Conflicting stories. - Chevy Impala SS Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 18 (permalink) Old 03-04-2016, 07:39 PM Thread Starter
Senior Member
 
popo8's Avatar
 
Join Date: Jan 2016
Posts: 945
 
Conflicting stories.

Looking for info from people who have actually done this and not required a new DS.

Ive been reading threads... Pming with people who say they know what they are talking about... but have no actual experience.


I want to lower my 1996 Impala. Id rather not purchase a new driveshaft, but IT MUST have the rear wheels re-centered in the wheel openings, so I know that means adjustable lower control arms.

My question is, is there a certain amount of drop that will allow me to adjust the rear axle without requiring a new driveshaft. Like where is the the line in lowering between needing a DS or not but still having the rear axle centered?

I know this has been discussed before and Ive read so much... but its full of conflict.

Thanks in advance.

Popo

************ IS my drug...
OWNER/ADMIN

1996 Impala SS: LE1 H/C by Lloyd Elliot. CPT "race" trans. Long tube headers, with off road X pipe.
popo8 is offline  
Sponsored Links
Advertisement
 
post #2 of 18 (permalink) Old 03-06-2016, 10:14 AM
Senior Member
 
Sshockr's Avatar
 
Join Date: Jul 2005
Location: Wichita, KS
Posts: 1,823
 
Garage
My dad is on Eibachs (1.5-2" I think.) with C3 Fab Adjustable Centering arms with stock DS. No problems in the probably 3-4 years he's had it.

I've got ST's (2") and UMI extended adjustables, and while the stock DS worked fine, I did switch to a CVPI shaft over concerns about the T56 being just a hair shorter combined with the centered arms and my increased power levels.

-Brian

'95 B4U LT1/T56 in Purple Pearl. 24x 355 with I believe most of the bolt-ons.
'63 C10 LT1/4L60E from B-Body. Rides like a Cadillac thanks to air bags.
'06 GTO LS2/T56 Torrid Red with CAI and Borla Cat-back thanks to the lady who rear ended me.
Still in Wichita.
Sshockr is offline  
post #3 of 18 (permalink) Old 03-06-2016, 10:27 AM Thread Starter
Senior Member
 
popo8's Avatar
 
Join Date: Jan 2016
Posts: 945
 
Quote:
Originally Posted by Sshockr View Post
My dad is on Eibachs (1.5-2" I think.) with C3 Fab Adjustable Centering arms with stock DS. No problems in the probably 3-4 years he's had it.

I've got ST's (2") and UMI extended adjustables, and while the stock DS worked fine, I did switch to a CVPI shaft over concerns about the T56 being just a hair shorter combined with the centered arms and my increased power levels.

-Brian
Thanku... by centering arms, do u mean adjustment from left to right?

Did he do any adjustable lower control arms that center the wheels in the wheel wells?

************ IS my drug...
OWNER/ADMIN

1996 Impala SS: LE1 H/C by Lloyd Elliot. CPT "race" trans. Long tube headers, with off road X pipe.
popo8 is offline  
 
post #4 of 18 (permalink) Old 03-06-2016, 09:50 PM
Senior Member
 
Sshockr's Avatar
 
Join Date: Jul 2005
Location: Wichita, KS
Posts: 1,823
 
Garage
By Centering Arms I mean they center the wheel in the wheel well.

Last fall my dad did airbag the rear axle of his car and as part of that he did move the spring perches fwd about 3/4" on the axle tube. While my springs seem to sit ok, I feel that this is on my list of things to do next in order to vertically line up the spring perches again.

-Brian

'95 B4U LT1/T56 in Purple Pearl. 24x 355 with I believe most of the bolt-ons.
'63 C10 LT1/4L60E from B-Body. Rides like a Cadillac thanks to air bags.
'06 GTO LS2/T56 Torrid Red with CAI and Borla Cat-back thanks to the lady who rear ended me.
Still in Wichita.
Sshockr is offline  
post #5 of 18 (permalink) Old 03-07-2016, 06:11 AM Thread Starter
Senior Member
 
popo8's Avatar
 
Join Date: Jan 2016
Posts: 945
 
Ok. I want to do a little 1" drop and if a new ds is not necessary, i dont want to waste the time or money. I do however need the rear wheels to sit centered in the openings to appease my ocd. Lol.

