upgrading the suspension on a c-4

[grumpyvette]

take the time to read thru the linked info, its well worth the effort

c4 alignment specs (Bluewasp)
VetteBrakes recommends straight from their 2002 catalog page6:

Daily Street:
Front: Toe = 1/32" in
Camber = 0 degrees
Caster = 5-7 degrees positive
Rear: Toe = 1/8" in
Camber = 0 degrees

Advanced Street:
Front: Toe = 0"
Camber = 1/4 degree negative
Caster = 5-7 degrees positive
Rear: Toe = 1/8" in
Camber = 1/2 degree negative

Autocross baseline:
Front: Toe = 3/16" out
Camber = 1 1/2 - 3 degrees negative
Caster = 4-5 degrees positive
Rear: Toe = 1/16" in
Camber = 3/4 - 2 1/2 degrees negative

Track baseline:
Front: Toe = 0 - 1/16" out
Camber = 1 - 3 degrees negative
Caster = 4-7 degrees positive
Rear: Toe = 1/8" in
Camber = 3/4 - 2 1/2 degrees negative

C4 Z51 spring rates/codes and sway bar sizing.
I thought I would share some facts found researching Z51 spring rates and swaybar sizes that some people might find interesting.
I posted this info in c4 tech, but thought that some of the c4 guys in this section might find the info usefull.

i will put the year/front spring/rear spring/front bar/rear bar.
also quote in N/mm and Lbs/inch.

'84 - 102 nmm/582 lbs 87.5/499 25/23
widely regarded as the stiffest suspension put on the c4, front BMB/rear BMH code springs (but wait till we get to '88)

'85 - 63.5/362 57.2/326 30/24
after customer feedback GM engineers go softer on the springs, but bigger on the swaybars. NYU code for the new rear spring.

'86 - 66.5/380 57.2/326 30/22
slightly more front spring rate, 2mm less on the rear bar.

'87 - 66.5/380 57.2/326 30/22
no change.

These are the 4 years that the c4 Corvette dominates the SCCA championship and promptly gets banned from the series !
From what I have read a lot of racers used the 102/582 front spring with the 57.2/326 rear spring with 30/24 swaybars, although there was some mixing and matching (within the rules of course

)

'88 was the beginning of the Corvette Challenge series, a race series for the Corvette only. The front geometry of the C4 was also changed.

'88 - 115.5/659 - 57.2/326 30/24
where did that front spring come from, it makes the 84 BMB spring look like it came off a luxury car ! The GM engineers had racing on their minds for sure with this combo.

'89 - 115.5/659 - 57.2/326 30/24
this is the year the R9G was offered for sale, a factory race car !
R9G 115.5/659 - 57.2/326 30/24
no doubt that spring/swaybar combo was being developed for racing.
'88 and '89 were the only 2 years of the Corvette Challenge Series.

'90 - 115.5/659 57.2/326 30/24
R9G 115.5/659 57.2/326 30/24
Corvettes were invited back this year to the World Challenge Series.

'91 - Z51 number dropped, replaced with Z07 code. No R9G available.
'91 - 115.5/659 57.2/326 30/26
the only year of the 26 mm rear bar, 2 mm more in the rear bar, engineers looking for more oversteer ?

'92 - 90.1/514 57.2/326 30/24
softer front spring, smaller rear bar.

'93 - 90.1/514 57.2/326 30/24
no change.

'94 - 90.1/514 57.2/326 30/24
no change.

'95 - 90.1/514 57.2/326 30/24
no change.

'96 - Z51 designation returns.
'96 - 73.2/418 33.0/188 26T/24
the 96 Z51 was the Cadillac version, spring rates verging on FE1 rates.

Interestingly, the rear Z51 spring rate did not change from 85 to 95, even though the front rates varied quite a bit.
Ride comfort in the C4 is mainly affected by rear spring rate, the engineers were obv happy with the 57.2/326 as a performance/street driven rear spring rate.
People who have used the 84 BMH rear spring 87.5/499 have stated it gives a harsh street ride, and tends to bind up the rear end of the c4 under cornering in racing.


Reference is from the Corvette Action Centre 84-96 suspension chart.

Does anyone else have any information (or corrections), especially spring codes ?
Hopefully this will be helpful to anyone looking at changing spring rates whilst using leaf springs in a performance/racing application.

SPRING CODES

FRONT 84-87
BMB 102
HMZ 63.5
FHU 63.5
HKX 39.9
HMP 39.9
HM2? 57.2
HMN 54.4

FRONT 88-96
FHA 93.1
FHB 115.5
FHC 93.1
AA 96.2
FSK 90.1
FSM 75.4
FSS 90.1
FSR 73.2
HA 60
JA 60

REAR 84-96
BMF 72
BMH 87.5
NYU 57.2
NYR 39.9
RCA 39.9
RHY 39.9
RHZ 39.9
RR 26




REAR SPRING CODES

Code #/in N/mm Year(s) GM part # GM Service Parts Catalog
---- ---- ------- ------- -------- ------------------------
BMH 499 [87.5] 1984 14045786 . . . . . . . . . . 7-H19


BMF 411 [72.0] 1984 14045785 . . . . . . . . . . 7-H19

NYU 326 [57.2] 1985-95 14080196 . . . . . . . . . . 7-H19 7-H22 7-I3

NYR 228 [39.9] 1985-93 22112253 . . . . . . . . . . 7-H19 7-H22 7-I3

RCA 228 [39.9] 1986-96 14106787 . . . . . . . . . . 7-H19 7-H22 7-I4

RHY 188 [33.0] 1992-96 17999322 . . . . . . . . . . 7-I4

RHZ 148 [26.0] 1994-96 22112253 . . . . . . . . . . 7-I4

___?d 148 [26.0] 1994-95 22112254 conv FE1 (SR) FX3 . 7-I3 no 3 letter code -
Code #/in N/mm Year(s) GM part # GM Service Parts Catalog
---- ---- ------- ------- -------- ------------------------
FRONT SPRING CODES

