A legitimate C7 ride height question...
 

GM spent millions of dollars and conducted "millions" of miles of road and track testing and ultimately manufactured our cars at a specific ride height with specific suspension adjustments and settings.

Here's my question:

If handling and safety were optimum at the lower ride height many here on the forum have adopted, why didn't GM and Tadge build them that way?

I know from some extreme cornering in my Z51 on some curves on The Snake in Tennessee (up to .96G) at standard ride height that we were scrubbing the air dam on both sides at factory ride height. I know some like the lower look (I don't particularly), but I find it hard to believe that function is improved or even maintained at lower ride height, especially if no additional tuning to spring rates, shock valving, sway bar settings, etc. were done.

All of these adjustments affect each other...changing one will invariably cause effects on others...probably not in a good way.

Thoughts?

The lowering capabilities of the C7 are to "corner balance" a car at the track and the range of drop is less than an inch. Some say 7/8, mine was 3/4's an inch. I am purely lowered for cosmetic reasons, I can't stand the huge wheel gap. I doubt that the range you can lower affects too much. After all what most of us are using it for, was not the reason it was designed. In other words, any place you put the bolts is within operating spec acc to Chev designers.

I had to search for this a minute. This is a pic of this guy going who knows how fast. Given that he said he lowered it only 1/2 inch, it looks as though the downforce is significant enough to really push the car down on the suspension. I imagine that in testing, GM realized that for the daily driver, on questionable roads, a certain ride height was neccessary to protect the car. Just my WAG as to why it was set up as such from the factory.

Factory specs have always listed GM's specified ride height range. Up until 1996 Corvette ride height varied more, due to variations in springs and option content. Beginning with the C5 GM added ride height adjusters so the factory could easily compensate for variations. Those of us who like a lower ride height use them to lower our cars a bit, though they weren't really provided for us :thumbs:

Experience with C5 and C6s was that it varied how many turns each car could be lowered, depending on where the factory set the bolts to get the correct ride height.

As mentioned above by Glen the possible range of lowering is less than an inch on most cars, sometimes much less. Likely very close to being within the factory spec height range. Nothing to worry about although its a good idea to get the alignment checked at least (a good idea anyway after break-in considering the cost of these tires).



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I don't like the "slammed" look, but at the same time the 4x4 look is not fitting for a Corvette either. I think once the C7 settles a bit the stock ride height looks pretty good and it's a happy medium between those two extremes.

Many aftermarket coilover suspensions have a shorter shock body than OEM or Replacement shocks. So that tends to maintain bump suspension travel even after lowering since the shock length is shorter instead of the spring being shorter (and keeping in mind that most cars now have shocks that mount the springs). Then the question is, does the shock itself have enough travel to cover the spring travel ? One solution to that problem is a shock that is twin-tube construction (like Tein) and those have more shock travel then mono-tube construction.

But aftermarket coilovers often use a higher spring rate with the lowering as well. And then with the higher spring rate then there is less risk of bottoming-out.

When I get aftermarket coilovers, I look for both an adjustable shock body length and spring pre-load adjustment. And higher spring rates.

One note, aftermarket coilovers might produce less droop suspension travel. If the vehicle should snap too much when going off throttle in a hard corner that could be a problem of not enough rear droop. The simple solution there is to raise the front-end a little. Otherwise, the shock travel needs to be re-centered (and Ohlins street coilovers have a third factory-only adjustment for that).

Well, many things on a racecar are adjustable. And in engineering most everything is a compromise.


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Another note, many race car coilovers don't have adjustable shock body length but only spring pre-load adjustment. That means that spring length must be changed if a ride height change is wanted without a change in spring pre-load. Increased spring pre-load will raise the ride height but also stiffen the suspension. Then reduced spring pre-load will lower the ride height but also soften the suspension.

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There are several suspension architectures within the double-A-Arm model.
Some of these (model 1) have the property that the suspension geometry changes very little as ride height changes
Others (model 2) have the property that <small> variations in ride height are used to tune the handling of the car.

The C5/C6 (and I am assuming the C7) use model 1 where the car's handling is changed little as the car is raised or lowered. These cars can be lowerd with impunity as long as the tires are re-aligned to standard configurations after the ride height adjustment.

