'09 ZR1 LS9 Corvette engine leaked-- !!

Basicly, the anti roll bar offers a force opposite that of energy transfer from using the same spring for both wheels. The transverse spring creates a downwards force on the opposite side, the anti roll bar, creates an upwards force. If you hit a big bump on the left wheel with an anti roll bar, it picks up the right wheel. So long as the force of the anti roll bar is greater than that of leaf spring, then the transverse leaf spring is not an issue at all. The anti sway bar will weigh mildy more as its thicker, but if the overall setup is lighter, you are in the advantage.

Coil overs conventionally mounted , put a fairly hefty weight of the damper and spring fairly high off the ground, and require bracing on top of them, raising CG. Using linkages, and placing the springs and dampers more inline with the car, rather then vertical over the wheel, can help counter this. If you can centralize the structural areas of a car, you reduce the polar inertia, making it more agile. Lots of different setups to do that. Of course, the easier to rotate a car becomes, the trickier it can be to drive. My Porsche 944 allows a driver to get much closer to the limit, and still be comfortable driving there. Its got the gearbox in the back, and engine in the front, higher polar inertia. Driver's can be faster in a 944 around corners in it, than other cars, not because it handles better, but because its easier to manage. For a road car then, it doesn't matter as much, but with excellent drivers, and every moment counting, it will make a difference.

 

I've always wondered why people ***** about the suspension set up of vettes. A Corvette will post remarkable track times stock, especially a Z06, so who cars what the set up is? Isn't kind of pointless to worry about it as long as it handles great from the get go? If they used an erector set to build the suspension and it pulled a .98G lat I wouldn't care.

 

Not talking ****. Simply having an adult conversation on a internet chat room. As good as the vettes suspension is, it COULD be better. If you do not believe me , simply read just about ANY track review of the Z06. Every one I have read tells of the very unpredictable nature of the rear end breaking away. This is also stated buy the people I know who own them. Snap oversteer on a VERY fast car is not a fun thing to have. A lot of cars in the vettes performance catagory have a much more progressive nature to it's oversteer (Viper included) . There are a number of aftermarket companies offering coilover conversions for the Z06 which helps tame this trait. Nothing wrong with the vette. It's a great car and performes fantastic. And yes it's very fast. But, there are always gains to be made. This whole thing started when I stated that I hoped the new model (what ever it is) comes with coilovers. I don't think anyone would be telling the truth if they said they hoped the new model comes with a transverse leaf spring instead of a fully adjustable coil over.



Darrell.

 

Coil overs give access to readily available springs, so tuning the suspension is easier. However they will raise the center of gravity, which to the best of my knowledge is never a good thing. If the root of the Vette's handling problems you speak of is the spring rate, I'd prefer the tranverse spring be modified than be substituted for coils. Truthfully ;-)

PS: if the car sees a lot of track days I acknowledge the coil over may be a more practical way to achieve adjustability.

 

OK you lost me. How does a coil raise the center of gravity? You could just as easyily run the spring off the lower control arm. It's very common in off road, to keep the large springs out of the drivers view.


Darrell.

 

The composite transverse spring is approximately 6" from the ground (estimated from photos). How could a coil over spring be mounted any lower than this?

 

Because it is mounted lower in the car and weighs less, of course.

I still do not get this "weight transfer" thing. The "monoleaf" spring is mechanically two separate springs, one to each wheel. This is because they are solidly bolted down to the frame of the car in the center and not allowed to move or pivot. Let's try this for a thought excercise:

C6 Corvette is modified with fairly stiff coil-over springs; you pick up the left rear by about 6"...with both it and the other three wheels on a set of scales. What would they read? They too would give a small amount of "transfer", just from jacking up and tilting the car a little, but it is not because they are "coils".

Note also, that in cornering, we are more concerned with the overall roll center of gravity vs. shock rates vs. anti-roll rates, etc. It is naive to just assume that certain handling issues automatically come from one component, like the spring.

Most of the newest media says the current Z06 C6 has effectively tuned out this little tendency for the rear end to twitch by subtle changes rather than making over the whole suspension.

Having said, we all have our own prides and prejudices; as a ZR1 owner, I am very reluctant to accept a blower and pushrods as a cheap way to power after experiencing the sounds and effects of the DOHC engine. I may break a personal tradition and skip over this new model just on that basis.

So, I guess if anybody hates the unileaf that bad, there are some other car options out there.

 

That's not a real image. It's a computer image.

 

It's funny to watch the corvette guys get their feathers all ruffled when anyone makes comments about the car. Do i HATE, LEAF SPRINGS, NO. There are just better options out there.I happen to not be blinded by "Corvette Fever" to se it. The rear leaf is one of the reasons the Z06 has such a poor ride quality on the street when encountering uneven pavement. But It works very well on smooth racecources. As for the center of gravity??? Do you really think a coil spring will raise the entire center of gravity of the vette if it were fitted? Talk about naive and uninformed. (should I throw other jabs as you did?) Or can we keep it at an adult level? How would the roll center of the car change with a coil if properly engineered? Maybe you should ask the guys that run Corvette racing. They seem to work great for them. As for the packaging, it seems that just about every other sportscar out there is able to make it work.



Best regards.

Darrell.

 

Darryl, I will uncoil if you will promise to turn over a new leaf...

