Rustysocket

I have a new to me 2007 3LT with the Z51 package. Car has 20k on it. New Michelin A/S ZP tires. To the best of my knowledge it has not been lowered.

I have had the car for a few months and recently just took it on it's first long freeway trip.

I'm not really sure how to describe what is happening but it feels like bump steer, but in the rear end of the car. If I hit a bump on the freeway at 75mph + as the suspension unloads and then compresses again its as though the rear end wants to kick to the right, then left and then it settle in. It is hard to describe, but it almost feels like a slot car.

I know bump steer doesn't really apply to this situation but it's the only term I can really come up with to describe the sensation. It just feels real loose in the rear end.

Anybody else experience this. I have searched a lot and I think the problem is that I don't know what terms to use to search.

Anybody have any comments, normal or not?

Tide Will Roll!

Perhaps have the alignment checked.

Rustysocket

Meant to add that to the post. It is scheduled to get checked next week.

laconiajack

The Z51 suspension is more subject to bump-steer than the standard suspension.

mpuzach

It's a 3LT, not LT3.

DSOMC6

If the front has been dropped disproportionately (additionally more than the rear) it throws off the rake and the car will bump steer worse.

As mentioned it could also be allignment adding to the issue.What it sounds like you are feeling is the "swaying" or "wallowing" effect you get from the leafsprings. It's really bad over bumps when cornering at frwy speeds and expansion joints etc. Coilovers eliminates it entirely but at the cost of some comfort.

Rustysocket

Duly noted, my mistake.

Rustysocket

I should add that I don't really notice it while cornering, it seems to be more prominent when driving in a straight line.

v26278

Not normal. I have same year/ tires/ suspension/ milage and have never experienced that

JerriVette

sounds like alignment ....but its not normal...

Also could be a shock ? Bilstein sport shocks from tire rack are a nice replacement if needed.

Good luck.

Rustysocket

I had considered bad shock a possibility also. I will start with an alignment and go that direction if necessary.

Thanks for the advice.

raspyc6

Dude...this is the life of a Z51 option. The shudder in your car will NEVER go away until you remove the leaf springs the general gave all of us. It's worth it to upgrade your shocks.

jamesw95

None of this makes any sense.

Rustysocket

So a little research found this thread.

http://forums.corvetteforum.com/c6-c...-with-z51.html

If the end link shown in post #6 is worn could this cause the problem?

raspyc6

please advise sir

Mike's LS3

What the OP is describing is not normal for a Z51 optioned car!

Mike's LS3

That is not the life of a Z51 optioned car. It could be the life of a car with bad shocks. I have taken my 08 Z51 to triple digit speeds over bumps and the car has always stayed planted. But I do suspect wheel alignment and/or bad shocks. I replaced my shocks at 43k miles with Bilstein sports and it made a significant difference.

Mike's LS3

I would check all suspension components, check alignment and possibly replace the shocks. I had worn oem end links that were replaced with GM's redesigned end links that caused a popping noise when going over speed bumps at parking lot speed, but not bump steer while going over bumps at high speed.

glenB

Depending on the bump, yes, it is normal. Even the build-up of the paint used to mark cross walks and stop lines across the street, so that it is a 1/4" or so above the road surface, is enough to unsettle the rear of the car.

Alignment will only help if one side has the toe way out of spec relative to the other side. The factory alignment leaves a lot to be desired, on the front, but there hasn't been much written about the rear being significantly out of alignment.

This characteristic is normal and really noticeable with a Z06.

Adjustable shocks can help, as well as mentioned above, coilovers.

JerriVette

I have 57 k miles on my 2008 Z51 and never experienced what you are describing as normal.

I would have a reputable technician inspect the rear suspension inclusive of the shocks. The alignment is probably all it is.....but a broken shock is a possibility..

I would check with a gentleman on facebook who goes by the name of The corvette mechanic aka Paul Koener and he will give you his dozen year experience of what might be causing this. He's a good friend and always willing to help out. Go ahead and ask him ...

He does seminars at carlisle, at bowling green and Mid america. He is very friendly and a nice person who will give you good insight ...which might help your local tech find what the issue might be.

Stay safe.... and feel free to ask for his opinion..

Good luck.

Thecorvettemechanic