FHB 590 [115.5] 1988-91 10048553 . . . . . . . . . . 7-E9 7-E13 7-E19

BMB 521 [102.0] 1984 14045782 . . . . . . . . . . - not in microfiche

AA 491 [96.2] 1990-91 17988598 . . . . . . . . . . 7-E13 7-E19

FHA 476 [93.1] 1988-91 10048552 coupe FX3 FE7 + L98 7-E9 7-E13 7-E19

FHC 476 [93.1] 1988-91 10048574 conv FE1 (SR) . . 7-E9 7-E1347-E19

FSK 460 [90.1] 1992-95 17997091 . . . . . . . . . . 7-E19

FSM 385 [75.4] 1992-95 17997093 . . . . . . . . . . 7-E19

HMZ?a 379 [66.5] 1986-87 14106617 coupe FE7 ___ . . - not in microfiche

FSR 374 [73.2] 1992-95 17999031 conv FE1 (SR) . . 7-E19

FSS 374 [73.2] 1992-96 17999032 coupe FE1 (SR) . . 7-E19 7-E20

HMP 362 [63.5] 1984-87 14106617 . . . . . . . . . . 7-E5

HMP 379 [66.5] 1984-87 14106617 . . . . . . . . . . 7-E5

HA 306 [60.0] 1989-95 22145203 coupe FE1 (SR) FX3 7-E13 7-E20

JA 306 [60.0] 1994-95 22145227 conv FE1 (SR) FX3 7-E19

...?b 306 [60.0] 1995 22173029 conv FX3 (ER) . . 7-E19 no 3 letter code
...?c 306 [60.0] 1996 22173028 coupe FE1 (SR) . . 7-E19 no 3 letter code

HMN 278 [54.4] 1986-87 14094457 conv FE1 (SR) . . -

HKX 276 [54.0] 1985 14094458 . . . . . . . . . . page 7-C24 microfiche

HMP 261 [51.8] 1986-87 14094458 . . . . . . . . . .

http://tech.corvettecentral.com/2013/11/c4-suspension-overview/

http://garage.grumpysperformance.com/index.php?threads/you-need-decent-jack-stands.672/#post-28211

http://garage.grumpysperformance.com/index.php?threads/c4-vette-alignment-specs.14542/

http://garage.grumpysperformance.co...c4-corvette-wheel-tech-info.12099/#post-58082

https://www.wheel-size.com/calc/?wh...-18X9.5ET40&fcl=50mm&wcl=30mm&scl=50mm&sr=0mm

viewtopic.php?f=27&t=2735&p=7113&hilit=press+hydraulic#p7113

viewtopic.php?f=71&t=1770&p=12626&hilit=press+hydraulic#p12626

viewtopic.php?f=34&t=11058&p=49146#p49146

http://www.miata.net/garage/tirecalc.html

http://garage.grumpysperformance.co...one-to-get-the-vette-to-run.12668/#post-64847

http://www.airbagit.com/product-p/fbx-f-che-52.htm

http://www.ridetech.com/store/suspe...97-chevy-corvette-shockwave-front-system.html

http://www.truckshop.com/product.php?productid=20871

http://www.streetdreams.org/interactive/

http://www.vansteel.com/index.cfm?fusea ... Group=1972

http://temp.corvetteforum.net/c4/vader8 ... joint.html

http://www.corvetteactioncenter.com/tec ... kDSAhA9mqE

owning a low cost hydraulic press and a drill press will sure make the process go smoother, obviously if you do work frequently youll tend to want better than bargain basement tools
http://www.harborfreight.com/12-ton-sho ... 33497.html

http://www.harborfreight.com/heavy-duty ... 38144.html

if your car shakes or pulls its usually a symptom of a suspension, or tire related problem, swapping the tires from side to side will usually tell you if its tires, because the location of the problem should change with the tire swap[/color]
but its usually well worth the time and cost have a decent corvette shop, or dealership or tire store you trust, inspect and check your ball joints and control arm bushings,wheel bearings,brakes ,shocks and motor and transmission mounts

these components can and do fail and result in different symptoms with shaking at higher speeds being far from rare

http://www.summitracing.com/parts/ENS-3-18123R/

http://vette.ohioracing.com/susp.html

http://corvetteactioncenter.com/tech/c4/susp_chart.html

replacing c4 corvette suspension bushings

http://webpages.charter.net/khasting/ut ... hings.html

http://corvettes.about.com/od/restorati ... ndling.htm

http://garage.grumpysperformance.com/index.php?threads/wheel-bearing-replacement.3128/#post-8340

http://www.banskimotorsports.com/C4_Rea ... sioin.html

http://www.oddfiddlythings.com/2009/roc ... uspension/

http://www.corvettemagazine.com/suspens ... joint.html

http://www.corvettefever.com/techarticl ... index.html

http://en.wikipedia.org/wiki/Corvette_l ... eaf_spring

http://www.idavette.net/hib/c4/sustunch.pdf

http://www.miata.net/sport/Physics/

viewtopic.php?f=87&t=2031&p=5411#p5411

http://www.corvetteactioncenter.com/kb/ ... l+Corvette

AS AN EXAMPLE
,I recently helped install a front end suspension upgrade kit ,in my opinion its component parts were just barely functional and the parts were of low quality, the grease seals all the ball joints had flaws

the owner got a DEAL on IMPORTED ball joints, we took them out of the packaging and noticed the crappy grease boot seals, as cast body and metric thread,s I suggested returning them, but we had them and the owner felt returning them would be difficult and waste a week or more time, they were difficult to press into the lower a-arm so we measured the diameter of the clamping surface diam. where it inserts into the a-arms, the original ball joints measured 2.070, the replacements measured 2.085" obviously they needed to be carefully machined to the slightly smaller diam.
a bit of research showed the import ball joints sell for about $30 each, the American made replacement parts sell for about -$57-$110 each depending on the vendor and brand selected, locally so its no surprise that many guys select the less expensive route, but it may be a mistake, the quality looked to be significantly lower, the parts needed to be slightly modified to fit and the grease boots were leaking right out of the packaging.
ON a C4 corvette,(1984-1996) the OEM ,top or upper ball joints are installed with rivets that need to be drilled out and replaced with bolts
the lowers are pressed into and out of the lower a-arm so youll need a decent press to install or remove those
these look to be better in the picture but I have not seen these personally
http://www.mamotorworks.com/corvette-c4 ... -1122.html

