Get the alignment setup and it should be rock solid. 
Hi speed stability....
Safety Car
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Race Director
Joined: Apr 2007
Posts: 12,092
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From: Okiehoma
My 07 Z51 seems a little "light" in the rear when going 120 + ... it's still stable but I think I know what you're talking about.. I was planning on GM full race spoiler anyway so I will get that on and see what happens and report back..
Le Mans Master
Joined: Jul 2005
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Melting Slicks
Joined: Nov 2003
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From: Ridgeland MS
St. Jude Donor '06-'07-'08-'09-'10-'11
I took the car in my avatar on the autobahn in France headed toward Switzerland There is no speed limit on that section. My friend had his ''04 Z06 and we played follow the leader for a couple of hundred km. The '04 06 front fenders would swell above 150 due to the air pressure on the front brake vents, making the front end light between 150MPH and 175MPH. The '05 Z51 was rock stable all the way to 175MPH. By the way, we did get passed by a red Lambo that had to be over 200MPH. 
Burning Brakes
Joined: Feb 2007
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From: Valrico, Florida
Drifting
Joined: Dec 2002
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I took the car in my avatar on the autobahn in France headed toward Switzerland There is no speed limit on that section. My friend had his ''04 Z06 and we played follow the leader for a couple of hundred km. The '04 06 front fenders would swell above 150 due to the air pressure on the front brake vents, making the front end light between 150MPH and 175MPH. The '05 Z51 was rock stable all the way to 175MPH. By the way, we did get passed by a red Lambo that had to be over 200MPH.
aka allbottle¬hrottle
Joined: Jun 2007
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From: Brooklyn New York The DVL and the chicken sleep with the fishes....
St. Jude Donor '08
I agree that the my C5's FELT more stable at speed compared to my C6 z51 - then I drove my car back to back with a c5 and the c6 was clearly more stable , IMHO . I guess the grass always seems greener on the other side.....
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Safety Car
Joined: Aug 2006
Posts: 4,347
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From: Apache Junction AZ
I agree. Before I did the mods on mine it would wander at 130 plus.
After power, suspension, alignment and brake upgrades (see my sig) it is rock solid up to red line in 4th gear. Of course it gets there so fast that the forward momentum could help keep it stable.
BJK
After power, suspension, alignment and brake upgrades (see my sig) it is rock solid up to red line in 4th gear. Of course it gets there so fast that the forward momentum could help keep it stable.
BJK
Instructor
Joined: Jul 2006
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From: Santander Santander
Guys/gals, I'm looking for feedback on how your car handles basically stock. My old 04Z seemed to get more stable at high speeds (and improved with lowering); the faster it went, the more stable it felt.
This car is different (07 Coupe Z51.) At higher speeds the rear end feels like it's walking around on me, and makes me rather uncomfortable. It's like too much oversteer. Dealer again says "normal" and to upgrade the rear spoiler. I'm not buying that. Also says alignment is good (had them check most obvious first.)
Ideas?
This car is different (07 Coupe Z51.) At higher speeds the rear end feels like it's walking around on me, and makes me rather uncomfortable. It's like too much oversteer. Dealer again says "normal" and to upgrade the rear spoiler. I'm not buying that. Also says alignment is good (had them check most obvious first.)
Ideas?
Instructor
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From: Santander Santander
Melting Slicks
Joined: Sep 2005
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From: merritt island fl
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Thread Starter
Burning Brakes
Joined: Jun 2004
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From: McKinney TX
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 884
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From: McKinney TX
So what would be the next upgrade from a Z51 spring, a Z06 spring? I'm going to try and play with the alignment settings, but I've got to start over since the dealer didn't print out the current specs after they supposedly aligned it. Seems to me my Z06 had a similar feel till I got the alignment right, but not NEAR this bad. The car wants to oversteer at high speed. Wondering if I shouldn't just lower it more, but that's going to involve cutting the pucks.....not a big deal to me (did it on the last car) but was trying to avoid the clearance issues (and the dealer complaints about having to work on it.) Appreciate everyone's input.
Instructor
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From: Santander Santander
One of the most relevant characteristics of a spring is the spring stiffness, which is the force necessary to compress the spring for example 1 inch. If we put any weight on a spring we'll get an oscillation at some rate. This oscillation is the imporant characteristic for cars, it is measured on cycles per second. This oscillation depends on spring stiffness and also on the weight of the car. If you have a slow ratio your car will be more confortable, and if you have a higher ratio it will react quicker to bumps and will become less confortable.
So if we change spring stiffnes or change the sprung weight of the car, we will change the oscillation rate. To increase the stiffness of the spring has the same effect than reducing the mass of the car: we will increase the oscillation rate of the system. If you make your car lighter and do not change springs, your car will react as a car with stiffer springs. Of course the opposite is also true, if you increase the mass of your car and don't change spring stiffness, your car will react as a car with softer springs.
