Spindle Extensions Installed and Article - Chevy Impala SS Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 78 (permalink) Old 02-27-2004, 12:16 PM
bengston
Guest
 
Posts: n/a
Post

Just found this;
Quote:
Spindle Extender
--------------------------------------------------------------------------------
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?
Sponsored Links
Advertisement
 
post #2 of 78 (permalink) Old 02-27-2004, 04:24 PM
Don2
Guest
 
Posts: n/a
Post

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.
post #3 of 78 (permalink) Old 02-27-2004, 05:10 PM
AutocroSSer
Guest
 
Posts: n/a
Post

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.
 
post #4 of 78 (permalink) Old 02-27-2004, 06:22 PM
bengston
Guest
 
Posts: n/a
Post

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.
post #5 of 78 (permalink) Old 02-28-2004, 07:56 AM
bengston
Guest
 
Posts: n/a
Post

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.
post #6 of 78 (permalink) Old 02-28-2004, 09:37 PM
AutocroSSer
Guest
 
Posts: n/a
Post

I'd do the spindle spacer and leave the bushings alone.
post #7 of 78 (permalink) Old 02-28-2004, 10:06 PM
bengston
Guest
 
Posts: n/a
Post

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.
post #8 of 78 (permalink) Old 02-29-2004, 01:02 AM
AutocroSSer
Guest
 
Posts: n/a
Post

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).
post #9 of 78 (permalink) Old 02-29-2004, 09:19 AM
bengston
Guest
 
Posts: n/a
Post

Thanks!
post #10 of 78 (permalink) Old 02-29-2004, 09:47 AM
arnie
Guest
 
Posts: n/a
Post

Quote:
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.
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevy Impala SS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome