Koni fsd review
Race Director
Joined: Oct 2005
Posts: 14,999
Likes: 200
From: Bay Area Ca.
Huge improvement over the factory base setup.
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
Lowering the car 1/2" or less probably will not do all that much. You can adjust the ride height of the car that much just on its stock bolts so the GM engineers have to have factored that in.
I'd love to hear what the OP has to say about how the car handles over rough roads - especially when there are midcorner bumps involved. Is there really a difference in traction? How much?
And can you post pics of your car as its ride height has settled? Thanks!
I'd love to hear what the OP has to say about how the car handles over rough roads - especially when there are midcorner bumps involved. Is there really a difference in traction? How much?
And can you post pics of your car as its ride height has settled? Thanks!
I'd be quite interested in the OP's response as well. I picked up a low mileage (13K) GS earlier this year, and was very displeased by it's cornering antics. Mid speed (60 - 70), moderately hard cornering (say .75 G) and the car felt unglued - I thought I had significant rear toe out the car was so schitzo. Road undulations made the situation even worse. My Scion Tc DD handled those same corners at the same speeds far better!!!
I had a good alignment done, and that didn't help. I just changed out the OEM Sachs shocks for the DRM Bilsteins, and that did seem to help things, but I'm not there yet. The OE rubber is basically gone, and when the car comes out of hibernation in a couple of months - it will be getting new non run flat rubber (not sure about what I'll go with yet - thinking of the Continentals, the Michelin Pilots or possibly even the Bridgestones).
Put nicely - the way the car was handling was simply not acceptable for a car of this caliber. I'm sure that the factory engineers had to make compromises, but it appears that they dropped the ball on the shock valving....
Melting Slicks
Joined: Jul 2004
Posts: 2,721
Likes: 149
From: North Carolina
I'd be quite interested in the OP's response as well. I picked up a low mileage (13K) GS earlier this year, and was very displeased by it's cornering antics. Mid speed (60 - 70), moderately hard cornering (say .75 G) and the car felt unglued - I thought I had significant rear toe out the car was so schitzo. Road undulations made the situation even worse. My Scion Tc DD handled those same corners at the same speeds far better!!!
I had a good alignment done, and that didn't help. I just changed out the OEM Sachs shocks for the DRM Bilsteins, and that did seem to help things, but I'm not there yet. The OE rubber is basically gone, and when the car comes out of hibernation in a couple of months - it will be getting new non run flat rubber (not sure about what I'll go with yet - thinking of the Continentals, the Michelin Pilots or possibly even the Bridgestones).
Put nicely - the way the car was handling was simply not acceptable for a car of this caliber. I'm sure that the factory engineers had to make compromises, but it appears that they dropped the ball on the shock valving....
I had a good alignment done, and that didn't help. I just changed out the OEM Sachs shocks for the DRM Bilsteins, and that did seem to help things, but I'm not there yet. The OE rubber is basically gone, and when the car comes out of hibernation in a couple of months - it will be getting new non run flat rubber (not sure about what I'll go with yet - thinking of the Continentals, the Michelin Pilots or possibly even the Bridgestones).
Put nicely - the way the car was handling was simply not acceptable for a car of this caliber. I'm sure that the factory engineers had to make compromises, but it appears that they dropped the ball on the shock valving....
I bought my '11 GS new and switched to FSD's pretty quickly because I wasn't happy with the stock shocks on anything other than perfectly smooth roads. Way too harsh on the crappy roads around DC. FSD's really smoothed the ride and improved the skittish feeling in the rear significantly. It immediately felt much more planted after the switch even on rough roads.
During my first track day with the GS (FSD's already installed), it felt very good, but tended to understeer a little too much for my tastes so I decided to change out the sways to Pfadt JOC's which provide great turn in and reduced understeer quite a bit. The OE tires were relatively new at that point, and were OK once they got warm but still not very good - the car definitely had higher limits than the tires could support.
My last autocross sealed the deal on the need for new tires (8500 miles) - couldn't get any grip and basically just slid around a not-all-that-challenging track. I generally drove near the top in my club, but couldn't break out of the middle of the pack. The transition from OK to crap seemed to have happened overnight. Transitioned to Michelin non-runflat PSS tires and it completely transformed the car. Now with the combination of FSD shocks, Pfadt sways and PSS tires the GS handles the way I like, and compared to stock is smoother, more composed, less road noise, and the grip is phenomenal.
Before I even picked up my car, I did the performance driving class at Spring Mountain. I remember one of the first things the instructors said is how we might notice how much better their cars handle compared to ours. They didn't do anything to them except change out the GY's to Michelin's and virtually everyone acknowledged how much better the cars felt and handled. GM really should have transitioned away from the GY's a lot sooner.
Race Director
Joined: Oct 2005
Posts: 14,999
Likes: 200
From: Bay Area Ca.
I doubt if the tracks run the base Vettes. Z51 at least.
The base will need more than a tire change. The oem shocks suck.
Tires are a factor though and a good upgrade for sure.
The base will need more than a tire change. The oem shocks suck.
Tires are a factor though and a good upgrade for sure.
Last edited by Boomer111; Jan 2, 2016 at 04:31 PM.
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
I can't say enough how much the OEM tires suck. I think once you shift to any of your selected tire options you'll notice a significant difference.
I bought my '11 GS new and switched to FSD's pretty quickly because I wasn't happy with the stock shocks on anything other than perfectly smooth roads. Way too harsh on the crappy roads around DC. FSD's really smoothed the ride and improved the skittish feeling in the rear significantly. It immediately felt much more planted after the switch even on rough roads.
During my first track day with the GS (FSD's already installed), it felt very good, but tended to understeer a little too much for my tastes so I decided to change out the sways to Pfadt JOC's which provide great turn in and reduced understeer quite a bit. The OE tires were relatively new at that point, and were OK once they got warm but still not very good - the car definitely had higher limits than the tires could support.
