Want 'Vette spindles on my 818R... Suggestions?

[Scargo]

I hope you guys do not mind me playing in your sandbox. I could use some advice. I am building an 818R for ST2 without a donor car and am wide-open to how I build a front suspension. Had I known it earlier I might have used Corvette uprights front and back. I particularly like the C5 because I can mount about any brand of racing brakes on it that I want without special adapters.
Going with the Corvette or "Corvette style" spindle or upright (like AFX, meaning it uses the Z-1 SKF HD bearing assembly and hub for the C5 and C6 and mounts 'Vette brakes or better) , then I have at least ten permutations of that if I include aftermarket offerings:
Corvette C5, Corvette C6, "dropped" variations (from .75" in to 2" offset), Chevelle A body(9" center to center), tall Chevelle (two inches more) Camaro, tall Camaro, and two different OTS steering arms for the AFX spindles. I'm pretty sure all will not all have the same KPI.

I will run 13 inch Stoptech Trophy brakes on the front and 17 inch wheels. I suspect I will be making my own lower control arms and reworking and re-positioning all the brackets. I want inboard shocks.

AGH (http://thefactoryfiveforum.com/member.php?9982-AGH) said, "The size and overall geometry of the suspension components on the C5 and C6 is identical and will bolt in place. All four spindles are interchangable and use the same bearing units. The C6 spindle castings however are much beefier. The front arms are directly interchangable and use the same ball joints."

I am looking at C5 then because it is lighter. Either will be overkill on the 818. Can anyone tell me what they used (for racing) and why? Differences in KPI and so-forth? Is there possibly any LCA that would be suitable for the 818 that plays well with the Vette spindles? I haven't really investigated the similarities of the GTM and 818 frames and mounting points.
Thanks!

[kabacj]

Hi Scargo.

Looking forward to seeing you run ST2.

Regarding your question of using the c5 front suspension. I get the benefit of the heavy duty bearing packages and the freedom for brake fitment.

I also use a stoptech trophy big brake kit with 14 inch rotors 6 Pistons up front and 4 out back.

They are easy to modulate and pads last forever. I can see how you would want that on an 818R

I think you are going to end up doing quite a bit of fab work and engineering to gain the ease of brake fitment.

I'm not telling you to abandon your dream, however, you might consider running the factory five setup then looking for how you want to change it.

Developing the 818 is going to be just like developing the GTM for racing. Of course the 818r is much farther along the development curve, but you should budget time to get the car sorted to your driving style. The less you change the more you can use other folks on the forum as a resource.

For racing the GTM my suspension setup required converting all bushings to spherical bearings. The stoptech trophy big brake kit that they customized to the weight of the car and the wilwood master cylinders. Skf wheel bearings. Heavy duty rebuldable lower ball joints. Replacement of the corvette tie rods with beefed up aluminum struts with rod ends. And bump steer kits front and rear.

Hope to see you at the track in the spring.

John

[Scargo]

Thanks for the reply. I know I will be doing fab work and that does not bother me. Figuring out the geometry does. I'm not an automotive engineer. I am debating whether to get a suspension design program like Mitchell (also called WinGeo), which FFR uses, or one called Susprog 3d.
I found a custom upright that would have saved me over twenty pounds of unsprung weight but they are pricey and the builder wouldn't come through on giving me datum points for adapting them. With the money I will save using Vette or aftermarket Vette based spindles I can buy the best design software in the world!
It's certainly not just the brake adaptability that is driving this. The Vette part will save me a lot of weight, too... I can only imagine that the WRX AWD upright is a very compromised part for road racing applications!
That's why I thought you GTM guys could provide info about what you used, if you went with something other than the C5 spindle. Or, if anyone even looked at or researched a comparable aftermarket racing spindle using the Vette bearing pack/hub.

[Taz Rules]

Here's 4 books I really like that may help with the geometry...