 

After reading all this I have to ask.....

If there's better suspension set ups, like coils, that would make the Vette handle better, why isn't GM putting them in the Vette?

I've read many stats in magazines at stores on the C6 Z06 around the track compared to many others exotics and it seems to be king.

 

Agreed.




Darrell.

 

Unless you're a suspension engineer who's fully analyzed the Corvette's design, you have no basis for blaming any of its handling traits on the spring type. Identical problems can also be found in cars with coil springs. There are inumerable ways to make a car skittish on uneven pavement, and leaf springs have very little to do with it. The whole notion of leafs causing an unwanted coupling between the two sides of a car is silly IMO.

As far as suspension design is concerned, a spring is just a device for generating a certain amount of force for a given deflection. A bar of composite will do that just as well as a coil, and weigh less in the process.

Despite what you claim, transverse leaf springs do allow different packaging than coil spring suspensions. If you haven't noticed, Corvettes have a very large amount of interior room for their size and configuration. They also manage to have a low fender height, a large amount of hood volume, and SLA suspension at each corner. This is all a lot harder to manage with coil springs, and many other sports cars don't do such a good job of it. In the end, though, a car's overall performance and feel comes from the details of its design. A lot of apparent deficiencies can be made up with clever tuning (see Porsche).

So why do the racing Corvettes use coils? I don't know for sure, but there are several possibilities. Interior space certainly isn't a concern, so that advantage goes away. Adjustability is probably the main advantage of a coilover setup. It might also not be such a good idea to mount a spring so low on a race car. Doing so would probably make it more difficult to manage underbody airflow, and the necessary body panels would certainly make it harder to swap out. This isn't very important for a street car, so I don't see any reason for Chevy to switch to coils in their regular Corvettes.

 

Oh yes. Once again a vette owner races to the rescue. As for the packaging, it's bull****t. Lotus does a great job at it. And it's just a BIT smaller than a vette. Oh I forgot,I should not have an opinion, I'm not a suspension engineer.



Darrell.

 

Lotus doesn't seem to be beating any Vettes around the track though either.

You seem just as bias against it as the Vette owners are for it.....

 

Just because I own a Corvette doesn't mean that I think it's a perfect car. Also, I have a C3. I can easily rattle off a list of its technical faults if you'd like. The packaging is terrible, to be honest (this was improved in 1978, but mine's older).

Anyway, vette owners care about this issue because it's a silly misunderstanding. The rest of the world probably hasn't cared enough to learn what's really going on, so they don't respond. That said, it's ok not to like a car. Just don't make up fake reasons for it. If the handling issues worry you, just leave it at that instead of blaming something that probably has nothing to do with it.

Why is the packaging argument bull? I never claimed that you can't package a car well without leafs. But it does obviously allow for different possibilities. Packaging is a major concern in any car's design, and a little extra freedom can be very helpful. Why do you think Lotus does a great job with this? I'm not saying that they don't, but an Elise is not comparable to a Corvette in exterior or interior size. Relating one to the other doesn't make much sense to me.

 

It's funny you say that, because I have owned a number of vetts over the years. And growng up in a house that almost always had at least one at any time (my father also raced a few) I'm not biased against the car at all. Infact it's a great car. And has fantastic performance. If you were to go back and read all of the posts you would see that. The entire point I am making (once again), is that there are better ways of doing things. And one of the things would be coil overs. This allows progressive spring rates, which allow better ride and handling over a greater range of surfaces, and more adjustability. I'm just not sure how you can call that, being biased against the Vette.



Darrell.

 

So tell GM.

....again as I already asked, if coils are so much better why doesn't GM use them?

 

If a leaf spring (lol) is so good, why isn't anyone else using it?

 

Progressive spring rates are not entirely the realm of coil overs mate. I was using some odd springs on an offroad vehicle, much more similar to leaf springs, but even then, still not quite the same. For different areas of travel, I had different spring rates.

As for the posts blaming leaf springs for the Vette being twitchy, please see the post where I talked about my Porsche 944. The Vette was built to be dastardly quick in the hands of a good driver, but most drivers will be slower, as they can't push it that fast. They realize this, and I'm sure future vettes will be dumbed down, and so, in the hands of most drivers, quicker. Its more to do with the actually setup of the car, than what provides the spring rate for the suspension.

 

I don't know.....

I'll tell you this though, I'm not sure if one is "better" then the other, but for the Corvette, I think they seem to work well and so do most magazines that test them around the track with a whole bunch of other exotics and some how or another the Vette seems to be tracking the best times with the old tech leaf springs.....

Don't know if we'll ever know?

 

Old timey leaf springs are a marvel of engineering and actualy work quite well if properly engineered. There are several advantages to them verse coil springs but I forget the details as engineering school was 28 years ago. The racers use the coil springs as they are easy to change and tune.

 

They do..... on the C6R.



Darrell.

 

wow, Darrell......you really took a big long crap on this thread........way to go champ.

 

Now, boys, I kind of think I may have had some 'elliptical' factor of irritation in there as well.

Maybe we need a special "composite leaf spring technology" thread in technical? This one was supposed to be about the new motor.

Which I also suspect may just be another bogus photoshop and story, from what little I am hearing on ZR1Net.

I would like to have more info on this engine, and am still searching my Vette sources...

James