giovanni432

Update- so the rear bushings were installed completely wrong. The upper mounts had about an inch of room to move freely! Fixed that and went Onto the front. Passenger side was fine but I still removed to install the new bushings. When I went to take off the driver side I noticed that the lower two bolts were completely missing...... What a great company I took the car too huh!. Funny thing is that's the best suspension shop in town!
So once I bought new bolts and installed everything I took the car out and it handles BEAUTIFULLY!!! Such an amazing ride. I completely fell in love with the car again! Thank you everyone who took the time to help out! I appreciate it!

So lets start with information about the car. Its 2003 z06 with 80k. I installed a set of DRM blisten sport shocks and c6 z06 front and rear sway bars (running 345's out back).The car is a daily driver. The car is lowered on longer bolts. We did reuse the original bushings. The car handles amazing on smooth roads (mostly highway) but once I get into the city it goes down hill. Every bump I hit will rattle the car like no other. I can feel all the imperfections in the road. Some of the roads I have to travel on have huge bumps and when I travel over them it'll shake the rear of the car so bad to where It almost makes me shift lanes. (Mostly oil field traffic here so roads are horrible). I was thinking maybe the reused bushings could cause some of this but it can't be the main culprit right? Any help is greatly appreciated guys!

GTJim

Have the bushings ever been replaced? With 80k on the clock I would have replaced the bushings. My 01 Coupe has 32k on it and I recently had QA1 shocks and Hotchkiss sways installed. I also had a thicker center tunnel plate installed. The bushings were replaced. The ride is firmer, ie I can feel more of the bumps and road imperfections but it's no worse than my stock C6 Z06.

giovanni432

No they never have been replaced. When I had everything installed I completely forgot about new bushings. I was expecting it to be firmer, but some bumps will just rattle the s*** out of the car. I wonder if its just the roads or something is up with the car.

95wht6spd

How lowered is it? I have the DRM shocks and they are better than OEM, and car is lowered.
My bet is it is lowered too much and not enough shock travel.

SaxyVette

I was also thinking about "upgrading" to bigger sway bars and heavy shocks on my hi-mile '99 Coupe. But after reading this I think I'll leave my car basically stock, except I do need a fresh set of shocks as mine are the originals. My car rides very quiet and smooth now, even over the bumps ripples and potholes.

This post reminds me of years ago when I changed to polyurethane bushings on a C4 Convertible I had to "improve" the handling..oh man, the squeaks, creaks and crummy ride made me wish I hadn't done it. I was really glad when I sold the car, the noises and harsh ride were driving me crazy.

BADBIRDCAGE

I have used upgraded (poly) bushings on a C2, a C3 and my C5. If not properly lubricated they will squeak, some types more than others.

Changing the bushings out simply takes the "slop" out of the "A" frame movement. It tightens up the geometry of the control arm travel and makes the shocks and springs do their job. You could have gone with roller bearings in the bushing positions if you had wanted to and would have had a similar, more pronounced, result.

Just my opinion but I feel that what has made your ride different is the change in shock/spring combination. You had used, original parts and you put new parts into the equation with different values than the originals.

The problem most likely lies with the shock/spring combination and the values on the components may not be compatible for any comfortable expectation on the ride. Lowering the car on the bolts does you no favor with the ride either. I don't know any C5 owner with a lowered car that can say the ride did not change to a stiffer street ride.

If track performance is what you are seeking you may be right in line. Street comfort and track performance are not one and the same.

Socko

If the rear of the car is the primary issue you sure you aren't on the bump stops? Is the car slammed on the stock bolts? That could be it.

Vetteman Jack

That would be an area I would certainly look at.

Guard Dad

I put in a poly tranny mount on my 99 Camaro SS M6, drove it for about 10 minutes and took it out. The gear noise transmitted into the car was insane!

Sledge Hammer

I am new to the Vette world, and have been considering lowering on stock bolts. I already have a stiffer ride in my 02 Z06 than I was expecting, but I have found that it has Pfadt sway bars front and rear. It would seem to me that lowering on stock bolts should make the suspension softer since you are taking tension off the spring. Is that not the case? Since the sway bars have adjustable end links, is it possible to adjust out some of the stiffness?

giovanni432

Could you explain what that means? I'm not sure what exactly that would be. Here's a picture of the car. It just rained here and the car is really dirty so excuse that! And the rear is the main problem. I think the lowering might be the problem. Ill probably have to invest in some coil-overs soon!

Guard Dad

Nope, doesn't work that way, lowering will reduce travel and make it harsher over any road that isn't in excellent condition. You'd need a softer spring and/or shocks and sway bars to improve the ride. Quite a few ZO6 owners have issues with ride harshness, it is the price you pay for such a track focused car as the ZO6.

Socko

looks pretty darn low. have to check the bolts to be sure but i bet you are hitting the bumpstop and thats whats causing the rear end to dart over heaves in the road. just raise it up till the bolts are centered and see how it feels.

racebum

what did you expect? poly bushings, drm shocks and bigger sway bars?

of course it's going to be more firm.

i have no idea why you did all that honestly, with 04z shocks the oem suspension is about as good as you're going to get with leaf springs for street performance driving around stock hp levels and 200-300utqg tires

JrRifleCoach

Sometimes looks aren't everything.

troyguitar

First thing I'd do is raise it up a bit, that's free and easy. It does sound like you're hitting the bump stops.

FWIW I have a similar setup (slightly more extreme than you) and the car is OK on decent roads, bad but tolerable on bad roads, and nearly unbearable on really bad roads but the car does not get tossed around. I have pfadt JOC shocks and sways, 305/30/19 Bridgestone RE-11's (significantly stiffer sidewall than your invo's), and full delrin bushings - but all at pretty much stock height.

Here's mine in the back:



It's also possible that we just have different definitions of tolerable and you would hate my car even more than yours.

95wht6spd

Was it lowered to the same height before mods or only after?
I think the Sports should feel similar to the OEM Z shocks, but I would think they should feel better just on the fact they are new. You dont look that low, but if not lowered before, and all the mods together might add up to a harsh ride for you. Like someone else said, harshness is subjective. I DD a C4 w stiffer springs, bigger bars, race revalved shocks, and lowered, so to me when I got my Z, it was smoother even though slammed. It looked great, but would hit bump stops, so I raised it up some, and put on DRM revalved Bilsteins and to me it rides really well, but to others, THEY think it is harsh.

Sledge Hammer

Thanks for the feed back.

0Randy@DRM

So I have read your post a couple of times. When you say "rattle" is that a sound or a movement.

A couple things to check,
1. swaybars, do they move pretty freely?
2. Alignment, if you didn't change this during the lowering, well it's going to be bad.
3. Huge bumps should be treaded extremely carefully with sports cars. Lowered, big bars, fresh shocks, and big wheels. This isn't a 4x4 or rally car. Drive with extreme caution.
4. I think it's time to raise the car up, based on your roads.

Randy

alxltd1

Sounds familiar…..I first put on C5 Z51 springs, C6 Z06 shocks and sways and lowered on stock bolts…this on my 2000 base coupe. …car handled very flat, no roll etc, but was bottoming out on the bump stops…raised the car back up and it improved but now I did not like the raised look again….so went with coil overs and cured both the bottoming out problem and the raised look, as well as maintained the flat taught handling I was looking for.