So if we change spring stiffnes or change the sprung weight of the car, we will change the oscillation rate. To increase the stiffness of the spring has the same effect than reducing the mass of the car: we will increase the oscillation rate of the system. If you make your car lighter and do not change springs, your car will react as a car with stiffer springs. Of course the opposite is also true, if you increase the mass of your car and don't change spring stiffness, your car will react as a car with softer springs.
Burning Brakes
Joined: Jan 2002
Posts: 781
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From: Reno Nevada
I've driven 150+ for about 1/2 hour. 2005 Vert.
Car as solid as a rock. You do need both hands on the wheel, but it drives just fine.
Wife was riding with me, air running and XM playing...
I was in a small group of other Corvettes (7 I think), we were in a line, was kinda fun.
Same trip, 125-ish on Cruise Control for about 45 min.
I live in Nevada, we have a lot of long, straight, smooth roads with NO TRAFFIC.
Car as solid as a rock. You do need both hands on the wheel, but it drives just fine.
Wife was riding with me, air running and XM playing...
I was in a small group of other Corvettes (7 I think), we were in a line, was kinda fun.
Same trip, 125-ish on Cruise Control for about 45 min.
I live in Nevada, we have a lot of long, straight, smooth roads with NO TRAFFIC.
Melting Slicks
Joined: Sep 2005
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From: merritt island fl
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One of the most relevant characteristics of a spring is the spring stiffness, which is the force necessary to compress the spring for example 1 inch. If we put any weight on a spring we'll get an oscillation at some rate. This oscillation is the imporant characteristic for cars, it is measured on cycles per second. This oscillation depends on spring stiffness and also on the weight of the car. If you have a slow ratio your car will be more confortable, and if you have a higher ratio it will react quicker to bumps and will become less confortable.
So if we change spring stiffnes or change the sprung weight of the car, we will change the oscillation rate. To increase the stiffness of the spring has the same effect than reducing the mass of the car: we will increase the oscillation rate of the system. If you make your car lighter and do not change springs, your car will react as a car with stiffer springs. Of course the opposite is also true, if you increase the mass of your car and don't change spring stiffness, your car will react as a car with softer springs.
So if we change spring stiffnes or change the sprung weight of the car, we will change the oscillation rate. To increase the stiffness of the spring has the same effect than reducing the mass of the car: we will increase the oscillation rate of the system. If you make your car lighter and do not change springs, your car will react as a car with stiffer springs. Of course the opposite is also true, if you increase the mass of your car and don't change spring stiffness, your car will react as a car with softer springs.
Doesn't increasing or decreasing the mass of the car not alter the spring (or wheel) rates? I thought it simply changes the pre-load, and that results in changing ride height.
Changing wheel or suspensiom mass will change the oscillation rate of the suspension, though.
Last edited by davekp78; Jul 18, 2007 at 04:49 PM.
CF Senior Member
Joined: Feb 2006
Posts: 23,313
Likes: 25
From: Tucson Arizona
So what would be the next upgrade from a Z51 spring, a Z06 spring? I'm going to try and play with the alignment settings, but I've got to start over since the dealer didn't print out the current specs after they supposedly aligned it. Seems to me my Z06 had a similar feel till I got the alignment right, but not NEAR this bad. The car wants to oversteer at high speed. Wondering if I shouldn't just lower it more, but that's going to involve cutting the pucks.....not a big deal to me (did it on the last car) but was trying to avoid the clearance issues (and the dealer complaints about having to work on it.) Appreciate everyone's input.
For alignment specs...this is what he recommends:
FRONT: -1 DEGREE NEGATIVE CAMBER
6 DEGREE CASTER
0 TO 1/8 TOE-IN
REAR: -3/4 DEGREE NEGATIVE CAMBER
1/8 TOE-IN
Instructor
Joined: Jul 2006
Posts: 155
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From: Santander Santander
I don't think so.
Doesn't increasing or decreasing the mass of the car not alter the spring (or wheel) rates? I thought it simply changes the pre-load, and that results in changing ride height.
Changing wheel or suspensiom mass will change the oscillation rate of the suspension, though.
Doesn't increasing or decreasing the mass of the car not alter the spring (or wheel) rates? I thought it simply changes the pre-load, and that results in changing ride height.
Changing wheel or suspensiom mass will change the oscillation rate of the suspension, though.
Safety Car
Joined: Dec 2005
Posts: 4,184
Likes: 1
From: CT
I also prefer the C5Z feel overall.
These alignment settings helped a lot:
Front
-1.3 camber per side
MAX Caster
ZERO toe
Rear
-1 per side
.02 toe in
I think the car is rock solid at high speeds, but these settings definitely gave me more confidence in the car.
Also, shocks might help a lot. Koni FSD or Bilstein Sports. Might make the car feel less "floaty" and more "planted"
These alignment settings helped a lot:
Front
-1.3 camber per side
MAX Caster
ZERO toe
Rear
-1 per side
.02 toe in
I think the car is rock solid at high speeds, but these settings definitely gave me more confidence in the car.
Also, shocks might help a lot. Koni FSD or Bilstein Sports. Might make the car feel less "floaty" and more "planted"