Anti dive
Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Very good question, and I'll admit I've never seen the number published anywhere.
I converted to a C4 suspension in my '69 a couple years ago, and during fabrication I was interested in comparing the C3 and C4 numbers to decide how I wanted to configure the front end. But I struck out finding the C3 info so I just set up my front end so I can change the amount of anti-dive I have. (Not easy to do on a stock frame.)
Let me know if you find the number or have some technical information to pass on to the collective.
I converted to a C4 suspension in my '69 a couple years ago, and during fabrication I was interested in comparing the C3 and C4 numbers to decide how I wanted to configure the front end. But I struck out finding the C3 info so I just set up my front end so I can change the amount of anti-dive I have. (Not easy to do on a stock frame.)
Let me know if you find the number or have some technical information to pass on to the collective.
Le Mans Master
Joined: Apr 2007
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From: Graceland in a Not Correctly Restored Stingray
Haven't ever gone to the trouble to measure/calculate it myself, and can't recall if I've seen the percentage published, but IIRC the upper A-arm mount is at a 9* angle.
Burning Brakes
Joined: Sep 2009
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From: hickory NC
C4 of Year Finalist (appearance mods) 2019
2017 C4 of Year Finalist
Looking it up in an OLD Chevrolet power book, it says that in "general todays cars are designed to give approximately from 30% to 50% anti-dive."
There is 2 pages of equations, figures and diagrams explaining how to figure the anti-dive.
Take it for what it's worth, the book I got it from was printed back in 1984.
There is 2 pages of equations, figures and diagrams explaining how to figure the anti-dive.
Take it for what it's worth, the book I got it from was printed back in 1984.
Burning Brakes
Joined: Sep 2009
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From: hickory NC
C4 of Year Finalist (appearance mods) 2019
2017 C4 of Year Finalist
So, is that percentage published in the Vehicle Dynamics section?
I'd scan it, but the one I have here at home is on the fritz.
See if the one the wife has at work will work if you want it.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
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From: Beringen
That would be great. I need it to calculate the angel the lower control arm has. I'm trying to find out where my bracket needs to be. One of them is faulty, but i don't seem to be able to find any dimension related to it.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
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From: Beringen
Another question about this.
I drew up a drawing of the side view swing arm based on some dimensions I have got here. The swing arm seems pretty short, ending well before the rear wheel and making the line drawn from the front tire center contact patch through the intersection point of the arms end well above the rear tire. Is this a good situation or should the svsa be longer and the intersection point with the vertical in the rear axle lower ?
(don't know if this makes sense, but its hard to discribe in words)
I drew up a drawing of the side view swing arm based on some dimensions I have got here. The swing arm seems pretty short, ending well before the rear wheel and making the line drawn from the front tire center contact patch through the intersection point of the arms end well above the rear tire. Is this a good situation or should the svsa be longer and the intersection point with the vertical in the rear axle lower ?
(don't know if this makes sense, but its hard to discribe in words)
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Burning Brakes
Joined: Sep 2009
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From: hickory NC
C4 of Year Finalist (appearance mods) 2019
2017 C4 of Year Finalist
I THINK I know what you mean.
Can you post a picture of what you drew up?
Also, I've got those anti-dive pages copied. Wife could not e-mail them to me. If you send me your address I would mail them to you.
There is also a lot of pages relating to suspension geometry and how to figure what you are trying to achieve. If you want those also, let me know.
Can you post a picture of what you drew up?
Also, I've got those anti-dive pages copied. Wife could not e-mail them to me. If you send me your address I would mail them to you.
There is also a lot of pages relating to suspension geometry and how to figure what you are trying to achieve. If you want those also, let me know.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
This is a picture of it. Don't know if it will make more sense, but here goes.
Apparently the upper control arm has an angle of 19,44°. The lower is 10 mm higher in the rear normally (not what it is on my car, but nonetheless). However, i did calculate things from the dimensions of TT that were put on the corvette suspension wiki.
The arm are not perpendicular with the frame axis. Each of them (top and lower are angled inwards at the rear about 10 mm. The intersection point of the arms viewed from above is somewhere right in the middle of the rear axis.
Apparently the upper control arm has an angle of 19,44°. The lower is 10 mm higher in the rear normally (not what it is on my car, but nonetheless). However, i did calculate things from the dimensions of TT that were put on the corvette suspension wiki.
The arm are not perpendicular with the frame axis. Each of them (top and lower are angled inwards at the rear about 10 mm. The intersection point of the arms viewed from above is somewhere right in the middle of the rear axis.
Last edited by Belgian1979vette; Jan 30, 2011 at 11:09 AM.
Racer
Joined: Nov 2010
Posts: 331
Likes: 108
Your drawing does not look right to me. The distance from the ground plane to lower pivots seems greater than the distance between upper and lower pivot axes. My car is lowered some but the distance between the ground plane and the lower pivot is much less than between upper and lower pivots.
Also the rear lower pivot point is not more than 5mm higher than the front pivot point on my car.
Grampy
Also the rear lower pivot point is not more than 5mm higher than the front pivot point on my car.
Grampy
Thread Starter
Melting Slicks
Joined: Mar 2002
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From: Beringen
Your drawing does not look right to me. The distance from the ground plane to lower pivots seems greater than the distance between upper and lower pivot axes. My car is lowered some but the distance between the ground plane and the lower pivot is much less than between upper and lower pivots.
Also the rear lower pivot point is not more than 5mm higher than the front pivot point on my car.
Grampy
Also the rear lower pivot point is not more than 5mm higher than the front pivot point on my car.
Grampy
Are you sure about that last thing (the 5 mm) ? I used the dimension of TT's measurements to see how high the rear pivot is in relation to the front of the lower arm. As you know, i'm trying to get a correct placement of my bracket(s)
Racer
Joined: Nov 2010
Posts: 331
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My tires are about 25 inches in diameter. My front pivot is 8.06 inches above the ground plane. Z height is 1.25 inches. The rear pivot is about 8.25 inches above the ground plane so 5mm front to back. Side to side is just about the same with left side 0.06 higher as it sits. The car has not been on scales.
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
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From: Beringen
Thanks for all that info.
If i look at that drawing, the lower pivots of the lca are sitting at equal height. That would make the replacement of my bracket a lot easier.
What I would also like to know in this respect is the angle the pivots have towards the rear. In my car they are each angled about 10 mm towards the rear, but someone was in there before me. They are not by any change perpendicular with the frame axis are they ?
If i look at that drawing, the lower pivots of the lca are sitting at equal height. That would make the replacement of my bracket a lot easier.
What I would also like to know in this respect is the angle the pivots have towards the rear. In my car they are each angled about 10 mm towards the rear, but someone was in there before me. They are not by any change perpendicular with the frame axis are they ?
Drifting
Joined: Oct 2008
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From: Rochester Hills Michigan
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
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From: Beringen
