lowering F55 suspension "safe?"

[mvvette97]

I was wondering if anybody has lowered a f55 suspension without damage? Never was sure. Thanks

 

[mvvette97]

anybody?

 

[Jersey-vinny]

My stock C5 scrapes the front spoiler on my not very steep driveway where my C4 never did. Why on earth anyone would want to make these front ends lower is beyond me. (competition cars excepted) There's only about 2 inches of clearance as it is.
VINNY

 

[mvvette97]

My stock C5 scrapes the front spoiler on my not very steep driveway where my C4 never did. Why on earth anyone would want to make these front ends lower is beyond me. (competition cars excepted) There's only about 2 inches of clearance as it is.
VINNY

I don't seem to have much problems with mine scraping. I have mine lowered way down. My friend is the one that has the vette with the F55 suspension. He had heard that lowering the F55 could damage it.

 

[Remo]

Why on earth anyone would want to make these front ends lower is beyond me.VINNY

Because they look better just a little lower.

Remo:cool

 

[mqqn]

Hi mvvette97 -

I have lowered several C5's - no F55 cars, but it really doesn't matter -there are four adjusters - one on each of the ends of the two transverse leaf springs and they are designed to be adjustable.

No harm will come from lowering - and except for 1" less clearance, and a MUCH better look IMO, there will be no noticeable change.

I drove my 2002 Z06 around for a couple of years looking like a 4x4 vette until I finally lowered it to the stock limits. I have never ever scraped the nose of my car on anything either prior to, or after the lowering.

I have both of my cars lowered and would never go back to the four-wheel-drive look.

It is simply a judgement call. I doubt there would be adjusters and specific instructions in the owners video (as on my 2002) if it were harmful.

best regards -

mqqn

 

[mvvette97]

Thanks man. I have mine lowered but it has the Z51 suspension. The reason I was asking about the other suspension is because my buddy has that kind. Again thanks.

 

[cmaxwell]

Not quite so simple as some may make it sound. At minimum, it will be necessary to realign and rebalance the car after any ride height changes.

If you do not fully understand the suspension geometry of the car, you may find yourself introducing handling, transition and even braking characteristic changes.

Don't jump into this adjustment without competent understanding and/or assistance, and alignment equipment and scales.

 

[mqqn]

Not quite so simple as some may make it sound. At minimum, it will be necessary to realign and rebalance the car after any ride height changes.

If you do not fully understand the suspension geometry of the car, you may find yourself introducing handling, transition and even braking characteristic changes.

Don't jump into this adjustment without competent understanding and/or assistance, and alignment equipment and scales.

Hi cmax -

It really IS as easy as some make it sound.

It if takes more than an hour, you are moving too slow.

And I did have both cars realigned after the lowering -

My 2002 Z06 with 19" rims all the way around required no adjustments per the dealer.

The 1999 coupe with stock Z06 wheels and tires required rear adjustments.
The braking will not be affected whatsoever. Period. The car will be lower by about 7/8" all around. The front air deflector will be that much lower to the ground , and there will be that much less visible gap between the tops of your tires and the bottom of the fenders. That is all.

As to changing the driving characteristics of the car, well, yea. It makes it handle better. that's why it IS adjsutable, and the owners video and manual informs you that to achieve better on-track handling, you can lower the car . No big deal.

best regards -

mqqn

 

[68Roadster]

mqqn,
Would the manual you reference in your last para. be the Chevrolet Service Manual?
I woudl like to lower my C5 a bit.

Thanks.

 

[mqqn]

mqqn,
Would the manual you reference in your last para. be the Chevrolet Service Manual?
I woudl like to lower my C5 a bit.

Thanks.

Hi 68Roadster -

I'll look in the service manual and see what it says - I was referring to the owners manual and video that came with the car when new.

There is a ton of tutorials and "how to's" on the web about lowerg a C5 -

Here's one -

http://www.z06vette.com/diy_lower.php

best regards -

mqqn

 

[cmaxwell]

mqqn,

I am not particularly interested in changing your opinion on this. but I'd like to make sure others have more understanding of the issues before they decide to out-engineer the folks at Corvette. There is little doubt that the car can be lowered with relative ease, just as you could be shortened by cutting off your feet or by compressing your spine. The distinction lies in proper functionality afterwards.

Issue one - camber curve: a fundamental element of modern suspension design is to alter the degree of camber depending upon how much the suspension is either compressed or extended (this being determined by the direction of turning and degree of chassis roll). The rate of change is not constant throughout the entire travel of the suspension. For example (and these numbers are example only), if at factory ride height your static front wheel camber is set at 0 degrees, one inch of suspension compression may create negative camber equal to -1 degree, compression of 2 inches may result in total negative camber of -2.5 degrees, and compression of 3 inches may result in total negative camber of -4.5 degrees, demonstrating that the rate of change is not linear throughout the designed camber curve.

Now imagine that you lower the car by 1 inch. Static camber is now -1 degree instead of 0. There is the need for realignment. Assuming you reset static camber to 0, you are still have the non-linear rate of change to consider. Now your first inch of compression will result in -1.5 degrees camber change instead of the -1 at factory ride height, and the second inch of compression will result in an incremental -2 degrees for a total of -3.5 vs. the original total of -2.5 at 2 inches of compression. Same issue on the unloaded side of the car with suspension extended. If you are pretty sure that you understand the camber curve vs. relative roll rates better than Corvette engineers, then jump right in. If this raises any doubts, then take a minute and decide if you are really passing along advice that is good for other non-technical Corvette owners.

