danvan1

I have had 4 C4s and lowered all of them using long bolts in the rear and removing the front spring rubber spacer blocks.
Between lowering and alignment they are quite a bit faster through the corners.

Any way I did not come here to play keyboard warrior, was just looking for ideas and conversation with people with a common interest but it looks like we don't have anything in common.

pologreen1

Ohhhhh, that explains the 4 "lowered" c4s and 20 posts in the last 8 years.

I'm just wondering what pushed you from the kits you were doing to getting a zr1 and wanting dropped spindles.

You might try the autocross section or go to the track and talk to people.

If you are not a troll You don't need to lower the car to handle better and be faster. You need to spend a few thousand dollars on:

-new bushings
-larger stabilizer bars
-race springs or coil overs if you know how to tune them
-new hubs
-new u joints
-race tires
-larger wheels
-race seat and harnesses
-brakes
-new fluids
-general maintenance

Or just take it to the track with some tires and go for it and worry about the rest later or when it brakes.

danvan1

Nice collection all way nicer than mine mine is just a rough and dirty GTL race car fast and fun though

danvan1

Pretty much everything on your list is all ready done other than the race seat and coil overs all ready have a harness bar and 5 point and i like the seat so no point changing that. Looks like the coil overs will be this years project.
It spent this summer racing with our local Corvette Club Corvettes North we run 15 events so its been on the track as for the lack of posts just not a big poster unless I have a question which I did and its been answered so thank you

rocco16

Other than that, you are dead right!

MatthewMiller

Nope, he's right on pretty much everything. Everyone who says drop spindles retain "correct" or "factory" suspension geometry is wrong. In fact, there is no part more fundamental to determining suspension geometry than the upright/spindle.

RC theory is kind of old and busted anyway, but it's based on a line drawn from the contact patch to the instant centers in front-view. A drop spindle very much changes that line's angle, and therefore the point at which it intersects the CG dropline. Sitting on the front bumper would change the RC in the way that lowering the car on the spring bolts would, NOT in the way that drop spindles would. You need to go brush up on RC theory, dude.

Drop spindles change the percentage of load taken by the upper and lower arms because they move the actual spindle/axle vertically, further from the lower arm ball joint and closer to the upper arm ball joint. So with any lateral loading (i.e., cornering), more of the lateral load is now reacted through the upper arms and less is reacted through the lower arms. I don't know how big an issue this really is, but understand that from the factory the arms, bushings, and ball joints are sized for the amount of load they respectively see.

I don't think drop spindles will change the camber curve (I'm trying to envision that without any drawings in front of me), but because they change the RC and jacking effects, they will definitely change the amount of roll for a given cornering force, and therefore the required static camber settings required are likely to change. They may or may not change steering geometry, depending on how the steering arms on the new spindles are arranged. I'd have to look at the stock spindles and arms to see, but I'm not sure it's possible to retain stock steering arm geometry on a spindle with significant drop, because the arms might interfere with the wheels. Chalk this up to a big fat "maybe."

Another aspect of geometry not previously that will change is scrub radius. That brings all kinds of other changes along with it, too. And you may no longer be able to run the same wheel offsets with drop spindles - you'd probably need less. So yeah, drop spindles bring about all sorts of geometry and fitment challenges. There is nothing simple or "factory" about them.

Kevova

Drop spindles for the front - maybe something for a late model stock car could be used. I actually was looking at it, because of non serviceable hub bearing. LMSC use larger high load serviceable bearings. The rear I have no clue.

rocco16

Lowering the car by any other method would change RC the same amount. The poster gave the impression that drop spindles are unique in changing RC.
You are correct though; lowering the car via drop spindles does change RC. I worded my response poorly.

MatthewMiller

No, it's not the same amount. Draw the two out on paper, using a C4/typical SLA suspension. With drop spindles, the virtual swingarm stays the same but just gets lowerl: both ends of it drop the same amount, but the VSA is just as long and at the same angle. So the instant centers drop by exactly the amount of the drop in the spindle, but the VSA is the same length and inclination - the ICs just move straight down without changing positions laterally at all.

When you drop the car on the springs (i.e., move the suspension further into bump when at rest), the angles of the control arms change, so the VSA changes angles and changes lengths (it won't change lengths if the upper and lower arms are equal lengths and parallel, but only an idiot would design a suspension that way). So the ICs in this case move both vertically and laterally. The ICs typically move downward and toward the upright they are attached to (i.e., the VSA gets shorter and angles downward or less upward from upright to center), but it depends on the relative lengths and angles of the upper and lower control arms.

So the RCs don't end up in the same places with the two different lowering methods.