KITS SOLD BY MANY VENDORS INCLUDE LESS THAN DESIRABLE QUALITY PARTS (IMPORTS OF UNKNOWN QUALITY)TO KEEP THE PRICE LOW, THIS IS ONE AREA WHERE IT PAYS TO SPEND A BIT MORE AND SELECT BETTER QUALITY PARTS

THESE JOINTS BELOW APPEAR TO BE MUCH BETTER QUALITY

http://www.autopartswarehouse.com/detai ... K6345.html

http://www.autopartswarehouse.com/detai ... K6346.html

http://www.corvettefever.com/techarticl ... index.html

http://www.ehow.com/how_7649253_replace ... te-c4.html

MOGG and Mevotech make a decent replacement ball joint

The C4 Corvette was produced from 1984 though 1996 by Chevrolet with a control arm-based front suspension. This suspension incorporated both upper and lower ball joints. Ball joints require replacement over time. Ball joints cannot be repaired and should be replaced when the rubber boots are split or worn out. Signs of wear can include uneven tire wear, poor handling and movement of the front wheel when inspected.

Difficulty:
Moderately Challenging

Instructions
things you'll need:

Wheel chocks
Floor jack
Jack stands
Metric sockets
Breaker bar
Pliers
Hammer
Ratchet and extensions
Metric wrench
Hydraulic press
Lower ball joint
Light lubrication oil
Torque wrench

1

Engage the emergency brake and place wheel chocks behind and in front of the rear wheels. Raise the vehicle using the floor jack, place the jack stands and lower the Corvette to securely rest on the jack stands.
2

Remove the front wheels with the assistance of the metric socket and breaker bar.
3

Place the floor jack under the front control arm and raise the jack to compress the shock absorber. Remove the two bolts securing the shock absorber to the lower control arm with a ratchet, extension and socket. Remove the cotter pin from the lower ball joint with the aid of pliers. Remove the nut securing the lower ball joint with a metric wrench. Gently tap on the lower ball joint with a hammer to disconnect it from the suspension mounting point. Lower the floor jack and pull it away from the car.
4

Remove the four bolts that secure the control arm to the cross-member. Use a wrench on the nut side and the ratchet with a socket on the bolt side to loosen each bolt.
5

Remove the two carriage bolts that secure the lower control arm to the chassis. Use a ratchet and socket to turn the bolt and a wrench to secure the nut. Pull the
6

Remove the lower control arm from the car and position it in a hydraulic press. Use the hydraulic press to apply pressure to the top of the lower ball joint. Press the ball joint out the bottom of the control arm.
7

Apply a thin coat of oil on the control arm, in the hole for the lower ball joint. Insert the new ball joint into the control arm. Use the hydraulic press to seat the ball joint into the lower control arm.
8

Replace the lower control arm into the brackets attached to the chassis. Insert the two carriage bolts securing the control arm to the chassis. Tighten the bolts to 96 foot-pounds of torque with the torque wrench.
9

Insert the remaining bolts used to secure the control arm to the cross-member. Tighten each bolt to 96 foot-pounds with the torque wrench. Raise the control arm with the floor jack to install the shock absorber mounting bolts. Tighten the mounting bolts to 22 foot-pounds of torque.
10

Insert the shaft of the lower ball joint into the steering knuckle. Install the nut securing the lower ball joint to the steering knuckle and tighten to 33 foot-pounds of torque. Insert a cotter pin into the lower ball joint and secure the cotter pin using a pair of pliers.
11

Install the wheels on the hubs and secure using the lug nuts. Tighten each lug nut to 100 foot-pounds of torque with the torque wrench.
12

Use the floor jack to remove the jack stand and lower the Corvette. Remove the wheel chocks and release the emergency brake.


http://www.harborfreight.com/four-wheel ... -4065.html

http://www.harborfreight.com/14-piece-m ... 66958.html

http://www.harborfreight.com/20-ton-sho ... 32879.html

keep in mind that if you have BOTH a two post LIFT and a HYDRAULIC PRESS, an the tools listed above you can press the lower ball joint IN AND OUT while the A-arms still on the car in MANY cars if you can move the press into the wheel well, and raise the car to the correct height to use the press

 

[grumpyvette]

http://www.dougrippie.com/

The DRM coil overs and a alignment ( per DRM specs ) will turn your C4 into a different animal . (quote from pleased customer)

http://www.dougrippie.com/

 

[grumpyvette]

http://www.corvettefever.com/techarticl ... index.html

http://www.corvettefever.com/techarticl ... hings.html

http://www.stevenemichael.com/RestoModC ... Joint.html

http://www.vetteweb.com/tech/vet_0311_c ... index.html

http://www.mamotorworks.com/corvette-c4 ... -1118.html

http://www.ikerds.com/miva/merchant.mvc?

http://www.ikerds.com/catalog/group04/group04.html

 

[grumpyvette]

obviously theres the higher cost option of swapping to an aftermarket frame that gives the cars suspension a great many more options
info on spring rates
http://www.banningcohen.com/buick/handl ... 0chart.pdf

If your planning on using a C4 frame for another project I have bad news the C4 is sort of a hybrid unibody.
its designed with a structural (BIRD CAGE)

heres a few potential sources

http://www.vettetech.com/
(posted these tips)

http://www.sriiimotorsports.com/196382corvette.html
Art Morrison
SRIII
Car Creations (Newmans)
http://www.newmancarcreations.com/63-82-corvette/
Jim Meyers
Corvette Connection
Jamisons
Street Shop
etc.

