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Old 05-18-2006, 11:10 AM   #31
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Quote:
Originally Posted by rcnewb2004
what does tighten the car up mean? or loosen the car up? sorry.. newbo
Tighten up is more traction.
Loosen up is less traction.
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Old 05-18-2006, 11:50 AM   #32
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Last race outdoors on rubbers, Wise suggested to me anti-squat. What it did was drop my laptimes 0.2 or 0.3 ever lap even though motor, tire, battery had not changed (if anything got worse).

When I went into corner and lifted, car's rear end almost seemed to hike up more, but it carved harder to apex-just plain old got there faster and I was able to get back on throttle out of 180's a good foot or two sooner as car was not only planted, but almost fully rotated already.

I think this supports what everyone is saying.

Ray
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Old 05-18-2006, 12:22 PM   #33
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Gee-dub, how the heack are you? Miss seeing you at the races. Hope to see you soon. 05 is up and running pretty darn good.
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Old 05-18-2006, 01:11 PM   #34
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Ray, with the arms angled like that it will let the rear end raise up more off-power when going into the corner, transfering more weight up front, unless when putting in pro-squat, you limit the droop screws more.
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Old 05-18-2006, 02:17 PM   #35
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Ricky- How you doin?
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Old 05-18-2006, 04:14 PM   #36
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Quote:
Originally Posted by CarbonWorks
Anti-squat will tighten a car up under power, and loosen it up off-power.

Pro-squat will loosen a car under power, and tighten it up off-power.

The key words are on-power and off-power. That's it.
100% the opposite
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Old 05-18-2006, 04:24 PM   #37
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After reading through this entire thread, I am still not sure what does what - seems we have conflicting opinions on what the true effects of anti-squat and pro-squat have on a cars handling characteristics

Who out there can give us the once and for all correct answers without a doubt?

Any team drivers out there?
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Old 05-18-2006, 04:32 PM   #38
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Several of us have stated the facts, but I guess the facts are open to the opinion of others. I suggest that the next time you are at the track make these adjustments for yourself. Make the adjustments in large amounts so you can more easily feel the effects. This way you will arrive at the answers for yourself. Apparently Ralph Burch had told someone else in the thread that the xray manual that was quoted was backwards. He said this because it is backwards. Just like the Pro 4 manual when it talks about roll center.
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Old 05-18-2006, 05:27 PM   #39
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You've actually had at least 3 team driivers from major chassis manufactures.
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Old 05-18-2006, 06:09 PM   #40
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Quote:
Originally Posted by CarbonWorks
Anti-squat happens when the rear tires are pushed downward by the twisting forces of the drivetrain. When the tires are pushed downward it creates a larger amount of traction for a moment. This is what you see when a drag car accelerates. The pinion gear tries to climb up the ring gear. The rear suspension is configured in a manner that translates this energy into a downward pressure on the tires. This is anti-squat. The exact opposite happens when the car decelerates. The suspension lifts the tires from the surface of the road , which causes the rear of the vehicle to "squat". Pro-squat does the opposite of what anti-squat does. On a RC vehicle, anti-squat places downward pressure on the tires because when you apply the throttle the car wants to remain still so the rear tires try to walk forward under the car due to the angle of the hinge pin. Since the hinge pin has a positive angle to it(front is higher than rear) the force is translated into a momentary downward pressure from the rear arms. If the hinge pin angle was negative (lower at the front than the rear) the tires walking forward would cause the rear arm to rise momentarily which would result in a loss of traction(pro-squat). This is almost exactly how a modern 4-link suspension produces down force from throttle input(anti-squat). I was a suspension and telemetry man for a many time national champion SCCA Trans-Am and IMSA GTS driver, and if this was not the way things worked we never would have won anything. It is all physics.

Great Stuff !! I'am having trouble visualizing weight transfer when you say that the rear tires try to walk forward under the car due to the hinge pin angle (anti-squat). My mind's eye sees the rear of the chassis going up at this moment and that seems to me to be in the wrong direction for weight transfer. I also think I see the tire walking forward and pulling the chassis down because of the opposite hinge pin angle (pro-squat) which seems to be in the right direction for weight transfer. This seems to be the opposite of what is happening. What am I missing ?

Thanks.
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Old 05-18-2006, 06:19 PM   #41
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Dont confuse weight transfer with yaw or body roll. Weight will always transfer regardless if the springs compress.

When you use anti-squat the suspension tries to resist the squatting effort of the increased load transfer to the rear of the car. When the load transfers and this springs dont compress, it forces the rear tires into the ground harder.
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Old 05-18-2006, 06:49 PM   #42
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Imagine that you are stuck in the mud and are hopelessly spinning the tires. You ask your buddy to climb on the back bumper of the car and start jumping up and down. As he is on the downstroke, the rear tires momentarily gain traction. This is essentially what happens with Anti-Squat. You have to distinguish between downward pressure on the rear arms and weight transfer. It has less to do with the weight transfer. Just jacking up one end of a car won't change the weight distribution much. It is the dynamic motion of this event that is doing the weight transfer. The forward acceleration is already transfering weight to the rear of the vehicle, you are just adding extra downforce by pressing downward on the tires(which actually raises the rear end). Remember that the force on the tires is coming from the chassis, its not like you are just pressing down on the back of the car which would lower the rear end. As the tires try to walk under the chassis, it must lift the rear of the chassis which is where the weight come from. The greater the angle of the hingepin, the quicker the reaction-but shorter lasting the pressure and vice-versa. The opposite happens when you let off power. These forces are so dramatic in dirt oval racing that the rear suspension must have a very strong shock absorber to cushion the effect when letting off the gas. The shock is a 90/10 shock, which provides very little damping when on the throttle, and alot when you let off. Its tough to fully explain without pictures to reference.
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Old 05-18-2006, 06:50 PM   #43
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That was a much more concise explanation (Jack Smash). Right on!
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Old 05-18-2006, 06:52 PM   #44
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i agree 100% also.
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Old 05-18-2006, 07:44 PM   #45
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pro squat ===

when a Pro driver squats on your car, and gets crap alllll over it, i had it happen to my rustler, but only it was dog squat...
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