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Discussion Starter #1
Just found this;
Spindle Extender
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Article in Chevy High Performance

Spindle Extenders for even better handling

While we had the front end apart, we decided to try out Pro Motorsports' new spindle extenders. Without going into too much theory about suspension geometry, changing spindle height changes the upper control arm's arc under suspension movement. A taller spindle generally means that under bump (when) the tire moves into negative camber, which is highly desirable for maximum cornering power. Pro Motorsports' spindle extenders do this for a very reasonable cost. We performed before-and-after testing on the Camaro with these parts, and they work. Not only that, they're remarkably easy to install.



The Extender adds 1 15/16 inches to the total spindle height. The design allows the car to be easily returned back to stock, if desired.



After separating the upper control arm and ball joint, the top half of the extender installs over the ball joint with the stock nut. A piece of bar stock is included to hold the extender and keep it from turning while the nut is tightened. Use a new cotter pin. Once that step is done, six Allen-head screws connect the two pieces of the extender together.



In place of the ball joint is a bolt that goes through the spindle and threads into the extender.



Jim Sleeper at Precision Alignment installed the extenders and aligned the car in both configurations. Sleeper also measured the camber gain at 1 and 2 inches of bump and rebound. The chart shows the results.


Specs Stock w/Extender
Camber: -3/4 -3/4
Caster +2 +3 3/4
CAMBER CURVES
Ride_Stock__SpindleExtenders
Hgt_ Camber_Camber
+2" -11/16 +1
+1" -13/16 +1/4
Static -3/4 -3/4
-1" +1 15/16 -1 3/4
-2" +1 5/16 -3 1/8



As you can see, the spindle extenders have the as-advertised effect on suspension geometry. In stock form, with the front end set at a typical performance alignment of 3/4 degree of negative camber, when the car goes into a corner and the tire moves up into the fender, it rolls out to 15/16 degrees of positive camber. That usually results in a serious case of understeer. With the extenders, the tire rolls to a whopping 31/8 degrees of negative camber.


Does this theory work in the real world? You bet! With the stock suspension set at 3/4-degree negative, the Camaro ran through our sister magazine Motor Trend's 600-foot slalom at 60.60 mph and ran around the skidpad at .87g wearing p255/45Z-17 front and p275/45Z-17 rear BFGoodrich Comp T/A tires. We bolted on the spindle extenders, put in the right alignment shims (for a 3/4 negative static setting) and reran the test. The car then went through the slalom at 62.93 and pulled .90g on the skidpad. For a bolt-on, that's a significant difference.


Spindle Extender Kit . . . . . . . . . . . . . . $179.95
I know this is not the same application, but it sure made a big change in the Camaro application.

My next though is; What effect would that amount of camber change have on braking?
 
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Discussion Starter #2
My thought would be that you would be able to brake harder than you could previously in a turn because you have increased the tire patch available.
 
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My guess is that braking ability will be actually HURT.....a tiny bit.....by changing the camber curve.

One of the few "benefits" to our screwed up camber curve is that when you compress the suspension under braking you are taking OUT the negative static camber that is usually dialed into a "performance" alignment on these cars. So the tire ends up flat under braking. Of course, if you have a "zero" camber alignment (like one would do on our cars for comfort reasons) then the tires will camber out under braking enough to pull rubber off the road and get rid of this benefit.

With the corrected camber curve from the taller spindle, the tire will camber in more under braking, removing rubber from the road.

That said, for the amount of camber change we are talking about here (in the compression under braking force case) I would guess the change would be slight.
 
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Discussion Starter #4
Well, I think I'm going to give it a try. Soon as my last expense check comes in, I'll order my front-end stuff.
 
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Another question. If it's this with rubber bushings or DelAlum CA bushings without the extensions, which whould be the better investment, from a handling point of view?

Also, I've been told that Poly CA bushings do fine in the uppers, but can not handle the lowers, long term. Has anyone tried DelAlum lowers with Poly uppers? Is it possible to buy only the uppers in Poly?

Would it make any sense to go with Poly Uppers and rubber lowers, since the rubber is better able to handle the lowers?

I'm looking at this from a "bang for the buck" perpective, and please keep in mind, I'm still paying for this car<almost 3yrs left>, so a good portion of my available car funds<after payments and insurance> goes to maintenance and repair. I'd like to take this opourtunity to do a cost effective upgrade, but not break the bank also.

Main thing I'm looking for is a better handling car on the street, with improvements for ocassional AutoXing.
 
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Discussion Starter #6
I'd do the spindle spacer and leave the bushings alone.
 
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Discussion Starter #7
Thank you. Do you think the stock bushings are ok? They have over 80k on them, though I've gone double that on other cars before. That would certainly make the job easier...

I'm ordering everything next week. Going to replace all of the steering linkage and the ball joints and do the spindle spacers.
 