Things to consider:
cost to do the swap, obviously
Front Suspension Options
Rear Suspension Options
Modifications to body if any
Engine and Transmission options
Bolt on?
Fuel Tank Requirements if any (Stock or aftermarket)
Exhaust (Stock or aftermarket?)
Wheel and Tire limitations?
Price
Weight
Shipping?
Design (Strength)
Customer Service
Finish Options (Paint or Powdercoatin)
Roller Available?

Factory Alignment Specifications for Corvette
There has been a few requests for this information. So I will be compiling this here from my hunter alignment database.

1954-57
front
camber 0.50* +/- 0.50*
caster none
total toe none
--------------------------------------------------------------

1958
front
camber 0.50* +/- 0.50*
caster 2.00* +/- 0.50*
total toe 0.13* +/- 0.13*

rear
camber none
total toe none
----------------------------------------------------------
1959-62
front
camber 0.00* +/- 0.50*
caster 2.00* +/- 0.50*
total toe 0.13* +/- 0.13*

rear
camber none
total toe
-----------------------------------------------------
1963-65
front
camber 0.75* +/- 0.50*
caster 1.75* +/- 0.50*
total toe 0.50* +/- 0.13*

rear
camber -0.33* +/-0.50
total toe 0.13* +/-0.13
---------------------------------------------------------------
1966-67
front
camber 0.75* +/- 0.75*
caster 1.00* +/- 0.50*
total toe 0.50* +/- 0.13*

rear
camber -0.50* +/- 0.50*
total toe 0.25* +/- 0.13*
--------------------------------------------------------------------------
1968-74 power steering
front
camber 0.75* +/- 0.75*
caster 2.25* +/- 1.00*
total toe 0.50* +/- 0.25*

rear
camber -0.88* +/- 0.75*
total toe 0.25* +/- 0.13*
--------------------------------------------------------------------------
1968-74 manual steering
front
camber 0.75* +/- 0.75*
caster 1.00* +/- 0.50*
total toe 0.50* +/- 0.2*

rear
camber -0.88* +/- 0.75*
total toe 0.25* +/- 0.13*
--------------------------------------------------------------------------
1975-76 manual steering
front
camber 0.75* +/- 0.75*
caster 1.00* +/- 1.00*
total toe 0.50* +/- 0.25*

rear
camber -0.88* +/- 0.25*
total toe 0.13* +/- 0.13*
--------------------------------------------------------------------------
1975-76 power steering
front
camber 0.75* +/- 0.75*
caster 2.25* +/- 1.00*
total toe 0.50* +/- 0.25*

rear
camber -0.88* +/- 0.25*
total toe 0.13* +/- 0.06*
--------------------------------------------------------------------------
1977-78
front
camber 0.75* +/- 0.75*
caster 2.25* +/- 1.00*
total toe 0.50* +/- 0.25*

rear
camber -0.88* +/- 0.25*
total toe 0.00* +/- 0.06*
--------------------------------------------------------------------------
1979
front
camber 0.75* +/- 0.75*
caster 2.25* +/- 1.00*
total toe 0.50* +/- 0.2*

rear
camber -0.50* +/- 0.50*
total toe 0.19* +/- 0.06*
--------------------------------------------------------------------------
80-82
front*
camber 0.75* +/- 0.75*
caster 2.25* +/- 1.00*
total toe 0.50* +/- 0.25*

rear
camber 0.00* +/- 0.50*
total toe 0.13* +/- 0.13*
--------------------------------------------------------------------------
1984
front
camber 0.81* +/- 0.50*
caster 3.00* +/- 0.50*
total toe 0.00* +/- 0.20*

rear
camber 0.00* +/- 0.50*
total toe 0.00* +/- 0.20
--------------------------------------------------------------------------
1985
front
camber 0.81* +/- 0.50*
caster 3.00* +/- 0.75*
total toe 0.00* +/- 0.20

rear
camber 0.41* +/- 0.50*
total toe 0.00* +/- 0.20
--------------------------------------------------------------------------
86-88
front
camber 0.80* +/- 0.50*
caster 6.00* +/- 0.50*
total toe 0.00* +/- 0.20*

rear
camber 0.40* +/- 0.50*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------
89-96*
front
camber 0.50* +/- 0.50*
caster 6.00* +/- 0.50*
total toe 0.00* +/- 0.20*

rear
camber 0.00* +/- 0.50*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------
97-2000
front
camber -0.25* +/- 0.50*
caster 6.50* +/- 0.50*
total toe 0.10* +/- 0.20*

rear
camber -0.18* +/- 0.20*
total toe -0.02* +/- 0.20*
--------------------------------------------------------------------------
00-04 except Z06
front
camber -0.20* +/- 0.50*
caster 7.40* +/- 0.50*
total toe 0.08* +/- 0.20*

rear
camber -0.18* +/- 0.50*
total toe -0.02* +/- 0.20*

Z06
front*
camber -0.70* +/- 0.50*
caster 6.90* +/- 0.50*
total toe 0.08* +/- 0.20*

rear
camber -0.68* +/- 0.50*
total toe -0.02* +/- 0.20*
--------------------------------------------------------------------------
05-06 except Z06
front*
camber -0.45* +/- 0.50*
caster 7.90* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -0.45* +/- 0.50*
total toe 0.00* +/- 0.20*

