Suspension question
Team Owner
Joined: Jan 2003
Posts: 20,335
Likes: 264
From: Summerland B.C. Canada
VBP sells a spring they call "sport"
http://www.vbandp.com/detail.aspx?ID=381
And one they call "extreme"
http://www.vbandp.com/detail.aspx?ID=727
http://www.vbandp.com/detail.aspx?ID=381
And one they call "extreme"
http://www.vbandp.com/detail.aspx?ID=727
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
I urge that time be taken to ensure that any given spring is
suitable for your intended purpose.
Find out what the N/mm or Lbs/in rate of the spring is. For
comparison, the rates of factory installed springs have been
gathered into a document by Hib Halverson available at
CorvetteActionCenter
If desired, use N/mm * 5.710 = lbs/in as a conversion factor.
.
suitable for your intended purpose.
Find out what the N/mm or Lbs/in rate of the spring is. For
comparison, the rates of factory installed springs have been
gathered into a document by Hib Halverson available at
CorvetteActionCenter
If desired, use N/mm * 5.710 = lbs/in as a conversion factor.
.
Melting Slicks
Joined: Mar 2001
Posts: 2,153
Likes: 304
From: Timra, Sweden
I urge that time be taken to ensure that any given spring is
suitable for your intended purpose.
Find out what the N/mm or Lbs/in rate of the spring is. For
comparison, the rates of factory installed springs have been
gathered into a document by Hib Halverson available at
CorvetteActionCenter
If desired, use N/mm * 5.710 = lbs/in as a conversion factor.
.
suitable for your intended purpose.
Find out what the N/mm or Lbs/in rate of the spring is. For
comparison, the rates of factory installed springs have been
gathered into a document by Hib Halverson available at
CorvetteActionCenter
If desired, use N/mm * 5.710 = lbs/in as a conversion factor.
.
1984 base front 363 lb/in
1984 base rear 411 lb/in (445 lb/in in my table )
1984 z51 front 582 lb/in (591 lb/in in my table )
1984 z51 rear 500 lb/in
1985 base front 308 lb/in
1985 base rear 228 lb/in
1985 z51 front 363 lb/in (380 lb/in in my table )
1985 z51 rear 327 lb/in
1986-87 base front 296 lb/in
1986-87 base rear 228 lb/in
1986-87 base front 380 lb/in
1986-87 base rear 327 lb/in
1986-87 cnv front 311 lb/in
1986-87 cnv rear 228 lb/in
This is the information I have:
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
A 34lb rate difference between the charts is significant.
(But both 411 and 445 would be jarring in a street car.)
It might be more of a challenge to detect differences
of 9-17lbs.
I can't speak to why the charts vary.
The reason I posted is that the 'Sport' adjective provides
no quantitative information about the actual spring rate.
If someone with an '94 car and the FE1 suspension installed
a 'Sport' rear spring, the change from a 228#/in rate
to a "480-510#/inch" rate might not give the owner the
desired results.
Let's see what dan6712cc has to say about this ...
.
(But both 411 and 445 would be jarring in a street car.)
It might be more of a challenge to detect differences
of 9-17lbs.
I can't speak to why the charts vary.
The reason I posted is that the 'Sport' adjective provides
no quantitative information about the actual spring rate.
If someone with an '94 car and the FE1 suspension installed
a 'Sport' rear spring, the change from a 228#/in rate
to a "480-510#/inch" rate might not give the owner the
desired results.
Let's see what dan6712cc has to say about this ...
.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Look at VB&P's descriptions further, the descriptive terms
they use are not in sync with the rates from the factory.
47-61 N/mm STOCK front? Well, 60 N/mm is the lowest published rate
and only appeared near the end of the C4 model run. (47 N/mm?
now that would be cushy.) Stock was more like 73 and was up
at 93 in earlier years.
59-67 N/mm STOCK rear? Nope, 57.2 N/mm was the OEM SPORT rate
from '85-'95. GM went further down to 33 N/mm in '96, according
to the chart.
