I recently installed Pfadt Coilovers and Pfadt Competition Swaybars in my 02 Z06 and am in need of some advice regarding the tuning of the supension. First off, i daily drive this car and will also be using it for Track days throughout the summer. My intent is to properly set the spring preload so that the only adjustment I make between street and track is adjusting the stiffness of the shocks.

Current Setting for Stiffness of Shocks is 7 in front and 6 in the rear.

My biggest concern is regarding spring preload: When I received the coilovers the springs were pretty much loose with no preload at all. I adjusted the seats so that the spring was tightly held in place without compressing or preloading the spring. But it quickly became obvious that no preload = bad characteristics when hitting bumps on the freeway. The lack of preload seemed to allow the rear end to float as if it was getting airborne whenever I hit a bump.

Recently I added 3 full turns of tension to the front and rear coilovers by adjusting the lower seat of the springs. Since this would also lower the car even more, I compensated for this by increasing the length of the shock body to maintain my previously set ride height. The effect that I noticed was that this adjustment of preloading the spring and increasing the length of the shock body also increased the amount of travel in the shock. Perhaps this could be a problem as well?

Adding the three turns of preload eliminated the problem of the rear floating when hitting bumps, but now rear end feels very harsh. But the front end of the car feels balanced.

I am unsure whether to reduce or add more preload to the rear springs. Or whether I am headed entirely in the wrong direction... I am looking for recommendations on how others have set up these coilovers on their cars, including shock stiffness, number of turns of preload on the springs, etc... Thanks in advance for your feedback.

 

kooz.

 

Contact Aaron (or Robin his wife) over at Pfadt....

He will be able to give you the best advice concerning your issues and probably be able to advise you about shock settings etc. for best results in your particular application.

They are very helpful and Im sure will be able to get you straightened out. Seems most people who run their coilover set-up love them

Cheers,
Tony

 

You need to four wheel balance your car.

 

Let me get this straight .... you removed a suspension system that had been tuned by numerous engineers with many many years of tuning experience ... and replaced it with a system that you have no idea what you are doing with ????????



There is a large bridge over the entrance to San Francisco Bay that I have an INCREDIBLE deal for you on ........

contact me ....

 

The stock suspension is base on a budget performance. I agree with you on the stock suspension is a great platform. The Pfadt coilovers are a great upgrade for the Vette.

 

I had the same concerns as you commented on regarding the spring preload. I suggest as Tony posted call Arron....their are very good reasons & set up recommendations that do make sense.

 

the stock suspension wasn't designed for all out performance. it was made to fit within the budget given to the engineers, and to be cost effective for gm to mass produce. there is a reason that the C5-R has coilovers.

 

And you are another freakin idiot ...

 

i tried changing that before anyone would see it because i thought it may have been a little mean, haha. oh well.

 

More intelligent comments from incredibly intelligent people. I would like to commend you over your great knowledge in corvette suspension. Thank you.

 

lol you crack me up man.....

 

Uhhhh .... NO ...... the "problem" with the C5's suspension is not a "budget" issue ... it is that the suspension engineers had to find a "solution" that works well on bumpy roads, smooth roads, REALLY bumpy roads ....etc ..... it is a "compromise" set-up because they have to make the car handle well under many different conditions.

Look at a race team ... NASCAR, F1, whatever ... any race team is adjusting the suspension before a race (and even during) not because they are "cheap" suspension systems, but because one track is different from another, and even a single track changes as its temperature varies, the amount of grip due to rubber on the track varies, etc.

The reason for a suspension set-up like the Pfadt system is to allow people who actually KNOW what they want/need from the suspension to adjust the suspension to accomplish their goals. Another way to do it could be by allowing the user to alter the "programming" of cars fitted with the MSRC system. Another way to alter the cars suspension is by choosing a shock with a differnt valving, such as the 2004 Z06 shock .... there are MANY ways to alter how the car handles .... even GM offers you "choices" such as MSRC (F55) and Z51 ....

Make no mistake .... GM spent many MILLIONS of dollars designing and tuning the Corvette suspension .... even to the point of shipping cars to Germany for testing at the Nurbergring ... after many many months of testing at Milford .... the suspension is not cheap .... you need to be a pretty good student of suspension systems to do better than GM did ... installing an "adjustable" system is STUPID if you don't know what to adjust .........

 

For the OP, I would suggest that you repost in the Racing section. They do know how to adjust shocks for your purpose.

 

You need to go to a shop that specializes in setting up racing car suspensions and have them tune and align your suspension. Since you are going to track the car I would also have it corner balanced.

 

Hey blackz you have a great point but look at Pratt&Miller do they still use stock suspension? No they don't. Like said the stock suspension is a reat platform.

 

big difference between us street cars and c6r's

 

i will stand by the idea that GM would not have gone with a leaf spring setup had a large enough budget been allocated to them.

do the leaf springs work? yes.
do the coilovers work better, and have more potential? yes.

 

Thanks for the info. I know that my point is if you want good suspension setup look at what the road race guys are using. People run C5R blocks, those blocks are made for the 24 Lemans races overkill for a street car yes, but badass motor yes. Samething goes for coilovers. Have a nice day .

 

Corner weight the car for spring preload, and then shocks are generally driver/lap time dependent