Chassis Engineering HP 1055 by Herb Adams (http://www.amazon.ca/gp/product/1557880557?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00)
How to Make Your Car Handle HP 46 by Fred Puhn (http://www.amazon.ca/gp/product/0912656468?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00)
Advanced Race Car Chassis Technology HP 1562 by Bob Bolles (http://www.amazon.ca/gp/product/1557885621/ref=ox_ya_os_product)

And the last one, which I liked the least of the bunch, as least as far as usefulness is concerned, Race and Rally Car Source Book by Allan Staniforth (http://www.amazon.ca/gp/product/0857333488?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00)

Hope this helps

[Scargo]

I appreciate the responses but I think I am being misunderstood. I said:
Can anyone tell me what they used (for racing) and why? Differences in KPI and so-forth? Is there possibly any LCA that would be suitable for the 818 that plays well with the Vette spindles? I haven't really investigated the similarities of the GTM and 818 frames and mounting points.

I have now investigated the LCA placements on the GTM frame and I must make my own LCAs for my 818R.

I don't require advice about how to design or construct the suspension. I don't have any Corvette spindles in front of me to measure and have found getting the information I need to be a lot of work, and you know how some internet info can be.
I'm looking for the angles and dimensions for the C-5 spindles and any spindle variants people may have used. I'd like KPI, ball joint distances, steering arm length and offset. Is there a resource for the stock parts?

[mikespms]

Was looking in the 818 forum and noticed that the upper control arm is adjustable and the subaru spindle has an adapter for the ball joint. The things you need to look at is the way the ball joints mount on the spindles and the taper of the ball joint. On the corvette spindle the upper ball joint is pressed on the spindle and the ff5 adapter on the 818 has the socket for the ball joint and the ball joint is mounted on the control arm. the next thing you need to know is the taper of the lower subaru ball joint. Assuming that the lower ball joint on the subaru control arm has the same taper and diameter as the corvette or you can modify it to use a 10 deg taper GM ball joint, then you need ball joint plate with a socket for the upper ball joint and that is not available anywhere.The upper control arm on the 818 uses SPC components and it could be modified to the proper geometry. I am working on an adjustable upper control arm for the GTM and the upper control ball joint plate is one of the part that I am fabricating but in your application I think it would be better to look for an aftermarket conversion camaro/chevelle spindle that has the c5 hub and brake mount for the big brakes and the ball joint sockets are on the spindles, just make sure that the steering arms are in the front. then all you need is to get longer adjustment sleeves for the upper control arm and find the proper ball joints.

[Scargo]

Long ago I abandoned using anything Subaru on the front suspension! I want a racing suspension top and bottom with Heim joints. Custom rack and pinion, too.
"On the corvette spindle the upper ball joint is pressed on the spindle and the ff5 adapter on the 818 has the socket for the ball joint and the ball joint is mounted on the control arm." Yes, exactly. Looking at C5 spindles I now see that the upper ball joint is in the spindle and would make adapting the end of my FFR provided, adjustable upper arms difficult. I agree I can get whatever length SPC components I need to make that work up top when I re-position the mounting points on the frame.
Now, Speed Tech's ATS AFX Camaro or Chevelle long spindles? Don't yet know the differences in geometry. Might be machining my own steering arms.
Anyone have experience with rack and pinions and know who's is good?

[Santiago]

Hey Glyn,

I've got a couple of C5 spindles collecting dust in a storage container somewhere. Parts to a long-lost project that died on the vine. I could ship them to you for measuring (you pay shipping to & fro as I'd like them back when you're done), but I can't say I could get to it super soon. Is there any special urgency on your end or could you tolerate waiting (maybe until after the holidays)? Let me know.

Best,
-j

[Scargo]

John, Thanks for the offer but I suspect I will go with aftermarket stuff that lets me use some of the FFR hardware. I appreciate the offer. I have tons of STi stuff I should be Ebaying...

[mikespms]

Classic Performance has a line of c5 coversion spindles http://www.classicperform.com/C5-Spindles/C5-Spindles.htm