A similar set of issues presents itself when dealing with the rear as to camber curve and relative changes, AND there are more issues that can result from changing (i) relative front to rear grip level (due to camber curve changes), and (ii) possible changes in relative ride height, front to rear. Weight transfer under braking and under acceleration can be significantly affected by a few milimeters change in rear to front to rake, as can the ratio of front to rear roll rates.

Issue two - Balance: After you have changed both height and alignment (intentionally or otherwise) at all four corner, the car will be unbalanced. Think about how unstable most restuarant tables you have ever sat at are. A four legged "X" pattern, usually with adjustable feet. Get it the slightest bit wrong and the table rocks on two legs. Get it right and the table is rock solid, any direction you lean on it.

Without scales and a known flat surface, you have no chance of getting the car right.

In application, the balance of a car is only found at its adhesion limits, below which most faults are concealed. You probably feel great taking turns well below the limit, simply due to a lower center of gravity acting your body, but I would not want to drive your table at racing speed.

Could this be how you got to "Location: in the cornfield"? <g>

 

[Pac-man]

I don't think anyone is out engineering GM when the car is made to be adjusted. It performs better lowered period. Also eliminates the 4x4 look. GM has Govt. set parameters that they work within as well(emisions, ride height, etc., etc.) So just because the car comes out of the factory a certain way,does not mean its at optimum levels, its definately a compromise of many influences. And while all of cmaxwell's above info is certainly interesting, it really has no real world application. I've lowered every C5 I've had and the result is better looks and handling. Just make sure it is aligned after it is lowered. The front end scrapes wether it is lowered or not. The spoiler that you hear scraping is highly durable but if you do manage to wear one out, they only cost $100. I'd like to know if anyone has lowered a C5, driven it hard, and crashed because it was lowered? Doubt it. I bet there have been C5 owners that took a corner a little too fast and crashed because it was'nt lowered. Nuff said.

 

[mqqn]

Hi cmaxwell

[quote by cmaxwell]

If you are pretty sure that you understand the camber curve vs. relative roll rates better than Corvette engineers, then jump right in. If this raises any doubts, then take a minute and decide if you are really passing along advice that is good for other non-technical Corvette owners. [/quote]

Sheesh man. Trust me. I know about high-falootin technical terms like "camber" and "degree", and I appreciate the schoolin' boss......

But In practice, in the real world, when GM sells a Corvette, it might be to the same person to whom McDonald's sold the scalding coffee.

Not my problem. Chevrolet shows us in the owners video that the suspension is ADJUSTABLE and can be ADJUSTED to achieve better handling on race days.

I can only assume it is YOU that is "more smarter" than the old bumpkins at GM.

Removing my tongue from my cheek a moment, I do appreciate that you are trying to save a newb some pain with lowering a car - and I do not recommend lowering more than the GM standard bolts allow- nor cutting bushings etc.

I have to add that, as a new member here, and showing only 8 posts, while post count does not mean you know a lot about corvettes or not, you certainly are going overboard about this topic -

Do a little searching and save yourself some embarrassment next time.

If you had searched some on this particular topic before going off on a rant, you may have learned that many, many folks have sucessfully lowered C5s with no deleterious effect.

best regards -

mqqn

 

[cmaxwell]

mqqn,

Never been any doubt that it can be done and done right. The issue is doing it right. Ones does not set suspension and corner balance by guessing.

If a car is never driven near its limits of adhesion, one will never know how it really approaches and crosses limits. Do you have a lot of experience with your car on a track?

You are correct that I had made only 8 posts, but then no one ever gained any knowledge by talking. I have gained some by owning five of these things over 20+ years and road racing them successfully.

So long as your mission is just racking up more posts, and considering that to be some measure of knowledge, you'll be fine.

 

[mqqn]

cmaxwell -


[quote cmaxwell smart]
So long as your mission is just racking up more posts, and considering that to be some measure of knowledge, you'll be fine.
[/quote]

Yes, that is my motivation.

I was just giving real world experience from my having lowered many C5 corvettes on my lift in my garage with no problems. WE did not have to "rebalance" each car, nor did the owners of the cars I have lowered (2 of them are MINE) spin off to a fiery death on any racetrack.

And yes, Mr. Know-it-all, some of these lowered cars have been on a race track.

Here is the quote from my post to you, where, in a friendly way, I was trying to tell you that you were being rude, but that since you had only 8 posts here that I was cutting you some slack for not knowing the etiquette.

I have to add that, as a new member here, and showing only 8 posts, while post count does not mean you know a lot about corvettes or not, you certainly are going overboard about this topic -

If learning comes from reading, you might just have picked up on this one.

Why do I attract the tools?

Congratulations! My first ignore!!!!!

Thanks your highness, and have a great day. :eyerole

I apologize to Patrick, Tammy and the rest of you for this thread going south.

mqqn

 

[cmaxwell]

As I said at the outset, I have not desire to change your mind, just to make sure that other here have more information, and you seem to have a problem with the idea that you are not the last word guru for Corvettes.

Fortunately, given enough information, people will decide for themselves what has value and what does not.

Sorry if your ego is bruised.

 

[mqqn]