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  #16 (permalink)  
Old 03-04-2003, 04:57 AM
TurboS10's Avatar
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I guess I am just confused. I thought you were thinking this was an 11 second car. I am not trying to be a *****, it is just that there are alot of people who come to this site with imaginary cars or imaginary engines making imaginary power. I am not accusing you of this, but when this happens it makes it is misleading to those following along if all the details of the car or situation in question do not make sense. It can give people a false sense of the answer to problems that may not even exist. This could lead someone else down a path that is just plain wrong.

That said, I think if the car has never been to the track you really dont know how it will react. You said it unloads the tires after it moves a couple feet. Are you testing it on the street? Nothing will hook on the street. The only way you will know if this car will hook and launch is at the track. There is no substitute for a concrete launch pad covered in rubber.

You need to get to the track to do your testing. It is pretty much impossible to set up a car on the street to see how it will run at the track. The point is that a well tuned race car will roast the tires on a standard asphalt street surface.

Chris

[ March 04, 2003: Message edited by: TurboS10 ]</p>

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  #17 (permalink)  
Old 03-08-2003, 06:18 PM
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well we went out to the local rubber coverd go fast spot with the ladder bars lowered one hole (now second from bottom) took most of the preload out of the coilovers (7 threads showing about 25% up) and turned the adjuster knob on the QA1's down to two outa twelve

the car sat alittle lower and drove well
after a breif tire warming the car left realy realy hard lifted the front till it ran out of travel (8-10 inches ) ans slamed the rear till it bottemd out as well then spun a little and did this two more times (hook spin hook spin hook spin ) then grabed one last time witch planted the rears well and went the last 900 -1000 ft

so i figured the shocks were alittle loose and went up a click ......
next pass spun like hell
same line same tire temp etc...

went back to click #2 to verify and did similer to pass#1

so whats next? anyone? turbo..., willys

thanks
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  #18 (permalink)  
Old 03-08-2003, 07:27 PM
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Okay, I think you said it just then. You said it lifted untill the rear bottomed out. That is the problem. At that point the suspension bouces and and you loose it all. It sounds like the coil overs are not set properly or the springs are too soft for the car. The coil overs should be set so that they are mid stroke when the car is setting still. If the springs are too soft, this will not be possible. Also remember, if you reset the ride hieght to correct any spring problems, the ladder bar geomtry will also change. If if fact the springs are too soft or set too low and you raise them, the bars will be pointed more upward, and will hit the tires less. This might not be a bad thing if it is bottoming out rihgt now.

Chris
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Old 03-09-2003, 02:51 PM
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Turbo is right on. As soon as the suspension bottoms out, all bets are off. You need stronger springs to keep the wheels planted.
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Old 03-09-2003, 08:46 PM
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ok guys we will turn the spring nuts up they are very low right now
thanks
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Old 03-09-2003, 11:49 PM
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There should be an inch or so left in the spring travel during a full launch, you can use a short piece of rubber hose cut in a spiral and slipped over the shock shaft to tell how much it has moved after a good launch. Do both sides because they will be different.

Why not move the bar to the highest position?
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Old 03-10-2003, 09:01 AM
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hey 4 jaw
what bar were you refering to
i hope not the ladder bars becouse we moved them down one from the center hole ( 5 holes)to the 2nd from bottom and seem to be making progress
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  #23 (permalink)  
Old 03-11-2003, 03:18 PM
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[quote]Originally posted by strawntech:
<strong>ok guys we will turn the spring nuts up they are very low right now
thanks</strong><hr></blockquote>

Most Coil over shocks have a recommended ride hieght. It is usually recommended that they be right in the middle of the stroke. Be sure you dont get so far up you have problems with topping out. If you have to set the shocks in the top 2/3 of the stroke, it might be a good idea to get some stiffer springs.

Chris
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  #24 (permalink)  
Old 01-21-2004, 12:02 PM
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This might help, whether you're running a ladder bar, 4link, or even a 3link:

Consider a side view of the car. Imagine a vertical line drawn through the front tire patch. Then, a horizontal line through the center of gravity. These two lines intersect at a point above the front tires. Finally, consider a line drawn, from that intersection, through the rear tire patch. Detroit calls this the "no squat/no rise" line. If the rear suspension instant center (pivot point of a ladder bar or the intersection of lines through the upper and lower links of a 4link) falls anywhere on this line, the rear of the car will neither squat nor rise on acceleration. If it falls above, the rear will rise; if below, it will squat.

Since the front suspension links do not carry similar dynamic loads during launch, there exists no similar trick. In other words, the front will always rise. By using "softer" (lower rate) springs at the front, you can get the front to rise even more, of course. This raises the center of gravity very slightly and thus increases the weight transfer.

There is a little trick available at the front which will affect rear tire loading, however. By using a lower rate spring at the left front than at the right, the left front will rise more than the right. This then forces the right rear down (compared to the left rear). The result is a dynamic loading of the right rear, tending to cancel the tendency of the driveshaft torque to unload it. It is necessary, of course, to have adjustable coilovers when taking advantage of this trick, as the lower rate spring will require more compression to support the same load. Note that this is NOT the same as a preload. The load is applied dynamically, not statically.
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