I really do not want to lower my car to much, just level the rear with the front. Can this be done, with springs and not changing strusts too?
Not really. The car is supposed to lean forward like that, it's called positive rake. So you'll mess up the handling by leveling it. But people do it for the looks all the time.
read the FAQ... dont lower a car and use stock struts, especially on a safety issue....
and if you are worried about looks, get coilovers or air ride.
with the strut issue aside, why can't a cavalier's chassis be leveled out? that would in theory make the weight distribution closer to 50/50. not by much, but a little away from 60/40.
michael groves wrote:with the strut issue aside, why can't a cavalier's chassis be leveled out? that would in theory make the weight distribution closer to 50/50. not by much, but a little away from 60/40.
do you know anything about rake angles?
when people make their car appear level, by looking at the body and how the trunk it higher than the hood, the chassis is then higher in the front and lower in the rear....
you basically start trapping air underneath the front of the car, at speed , causing handling to be less predictable.
most people talk about "level" as in the same amount of gap in the rear as in the front via the wheel wells....
measuring wheel well gap has nothing to do with performance really.
is the frame level to the ground on stock springs for sure?
When you lower a car, to handle, you are lowering the roll center (the lower the roll center the more balanced the car is) also, you want the weight distributed, more balanced . The weight is more in the front, so car lower in front will have the weight up front. Equal balance is better for handeling, and air underneath??? we are talking about cars doing 50 - 90 mph, not CHAMP Cars, INDY RACE LEAGUE or NASCAR.
Keep in mind though, that part of the reason for the positive rake of the car is the engineering of the load handling. The car has to be able to seat two or three adults in the back and a bunch of luggage in the trunk and still handle safely. To do this, you need some extra suspension travel in the back.
The Eibach Sportline kit, properly installed with some Koni shocks, does a nice job of levelling out the car but you have to keep in mind that by doing this you're reducing the load carrying capability of the car. My car sits fairly level right now on coilovers and I avoid carrying more than one passenger in the back if I can.
The last thing you want is the car to end up sitting lower in the back than the front and creating positive pressure underneath.
basically there are 3 things you guys are going around and around about.
Lowering the rear of the car has nothing to do with air pressure under the car, if that were the case gm would be designing under trays for vettes. Basic aerodynamic principle states that air flowing slower over the top then under the bottom creates lift so letting more air under the car could in theory have a dynamic effect on lift, but unless you were clickin off 100+mph everywhere you go the forces are not enough to lift a car, otherwise every car built in the last 10 years would have huge wings and front air dams designed to grip the road tighter.
Now the one issue you could have in lowering the rear of the car is that you are shifting weight around in the car, not physical weight mind you but rather how the weight rides on the car in motion, when you shift weight from the front of the car to the rear in motion you shift the center of gravity, in racing you can preload the front or rear shocks for different results, much the same as drag cars intentionally rock onto the back tires putting all the weight and energy on the rear tires making them bite harder, road racing can benefit from alittle lower front because the weight is already leaning over the front tires making the car turn more effectivly, the downside is that to much lean either way effects the other end in a negative way.
Front tires carrying more weight leaves less in the rear, making the steering more positive and the rear lighter which can cause it to spin easier, or in the case of our cars control understeer alittle bit better. if the rear is level the weight transfer is effected, your braking, steering and overall drivability of your car could be negativly effected, now how much of an effect if any you'll notice in daily driving i dunno, probably not enough to cause problems, the only time you should really concern yourself with these issues is if you plan to race the car.
and yes the unibody(frame) of the car is pretty much level on the ground on most cavaliers, the car is just designed where it looks like the ass is in the air, your best bet is to buy a high quality pair of coilovers and shocks and you can play around alittle and get that perfect stance, just keep these things in mind when you do it.
J~
J:
1. Air moves faster over the top of cars. And cars are basically shaped like air foils. A typical J-Body will physically lift off the ground between 250 and 300 mph, if nothing is done to keep it on the ground. At 100mph the lift is significant enough that adding a stock spoiler is noticably different. Note: spoilers get their name from the fact that they "spoil" the air foil effect to a degree.
The airdam on the front is there to keep the pressure under the car lower at high speeds. Making the car lift less. You obviously underestimate this effect; we're not concerned with the car lifting off, were concerned with every bit of traction we can get.