************ IS my drug...
OWNER/ADMIN

1996 Impala SS: LE1 H/C by Lloyd Elliot. CPT "race" trans. Long tube headers, with off road X pipe.
popo8 is offline  
post #6 of 18 (permalink) Old 03-07-2016, 07:21 AM
Senior Member
 
The Bolt-On Terror's Avatar
 
Join Date: Jul 2000
Location: Bright, IN
Posts: 3,774
 
Quote:
Originally Posted by popo8 View Post
..I want to lower my 1996 Impala. Id rather not purchase a new driveshaft, but IT MUST have the rear wheels re-centered in the wheel openings, so I know that means adjustable lower control arms...Popo
************ IS my drug...
OWNER/ADMIN
I think you mean longer fixed LCA's and adjustable uppers.
I don't know of any LCA's with adjustment. Since those are in tension on launches, that would be a risky proposition. Lowers are fixed and the uppers (in tension) are adjustable to get the pinion angle correct.
Are you currently running the stock driveshaft? What gear ratio? I take it you already know about the stock shaft's 1st bending natural frequency falling into the mph range of a stock powered car with 3.73 and higher gears?

Stock bottom 350, Built by B-Body Performance
NA: 10.98 @ 122
100 shot: 10.35 @ 128
2012 ISSCA SSuperPro Champion
2013 ISSCA SSuperNatural Champion
2013 ISSCA Roadrace Runner-up
2014 ISSCA SSuperNatural Runner-up
2014 ISSCA Autocross Runner-up
2015 ISSCA Roadrace Champion
The Bolt-On Terror is offline  
post #7 of 18 (permalink) Old 03-07-2016, 07:24 AM
Senior Member
 
1963SS's Avatar
 
Join Date: Dec 2003
Location: Eastern Kentucky
Posts: 1,114
 
I just centered my wheels with upper and lower control arms and installed the Hotchkiss springs at the same time. The lowering didn't really change the driveshaft length at all. I went with a Ford Crown Vic MMC driveshaft. It's about 1/2-3/4 inches longer and it's aluminum. It appeared as though the stock DS would have worked. It was just 1/2" further backed out of the tailshaft. There is still a ton of driveshaft yoke in the tailshaft housing.

I'd be tempted to just install the springs and mark the driveshaft with a magic marker where it goes into the tailshaft housing. Then, jack the rear of the car up using the frame and see how much more the driveshaft comes out of the tailshaft. Maximum suspension droop should be the minimum driveshaft engagement.

Bill Burgette
Kentucky
ISSCA # 2216
1963SS is offline  
post #8 of 18 (permalink) Old 03-07-2016, 07:54 AM
Senior Member
 
Sshockr's Avatar
 
Join Date: Jul 2005
Location: Wichita, KS
Posts: 1,823
 
Garage
UMI's are adjustable lowers and uppers. I've got them on my car along with a set of weld on lower attach point brackets. No issues with launching yet. I would be curious to see what the tension/compression limits of the threaded adjuster are compared to what my car can actually create in the arm.

-Brian

'95 B4U LT1/T56 in Purple Pearl. 24x 355 with I believe most of the bolt-ons.
'63 C10 LT1/4L60E from B-Body. Rides like a Cadillac thanks to air bags.
'06 GTO LS2/T56 Torrid Red with CAI and Borla Cat-back thanks to the lady who rear ended me.
Still in Wichita.
Sshockr is offline  
post #9 of 18 (permalink) Old 03-07-2016, 08:05 AM
Senior Member
 
The Bolt-On Terror's Avatar
 
Join Date: Jul 2000
Location: Bright, IN
Posts: 3,774
 
Quote:
Originally Posted by Sshockr View Post
UMI's are adjustable lowers and uppers. I've got them on my car along with a set of weld on lower attach point brackets. No issues with launching yet. I would be curious to see what the tension/compression limits of the threaded adjuster are compared to what my car can actually create in the arm.
-Brian
Learn something every day
Of all the B-bod's I've been around, I've never seen a set of those.
Of course they can be designed to resist buckling under compression loads; they'll just be beefier and heavier than the upper adjustment design has to be. It's probably only a risk from an OEM point of view; any damage/bend to the lower arms from a road hazard or incorrect jacking could make them fold up under load.
The Bolt-On Terror is offline  
post #10 of 18 (permalink) Old 03-07-2016, 10:13 AM
Senior Member
 
Join Date: Sep 2000
Location: Central IA
Posts: 2,379
 
The amount of lowering does not have much impact the requirement of a new driveshaft or not. One can experience vibrations with the extended control arms at both stock ride height and at a lowered one. It really seems to depend upon the tolerance stack-up of each vehicle - some get a vibration right off the bat, others are OK up to a certain MPH (driveshaft RPM).

I had a set of 3/4" extended arms on a 2" lowered SS that was fine at regular cruising speeds, but did experience a vibe at higher speeds.

If you want to center the rear wheels, you must use BOTH extended upper and lower control arms. If you use only the lowers, it will screw up your pinion angle tremendously.

Mike - '94 BBB SS (RIP 06/16) - '95 DGGM SS - '96 DCM SS - '92 BBB Wagon
threeimpalas is offline  
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 not post new threads
You may not 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