D height / Z height
Thread Starter
Instructor
Joined: Jan 2003
Posts: 237
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From: TAMPA FL
D height / Z height
This weekend I set my ride height up per the Vette Improvment Program by Greenwood.
The D height on the rear was no problem, had to raise the rear 1/2 inch. I then reset the camber and took her for a rided. It really seemed to help the oversteer.
The front end needed to be lowered 2 3/8 inchs to bring the Z height to 1 inch. I had to cut 1 1/4 coils to get it this low. Problems are as follows.
1) My oil pan is only about 3 inches off the ground.
2) 1 degree neg camber, with no shims and my strut bar pre loaded.
3) Tire clearance, to the fender is way to tight. Less than 1/16 inch
I run 255/60r15
I know someone else on the forum has had to try this and I would like your input. I can drive her on good roads and it handles a lot better than it did. It has little or no oversteer. But it just sits to low in the front to drive on city streets.
Dennis
The D height on the rear was no problem, had to raise the rear 1/2 inch. I then reset the camber and took her for a rided. It really seemed to help the oversteer.
The front end needed to be lowered 2 3/8 inchs to bring the Z height to 1 inch. I had to cut 1 1/4 coils to get it this low. Problems are as follows.
1) My oil pan is only about 3 inches off the ground.
2) 1 degree neg camber, with no shims and my strut bar pre loaded.
3) Tire clearance, to the fender is way to tight. Less than 1/16 inch
I run 255/60r15
I know someone else on the forum has had to try this and I would like your input. I can drive her on good roads and it handles a lot better than it did. It has little or no oversteer. But it just sits to low in the front to drive on city streets.
Dennis
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
It sure sounds like the front is below spec, but Chevy Power / VIP road race prep settings are low. Before going to stiffer springs, I had clearance issues on the street, but I know my pan isn't that close. If my shark were here, I'd measure it for you.
First, do you have an aftermarket pan with at deep sump?
Next, I'm not questioning your workmanship, but I just want to review... Z height is the distance from the lower control arm front pivot bolt CL (centerline) to level ground, minus the distance from the bottom surface of the spindle support (also referred to as the steering knuckle) to level ground. That last point is the underside on which the lower ball joint nut bears. Measurements should be taken with a full tank of fuel and the driver's weight on board (tube sand works well), with the car sitting on level ground and the suspension fully settled. Race prep Z height spec is 1" - 1 1/4". Is that what you've got measured by this method?
BTW. Older C3's have less fender clearance than '78 and later. Also, given the tremendous advancements in modern tire technology, I suggest ignoring any recommendations to use rubber bushings for anyone serious about handling enough to lower their suspension to race prep settings.
First, do you have an aftermarket pan with at deep sump?
Next, I'm not questioning your workmanship, but I just want to review... Z height is the distance from the lower control arm front pivot bolt CL (centerline) to level ground, minus the distance from the bottom surface of the spindle support (also referred to as the steering knuckle) to level ground. That last point is the underside on which the lower ball joint nut bears. Measurements should be taken with a full tank of fuel and the driver's weight on board (tube sand works well), with the car sitting on level ground and the suspension fully settled. Race prep Z height spec is 1" - 1 1/4". Is that what you've got measured by this method?
BTW. Older C3's have less fender clearance than '78 and later. Also, given the tremendous advancements in modern tire technology, I suggest ignoring any recommendations to use rubber bushings for anyone serious about handling enough to lower their suspension to race prep settings.
Burning Brakes
Joined: Feb 2005
Posts: 1,235
Likes: 0
From: Mesa AZ
i put in the 550 lb springs and my front measures about 1.25". i have plenty of clearence, my fender lip is at about 27.5"
i just ordered new 10" bolts for the rear because with the 8" bolts it still needs to go down another inch on mine.
i just ordered new 10" bolts for the rear because with the 8" bolts it still needs to go down another inch on mine.
Safety Car
Joined: Dec 2004
Posts: 4,876
Likes: 1
From: Jersey Shore Exit 98
sounds like you lowered it too much. I would put a set of 550 springs on it asap before you break something like an inner fender or oil pan.
Thread Starter
Instructor
Joined: Jan 2003
Posts: 237
Likes: 0
From: TAMPA FL
It sure sounds like the front is below spec, but Chevy Power / VIP road race prep settings are low. Before going to stiffer springs, I had clearance issues on the street, but I know my pan isn't that close. If my shark were here, I'd measure it for you.
First, do you have an aftermarket pan with at deep sump?
Next, I'm not questioning your workmanship, but I just want to review... Z height is the distance from the lower control arm front pivot bolt CL (centerline) to level ground, minus the distance from the bottom surface of the spindle support (also referred to as the steering knuckle) to level ground. That last point is the underside on which the lower ball joint nut bears. Measurements should be taken with a full tank of fuel and the driver's weight on board (tube sand works well), with the car sitting on level ground and the suspension fully settled. Race prep Z height spec is 1" - 1 1/4". Is that what you've got measured by this method?
BTW. Older C3's have less fender clearance than '78 and later. Also, given the tremendous advancements in modern tire technology, I suggest ignoring any recommendations to use rubber bushings for anyone serious about handling enough to lower their suspension to race prep settings.
First, do you have an aftermarket pan with at deep sump?
Next, I'm not questioning your workmanship, but I just want to review... Z height is the distance from the lower control arm front pivot bolt CL (centerline) to level ground, minus the distance from the bottom surface of the spindle support (also referred to as the steering knuckle) to level ground. That last point is the underside on which the lower ball joint nut bears. Measurements should be taken with a full tank of fuel and the driver's weight on board (tube sand works well), with the car sitting on level ground and the suspension fully settled. Race prep Z height spec is 1" - 1 1/4". Is that what you've got measured by this method?
BTW. Older C3's have less fender clearance than '78 and later. Also, given the tremendous advancements in modern tire technology, I suggest ignoring any recommendations to use rubber bushings for anyone serious about handling enough to lower their suspension to race prep settings.
I am running a 7qt moroso pan.
The distance from ground to fender lip is 26 1/4". My tires are 27.1" in diameter. If I had enough room on the camber adj. to bring the top of the tire out to .25-.50 neg. camber my tires would be into the fender lip.
I am running 460 lb VBP front coils and really don't want to go any stiffer. I ordered another set today, from Vann Steel. I know I have to bring it back up some, but was wondering if anyone else had ran into this. I could go with a smaller tire on the front, to clear the fenders, but this would also set me lower to the ground than I am now.
Dennis
