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ANTI Squat calculator for ladder bars ? #2829360
10/06/20 04:11 PM
10/06/20 04:11 PM
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n20mstr Offline OP
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I can find calculators for 4 links, but not for ladder bars. I put the front bolt at the same length and it did seem to work, but my antisquat is less than i thought. Can i use the 4 link one for a ladder bar?
Im using the one on Baseline suspensions


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Re: ANTI Squat calculator for ladder bars ? [Re: n20mstr] #2829385
10/06/20 04:58 PM
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Probably not on the anti squat calculations, maybe so on the instant center calculations confused
I'm thinking ladder bars lift the chassis, no matter how high or low the front heim joint bolt height is work shruggy

Last edited by Cab_Burge; 10/06/20 04:58 PM.

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Re: ANTI Squat calculator for ladder bars ? [Re: Cab_Burge] #2829442
10/06/20 06:00 PM
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The intersection point of the upper and lower bars of a 4 link determines the location at which anti-squat calculation is measured. Same as the ladder bar front pivot point.
Doug

Re: ANTI Squat calculator for ladder bars ? [Re: n20mstr] #2829490
10/06/20 07:28 PM
10/06/20 07:28 PM
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The only “calculator” That will work accurately involves a jack, scales, trig, and a tape measure. You need to know your placement of the center of gravity front to rear, and top to bottom.
Hoping my answer doesn’t come of as sarcastic, but finding the CG is the only way of accurately predict the antisquat line. No online calculator will help without that piece of info.


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Re: ANTI Squat calculator for ladder bars ? [Re: TRENDZ] #2829555
10/06/20 09:18 PM
10/06/20 09:18 PM
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don't need an anti squat calculator for ladder bars.

Its lots.


67 Barracuda street/bracket car 11.27-119
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Re: ANTI Squat calculator for ladder bars ? [Re: n20mstr] #2829579
10/06/20 11:28 PM
10/06/20 11:28 PM
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I use this software for my fourlink, but it can do ladder bars and several other suspension types as well. http://performancetrends.com/4link.htm

Re: ANTI Squat calculator for ladder bars ? [Re: moparacer] #2829596
10/07/20 12:34 AM
10/07/20 12:34 AM
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Originally Posted by moparacer
don't need an anti squat calculator for ladder bars.

Its lots.


Fact. I've never seen a ladder bar car squat.

The differences between 4 links and ladder bars is way more involved than just "more adjustments". Upper and lower bars are independent of each other and are doing different things to the chassis and the housing when the housing tries to rotate. A ladder bar does one thing - lift.

Last edited by CMcAllister; 10/07/20 12:36 AM.

If the results don't match the theory, change the theory.
Re: ANTI Squat calculator for ladder bars ? [Re: TRENDZ] #2829607
10/07/20 01:10 AM
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Originally Posted by TRENDZ
The only “calculator” That will work accurately involves a jack, scales, trig, and a tape measure. You need to know your placement of the center of gravity front to rear, and top to bottom.
Hoping my answer doesn’t come of as sarcastic, but finding the CG is the only way of accurately predict the antisquat line. No online calculator will help without that piece of info.


Also fact.

However, a person can make (or plan to make) a bar change, plot the difference in locations in reference to the imaginary line drawn according to cam height, front axle C/L, etc. and have a reasonable expectation the the car will want to squat or rise, less or more, as a result of that change. If it doesn't, see my sig line. Testing will tell you if you were right. Good shocks will be useful (needed) as you get further away from 100% A/S, wherever that happens to be.


Shocks, weight location, specific bar geometrys, etc. are what really make the difference. The A/S number is more of a reference for where you've been and where you're going and what you should expect to see. Not an exact location without doing all of the calculations. Moving the IC lower in reference to your A/S line on your 4 link map, will make the car want to squat more, or rise less, after the hit. Not because of where that imaginary line and the IC are. But because you have lowered the angle of the bottom bar and/or changed the leverage of the top bar.

Last edited by CMcAllister; 10/07/20 01:26 AM.

If the results don't match the theory, change the theory.
Re: ANTI Squat calculator for ladder bars ? [Re: CMcAllister] #2829639
10/07/20 08:30 AM
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Top hole is more anti squat then bottom

Re: ANTI Squat calculator for ladder bars ? [Re: CMcAllister] #2829650
10/07/20 08:49 AM
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Originally Posted by CMcAllister
Originally Posted by moparacer
don't need an anti squat calculator for ladder bars.

Its lots.


Fact. I've never seen a ladder bar car squat.