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Discussion Starter #8
The stock upper bushings aren't near the wear item than the lower ones are. Chances are, at 80K they are fine.

I would however check your lower balljoints while in there (i.e. it'd probably be a good idea to replace them if they are original).
 
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Discussion Starter #10
Originally posted by AutocroSSer:
My guess is that braking ability will be actually HURT.....a tiny bit.....by changing the camber curve.

One of the few "benefits" to our screwed up camber curve is that when you compress the suspension under braking you are taking OUT the negative static camber that is usually dialed into a "performance" alignment on these cars. So the tire ends up flat under braking. Of course, if you have a 'zero' camber alignment (like one would do on our cars for comfort reasons) then the tires will camber out under braking enough to pull rubber off the road and get rid of this benefit.

With the corrected camber curve from the taller spindle, the tire will camber in more under braking, removing rubber from the road.
If I'm reading the results comparo above, from Wayne's post, the results are 'gross' figures. That is, the results noted, include the static amounts, not just the 'net', or actual amount of change, for each height position checked.

In that case, using a neg. 1/8* chamber static setting (for sake of argument), 'gross' change with oem hardware, would be 1 15/16* positive, compared to 2 1/2* negative, using the altered chamber arc/curve, under a 2" braking dive. To me, it would appear to be slightly worse, as you mentioned, with the altered chamber curve, from the extender kit.
 
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Discussion Starter #11
Good catch. I had not looked at it that way.

Carrying it a bit further, setting -1/2*(what I was planning on going to) and 0* with the spindle extensions.
2" -7/16 +1 3/4
+1" -9/16 +1
Static -1/2 0
-1" +2 3/16 -1
-2" +1 9/16 -2 3/8

Again, slight difference...

Should I go with 0*? Or maybe even a little positive? I'm now looking at best highway manners instead of tweaking handling via static settings.

I'll try to find a shop that will give me the current camber change and post-spindle extension one to get some real numbers.
 
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Discussion Starter #12
Wayne : it'll be a bit of a "guess" here (hello and welcome to being a guinea pig.....thanks for volunteering :D ), but I'd say aim for 0 camber on the initial alignment and see what happens.

If you don't already have one, get a tire tread depth gauge (few bucks at Pep Boys) and take measurements on your inner, middle, and outer part of the tread. You'll probably wanna repeat every 500-1K miles for the first 3-5K on the new setup to get an idea of how things are wearing and if the alignment is right or needs to be tweaked.
 
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Discussion Starter #13
Originally posted by Wayne Bengston:
Carrying it a bit further, setting -1/2*(what I was planning on going to) and 0* with the spindle extensions.
2" -7/16 +1 3/4
+1" -9/16 +1
Static -1/2 0
-1" +2 3/16 -1
-2" +1 9/16 -2 3/8
If my math is accurate, I believe some plus and minus math computations are off, but we are still on the same page.
 
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Discussion Starter #14
What about turning with a side load on the tire? Is this not the primary reason you are changing the control arm arc? Your braking loss due to camber change when braking straight ahead makes sense, but not during a turn.
 
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Discussion Starter #15
True, but much more often than not, emergency braking is done in a straight line with minimal maneuvering.
 
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Discussion Starter #16
Originally posted by Wayne Bengston:

Also, I've been told that Poly CA bushings do fine in the uppers, but can not handle the lowers, long term.
Stay away from Poly bushings in the front CA's. I put b-body spindles and Gulstrand tubular CA's on my '86 Monte SS. I had poly bushings in the uppers figuring it would enhance the handling. Only problem is that they had no provision for greasing without disassembly. They started to squeak and to bind and within about 5K miles I had destroyed a set of BFG TA's because the suspension bound into a negative camber of about 3*. Tore the inside half off the tires in no time. I pulled the CA's and had stock bushings installed and put on a new set of tires and all was well and I couldn't tell the difference in the handling. But they didn't squeak or bind.

SStewart
 
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Discussion Starter #17
Only problem is that they had no provision for greasing without disassembly.
Don't they make greaseble ones now?

I'm going to leave the stockers in, I'll make sure they are still good, but if they are, I'll just do ball joints and steering linkage.
 
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Discussion Starter #18
I think they make greasable poly ones but I'd still stay away from them. I'd love to do the Del-A-Lum but it's not in the budget right now.

SStewart
 
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Discussion Starter #19
Another question...

Where do I find taller rebound stops?
 
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Discussion Starter #20
Where do I find taller rebound stops?
What I'd do is take the old stops with you (they sort of "pull out" of the uppercontrol arms) and find a 4x4 type store in Houston. 4x4 stores tend to have all kinds of cool suspension bumpstops and bits like that, since they deal with "altered" suspension travel and length all the time.
 
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