04 Z06 shocks on an 02Z06
 

I changed my stock shocks on my 02 out for an 04 set three days ago. This Sunday I'll have the car on Pocono north, hoping for a nice change that I can feel. I'll post up my on track thoughts when I get back. The limited street driving I've done since tells me the car is somewhat stiffer over bumps, but that could just be me wanting to feel something. If anyone else has done this mod, please post up what you've felt the differences are, or if you've felt no change at all.

Oh there's a definately difference ... but only in certain circumstances ....

Driving down a smooth road, I couldn't tell any real difference between my original 2001 shocks and the 2004 shocks.

Then I went to an HPDE.

I had driven the track before, and it has a right hand turn that as you enter the turn you are going uphill, the apex is almost exactly at the top of the hill, and then you sweep downhill after the apex.

With my original shocks (2001) the rear of the car at the apex, and after the apex, felt very "floaty". It felt as if the body of the car had no shocks at the rear, just springs, and the springs were extended and the car's body was going through the corner with a different rate of "rotation" than the rear axle.

With the 2004 shocks, the exact same corner felt TOTALLY different. The rear body suddenly felt like it was closely tied to the rear axle. I felt much more confident that the car would go where I pointed it, and that I could use either steering or throttle to control the car's direction.

I guess another way to put it is .... driving on the street, you really won't notice the difference with the 2004 shocks over your originals. Press the car towards its handling limit, and you will feel the difference.

:cheers:

There were a couple of recent posts where people swapped out their 02/03 shocks for some 04s and ended up going back to stock since the car didn't handle as well at HPDEs. Apparently, the 04 shocks were designed to balance performance and comfort and were actually too soft or "mushy." This is the opposite of what others might've heard, but these are real world results.

This is exactly what I had heard. I was going to get the '04 shocks to minimize wheel hop at the drags and also for the road course. But most said they don't cure the hop and I don't have any problem with my car's handling on downhill apexes. Just be smooth with the throttle, you aren't going to loose the car like that. You lose the car by lifting the throttle in the wrong spot!!

I don't know where you saw those posts ... but those people have no clue .... the shocks were not developed for comfort .....

From the Corvette Museum site .....

Nurburgring-inspired chassis tuning

All 2004 Z06 Corvettes will benefit from the continual pursuit of performance enhancements that have characterized the C5 era. The enhancements for 2004 are subtle in terms of physical parts, but significant in terms of the car's performance and feel.

GM engineers have refined the Z06's shock damping characteristics to provide improved handling in the most challenging conditions, while maintaining good ride control for the demands of daily driving.

Continual analysis, development and refinement of the shock valves in particular resulted in more damping control and force, delivered more smoothly. This new tuning is aimed at diminishing the impact of yaw and roll on the car, particularly in quick, transient maneuvers such as "S-turns" or a series of tight corners.

"While the Z06 already had an excellent blend of extreme handling capability and surprising ride quality, we're never satisfied," Hill says. "The enhancements for 2004 provide a bit more poised and smooth response, connecting the car better to the driver's input, without the penalty of ride harshness."

These refinements are a result of extensive testing and development, including several high-speed test sessions at Germany's famed Nurburgring circuit. Corvette Z06 is one of only a precious few cars to have broken the 8-minute barrier for lap times at Nurburgring. Corvette testing at Nurburgring isn't just about raw speed, as the Z06 provides plenty of that. Engineers gathered important learning on tuning the chassis to enhance the poise, confidence and smoothness of response, attributes that are of great importance under the severe demands of a 14-mile course that has approximately 170 turns and virtually constant elevation changes.

"Nurburgring, at the extreme edge of the envelope, provides conditions that can't be easily duplicated anywhere else," says Hill. "But, even for the Z06, we spend considerable time ensuring we don't make adjustments that compromise the normal daily driving character of the car."

:willy:

Again, regardless of what all of these copied and pasted quotes from Wikipedia say, I am talking about real world results reported by guys like me and you.

What are the published damping rates of all of the shocks mentioned? I think you will be surprised. :eek:

baloney.

I swapped them in my 02 2 years ago.

The biggest improvement I have found is that the car seems to get back to the road much quicker after going over a bump or over short hill.

The car hasn't seen the track much so I really can't comment about that aspect

You might try actually READING my post ... the quote is from the Corvette Museum site (as I said right before the quote) .... here's a link to it .....

http://www.corvettemuseum.com/specs/2004/index.shtml

It is actually the press release FROM GM when the 2004 was announced .....