The differences between 4 links and ladder bars is way more involved than just "more adjustments". Upper and lower bars are independent of each other and are doing different things to the chassis and the housing when the housing tries to rotate. A ladder bar does one thing - lift.

My Dart will squat; 30 inch ladderbars. The front bottom hole is below the neutral line, or was at 50/50 weight distribution. When i shifted a BUNCH of weight forward and got it below 47 pct on the rear, it became much less visible and i think now is close to zero squat. A ladder bar will be violent even below the neutral line because the instant center can't in most ladderbar cars be set below the neutral line, or if it can, not by much. So there are two forces at work. The whole axle trying to wind around the instant center, which is modulated by the shocks and springs, and that same force as it is redirected into push on the forward mount. I scratched my head over this one for a while, but the videos of my car kept telling me this.
At one setting i was On the neutral line I believe, and the car would violently torque roll, twisting the car to the point it would run out of rear shock travel, and the left rear slick would come off the track! That was seen by fellow racers watching time trials. This can be the result of torqueroll forces of the driveshaft trying to twist the axle like a propeller. The amount of twist can then pull the passenger side ladderbar one way and the other side the other way, and the result can be quite a ride!

https://photos.app.goo.gl/Wxsf1Jn627mQ43B26
This is a pic showing some of the twist; it got a lot worse for a acouple of runs till i figured it out.


8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
Re: ANTI Squat calculator for ladder bars ? [Re: TRENDZ] #2829665
10/07/20 09:27 AM
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Originally Posted by TRENDZ
The only “calculator” That will work accurately involves a jack, scales, trig, and a tape measure. You need to know your placement of the center of gravity front to rear, and top to bottom.
Hoping my answer doesn’t come of as sarcastic, but finding the CG is the only way of accurately predict the antisquat line. No online calculator will help without that piece of info.


I agree you need a set of scales to find the center of gravity, but once you have that info, give me the computer to plot the possible instant centers. And I built my fist 4-link using as you describe, using strings, tape, plumb bobs, and used scales at the local MFA for the weights, in 1979. My last link, I had access to a Hunter HawkEye alignment machine, and while yes I could jack and level the car, drop plumb bobs, it was just neat that I could get my wheelbase, setback, and square the axle with the center line within one hundredth of a degree, looking at a computer screen, while twisting on the link bars.

Re: ANTI Squat calculator for ladder bars ? [Re: jwb123] #2831436
10/11/20 09:29 AM
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Just a personal experience comment relating to plotting.

I've tried changing locations, on my ladder bar cars, and 4 link cars, so many times trying to reduce, or gain bite. Plotting it out on the ground, in software, and on and on. All that is fine for pro level racing where any wasted energy is a lost round, like PS. At my immeasurably low level racing, my concern is just about always making it hook, and go down. I'm either blowing the tires off, or wadding them up sometimes to the point of shake. Either case the shock alone can solve it almost every time.

What I've come to, may not be the best thing in the world, but it works for me. I've put too much of whatever setting works for each car, and use the shock to say no, or hell yeah, have at it. This takes a mean shock to do, but in the long run, when you go to a different track, or conditions change, a shock setting change is all that is required.

Re: ANTI Squat calculator for ladder bars ? [Re: dthemi] #2831530
10/11/20 01:50 PM
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Guys trying to cheap out on shocks don't get it. You can throw a basic 4 link set up in it. Shocks can make it trash or golden.

You don't need plotting, maps, or software, unless you want to plug the numbers in to see where IC is out of curiosity. Tape measure, angle finder, scales are needed.

Last edited by CMcAllister; 10/11/20 01:58 PM.

If the results don't match the theory, change the theory.
Re: ANTI Squat calculator for ladder bars ? [Re: CMcAllister] #2831655
10/11/20 06:21 PM
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Originally Posted by CMcAllister
Guys trying to cheap out on shocks don't get it. You can throw a basic 4 link set up in it. Shocks can make it trash or golden.

You don't need plotting, maps, or software, unless you want to plug the numbers in to see where IC is out of curiosity. Tape measure, angle finder, scales are needed.


I agree....


