Coilover front end spring rates?
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Coilover front end spring rates?
I don't want stiff, I want a decent ride, Mo is using 600 lb front spring rates.
Can you guys with Coilovers give me your spring rates and tell me if it is stiff to you or not?
My 1985 spring is tired and when I cut the rubbers off to lower the front, well, it really makes the front end feel dead and the car is dropped so low my spoiler drags alot. My car is 26" from the fender to the ground on the front.
Can you guys with Coilovers give me your spring rates and tell me if it is stiff to you or not?
My 1985 spring is tired and when I cut the rubbers off to lower the front, well, it really makes the front end feel dead and the car is dropped so low my spoiler drags alot. My car is 26" from the fender to the ground on the front.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
I believe that coil-overs open up spring rate selection to
a wide variety of choice.
Joby has pointed out that a consideration when switching is
'sway-bar like' anti-roll characteristic provided by the
transverse spring.
600 lbs/in? Was the fr spring changed to a '84 Z51 at some point?
Unless you're convinced that c-o is the way to go, there are a
number of OEM rates and probably some VB&P choices that might
get the ride and handling performance to a level that is right
for you.
From Hib Halverson's Chart. Conversion rate: N/mm * 5.710 = lbs/in
1984 FE1 63.5 (362 lbs/in)
1984 Z51 102.0 (582 lbs/in)
1985 FE1 54.0 (308 lbs/in)
1985 Z51 63.5 (362 lbs/in)
1986 FE1 51.8 (296 lbs/in)
Pattie from VB&P has posted here in the past to say that VB&P
'can manufacture any spring rate or target range you want'
.
a wide variety of choice.
Joby has pointed out that a consideration when switching is
'sway-bar like' anti-roll characteristic provided by the
transverse spring.
600 lbs/in? Was the fr spring changed to a '84 Z51 at some point?
Unless you're convinced that c-o is the way to go, there are a
number of OEM rates and probably some VB&P choices that might
get the ride and handling performance to a level that is right
for you.
From Hib Halverson's Chart. Conversion rate: N/mm * 5.710 = lbs/in
1984 FE1 63.5 (362 lbs/in)
1984 Z51 102.0 (582 lbs/in)
1985 FE1 54.0 (308 lbs/in)
1985 Z51 63.5 (362 lbs/in)
1986 FE1 51.8 (296 lbs/in)
Pattie from VB&P has posted here in the past to say that VB&P
'can manufacture any spring rate or target range you want'
.
Drifting
Joined: Jun 2001
Posts: 1,625
Likes: 1
From: Zagreb, Croatia
I bought front coilovers from CF member Insanity and he gave me
two sets of springs; 350 lbs/in and 400 lbs/in.
I haven't installed them yet so I can't tell you about stiffnes but
600 sounds too much.
two sets of springs; 350 lbs/in and 400 lbs/in.
I haven't installed them yet so I can't tell you about stiffnes but
600 sounds too much.
Burning Brakes
Joined: Feb 2002
Posts: 1,128
Likes: 70
From: Pineville Louisiana
Well 600lb's sounds a bit on the high side, I am running 400lb front and 275lb rear. I may go a bit firmer but not much, this set up is good for the track (keeps the car neutral and I can go into corners very hot) and is a good comprise for the street. The ride will also depend on what shock you use with the springs. Coilovers are not a "bolt on" mod, but are pretty easy, for you to get the most out of them you need to have the cross weights adjusted, with you in the car, after you have installed them, also change your bushings if you haven't already. I would check with forum member Randy@DRM if you really want it set up right (he stays in the autocross & roadrace section mostly).
Daniel
Daniel
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
Correct,
600 does sound like a lot, but you also have to remember that the front shocks are at a 30 degree angle.
So if you take 600 times the .75 angle that will give you the 450.
http://www.proshocks.com/calcs/anglefirst.htm
Here is a calc I passed on to LD85.
I have run as low as 400 in the front which equates to 300 which is equivelent to the FE1. ~which actually was a nice ride~
I was also using the chart as well that slalom4me also provided.
It really comes down to preference
I'm running slightly higher in front as I have a 70 pound supercharger and I was always scrubbing on the freaky California streets. This also allowed me to keep the lower stance as well.
With my QA1's I can set to what ever ride needed as well.
I hope this helps,
Regards,
MO
600 does sound like a lot, but you also have to remember that the front shocks are at a 30 degree angle.
So if you take 600 times the .75 angle that will give you the 450.
http://www.proshocks.com/calcs/anglefirst.htm
Here is a calc I passed on to LD85.
I have run as low as 400 in the front which equates to 300 which is equivelent to the FE1. ~which actually was a nice ride~
I was also using the chart as well that slalom4me also provided.
It really comes down to preference
I'm running slightly higher in front as I have a 70 pound supercharger and I was always scrubbing on the freaky California streets. This also allowed me to keep the lower stance as well.
With my QA1's I can set to what ever ride needed as well.
I hope this helps,
Regards,
MO
Racer
Joined: Apr 2002
Posts: 252
Likes: 30
From: San Diego Ca
I believe that coil-overs open up spring rate selection to
a wide variety of choice.
Joby has pointed out that a consideration when switching is
'sway-bar like' anti-roll characteristic provided by the
transverse spring.