Z06
front*
camber -1.00* +/- 0.60*
caster 8.00* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.00* +/- 0.50*
total toe 0.00* +/- 0.20*
---------------------------------------------------------
2007-08, 09-12 FE1/FE2/FE3, 10-12 FE3 w/o RPO XFA
front
camber -0.45* +/- 0.60*
caster 7.50* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -0.45* +/- 0.60*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------
2007 Z06
front
camber -1.00* +/- 0.60*
caster 7.60* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.00* +/- 0.50*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------

2008 Z06, 09-11 FE4, 10-12 FE3 w/ RPO XFA, 2012 FE4 (Z06) w/o RPO XFH
front
camber -0.95* +/- 0.60*
caster 7.60* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.20* +/- 0.60*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------
2009-11 FE5 (ZR1)
front
camber -1.00* +/- 0.60*
caster 7.70* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.25* +/- 0.60*
total toe 0.10* +/- 0.20*
--------------------------------------------------------------------------
2012 FE1/FE2/ FE3 w/o RPO XFA
front
camber -0.45* +/- 0.60*
caster 7.50* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -0.45* +/- 0.60*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------

2012 FE5 (ZR1) w/RPO XFH
front
camber -1.30* +/- 0.60*
caster 7.20* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.30* +/- 0.60*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------
2012 FE5 (ZR1) w/o RPO XFH
front
camber -0.95* +/- 0.60*
caster 7.70* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.20* +/- 0.60*
total toe 0.10* +/- 0.20*
--------------------------------------------------------------------------

2013 FE1/FE2, FE3 w/o RPO XFA/XFG
front
camber -0.45* +/- 0.60*
caster 7.50* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -0.45* +/- 0.60*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------
2013 FE3 w/RPO XFA/XFG, FE4 ( Z06 ) w/RPO XFA / XFG
front
camber -0.95* +/- 0.60*
caster 7.60* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.20* +/- 0.60*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------

2013 FE5 (ZR1 ) w/RPO XFG
front
camber -0.95* +/- 0.60*
caster 7.70* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.20* +/- 0.60*
total toe 0.10* +/- 0.20*
--------------------------------------------------------------------------

2013 FE4 ( Z06 ) w/ RPO XFH, FE5 ( ZR1 ) w/ RPO XFH
front
camber -1.30* +/- 0.60*
caster 7.20* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -1.30* +/- 0.60*
total toe 0.00* +/- 0.20*
--------------------------------------------------------------------------

2014 FE1 / FE2 / FE3/FE4
front
camber -0.50* +/- 0.60*
caster 7.40* +/- 0.60*
total toe 0.10* +/- 0.20*

rear
camber -0.50* +/- 0.60*
total toe 0.00* +/- 0.20*

 

[grumpyvette]

Ive always been a bit amused at the guys that want the racing look and that rather lopey race car engine sound, who want to lower their cars,but don,t want to bother with actually boosting the engines power or actual improving handling, or having increased braking efficiency,stiffening the chassis, increased engine or transmission cooling, better lubrication,and improved acceleration of the car,and guys that seem to think, changing the cars ,appearance, and engine sound , so they think they are looking like a racer without the slightest concept of actual improving their cars performance , some how gains them status.
just a question gentlemen, I,m well aware that lowering the cars center of gravity and roll center and adding a few carefully selected suspension components and better tires can improve handling,and carefully selecting light weight components, larger brakes and a roll cage can improve handling and traction, but from what I see 90% of the lower corvettes skip the additional enhanced suspension components and about 60% or more skip adding significantly better tires, so if your not doing whats required to really improve the handling significantly, lowering the car effectively gives you a bit more of that (RACER STANCE" and a good deal more chance of speed bumps and higher than ideal manhole covers to radically and almost instantly do massive lower oil pan and transmission damage and not much else?
so if your not racing the car why bother, its not like the stock suspensions that bad for street car use?

bits of related info

http://www.greenwoodcorvettes.com/C4s.html

http://www.corvettephotographs.com/c4ve ... rmance.htm

http://www.mamotorworks.com/corvette-te ... -3862.html

viewtopic.php?f=34&t=13

http://www.shop.banskimotorsports.com/c ... tegoryId=9

http://www.corvettefever.com/techarticl ... index.html

http://books.google.com/books?id=1Ti3kH ... &q&f=false

http://www.teamzr1.com/vetfacts.html

http://www.zfdoc.com/c4beamplate.htm

http://www.corvettefever.com/techarticl ... index.html

http://www.corvettefever.com/techarticl ... index.html

http://www.corvettefever.com/techarticl ... index.html

http://www.corvettefever.com/techarticl ... index.html

http://www.corvettefever.com/techarticl ... index.html

http://www.corvettefever.com/techarticl ... index.html

 

[grumpyvette]

tools Id suggest you have as it makes the job easier

http://www.corvettefever.com/techarticl ... index.html

youll want a decent floor jack and jack stands or a lift to gain access to the suspension
youll want to use a drill of about 3/16" on the 4 rivets on each upper ball joint, you don,t need to drill deeper than 1/2" max, but you will need a center punch to get the drill centered on the rivet, once the 3/16" bits drilled 1/2" deep swap to a stepp drill opr a 3/8" bit that will shear off the upper rivet from the main shaft , once thats done you can drive out the rivet from the top with a 1/4" drift.
the bolts that hold on the new upper ball joint should inseart from below so the ball joint grease seal has max clearance from the bolts as the bolt threads will extend upwards out of the nuts.
be aware of the quality of the components you select, there are several merchants that advertise a great deal based on lower prices,
who generally deal in the lower and mid range quality products,
and their goal seems too be a low price volume discount supply house.
now Ive seen a few good deals, over the years but keep in mind,
youll generally find discount price parts, use lower quality components or,
less extensive precision machine work, or imported components or a combination of those factors to reduce price.
now I'm not picking on the lower price parts suppliers, they certainly have a place in the economy and hobby.
I use rockauto and advanced auto, walmart and several other suppliers,
if I need too ,but I generally know the parts and use name brands not cheaper import clones.
remember thats frequently a very noticeable difference in quality, in similar components,
you may pay more for name brand parts and at times the higher cost is not justified in my opinion,
but many of the better known brands do tend to have better quality control and R&D
I would suggest you do research and avoid using the lowest cost import parts like bearings, brakes, and suspension parts ,
as Ive seen horrendous quality control on some import component examples
youll need a drill to remove rivets a punch to remove rivets, a hammer, cutting oil for the drill , wrenches for the bolts and clean up solvent, to remove crud,