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Re: ANTI Squat calculator for ladder bars ? [Re: Al_Alguire] #2832335
10/13/20 02:54 PM
10/13/20 02:54 PM
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Im not sure most of you realize what im trying to do...
My car runs on a 275 radial and has been inconsistent lately, spins more than it goes down. It leaves great, uses the front travel, wheels in the air...then spins
What im trying to do is map out my AS per hole in my ladder bars so im not just guessing.
Im currently at 122% and one hole up gives 147%, one more up gives 165%
Drag radials like to get hit hard, and you need a shock to keep it hit. I sent my shocks back to Santhuff to get revalved on the compression side


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Re: ANTI Squat calculator for ladder bars ? [Re: n20mstr] #2832346
10/13/20 03:26 PM
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I don't have a ton of time fooling with radial cars, but it looks to me like successful people are getting the suspension separated and holding the car up with the shock to keep the front end down. Keeping the front end down and the rear separated keeps the tire applied as it tries to drive over the CG rather than under it. I don't see fast radial cars hanging the wheels. I see the front tires stay on the ground.

Weight is a big deal as well. Guys tuning a car I helped with some would routinely move10 or 15 pounds around in the car to make it work. Moving some weight from the middle of the car to the nose would make it go from standing straight up to getting it down the track - or blowing the tires off if they moved too much weight.

You can measure all that stuff and come up with your numbers, but you have to think about where those numbers go when it hits the tire and the housing comes out of the car 4, 5, or 6 inches. The front mount goes with the chassis making the ladder bar angle go up far beyond what a simple hole adjustment provides.


If the results don't match the theory, change the theory.
Re: ANTI Squat calculator for ladder bars ? [Re: CMcAllister] #2832351
10/13/20 03:48 PM
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Put the bar all the way up and try it. As long as you have enough rebound control (and rebound travel) to keep the the housing from separating to quick my bet is it will help. Along with a little more weight on the nose You'll never know until you try it.
Doug

Re: ANTI Squat calculator for ladder bars ? [Re: CMcAllister] #2832370
10/13/20 04:37 PM
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Originally Posted by CMcAllister
I don't have a ton of time fooling with radial cars, but it looks to me like successful people are getting the suspension separated and holding the car up with the shock to keep the front end down. Keeping the front end down and the rear separated keeps the tire applied as it tries to drive over the CG rather than under it. I don't see fast radial cars hanging the wheels. I see the front tires stay on the ground.

Weight is a big deal as well. Guys tuning a car I helped with some would routinely move10 or 15 pounds around in the car to make it work. Moving some weight from the middle of the car to the nose would make it go from standing straight up to getting it down the track - or blowing the tires off if they moved too much weight.

You can measure all that stuff and come up with your numbers, but you have to think about where those numbers go when it hits the tire and the housing comes out of the car 4, 5, or 6 inches. The front mount goes with the chassis making the ladder bar angle go up far beyond what a simple hole adjustment provides.


Ultra and X cars, you see a lot carry the fronts, not high but up . Yes different ways of doing it, Your talking more RVW
Yes i know about the weight and how touchy it is. Im 56.6% now and if i wanted, i can get the car on the bumper


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Re: ANTI Squat calculator for ladder bars ? [Re: dvw] #2832371
10/13/20 04:39 PM
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Originally Posted by dvw
Put the bar all the way up and try it. As long as you have enough rebound control (and rebound travel) to keep the the housing from separating to quick my bet is it will help. Along with a little more weight on the nose You'll never know until you try it.
Doug


Thats the plan. But I like to be methodical and i will go up one hole at a time. Its got three holes above where it is now.
Shock sensor says its seperating anywhere from 2 to 2.6" so yea it probably needs more seperation


....BAD A$$ STREET CAR.....
Re: ANTI Squat calculator for ladder bars ? [Re: n20mstr] #2832530
10/14/20 12:44 AM
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Originally Posted by n20mstr


Im not sure most of you realize what im trying to do...
My car runs on a 275 radial and has been inconsistent lately, spins more than it goes down. It leaves great, uses the front travel, wheels in the air...then spins
What im trying to do is map out my AS per hole in my ladder bars so im not just guessing.
Im currently at 122% and one hole up gives 147%, one more up gives 165%
Drag radials like to get hit hard, and you need a shock to keep it hit. I sent my shocks back to Santhuff to get revalved on the compression side

First I have no experience with drag radials. But as several have mentioned instant center of a ladder bar or a fourlink is just one part of the picture. A couple years ago I installed a new converter, and it lost 60 foot, my light got terrible, but it picked up MPH, got to be a good converter right? Wore out the fourlink holes trying to find a better sweet spot than I had. Moral of the story, a different converter fixed it. This spring I put a fresh engine in the car, lots more power, started spinning the tires, changed the link a little better, but not perfect, went to a softer spring and wow what a difference, it pulled a 1.28 60 foot, average before was 1.35 60 foot. If the instant center is at a reasonable position, look other places, don't waste all your efforts chasing something for no returns. Ask this old man how I know that?

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