Rear Suspension Upgrades
Racer
Joined: Mar 2006
Posts: 276
Likes: 1
From: Pistoia PT (ITALY)
what you are talking about is known as the spring ratio and wheel ratio, the spring ratio operates at a certain rate vs. the wheel ratio, dependant on the spring position relative to the axis and the force arms applies.
EDIT, I was replying to Stroker before Dr. Phil here interrupted.
EDIT, I was replying to Stroker before Dr. Phil here interrupted.
Now is the time to buy some 450lbs (wich is the wheel ratio I have now)coilover system !!!
Burning Brakes
Joined: Feb 2000
Posts: 1,246
Likes: 1
At Stroker, I just installed some Pro Coil over shocks with 450# springs and the shocks are too long in compressed length for the ride height I'm after. I have too little shock travel left and the shock hits the travel indicator (wedged into the coil over hat from fully compressing) before it hits the bump stop (about 3mm difference) Depending on how low you want the car to sit, make sure you choose the right shock and spring.
You'll need either 8 or 6" long springs, any longer and you will not be able to get them installed.
Racer
Joined: Mar 2006
Posts: 276
Likes: 1
From: Pistoia PT (ITALY)
Yes... my concern now is exactely that!
I have to simulate the stroke of my dual wishbone system in the car..... and then I have to select the right coilover..... but I think that I will need something with long stroke and short length when fully compressed...... mha!
My idea was to buy a coilover with max length of 14" and around 10" when compressed..... but the risk is to have to short wheel travel.
Opinions??????
I have to simulate the stroke of my dual wishbone system in the car..... and then I have to select the right coilover..... but I think that I will need something with long stroke and short length when fully compressed...... mha!
My idea was to buy a coilover with max length of 14" and around 10" when compressed..... but the risk is to have to short wheel travel.
Opinions??????
Burning Brakes
Joined: Feb 2000
Posts: 1,246
Likes: 1
You can't get a long stroke short length shock. If you fabricate the mount so it's low enough you can get away with a 5" stroke shock. Anything longer will not fit (unless you mount it like the pics on top, those are carrera shocks and they're either 7 or 9" stroke, not sure)
The short wheel travel isn't really an issue, your wheel won't travel much up and down anyway, you just have to make sure you have as much bump compression as you can and have the shocks extend to their full length without the suspension hanging too low. If you do that, you have shock travel where you don't need it, no sense in having 4" of droop extention. IMO a shock close to 9" collapsed would be ideal. You'd end up with maybe 4 or 5" of shock travel but that should be enough
The short wheel travel isn't really an issue, your wheel won't travel much up and down anyway, you just have to make sure you have as much bump compression as you can and have the shocks extend to their full length without the suspension hanging too low. If you do that, you have shock travel where you don't need it, no sense in having 4" of droop extention. IMO a shock close to 9" collapsed would be ideal. You'd end up with maybe 4 or 5" of shock travel but that should be enough
Racer
Joined: Mar 2006
Posts: 276
Likes: 1
From: Pistoia PT (ITALY)
I agree with you that a long stroke is not mandatory..... but we have to take in consideration the spring ratio.
With a 450 lbs spring and a stroke of 4" the logical ride position should be nearly at alf stroe of the coilover.... the risk is that I may need a progressive spring.... for the following reason:
If my ride is a 2" of stroke, I will have only 900 lbs of dynamic....
A C3 corvette should weigth at the rear some +1500 lbs with full tank and a passenger.... let say 150lbs x 2 of unsprung weigth.... net result is some 600 lbs each spring at ride.
A normal road bump is in the range of 1g of acceleration = more 600 lbs on the spring = nearly 1-3/8" of stroke = only 5/8" of stroke left !!!
I think a progressive spring is the way to go..... !
With a 450 lbs spring and a stroke of 4" the logical ride position should be nearly at alf stroe of the coilover.... the risk is that I may need a progressive spring.... for the following reason:
If my ride is a 2" of stroke, I will have only 900 lbs of dynamic....
A C3 corvette should weigth at the rear some +1500 lbs with full tank and a passenger.... let say 150lbs x 2 of unsprung weigth.... net result is some 600 lbs each spring at ride.
A normal road bump is in the range of 1g of acceleration = more 600 lbs on the spring = nearly 1-3/8" of stroke = only 5/8" of stroke left !!!
I think a progressive spring is the way to go..... !
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Racer
Joined: Mar 2006
Posts: 276
Likes: 1
From: Pistoia PT (ITALY)
Don't be aware...... even in normal driving conditions, the BIGGER part of the dynamic load is carried by the shock... specially if you have sport shocks!
A normal road bump at criuse speed can apply a very high acceleration to the whell.... and the shock is the way that force is sent to the frame!
Take a look to the bolts fixing the shock to the frame!
A normal road bump at criuse speed can apply a very high acceleration to the whell.... and the shock is the way that force is sent to the frame!
Take a look to the bolts fixing the shock to the frame!
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Getting the upper end of your rear c/o's bolted in must be a PITA, but they look good.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
Your left halfshaft looks like it's missing a c-clip on the inboard u-joint, might be just the picture though.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
There are actually two different 5 bar C2/3 Vette designs out there, Riley did one for Greenwood (the best design) and Guldstrand did another 5 bar (system is OK.) Chevy reportedly tapped Guldstrand to help with C4 rear suspension layout and he did have input on the design.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Thanks Solid LT1. From what I can tell, the Greenwood setup may not be available(??), but I haven't called to inquire... And yes, I'm told Dick definitely did a bit more on the C4 than just sign off on the appearance of the GS.
