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Old 05-11-2006, 04:18 AM   #16
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Weight transfer is fundamentally about the acceleration forces, not about the roll and pitch of the chassis.

So, the effect of decreasing droop on weight transfer is actually tiny.

What makes more difference is keeping the wheels on the ground within the travel of the suspension.
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Old 05-11-2006, 06:55 AM   #17
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I think you underestimate what can be done to control weight transfer, droop is a very useful tool for this.
However I still don't see how altering droop will control wheelspin, assuming that it is not set wildly wrong in the first place.
I cannot comment on the last part of your post as I don't understand the sentence, maybe I'm stupid, it would explain why I don't understand the droop thing either.

See you at Snetterton, I'll be the person playing with droop screws to tune my weight transfer lol.
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Old 05-11-2006, 11:16 AM   #18
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I know this response may sound a little "simple", but I've seen guys display some VERY bad habits at races, so here goes...

Prep your tires (whatever your personal ritual is for your tires and track, etc.) for the race, then HAND CARRY your car over to the timing loop to "check in", then set the car down on the grid IN IT'S STARTING SPOT, making sure the grid area is "clean" (no grit or dirt, etc.)... This gives you optimum grip for the start... (Nice clean, prepped tires on a clean surface.) Even give the car a light downward "pump" a time or two to sort of "seat" the tires on the surface and to initiate a tiny bit of squat into the suspension...

What I see far too much is guys dropping their car down on the side of the track, where it's all dusty and dirty, drive around the track to check in, then drive up to their spot on the grid... Then they wonder why they have tire spin off the line... Their tires have picked up dirt, grit, etc. from all that messing around and it can take 1-2 laps to scrub them off once the race starts...

Just my 2 cents...
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Old 05-11-2006, 11:58 AM   #19
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Quote:
Originally Posted by tfrahm
I know this response may sound a little "simple", but I've seen guys display some VERY bad habits at races, so here goes...

Prep your tires (whatever your personal ritual is for your tires and track, etc.) for the race, then HAND CARRY your car over to the timing loop to "check in", then set the car down on the grid IN IT'S STARTING SPOT, making sure the grid area is "clean" (no grit or dirt, etc.)... This gives you optimum grip for the start... (Nice clean, prepped tires on a clean surface.) Even give the car a light downward "pump" a time or two to sort of "seat" the tires on the surface and to initiate a tiny bit of squat into the suspension...

What I see far too much is guys dropping their car down on the side of the track, where it's all dusty and dirty, drive around the track to check in, then drive up to their spot on the grid... Then they wonder why they have tire spin off the line... Their tires have picked up dirt, grit, etc. from all that messing around and it can take 1-2 laps to scrub them off once the race starts...

Just my 2 cents...
That makes good cents...

Using tire warmers with the method above will take care of putting heat into the tires, rather than a flying lap that doesn't count and uses precious voltage.
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Old 05-11-2006, 11:59 AM   #20
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Quote:
Originally Posted by pookat
In what way do you change droop to reduce wheelspin?
Adding a little front droop will allow more weight to transfer to the back end on acceleration. If the car is spinning the tires off the start this could allow the car to squat a little more and get the grip he needs. Personally, I'd never change setup to get a faster start. I think the best way to get a good start is to keep the tires clean before the race starts and use your throttle finger. You can control the throttle much more accurately than using these quick start adjustments on radios because the grip may be different one run to another. Get a feel for it and control it yourself. Traction control works by limiting the power laid down to not exceed the amount of forward bite. That's what your throttle finger is for. tfrahm has it right. Though I don't see a problem with running a practice lap or two to make sure the tires are up to temp as long as you set the car down in the groove and don't go off line and pick up a bunch of crap on your tires. Setting the car right on your grid spot is the best though as long as you know your tires are up to temp.
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Old 05-11-2006, 01:17 PM   #21
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Sorry Jon I still don't buy it. I suppose we have to assume the car is running a 1-way or a spool, in this case either all four wheels spin or the front spin and the rear diff slips, if the fronts don't spin neither can the rears.
So if we agree that the fronts are spinning how can taking weight off them stop this happening?
I am glad we both agree that altering droop will alter weight transfer.
I also agree with you that I would never alter a setup to get a better start, you can't win a race on the first corner.......
trfahm, nowt wrong with keeping it simple, what you said was just what 'should' be 'common sense'!
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Old 05-11-2006, 01:55 PM   #22
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I agree, the effect would be minimal if any off the start and could really mess up how the car handles the rest of the race. I was just trying to explain the theory. Like I said, it's not at all how I'd handle it and not what I'd recommend to anyone. Just trying to explain the thinking behind it.
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Old 05-11-2006, 02:28 PM   #23
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Quote:
Originally Posted by pookat
Sorry Jon I still don't buy it. I suppose we have to assume the car is running a 1-way or a spool, in this case either all four wheels spin or the front spin and the rear diff slips, if the fronts don't spin neither can the rears.
So if we agree that the fronts are spinning how can taking weight off them stop this happening?
I am glad we both agree that altering droop will alter weight transfer.
I also agree with you that I would never alter a setup to get a better start, you can't win a race on the first corner.......
trfahm, nowt wrong with keeping it simple, what you said was just what 'should' be 'common sense'!
How about a happy medium of thought. I agree that allowing the front to lift up more in order to transfer more weight rearward is probably not a good solution. However, I also agree that the best bet to minimize wheelspin is to make sure there is sufficient weight transfer to the rear tires. The laws of physics, in this case acceleration of a four wheel drive vehicle, will dictate that without a high grip track/tire combination, the front tires cannot supply adequate grip to keep them from spinning. Now another thing to remember is that if you have noticeable wheelspin from a dead stop, then you may also have unnoticeable slight wheelspin accelerating out of corners. Overheated rear tires and that 'greasy' drift feeling will be the end result.