http://www.harborfreight.com/14-piece-m ... 66958.html

the lower ball joints PRESS OUT and youll need a large adapter or socket to press them out and a press to re-install the lower ball joint but measure the old then the new ball joint mating surface diameter as cheap parts rarely have the correct diam, and may need to be filed, belt sanded etc. before they fit correctly, and don,t forget to use a good grease gun on them once installed

 

[grumpyvette]

http://www.racecars360.com/Corvette_Tec ... nsion.html

http://www.racecars360.com/Corvette_Tec ... n_-_2.html

http://www.racecars360.com/Corvette_Tec ... n_-_3.html

http://www.performancechoice.com/pc.html?frame=5.1128

http://www.robhealey.com.au/Corvette/scorp/

shocks are only part of the completed system,while they help they provide only about 30% of the feel, Ive replaced shocks and got only marginal improvement in the way the car felt, I then replaced the bushings and ball joints and together the combined difference in handling was truly amazing



RELATED STUFF

http://www.corvettefever.com/techarticl ... ewall.html

http://www.carcraft.com/techarticles/cc ... ewall.html


http://www.mamotorworks.com/corvette-c4 ... -1089.html

http://www.mamotorworks.com/corvette-c4 ... -3905.html

http://www.mamotorworks.com/corvette-c4 ... -3897.html

http://www.youtube.com/watch?v=e43LfjQjVlc

http://www.zip-corvette.com/ProductDeta ... .aspx?pid={cf1671d7-0bb0-4eff-bafc-bc0196bc0f89}&gid={d0217409-a9e8-483c-8f02-d04e7d4f24f9}&GroupName=Brake+Upgrade+Kits&pname=88-96+Wilwood+Front+6-Piston+13%22+Big+Brake+Kit+-+Red+Calipers&Referer=&Alias=&ptct=SGR-SR&CTitle=&

http://www.gmhightechperformance.com/te ... ewall.html

http://www.mamotorworks.com/corvette-c4 ... -1128.html

http://www.ebay.com/itm/1984-1996-Chevy ... es&vxp=mtr

 

[grumpyvette]

Re: upgrading the suspension on a c-4 LD85 posted this

LD85 posted this

I did this a couple of months ago and thought I would post some pics if you have not seen them.

OK, I bought the Coil-over part list from Mo's website, www.ndneyes.com

Since the 1985 shock towers are wimpy and narrow, I cut them as seen in the pic below.

Then I machined some 1/4" thick 1018 CRS to match the same angles as the stock towers and ol'RJ welded them up.

The last pic is just the mock up of the new QA1 in the new tower.

Once the wheel well area was cleaned it was repainted,

replacing u-joints

" grumpy??? I can't figure out how to replace my trucks u-joints I've never seen a u-joint removed or replaced, any tips" https://www.harborfreight.com/ball-joint-service-kit-for-2wd-and-4wd-vehicles-63279.html...

garage.grumpysperformance.com

Just an FYI, vette2vette.com and tabercorvetteparts.com had 1990-1996 front shock towers you can buy and weld onto your 85-89 (not sure where the thin towers end and the wider towers begin) to replace the factory towers.

The early years shock towers use .125" thick steel and the later years use .160" thick steel. I used .250" thick on the sides and .375" on the top due to the larger span

I would say that it would take @ 4 hours to cut off both towers,
1. IF you had a decent air compressor using a cutoff wheel
2. and a spot weld drill bit,,,
3. and if you removed the lower ball joint nut and swing the a-arm up out of the way.
4. Then you need access to a 220volt welder of your choice,


85 Rear Coilover mod
Well, in short, it looks like the 1985 Rear Upper Mount is not the same as the later years, so I can't weld a washer onto the mount plate and move it, I am not surprised really.

And to top it all off you can see that the mount hole is offset towards the edge of the frame (towards teh car center) and there is a rolled up edge there that prevents you from mounting anything flat on that edge.

It looks like I will have to weld up a mount bracket that replicates the factory mount,, then cut the factory mount off, and weld the new bracket on becasue I can't see how you can get into the boxed frame to put a nut on the mount bolts.

Spoke with QA1 tech today, their big issue with C4's and Coilovers is they say the mounting bracketsare flimsy,, well, I can take care of that, probably will use .250" thick CRS like I did on the front CO tower.

For you guys that have done this mod on later years,,,, do the pics look similar to the later years, except for the shock mount?

Here is a pic of the new spherical bearings that came today, this will help with the apparent misalignment on the shock loop.

You press out the Poly bushing, then press the bearing in and install a snap ring on the ID of the loop on both sides of the bearing. Part # QA1 EMB8-102pk

I cut the Towers off both sides. They are only @ .110" thick so we'll heli-arc weld .125" thick SS to the sides of each tower which will make them @ .245" thick,, then stick weld them back to the car hopefully tomorrow night.

Well, we welded 1/8 thick SS to the side of the stock mount, it ain't pretty, but its pretty strong, it was .105" thick before, now its .235" thick afte rthe SS was added

We also welded a larger base to the mount in an effort to spread out the load, the base is 1/4" thick 1018 CRS

Welded on and moved forward 1.250"

Painted and since I kept the factory mount in an effort to make this reversible in the future,, I put a rubber bushing in between the Spherical bushing and the mount wall, I will search out a better solution for this but with teh tires on, you dont see it.