Also, Wings are not Spoilers, and the two are not to be confused. Wings push down on the back of the car; spoilers spoil the air foil effect. Wings make our cars look like ricers, and have no function otherwise. Spoilers
can greatly increase handling at high speeds.
2. Sounds like a nice rehash of what Wild Weasel said.
3. Is the fact we've been trying to get across: "drivability of your car [will] be negativly effected".
Any questions?
If you dont believe that killing the rake of your car is bad, just think about this...How many cars come from the factory lower in the back than the front, or even level for that matter? NONE, because it hinders your ability to make a quick maneuver on the freeway because there is less pressure on the front tires.
Try this:
Driving on the freeway(or at a decent speed) with your window open, put your arm out the window with your hand flat and parallel to the ground. cuts smooth through the air right?
Now angle it so the forward part of your hand is slightly higher than the back. Your hand shoots up!
Angle it so the front is lower than the back, your hand goes down. Ideal for a car!
You want a slight rake coupled with an air dam to induce low pressure under your vehicle which sucks it down towards the ground giving you better traction at speed. If you only go 55 mph it probably doesnt matter what rake you have but as you increase speed from there it can become very dangerous.
J~ wrote:basically there are 3 things you guys are going around and around about.
Lowering the rear of the car has nothing to do with air pressure under the car, if that were the case gm would be designing under trays for vettes. Basic aerodynamic principle states that air flowing slower over the top then under the bottom creates lift so letting more air under the car could in theory have a dynamic effect on lift, but unless you were clickin off 100+mph everywhere you go the forces are not enough to lift a car, otherwise every car built in the last 10 years would have huge wings and front air dams designed to grip the road tighter.
nothing to do with air pressure under the car..... do you know what negative rake angle is or means?
do you know how cars are setup by use of a corner scale and how the lower end takes the brunt of the weight aka you can gain traction by shifting weight to certain sides and corners....
no one is talking about lifting the car to lift the tires completely, however the effect does help lighten the force pushing the tires to the ground.
visit any reputable shop that does corner scaling and ask
I said that unless you tool around at speeds of 100+mph your cars not really going to be that effected by airflow. I never said airflow doesnt matter, i just said that most people in normal driving dont put enough forces on a car to be worried about air pressure under the front of a car.
If air dams were an absolute need all cars and trucks would have them no if ands or buts. Now for all out performance which you guys are picking all over, YES they make a difference otherwise nascar would have no interest. Now was his question at all pertaining to performance? no, he simply asked can i lower the rear and set the car level, not if i lower the rear will my lap times be effected.
I provided a very easy to follow explanation of whats really happening without all the technical opinionated bull that is being fed to him, notice the bottom, i said it will have a negative effect on your car? who can really say how much .5" lowering will effect a cavalier on the highway at 65mph? personally i wouldnt screw with the ride of my car but i drive pretty aggressive, the average person doesnt use 2/10ths of what their car is capable of doing.
As for the spoiler argument, it was a quick statement not an in depth dive into the subject, and depending on how you setup your "spoiler" it is a wing because its creating downforce, now the factory trunks...those are spoilers, and there are many ways to "spoil" the air over a car non of which create much performance benifit, nascar uses spoilers to keep the car on the ground when they spin backwards, because their "wings" create lift at an alarming rate, airplanes use spoilers to help them slow down because the extra drag across the wings slows the plane, ya i'm all for running a spoiler on your car, makes it easier to drive right by ya
J~
you dont need to be at 100 mph to be affected by airflow....
also lowering the rear to make the car level.... people are giving him warning about the drivability factor.... not just worried about lap times...
hence the reason i brought up corner scales and the effect dropping one side of the car and not the other can bring about those factors..
thats why most all spring companies design springs that are to work together at a certain level
most all the stuff people mentioned is a factor in the driveability of the car.
as a final note, cause this whole thread has horribly spun off topic. i never said it wouldnt effect driveability, i just questioned how much, as stated personally i wouldnt screw with it, not worth the risk clear enough?
if you wanna know how much i can post some equations for anyone to figure it out.
as for how much, enough. trying different heights myself on the coilovers, and also the infamous "level" the ride feels float-like at highway speeds, and not at all responsive...
just speaking on experience...clear enough?
