yet, or bearing spacers yet, care to enlighten me on the bearings?! Sounds like a  good mod for the off season!

 

This may seem counter to what we're discussing but be careful getting lower control arms that are too strong.  A lot of these are over built and that leads to problems if you ever take a hit.  You don't want to have the crossmember and frame rail ripped up from hitting a pothole/curb.  On the GT2X arms I'd look at using aluminum rod ends on the crossmember side.  I'd do that for the TC rod too.  If you're going to modify any of these items then you're not that far from making what you want from scratch.  

 

When it comes to rod ends/sphericals remember to burnish/bed them (see page 22 of http://flipbooksbyadventure.com/RodEndsCatalog/files/assets/common/downloads/publication.pdf).  You need to turn the ball (100 RPM or slightly less) to polish the liner (probably wrong terminology) but it helps remove high/low spots and distributes teflon across all surfaces.  When you do this you'll feel the rod end suddenly lose torque and you want to remove from the drill or lathe and dunk in ice water.  Done right the bearing will also be very easy to move and that reduces friction in the suspension.  Very few people do this.  Once you get beyond getting the basic setup right almost all of the rest of the small gains come from working on deflection and friction removal.  Suspension friction (stiction) reduces mechanical grip.  The more of it you get rid of the better.  

 

With regards to bearings I'm not sure of your question.  Larger diameter or distance between bearings will make decrease load from cornering/brake forces.  I think a good compromise that could be used on the Z would be based on the NASCAR 5x5 hub setup.  The bearings for these look almost twice the size as a Datsun bearing.  You can get alloy or steel hubs, brake hats, spindles and bearing spacers for these fairly cheap.  Download the Howe Racing catalog and see all the options.  REM finished or ceramic bearings will help with friction and the ceramics can withstand huge loads and roll with minimal friction.  They would be a last step just the same as replacing all the turning/moving parts with Ti fasteners to save weight.

 

I've attached an example upright from a 2001 BTCC Peugeot 406.  Notice the large bearings and how everything is mounted in double shear.  If you fab a new upright this is  a good example to follow.  Just a bit of racing trivia, I asked a mechanic working on a historic BTCC BMW at a historic event where the large bearings came from.  He told me they used helicopter main rotor bearings for most of the uprights.  Now these are available from race bearing suppliers.  The BMW must have had 6 inch diameter bearings.  Pretty cool stuff.

front_upright.jpg

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On 9/3/2019 at 11:04 AM, tube80z said:

With regards to bearings I'm not sure of your question. 

Sorry, I was confused about the bearing spacer that you and Jon had mentioned. That part seems very trick, but I'll likely move towards a custom upright like you've pictured, so I'm not sure how much more optimization I care to give to these old parts. 

 

On 9/3/2019 at 11:17 AM, Neverdone said:

Ben I've got a pair of the TechnoToyTuning front arms that I havn't installed yet on my Z if you wanna come check them out in person.

I think I'll take up up on that. PM sent. 

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6 hours ago, JMortensen said:

Bearing spacer is easy to set. Even if you get some different spindles and arms, I'd run a bearings spacer anyway just because of the size of the tires. It's just better than not having it.

 

Which one are you running on your spindles? Was tough to tell how they sized them from the website and I'm not THAT ready to take my hubs apart. I see they have a Datsun roadster one on the shelf? I do really like the advantage it provides when tightening the hub!

 

It's been a real adventure seeing what will break on this car with the different loads that I'm subjecting it too. So far nothing critical, but I need to go through it again this winter! 

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Posted (edited)

On our Third Gen Camaro spindles we used to get a lot of spindle flex with Big sticky DOTs and slicks. We used thick walled ( 0.250" wall ) bearing spacers that were machined to slip over the the Bearing spindle with a matched Tapered ID . We used shims to get the preload correct.

 

 

Edited by Chickenman

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