600 lbs/in? Was the fr spring changed to a '84 Z51 at some point?
Unless you're convinced that c-o is the way to go, there are a
number of OEM rates and probably some VB&P choices that might
get the ride and handling performance to a level that is right
for you.
From Hib Halverson's Chart. Conversion rate: N/mm * 5.710 = lbs/in
1984 FE1 63.5 (362 lbs/in)
1984 Z51 102.0 (582 lbs/in)
1985 FE1 54.0 (308 lbs/in)
1985 Z51 63.5 (362 lbs/in)
1986 FE1 51.8 (296 lbs/in)
Pattie from VB&P has posted here in the past to say that VB&P
'can manufacture any spring rate or target range you want'
.
a wide variety of choice.
Joby has pointed out that a consideration when switching is
'sway-bar like' anti-roll characteristic provided by the
transverse spring.
600 lbs/in? Was the fr spring changed to a '84 Z51 at some point?
Unless you're convinced that c-o is the way to go, there are a
number of OEM rates and probably some VB&P choices that might
get the ride and handling performance to a level that is right
for you.
From Hib Halverson's Chart. Conversion rate: N/mm * 5.710 = lbs/in
1984 FE1 63.5 (362 lbs/in)
1984 Z51 102.0 (582 lbs/in)
1985 FE1 54.0 (308 lbs/in)
1985 Z51 63.5 (362 lbs/in)
1986 FE1 51.8 (296 lbs/in)
Pattie from VB&P has posted here in the past to say that VB&P
'can manufacture any spring rate or target range you want'
.
Jim
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
Thanks for the additional info Jim...
Here is also calculator for that as well...
http://www.proshocks.com/calcs/imotion.htm
Here is an example of
a= 15
b=12
380 for ball joint rate = MR of .64 593.75 final spring rate...
Mo
Here is also calculator for that as well...
http://www.proshocks.com/calcs/imotion.htm
Here is an example of
a= 15
b=12
380 for ball joint rate = MR of .64 593.75 final spring rate...
Mo
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Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Thanks guys, the calculators help alot, and I have time so I can check the wheel travel first too.
I guess in reality, I am looking at getting a stock ride quality with the added advantage of adjust-ability.
Since my car is currently down to 26" and the tires rub the wheel well on hard bumps and my spoiler drags alot, I think a 27" ride height would be nice and "IF" I wanted to stiffen it up a little I can do that too.
I will study this first and let it all sink in.
I guess in reality, I am looking at getting a stock ride quality with the added advantage of adjust-ability.
Since my car is currently down to 26" and the tires rub the wheel well on hard bumps and my spoiler drags alot, I think a 27" ride height would be nice and "IF" I wanted to stiffen it up a little I can do that too.
I will study this first and let it all sink in.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
However, as long as one is comparing rates for a given springing
system, such as the OEM transverse units under consideration above
where it is suggested that LD85 might be able to land in a good place
without moving away from the stock layout, then there is no need to
go to the additional trouble of figuring out wheel rate. This only adds
more calculation & complexity.
If the post appears to suggest that spring rates between systems
are comparable, this was not the intent.
.
Racer
Joined: Apr 2002
Posts: 252
Likes: 30
From: San Diego Ca
Thanks for the additional info Jim...
Here is also calculator for that as well...
http://www.proshocks.com/calcs/imotion.htm
Here is an example of
a= 15
b=12
380 for ball joint rate = MR of .64 593.75 final spring rate...
Mo
Here is also calculator for that as well...
http://www.proshocks.com/calcs/imotion.htm
Here is an example of
a= 15
b=12
380 for ball joint rate = MR of .64 593.75 final spring rate...
Mo
Jim
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
I agree Jim,
Onee of the things the calc does not take into consideration is the ride height. If one were to use both the coil over calc and the independant calc you would be pretty close....
Mine between the actual calculator and the actually measurements on my car is about .06 MR difference...
MO
Onee of the things the calc does not take into consideration is the ride height. If one were to use both the coil over calc and the independant calc you would be pretty close....
Mine between the actual calculator and the actually measurements on my car is about .06 MR difference...
MO
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Also, based on the calculations a 400# spring gets me close to stock for an 85 at 308#
Realalisticly, how much adjustment do you have before coil bind becomes and issue?
A 362# spring rate for the 85/Z51 - 482#'s
A 308# spring rate for the 85/FE1 - 408#'s
Can a 400# spring be adjusted to both rates without coil bind?
Realalisticly, how much adjustment do you have before coil bind becomes and issue?
A 362# spring rate for the 85/Z51 - 482#'s
A 308# spring rate for the 85/FE1 - 408#'s
Can a 400# spring be adjusted to both rates without coil bind?
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
This is putting each wheel on a scale and then optimizing weight at all four corners. This is one of the most important things that is part of "setting up" a race car and is just as important for perfecting the handling of any car after serious suspension modifications. Even a stock Vette could be optimized this way but getting the front right with the stock type front spring is a bit more work. You'd be surprised at how even a small adjustment at any wheel can affect the weight at all four corners. It's an interesting process to observe and quite an eye opening experience.
Last edited by Corvette Kid; Mar 24, 2007 at 02:01 PM.