J~ wrote:As for the spoiler argument, it was a quick statement not an in depth dive into the subject, and depending on how you setup your "spoiler" it is a wing because its creating downforce, now the factory trunks...those are spoilers, and there are many ways to "spoil" the air over a car non of which create much performance benifit, nascar uses spoilers to keep the car on the ground when they spin backwards, because their "wings" create lift at an alarming rate, airplanes use spoilers to help them slow down because the extra drag across the wings slows the plane, ya i'm all for running a spoiler on your car, makes it easier to drive right by ya
J~
I can't let rampant ignorance like this go by without saying a word or two. First,
a wing creates LIFT and
a spoiler creates DOWN FORCE. Spoilers do not keep the car on the ground when it is going backwards! They keep the back end down when the car is going forwards. This is because they create drag. Roof flaps keep the car down when a car is spinning out. The flaps on an airplane have a very different purpose from a spoiler.
I think the line " ya i'm all for running a spoiler on your car, makes it easier to drive right by ya" certainly qualifies for Event's stupid post of the week. Think about what you post before you make yourself look ignorant.
Man, everyone sure has a lot to say about this...an easy fix to "level" the front with the back would be to buy Tein's H-Tech springs and install them on the car. The drop in the front is 1.1 inches and the back is 0.9 inches. It should be safe to install on your stock struts, and it is a slight drop...
2003 LS Sport: Weapon R intake, Ported TB, and Underdrive Pulley...for now...
Terry S wrote:Man, everyone sure has a lot to say about this...an easy fix to "level" the front with the back would be to buy Tein's H-Tech springs and install them on the car. The drop in the front is 1.1 inches and the back is 0.9 inches. It should be safe to install on your stock struts, and it is a slight drop...
easy fix would be to buy a spring with 1.1 inches in the front (which is already lower in stock form) and a spring thats 0.9 in the rear, which doesnt lower it as much as the front...
when the car usually has more gap in the rear from a positive rake angle????
basically you;d be keeping the stock rake angle, just making the car overall lower, similar to the pro kits or any other springs that have even amounts of lowering front and back
now see event that was a straight forward real world answer,I like those
.
As for the spoiler argument,even if you wanna call it a wing, a wing on your cavy will make yours slower than mine if both cars are even before hand, mine has no wing/spoiler, as for the wing/spoiler creating downforce or lift, its all in what you watch really, drag racing, its a wing, nascar its a spoiler, the roof flaps are spoilers, they spoil the air flow across the top of the car killing lift, which is what was so nicely posted right above one of mine, spoiling the air does not create downforce, it simply slows the air over the car reducing lift, wings on the back however are creating downforce, due to angle or design they are designed to create a lifting force in the wind, be it up or down they are creating a lifting force, same as a plane flying upside down. so now my response was not sheer ignorance, simply miss worded or miss read
J~
pretty much all my posts are real world answers...
either from my own f-ups and learning the hard way
or
something i;ve done to produce a gain of some sort....
You are way confused.
1. Spoilers do add a touch of drag, but their purpose is not drag. Their purpose is to disrupt the airflow over the vehicle so it "spoils" the airfoil effect. Pic:
2. Wings add drag as well. They add drag in direct proportion to the downforce they create, which is exactly what they are intended to do. Pic:
3. Flaps, like what planes have on the wings, and nascars have on above the rear window, simply create drag to slow the vehicle. Any other upward or downward force is an unintended side effect. Pics:
There are of course products which cross lines here and there. The RK sport "spoiler" is one example. It's mostly spoiler, but has some wing effect too.
Now we're really off topic........ Anybody still confused?
I'm pretty sure the flaps on the roof of a NASCAR car aren't there to act as an air brake. They're there to prevent the airflow from lifting the car up.
Same goes for flaps on the wings of a jet. They generate a lot of lift at lower airspeeds so the plane can slow down to land. Otherwise if the plane slowed down that much it would drop out of the sky and if it didn't slow down it would blow up the tires when it landed or not have enough runway to stop.
Those flaps on the top of a nascar are to act as an air brake. That picture is from the back of the car, not the front. When the car goes backward, in a spinout, it will slow the car enough that air going under the rear bumper + airfoil effect can't lift the car; which still happens in some cases.
The flaps on the jet modify the airfoil effect so it will still work at slower speeds, so it doesn't stall. They don't directly push air down. They do create alot of drag though, which they are mean to do. You are right on the not having enough runway to stop...
How many of you have had any formal education in aerodynamics, beyond what people tell you in casual conversation?