Along those lines, my own method of base setup for any track uses the following thought process, in conjunction with others of course. In this case of controlling wheelspin under accleration from a dead stop or slow speeds, I believe the key is actually figuring out how much you should let the rear end squat under acceleration. I simply forget about using the shocks/springs to control the rear end squating, since they affect mid-corner handling much more. My option of choice is changing the slant of the rear arms (squat) to match the surface/tire grip.

For foam/carpet and extremely high grip rubber/asphalt racing (medium to high grip), I've always used anti-squat. Especially with the T2 since its rear end is more planted than bin Laden anywhere in the world. Since the tires & surface pretty much eliminate wheel spin, anti-squat actually helps the car accelerate a good bit quicker from a dead stop and low speeds. This is due to the fact that it keeps the cars inertia from being initially transferred downwardly into the rear springs when you pull the trigger hard. I always adjust the rest of the car to make sure it handles well in all other aspects.

For most asphalt and rubber/carpet racing (low to medium grip) I start with the arms flat and then add pro-squat if there is too much on-power wheelspin drifting action. In my book, less overall grip = more rear squatting action needed. For really low grip conditions, I always use pro-squat.

Here's food for thought, although I never had a chance to try this setup on a race day before switching back to carpet...

At the end of last summer, with a rubber shod FK05 on low grip, but clean and high temp asphalt, I had found a great combination of a spool up front and 1.5d of rear pro-squat. On-power, the pro-squat virtually eliminated excessive rear wheelspin and oversteer while the spool made sure the rear end still rotated nicely from the apex out. Off-power, the pro-squat (combined with enough rear droop) made up for the spools chief deficiency and provided great corner entry steering. Pro-squat accomplishes this by allowing the rear end to lift up and transfer weight to the front much quicker and more foreceably as the chassis increases its rate of roll all the way up to the apex. Each of these two options complemented the other very nicely with the result being a car that didn't wheelspin on launch, drift coming out of corners, or suffer from over/under-steer anywhere in the corners. I started off with using CS27's and then tried RP30's and CS22's. Each increase in tire traction gave more overall grip and steering, without any on or off power handling side effects.
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Old 05-11-2006, 02:45 PM   #24
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Could it be something like too much camber etc. THis would mean the contact patch of the tyre is minimal off the line allowing some wheelspin?

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Old 05-11-2006, 02:55 PM   #25
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Quote:
Originally Posted by Skiddins
Could it be something like too much camber etc. THis would mean the contact patch of the tyre is minimal off the line allowing some wheelspin?

Skiddins

Good point. Especially for the rear tires.

For low to medium grip situations, I've never run more than 1.5d of static rear camber. The usual rear setup is an even 1d static camber and fairly flat upper links for less camber gain. The higher my ride height and softer I have the suspension (springs), the more I shorten the links for increased camber gain as the chassis will roll more.
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Old 05-11-2006, 02:58 PM   #26
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just run foam tires on carpet... wheelspin eliminated
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Old 05-11-2006, 03:04 PM   #27
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Quote:
Originally Posted by peter_robinson
just run foam tires on carpet... wheelspin eliminated
Come down here and build me a carpet track and I will
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