flynhi

Any field reports out there on Speed Direct's Aluminum upper A arms? Comments on installation and performance appreciated.

ZD75blue

Twin_Turbo

I don't think anyone is running a set yet?

norvalwilhelm

I looked at them this week and the price is too high. Almost $1000 AM for a polished set.

flynhi

Is there merit to Speed Direct's claim that altering the mounting points of the control arm shaft lowers the roll center?
If so, does that make a significant difference in performance?

Oops. I misread Speed Direct's site. Their site states that the roll center is raised, not lowered.

Twin_Turbo

yes and you don't want to lower the roll center, you want to raise it, lowering the roll center causes more body roll. Don't know what the difference is, they don't supply any numbers.

MEGALADON

I seen that they are not made of GOLD
$250.00 a piece, and they would sell like hot cakes
I wait for the next 5 years for the price to come down

I would like to have upper and lower, but not at $2000 or $2500

norvalwilhelm

To raise the roll center you need to increase the length of the spindle or lower the inner mounting point of the upper A arm.
I feel both are difficult to do with a bolt in A arm.
To increase the splindle length with just the A arm they would need a special long upper Ball joint, not one with a lower pivot point.
While the change could be valid they could also be so small that they wouldn't be noticed
The only way would be redrilling the inner mounting for the A arm and lowering this point

It still suprised me that no one has come up with longer spindles??

Kid Vette

Norval, looks like they are lowering the mounting point with an offset bracket.

Kid Vette

Natural finish is $305 ea w/o ball joints. Not too bad IMHO.

Jason Staley

I purchased these last fall, but didn't get a chance to put them on before it got cold. As soon as I get the chance (bascially when I'm done rebuilding the Olds engine & tranny), I'm going to install them. I'm going to plot a before & after camber curve, and determine the roll centers to determine which setup I like better.
http://www.drgas.com/store/product.p...&cat=22&page=1

ZD75blue

Now that you guys bring it to my attention... That offset doesnt look super beefy for being aluminum.

From the corner, to the slot... hmm.

427V8

I'm not, the market is tiny, most Vette owners want stock vettes.
The Market is for stock replacement parts I think...

Also getting a custom forging done wouldn't be cheap. I mean who'd be willing to invest $50 - $100k ( as a guess) to develop such a product?

Keith

Jason Staley

I agree .... its not that bad considering the R & D your paying for. Just look at the parts for newer vehicles .... talk about high prices . A freaking air intake tube & filter for my new mustang runs $200+ dollars and if you throw in the required tuner to get the A/F ratio correct, your looking at $500+.

I know one of the main concerns that have been mentioned over time is that they are cast. I would think that if you purchased the as-cast ones, smoothed them out, and then shot peened them it would greatly increase their fatique strength. This is the same technique that has been used for years on factory connecting rods and aircraft parts to increase thier fatique strength by inducing compressive stresses at the surfaces which effectively works against the tension forces that start cracks in the first place.

75 Hot One

I agree. The only way to use these is to try to improve fatigue strength and that would be to smooth the surface either by buying the polished ones or finishing the as-cast ones. Peening would be a plus. I still believe forged is the right manufacturing process but cost is probably prohibitive. Then you have to ask yourself, is it really worth saving some $$$ if you end up destroying your car or yourself? Conclusion?- probably best to stay with the stock A-arms.

big_G

The C-5, I believe, uses forged a-arms. I have replaced them too many times to remember. It only takes a mild hit on the wheel sidewall or a really deep pot-hole to break one. I imagine the cast pieces are somewhat weaker. I would worry about them.

norvalwilhelm

Those ball joint extenders have been around forever. They tend to actually over produce negative camber. You will ge extremely negative at times.
Grisdale racing also sells extended ball joints that does the same thing.

norvalwilhelm

Yes I know but I was able to produce these relatively easily and they are 1 1/2 inch longer then stock. If I was more ambitious I would mass produce them.
They use all stock components and yet raise the roll center from below the ground to about 4 inches above the ground.
We had a fantastic guy Pete that helped with alot of this stuff

mrvette

It still suprised me that no one has come up with longer spindles??[/QUOTE]

Norval, on the olde tyme A body cars, a company I forget name of came out with a mod kit to ball joints and suggested a spindle like off a '80 caddy, forget which....but I had that kit on my '70 Lemans/GTO, and it did improve handling a good bit....

I think a junkyard trip with some BJ stems, and calipers and some heavy tools is in order....that or keep going to spot something allready taken apart....I know that in that infinate GM parts bin, there is another spindle and maybe lower/upper arms in there somewhere that would do the trick, it's a matter of finding them.....bet odds, been a GM hotrodder for too damn many years to NOT think that....

norvalwilhelm

You draw a line through the pivot points on the A arms so does it really matter how low you make the bracket. You still have the same pivot points so it doesn't change the slope of the curve just the visual appearance of the top of the A arm.