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As Requested. Put it all up in here. Any and all welcome.

NO Bashing of others!

PM me if anything needs attention, I'll try and visit frequently as well.
 

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I'm no expert by any means, but as far as the ride height is concerned, I would say it all depends on whether or not you are able to maintain the proper angle of the LCA's. Thats the issue that I'm having with my car right now; I'm going to try adding the rubber isolators back to the top of the springs to see how it helps. I believe Racecraft offers come LCA brackets that have like 5 or 7 holes in them, which should make having a lower car easier to tune.
 

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According to that article, the IC is the intersection point of the torque arm centerline and the lca. If this is true, then why are most torque arms so long? Surely there's more to it than just that, otherwise, wouldn't a short torque arm that doesn't extend so far up into the tight confines of the tailshaft area be way better? (Having more room toward the rear to make multiple t.a. mounting points)
 

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Dont know if the article is true but if you look at TA's by Madman, BMR, etc the drag racing app TA's are shorter and Madman's has multiple points like you stated but dont know about the others. I am new to this also and just been doing some searching wish someone had a nice site like Baselines 4 link calc for torque arm cars with pics illustrating what we need to do to get our values.
 

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I love this sticky! LCA angle is critical yes, in any car, but the lower the car gets, the harder it is to get a decent IC height due to the front LCA mount being so low. Now, of course if you bring enough steam, well, who needs the IC up there? If you don't have the power, the IC has to be relatively higher/shorter. How much, is fully a function of the CG height of the car.
Ask yourself: If the CarCraft diagram is right, why do cars hook harder with a simple change to a shorter torque arm that points in exactly the same direction? The diagram is not correct. IC distance from rear axle CL is defined by the front mount of the torque arm, IC height is defined by the point at which the extended LCA vector intersects a vertical line drawn through the TA front mount. IC changes are acheived by changing the angle and/or changing the TA length. Also, if modern torque arms are fixed length and adjustable only for a scant few degrees of axle rotation, what good is the adjustment? Pinion angle?
Thanks for the place for this subject, Mike!
 

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Yes, Mr Shope is absolutely spot on. Notice that there is no parameter for torque arm angle? Only length. Remember, too, that % anti-squat and % rise are guidelines and only partial contributors to the optimum combination, and horsepower plays a huge role in finding what these percentages should be. For instance, a 60% anti-squat might work well for a high horsepower car, but spin terribly with a lower power package. Conversely, 100% anti squat and lots of power would probably ruin the tires and lift the back of the car like it had a pinion snubber but work quite well for a medium powered car.
 

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Every diagram seems to contradict the next. We really need to have some people well versed in these cars to chime in! Im not sure there are too many people who know why it works but just how to make it work based on trial and error. As said many times the lca angle is big, but exactly how does the t/a work?
 

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Here is some information that I found, it was related to road race cars, but regardless the geometry and math reamain the same.

The key for me is that you can't analyze a T/A the same way as a ladder bar, or any multi-link suspension with a known SVSA. If you think of the forces in the suspension not as "jacking" effects, but as torques which must be reacted by the suspension members, it makes this easier.

Example: car with 100" wheelbase, 20" C.G. Call the ratio of these two, 20/100 = .20, the weight transfer ratio (WTR). If we have a ladder bar with forward mount point 10" off the ground and 50" forward of the axle center, we can construct another ratio, call it the anti-squat force ratio (AFR). In this case, the AFR is 10/50 = .20, and the percentage anti-squat = AFR / WTR = .2 / .2 = 100 percent. Easy.

Torque arm is more problematic, because the effective lengths we need for the above ratios are no longer determined strictly by a physical (ladder bar) or virtual (multi-link intersection) center point. Here's the torque arm analysis, starting with trailing links that are level with the ground. Think of the force on the contact patch generating a torque by acting on a lever arm which is the height of the level trailing links. This torque is reacted by an essentially horizontal arm, the torque arm. Thus, the anti-squat force ratio (AFR) becomes the height of the level trailing link, divided by the length of the torque arm. Back to our above example, if the level trailing link is 10" high and the torque arm is 50" long, the AFR is .2 and our anti-squat is 100 percent again. Note that for nearly level torque arms - which is always the case - the height of the front torque arm mounting point is essentially irrelevant.

If the rear trailing links are angled up or down in the side view, the analysis is complicated somewhat because the trailing links will add their own "jacking effects". If the links are angled down toward the front, they will reduce anti-squat, if up, they increase it. This effect is also simple to calculate: divide the vertical gain in distance from rear to front pivot by the horizontal distance from rear to front pivot. For instance, front trailing arm pivot is 10" high, rear pivot is 11", horizontal distance between pivots 20", the anti-squat force ratio contributed by the trailing links is (10 - 11) / 20 = -.05. Angling the trailing links upward to the rear "stole" a fourth of our anti-squat in this case. So the formula for anti-squat is: (AFRtorquearm + AFRtrailinglinks) / WTR. AFRtrailinglinks is a positive number for links angled down to the rear, negative number for trailing links angled up to the rear.

What if we do want to make our trailing links angle upward to the rear, to induce a bit of roll understeer? Well, we can shorten the torque arm proportionally to recover the desired anti-squat - in the above example, we need to increase AFRtorquearm to .25, which we can do by shortening the T.A. to 40". Won't that shorter torque arm lead to more brake hop? Curiously, maybe not in this specific instance. Remember that the front of the torque arm is constrained only in the vertical direction, it is not a pivot point. The actual side view arc of motion (the SVSA) will be larger in radius than the torque arm, because the links angled up to the rear will "push" the axle backwards somewhat as the rear of the car lifts. Of course, once the trailing arms move past level, the opposite will occur, and the SVSA will be shorter than the T/A length.
 

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Ive been 1.16 60fts on a 275 car and all i did was change rear gear and it carried the wheels but was going left in the air had to abort the run it still went a 1.15 60ft but all of the sudden its going left now,what can it be?:confused:
 

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Ive been 1.16 60fts on a 275 car and all i did was change rear gear and it carried the wheels but was going left in the air had to abort the run it still went a 1.15 60ft but all of the sudden its going left now,what can it be?:confused:
Bump,single beadlocks also had to mention that also!
 

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Have you checked the rear to see if it's square in the car? Sounds like a LCA is bent, somehow went out of adjustment, or you might have a bent axle/housing. I'd probably lean toward a control arm or mounting point issue. I don't really know if it's an issue with radials, but you might want to check the runout of the tires just to eliminate that.
 
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