 

[grumpyvette]

I posted this info else ware on the site but Id point out that when we bleed the brakes we made sure to remove all old brake fluid and you can usually tell the old fluid very easily because, I place a section of 1/4" I.D. clear vinyl tube over the nipple on the bleeder and old fluid tends to look yellow or brown due to rust forming due to moisture absorbed over time in the brake fluid, as old brake fluid tends to absorb water from the air,, over time, and once brakes get really heated due to hard use, in performance driving that moisture turns to STEAM, and you brakes stop working correctly, in fact if the brakes get really hot the brakes just stop working which can be a HUGE problem.
new brake fluid looks almost clear

YOU MIGHT WANT TO READ THESE LINKS

viewtopic.php?f=71&t=1848&p=16080&hilit=brake+fluid#p16080

viewtopic.php?f=34&t=380

I spent a good deal of time today helping my brother-in-law install new brakes on his 1974 big block corvette , he bought 4 new (rebuilt) brake calipers and brake fluid, brake pads, etc. from advanced auto parts because they said they had a life time guarantee , he also bought brake cleaner etc. we put the car up on the lift and pulled the wheels , pulled the calipers, 3 of the 4 looked like they had leaks , two of the ones that leak were obviously defective,one looked like the bleeder was loose.
further inspection showed the 3 leakers needed to be replaced, the pass side rear was the first caliper we pulled off and as we went to put on the rebuilt caliper we quickly found that the caliper re-builder had failed to notice the core they rebuilt had totally stripped threads on the hydraulic line location, I called around the area and eventually located a store with a replacement (different chain store) and while we were checking parts we found one package of brake pads, were obviously not for the corvette, so I made a trip back to exchange those, and took the old worn pads to show the parts counter guy the difference.
the end result was about 2 hours of UN-necessary running around to get replacement parts we already had to do the job, the car eventually got put back together and the brakes worked great, but I still feel that the jerks art advance auto could do a better job, after all one package of brake pads that don,t even fit the car and stripped threads on a "NEW" part are not what you should be dealing with, but Ive come to expect this, many of the local parts stores either don,t have the parts in stock and they must be ordered 24-48 hours in advance or the parts that come in are defective far too often,or the parts are just for the wrong car.
now I know its partly because they don,t give a crap, they get paid minimum wages, but it gets old fast!
I especially like the deer in the headlights stare , the parts guys give you when you point out the parts they sold you two hours earlier, are not even similar to the old part you bring in to show them. or guys that want to argue about if the part they sold you 2 hours ago is really defective.

 

[grumpyvette]

C4 Corvette Suspension Chart, spring rates & broadcast codes

Track Width Comparison
C5 Z06:

Length 179.7 in - 4565 mm
Width 73.6 in - 1869 mm
Height 47.7 in - 1212 mm
Wheelbase 104.5 in - 2655 mm
Front track width 62.4 in - 1585 mm
Rear track width 62.6 in - 1590 mm

C6 Z06:

Length 175.6 in - 4460 mm
Width 75.9 in - 1927 mm
Wheelbase 105.7 in - 2684 mm
Front track width 63.5 in - 1612 mm
Rear track width 62.5 in - 1587 mm


C3:

Front 58.7, Rear 59.5 -- 68-82 Chevy Corvette

Rear hub to hub (w/o rotors): 57.165

C4:
Front 59.6, Rear 60.4 -- 84-96 Chevy Corvette

just a few pictures I found posted that easily demonstrate internal tire damage can cause serious issues with stability, braking and control, and yeah, hitting a few curbs, chuck holes and speed bumps with your corvette,or muscle car,will be unlikely to help tire durability

http://garage.grumpysperformance.co...orvette-high-speed-stability.1566/#post-66937

http://garage.grumpysperformance.co...bought-lately-that-were-junk.4720/#post-12823

 

[Grumpy]

Have some shimmy in the front end on bumpy roads. Just replaced the shocks. Helped a little but didn't solve problem. Car has 62k miles.
Any ideas?

many times that indicates well worn ball joints, Id suggest inspecting and if in any doubt replacement and follow with an alignment, be aware most cheap import ball joints are
TOTAL CRAP Quality and won,t fit well so get a decent known name brand set of upper and lower ball joints.

ball joint tool set that makes changing them much easier in many cases
https://www.amazon.com/exec/obidos/ASIN/B0028QGT86/ezvid02-20

https://www.walmart.com/ip/4-In-1-B...8308&wl11=online&wl12=181980325&wl13=&veh=sem

https://www.harborfreight.com/3-4-quarter-inch-forged-ball-joint-separator-99849.html

https://www.harborfreight.com/14-piece-master-ball-joint-adapter-set-60307.html

be aware price and quality of ball joints for a corvette vary wildly ,
you can find a complete upper and lower set of ball joints for under $180,
\ they will in most cases be total crap,imported junk.
go with a name brand like MOOG or AC DELCO PROFESSIONAL brands
NOT A NO NAME IMPORT part ,
your life could depend on the suspension not failing
theres a reason that
some ball joints cost $20-$40
vs
$80-$100 each

http://www.homedepot.com/p/Powerbuilt-23-Piece-Ball-Joint-U-Joint-Service-Kit-648617/203120548?cm_mmc=Shopping|THD|G|0|G-BASE-PLA-D25T-Garage-Automotive|&gclid=CM7-rI-e-tQCFUa4wAodcnEHfg&gclsrc=aw.ds

http://www.homedepot.com/p/Powerbuilt-23-Piece-Ball-Joint-U-Joint-Service-Kit-648617/203120548?cm_mmc=Shopping|THD|G|0|G-BASE-PLA-D25T-Garage-Automotive|&gclid=CM7-rI-e-tQCFUa4wAodcnEHfg&gclsrc=aw.ds