My last autocross sealed the deal on the need for new tires (8500 miles) - couldn't get any grip and basically just slid around a not-all-that-challenging track. I generally drove near the top in my club, but couldn't break out of the middle of the pack. The transition from OK to crap seemed to have happened overnight. Transitioned to Michelin non-runflat PSS tires and it completely transformed the car. Now with the combination of FSD shocks, Pfadt sways and PSS tires the GS handles the way I like, and compared to stock is smoother, more composed, less road noise, and the grip is phenomenal.
Before I even picked up my car, I did the performance driving class at Spring Mountain. I remember one of the first things the instructors said is how we might notice how much better their cars handle compared to ours. They didn't do anything to them except change out the GY's to Michelin's and virtually everyone acknowledged how much better the cars felt and handled. GM really should have transitioned away from the GY's a lot sooner.
I bought my '11 GS new and switched to FSD's pretty quickly because I wasn't happy with the stock shocks on anything other than perfectly smooth roads. Way too harsh on the crappy roads around DC. FSD's really smoothed the ride and improved the skittish feeling in the rear significantly. It immediately felt much more planted after the switch even on rough roads.
During my first track day with the GS (FSD's already installed), it felt very good, but tended to understeer a little too much for my tastes so I decided to change out the sways to Pfadt JOC's which provide great turn in and reduced understeer quite a bit. The OE tires were relatively new at that point, and were OK once they got warm but still not very good - the car definitely had higher limits than the tires could support.
My last autocross sealed the deal on the need for new tires (8500 miles) - couldn't get any grip and basically just slid around a not-all-that-challenging track. I generally drove near the top in my club, but couldn't break out of the middle of the pack. The transition from OK to crap seemed to have happened overnight. Transitioned to Michelin non-runflat PSS tires and it completely transformed the car. Now with the combination of FSD shocks, Pfadt sways and PSS tires the GS handles the way I like, and compared to stock is smoother, more composed, less road noise, and the grip is phenomenal.
Before I even picked up my car, I did the performance driving class at Spring Mountain. I remember one of the first things the instructors said is how we might notice how much better their cars handle compared to ours. They didn't do anything to them except change out the GY's to Michelin's and virtually everyone acknowledged how much better the cars felt and handled. GM really should have transitioned away from the GY's a lot sooner.
Burning Brakes
Joined: Apr 2009
Posts: 899
Likes: 209
From: Louisville KY
The only regret is i waited 1 year and 11,000 miles, until i could not deal with the (08 a6 z51) bouncing, crashing, constant steering corrections etc. Alot of guys have no problems with the z51, must live down south. I was kicking myself for a year, since i was going for the f55, until the day i pulled the trigger.
However, i am very happy, these shocks are the real deal. Comfort, handling, total confidence. I have to retrain my driving habits to look far down the road, instead of looking a 100150 feet out for whatever road imperfections that would send me darting into the next lane, or worse. They work better in every condition. Even on a super smooth hi-way, the vet felt nervous, twitchy, never 100% composed. When i removed the stock shocks they were hard to compress, even with my body weight on them. The koni almost feel like they are broken they are so soft. But they work beautifully. I am still going to put in non-runflats, because i think this car will be awesome with that combo. However, i could definitely live with run-craps, with the fsd's. Forget about cai's, tunes, etc.. This is the best first mod for z51's, that roam crappy roads.
However, i am very happy, these shocks are the real deal. Comfort, handling, total confidence. I have to retrain my driving habits to look far down the road, instead of looking a 100150 feet out for whatever road imperfections that would send me darting into the next lane, or worse. They work better in every condition. Even on a super smooth hi-way, the vet felt nervous, twitchy, never 100% composed. When i removed the stock shocks they were hard to compress, even with my body weight on them. The koni almost feel like they are broken they are so soft. But they work beautifully. I am still going to put in non-runflats, because i think this car will be awesome with that combo. However, i could definitely live with run-craps, with the fsd's. Forget about cai's, tunes, etc.. This is the best first mod for z51's, that roam crappy roads.
Melting Slicks
Joined: Jul 2004
Posts: 2,721
Likes: 149
From: North Carolina
So, let me understand what you wrote: it seems as if Spring Mountain from everything that I've read in the past has really dialed in their cars fairly well. And, per them, it's been done solely with different tires. However, for you and your driving needs, it took tires, shocks, and sways. Interesting nonetheless.
Racer
Joined: Sep 2016
Posts: 270
Likes: 5
From: East Brunswick New Jersey
People are really finding the Koni's that much better over the Z51s?
I have Z51s on the car now (non Z51 car)... they are alright. I can feel the rear lagging behind on a tight turn.
I am getting Koni's for the car, no doubt about it. Just trying to see what the complaints are on the setup!
I have Z51s on the car now (non Z51 car)... they are alright. I can feel the rear lagging behind on a tight turn.
I am getting Koni's for the car, no doubt about it. Just trying to see what the complaints are on the setup!
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Brett Foote
Race Director
Joined: Oct 2005
Posts: 14,999
Likes: 200
From: Bay Area Ca.
Sounds great! Personally I am very happy with my Z51 setup; it makes the C6 one of the best handling cars I've ever driven, certainly the best handling stock car. I tried the magnetic ride for 2 days and hated it; way too soft.
I've been contemplating the FSDs, but some of the reviews claimed that they cause the car to drop down some, and for me that would be inacceptable; mine already scrapes every day on my way to work... Did your car get any lower?
I've been contemplating the FSDs, but some of the reviews claimed that they cause the car to drop down some, and for me that would be inacceptable; mine already scrapes every day on my way to work... Did your car get any lower?