As far as damping rates ..... a higher damping rate is not ALWAYS best .... a car will generally react better to a bumpy corner with a "soft" suspension than a "hard" suspension. High damping rates over a bump tend to transmit more of the energy of the bump to the chassis, and also don't allow the tire to return to the road as quickly as a low rate damper. Net result, a car with a high damper rate will tend to be skittish in bumpy corners, with a strong tendancy to suddenly understeer (as a front tire loses road contact) or suddenly oversteer as a rear tire loses contact. Makes the car VERY twitchy.

I can get my Corvette right down to the apex of turn 8 at Willow Springs with the 2004 shocks, while I couldn't do that with my 2001 shocks as the bumps at the apex were upsetting the rear end too much.

I can also assure you the 2004 shocks make a HUGE difference keeping the car "settled" down through the Corkscrew at Laguna Seca, and that is NOT a corner you want to mess up, there is virtually NO run-off area on your left as you make the right turn downhill towards turn 9.

:cheers:

Well, I ran on sunday, and I've got to say, no imagination or wishfull thinking, they're a big improvment over the 02's. I ran 32 hpde's in this car so far, and this was the strongest I've run. By strongest, I mean turning in, and carrying a lot more speed into and through the turn. I haven't really read the improvents as far as press relaese or whatever, but the car seemed to have way less bodyroll/movement. I was able to downshift and almost drift/throttle steer around turns. Pocono north has a left hander that when hit correctly is a balst, my turn in 95% of the time was right on target. Active handeling only came on three times, where last year it was on a lot. I was able to lose "better handling" cars in the turns. The only cars that got around me were some of the nasa full race cars, and a couple of vettes driven by some awsome drivers that i know. I'm glad I did this mod. for you street guys, don't bother, you'd probably never notice, road course guys, do it you will notice an improvment. Our runs sessions were an hour and a half long, and the shocks preformed better than I expected.:thumbsI'll be back at Pocono in three weeks and a week after that WGI, so I'll keep posting if anything changes from my feeling so far.

Sounds like your SOTP experience with the shocks, and mine, agree completely. It is a shock where you only realize the difference as you get the car to 8/10th and 9/10 of the "limit" ..... at 5/10 the 2001, 2002 and 2003 feel basically the same as the 2004. But boy did the GM chassis engineers hit a home run with the 2004 shocks .... it is valved beautifully for "extreme" cornering ....... that Nurbergring and Milford test time clearly paid off.

:cheers:

I read your post and couldn't agree more. I even posted it at www.ecsracing.com, where we were having a debate over the bilstiens and the 04's. Stiffer shocks make the car skitterish over bumps, curbing and some corners, unsettling the car, and we all know that smooth in roadracing is key, throttle, braking or cornering, and these shocks "are smooth"

Thanks for the report, George. Sounds like a worthy addition along with brake cooling ducts (better ones than factory!!) and Carbotech pads. For a newbie, I am guessing the pads & brake cooling will help more.

Thanks for the update! :thumbs:

I've had great success with hawk dtc 70's, on the stock calipers and cheap NAPA rotors.. I haven't done anything to the stock cooling ducts.

I haven't been around much lately but I happened to see this post. BlackZ06 is right as George found out. We have had this debate before on the 04 Z06 shocks vs Bilsteins. It is an old debate...

I swapped from 02 to 04 shocks on my 02 Z06 which is tracked in the real world. SOTP is what is described here. The earlier shocks also suffered from what is described as high speed hover. Getting through the high speed esses on any track with the 04 shock is way more stable. The 02 shock made me feel like I was floating through that section. The 04 also soaks up speed bumps better in that my car did not bottom out as easily. The only downside is that it makes the ride more taught. The shocks rebound quicker with less deflection to me anyway.

BlackZ06 and GeorgeZNJ. Put some T1 sway on it. They match well with the 04 shocks. You will get power down much better at mid turn and out. Also the car will corner flat. There are no 2 ways about it.

Unfortunately my QS Z06 was totaled in Feb/08 and I'm just getting around to replacing it with another 02. It will get 04 shocks or a Pfadt Coilover kit. Haven't decided just how far out I want to go yet :D

Graham

Did you post on this? What happened? You ok? I was wondering where you went. I hope your ok. Don

I've had the '04 shocks and T-1 bars with a Phoenix alignment on my '02Z for the past 2 seasons and the car tracks very well, a big improvement over the OEM equipment. See you at Pocono George.

This is exactly right! I had an 04Z and I now have an 02Z with the 04 shocks. I noticed that the 02 shocks would allow the rear to move a little more through bumpy turns with strong throttle input. The 04 shocks allow for better handling and a better ride.

Real track experience from George shows that this is the right way to go with shocks.