Time and again, there are posts from people wanting to
buy Z51 springs and swaybars. My vote is that the later
Z07 figures represent the evolution of the Z51. For sake
of discussion, let's set these Z07 values as a target and
go shopping at VB&P.
Here are the OEM values:
to wind up with a similar chassis set-up:
It is too bad about the propect of folks winding up with
spring combinations that may not satisfy their wants.
.
they use are not in sync with the rates from the factory.
Originally Posted by JCD
just to make things easy to compare vs. the suspension chart:
C-4 '88-96 Front Stock Spring - 47-61 N/mm
C-4 '88-96 Front Sport Spring - 79-96 N/mm
C-4 '88-96 Front Extreme Spring - 175-219 N/mm
(stiffest stock C4 springrate was 115 N/mm)
C-4 '84-96 Rear Stock Spring - 59-67 N/mm
C-4 '84-96 Rear Sport Spring - 84-89 N/mm
(stiffest was 87 N/mm in 1984, never used again)
C-4 '88-96 Front Stock Spring - 47-61 N/mm
C-4 '88-96 Front Sport Spring - 79-96 N/mm
C-4 '88-96 Front Extreme Spring - 175-219 N/mm
(stiffest stock C4 springrate was 115 N/mm)
C-4 '84-96 Rear Stock Spring - 59-67 N/mm
C-4 '84-96 Rear Sport Spring - 84-89 N/mm
(stiffest was 87 N/mm in 1984, never used again)
and only appeared near the end of the C4 model run. (47 N/mm?
now that would be cushy.) Stock was more like 73 and was up
at 93 in earlier years.
59-67 N/mm STOCK rear? Nope, 57.2 N/mm was the OEM SPORT rate
from '85-'95. GM went further down to 33 N/mm in '96, according
to the chart.
Time and again, there are posts from people wanting to
buy Z51 springs and swaybars. My vote is that the later
Z07 figures represent the evolution of the Z51. For sake
of discussion, let's set these Z07 values as a target and
go shopping at VB&P.
Here are the OEM values:
Z51: 115.5 N/mm/57.2 N/mm, 30mm/26mm
Z07: 90.1 N/mm/57.2 N/mm, 30mm/26mm ('92 forward)
It looks like we'd need the following items in our VB&P basketZ07: 90.1 N/mm/57.2 N/mm, 30mm/26mm ('92 forward)
to wind up with a similar chassis set-up:
C-4 '88-96 Front Sport Spring - 79-96 N/mm
- (ask for a hand-picked front to get closer to 90)
C-4 '84-96 Rear Stock Spring - 59-67 N/mm
- (ask for a hand-picked 'low limit' rear to get down closer to 57.2)
C-4 '88-96 Front Swaybar 28.5mm or 32mm (30mm is/was no longer avail)
C-4 '84-96 Rear Swaybar 26mm
I am glad that VB&P offers the selection of springs.- (ask for a hand-picked front to get closer to 90)
C-4 '84-96 Rear Stock Spring - 59-67 N/mm
- (ask for a hand-picked 'low limit' rear to get down closer to 57.2)
C-4 '88-96 Front Swaybar 28.5mm or 32mm (30mm is/was no longer avail)
C-4 '84-96 Rear Swaybar 26mm
It is too bad about the propect of folks winding up with
spring combinations that may not satisfy their wants.
.
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Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
If the latter, then spring rate will matter and more so because you
are working with a non-standard configuration.
.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
coupe/convertible.
CW for the '81 is listed as 3282 lbs.
Curb weight for the first of the C4 generation in '84 is publlished
as 3192/3164 lbs for the automatic/manual transmission versions.
Actual vehicle weights will vary according to options and other factors.
It may be difficult to predict what the curb weight will be for a C2
car ('63) modified to ride on a C4 suspension. The front/rear weight
distribution may well change, too.
Unless there is information from similar previous conversions, setting
up the suspension for ride height, compliance and so on will require
some trial and error before the ideal combination is determined.
.