Cars like the Ferrari F355/348 are very sensitive to ride heights variations and the ride heights is used directly to tune the oversteer/understeer relationship. In this model, rear ride height adjustmens as small as 3mm at the rear can change an oversteering pig into an understeering pig. Thus they have a very narrow window where all suspension stuff works properly. This property makes it possible to dial the car into the tires at hand, but makes it hard to find the proper operating window.

Be thankful that Corvette did not follow this path (model 2), but followed the path (model 1) where the ride height is a small variable in the overall handling department; so people can lower their cars with little understanding of how to make the car handle properly afterwards.

An independent suspension with both upper and lower links has a relatively small amount of camber change when raising or lowering the car and that if the lengths of the suspension links are relatively short.

So most front independent suspensions have a small amount of camber change with lowering.

And then most (street car) multi-link independent rear suspensions have a large amount of camber change with lowering.

But higher-end sports cars are likely to have shorter upper and lower links on their independent rear suspensions and this is closer to race car design.

(The modern multi-link independent rear suspension on average street-cars is probably based on Porsche adding semi-trailing arms to swing-axle rear suspensions and that in 1963 or so. In other words, the upper and lower links tend to be relatively long.)
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Ground clearance is a big deal for GM on daily drivers. They have clearance specs their cars have to meet to make them acceptable to the general public.

I have my C6 ZO6 lowered 3/4 inch on stock bolts. I scrape the front spoiler on even moderately sloped drives. I can see why you wouldn't want the car any lower if you used it for every day transportation.

First, just so there's no misunderstanding, this is not to argue. I too do not like the slammed look.

But when I saw that pic, what I thought interesting was that he said he had only lowered the car 1/2". Driving at speed, not sure what speed, it seems like this car produces alot of downforce. I it just my thought that GM set the ride height with this in mind.

While I think the ride height on many of the cars I've seen appears to be a little higher than you'd expect, I can also think of alot of roads in my area that I would be grateful that it is. Probably another reason that they put the protective plate on the bottom of the car.

This pic is a meaningless gauge of ride height because you have no idea what is happening at the moment of exposure. Could have easily hit a significant dip at that moment.
http://i1314.photobucket.com/albums/...ps231aaed0.jpg

[QUOTE=BlueOx;1585534861]This pic is a meaningless gauge of ride height because you have no idea what is happening at the moment of exposure. Could have easily hit a significant dip at that moment.

True, we don't know exactly what was going on with road at this instant. However, going back my theory, even if the car had hit a dip in the road, if it the ride height were any power, we might be seeing sparks coming from under the car.

My C6 was left at the factory settings. I had to be extremely careful or my air dam would scrape at intersections where a channel was created for water run off. My C4 doesn't scrape, I always cringe every time it hits. I am hoping the C7 will be more like the C4 in this regard. I don't know how people cope with anything lower than a standard C6 suspension set up.

Its setup high for ground clearance....obviously, the car's suspension still preforms well; however, even lowered on stock bolts (no bushings cut)...you still have a great handling suspension, and I would even say a better handling suspension due to lower CG.

From experience...anything beyond the lowering amount that the stock bolts give you, requires some form of aftermarket setup in order to maintain/increase performance (such as coilovers or drop spindles).

You just have to be aware of your surroundings, know what to avoid, and know how to drive a lowered car....it's definitely a differenty style and task as opposed to driving a normal height C6. But it is very doable and I've personally have had no problems at a very low ride height.

Does lowering the suspension on stock bolts affect the ride quality to any noticeable degree? In other words by lowering the suspension aren't you preloading the springs?

lowering by the bolts? - no change in ride quality for me

truly lowering with coils pr springs? - yes in every car I've done it to...

in summation - lowering by the bolts is not really lowering - it's "adjusting" 3/4 of an inch, that just makes no real perceptive difference...

Thanks guys! It is threads like these that make belonging to a car forum worthwhile. Reasonable, logical explanations and well thought out responses.

I doubt that I will be lowering my car even though after reading this I would be much more willing to try it. It's just that my driveway has an entry that would make it somewhat impractical...not to mention speed bumps on public thoroughfares in Charlotte to discourage and slow down "cut through" traffic!

(I am almost certain that the city council was heavily lobbied by alignment shops to put these in. Several neighborhoods around me, through which I must pass to go anywhere, have them and my front air dams scrape all of them...even at 10 mph! Grrrr!)

It seems that they all come from the factory @ different setting's . Mine came like this.

Here is another one. Both cars were very close in vin #'s with less than 20 miles.