its costs a bit more to use quality materials and manufacture parts to correct , dimensions and yes you need quality tools to install and remove parts

http://www.rockauto.com/en/catalog/...e,5.7l+v8,1041398,suspension,ball+joint,10070

http://www.mamotorworks.com/Corvette/newsearch.aspx?S=ball joints&Y=&G=&C=&gclid=CNeV36SZ-tQCFViewAodLMoLHw

https://books.google.com/books?id=2y7TZN_qDGEC&pg=PA212&lpg=PA212&dq=replacing+ball+joints+on+c4+corvette&source=bl&ots=QAwjPprspw&sig=k3xpotk6h1PO2zcbbTFtp803vkA&hl=en&sa=X&ved=0ahUKEwjh26bSo_vUAhVL2mMKHQufB0YQ6AEIgAEwCA#v=onepage&q=replacing ball joints on c4 corvette&f=false

https://www.amazon.com/Projects-Corvette-1984-1996-Motorbooks-Workshop/dp/0760314616

http://www.mamotorworks.com/Corvette/subcategory/c4-ball-joints-ball-joint-hardware

yes you can install a 4 link and dana 60 in a serious c4 corvette suspension modification upgrade

Well finally got around to lowering the 84', decided I would shoot some pics and do a write up. Here ya go...

Materials needed, lowering bolts wedges and durable strips of rubber.


How to lower you’re C4 Corvette:

Lowering of the front:

First off, you need to get your Corvette's front end off of the ground. Try to get it pretty high off the ground because you will need to get under your car to take some brackets off. Place the front end on two jack stands and make sure that it is secure before removing the jack. Then remove your front tires, and if you have ABS you should remove the sensor as well.


Remove the one bolt that connects the sway bar to the spring retainer plate. Next, take the cotter pin and castle nut off of the tie rod end using a 21mm socket. Do this on both sides.

Take your jack and place it under the lower control arm and raise it until your shock compresses a bit. Be sure to put a piece of wood between the jack and lower control arm. Now you can use your 13mm socket to remove the two bolts attaching the shock to the plate. Then remove the cotter pin and castle nut from the lower ball joint using a 21mm socket. You will probably have to use a ball joint puller to disconnect the knuckle from the ball joint as well as the knuckle from the tie rod end. An automotive fork and hammer will also work, which is what I used. Slowly lower the jack and get it out of your way. Then you can swing the knuckle assembly out of the way and support it with a 2X4 if you wish. Now run to the other side of your car and do it again.


Now you can remove the metal retainer that the shock attaches to. There are 4 bolts that need to be removed using a 13mm socket.


Next, remove the two 15mm spring bracket nuts. The bolt will probably spin and an impact tool may be handy here. What I did was I took a 15mm socket and attached it to a universal, then attached that to a long extension. From the top on the driver side you wiggle it onto the bolt coming down through the engine compartment and wedge it onto the bolt. Then you can go back under the car and use another socket driver to loosen the nut. On the passenger side there is about a one inch diameter hole in the frame rail that you can squeeze your extension with universal down into and do the same as on the driver side. The other bolt you can reach with a wrench to keep from spinning. Remove these brackets and set them aside.


To free the spring from the lower control arm I just stepped down on the control arm and this pretty much separates the spring from it. Now you have to remove the spring by twisting it and sliding it back and forth to free it from the car. Be careful not to scratch the spring because doing so can jeopardize the integrity of it.


Now remove the two spring pivots from the spring and cut the rubber down to the thin metal shim.


Now you can glue the wedges in place of the spring pivots with glue that is both moisture resistant and somewhat flexible. I used weather sealant polyurethane. Having these wedges are critical to the performance of your Corvette. Since the original ones are designed to pivot the spring back and forth when the car turns, you will still need this pivot point, which is why the wedges are wedges and not a flat piece of rubber. They allow the spring to still pivot between the suspension and the frame itself. Now if there were no wedges and the spring sat directly against the frame then the spring rate will be disrupted, altering the springs designed purpose. Also, the direct contact to the frame will eventually damage the spring and put gauges in it, which will allow moisture to enter and deteriorate the spring. If you insist on putting the spring back in without the wedges, perhaps just leave a little bit of rubber as an impact point.


But there is a solution if you want to keep your spring intact and lower it more than the wedges will allow. I used a belt sander to sand down the bottom of the wedges and left about 3/16" plus the actual wedge as shown in the pictures. I then glued these down to the spring and allowed it to dry overnight.

Before sanding on the left, after sanding on the right


Homemade wedge sanding equipment:laughing:


The aftermath


Wedges glued to the spring


84-87 Corvettes use a stamped steel spring bracket which is hard to modify when using these wedges. 88's and up use an aluminum bracket which is easy to shorten using a hacksaw. So, in order to fill the gap between the spring and the frame once the bracket is installed, I put a small strip of rubber on the inside bottom of the spring bracket to make up the difference in height that we lost from removing the spring pivots. Now when you screw these brackets in place there will be no gap and it should install tightly against the frame, compressing the rubber that we just installed into the bracket.



Assembly is the same as disassembly.

Lowering of the rear:

You don't even need to get the car off the ground to do the rear. First, take your jack with a piece of wood on top of it and raise the rear spring in order to take the tension off of it. note: driving the rear of the car onto ramps can help.

Now remove the cotter pin and castle nut (blue arrow) and slide the bolt out.

This is what will come out with the bolt. Make sure you remember how to put it back together.


Note where the old nut was located on the bolt, and mark it on the new bolt. Then, just experiment with how low you want to go by loosening and tightening the new nut.
Marked bolt


All finished


Before:


After:


You can still get a pretty low ride by trimming the wedges while maintaining the original pivot point and design of the spring. I was about 3.5" high in the front and rear before I started, now in the front I have a little less that 1.5" and the rear about 2".