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Old 04-30-2013, 11:24 AM   #1
Brad87gt
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Default Position of instant center effects on chassis

Say I have an instant center of 50" and it's 9" high. What should happen if I take that same 50" instant center and move it to a height of 15"? What should happen here more anti-squat?
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Old 04-30-2013, 12:38 PM   #2
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Default Re: Position of instant center effects on chassis

This is my understanding----

By raising the height you will raise percentage of anti squat. But this will be difficult to achieve with out changing the length.

By shortening the length you will affect how quickly the rear end can react at the launch.
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Old 04-30-2013, 12:56 PM   #3
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Default Re: Position of instant center effects on chassis

Well my instant center is short I have adjustable upper brackets to get the upper facing down. The lowers are almost perfectly level. So the instant center is short but very low. I was going to raise the rear of the car to raise it up some but I was not sure what the effect would be.
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Old 04-30-2013, 01:09 PM   #4
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Default Re: Position of instant center effects on chassis

http://www.shopeshop.org/tim.47.htm


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Old 04-30-2013, 01:09 PM   #5
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Default Re: Position of instant center effects on chassis

Quote:
Originally Posted by Brad87gt View Post
Well my instant center is short I have adjustable upper brackets to get the upper facing down. The lowers are almost perfectly level. So the instant center is short but very low. I was going to raise the rear of the car to raise it up some but I was not sure what the effect would be.
You will be changing more than just the CG you will be changing the IC at the same time
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Old 04-30-2013, 01:24 PM   #6
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Default Re: Position of instant center effects on chassis

Yes I think I want to raise the instant center height in order to raise the anti squat %
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Old 04-30-2013, 01:26 PM   #7
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Default Re: Position of instant center effects on chassis

Thanks for the link!
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Old 04-30-2013, 08:08 PM   #8
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Default Re: Position of instant center effects on chassis

i've learned alot lately suspension wise and im still semi confused but i think if you raise your a/s youll be asking for problems hitting the tires hard

the lowers should be 1/8'' uphill to body or as close to it as possible w/o going downhill to body. are your uppers adj on the body side or housing side?

before i forget....what tires? shocks? struts? spring rates?
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Old 04-30-2013, 09:02 PM   #9
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Default Re: Position of instant center effects on chassis

Quote:
Originally Posted by Brad87gt View Post
Say I have an instant center of 50" and it's 9" high. What should happen if I take that same 50" instant center and move it to a height of 15"? What should happen here more anti-squat?
Raising the IC height will increase the weight transfer.
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Old 04-30-2013, 09:07 PM   #10
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Default Re: Position of instant center effects on chassis

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Originally Posted by 86lxnotch View Post
i've learned alot lately suspension wise and im still semi confused but i think if you raise your a/s youll be asking for problems hitting the tires hard

the lowers should be 1/8'' uphill to body or as close to it as possible w/o going downhill to body. are your uppers adj on the body side or housing side?

before i forget....what tires? shocks? struts? spring rates?
With me in the car my lowers are 1* up towards the chassis. My uppers are adjustable on the rear housing (auto fab kit). I run a 26x10 et drag. I have strange single adjustables front and rear. 12" 130# springs in front, stock coil spring in rear with one coil cut. It is a stick car and has go e a best of 10.16 @134 I want to go 9.99 it only 60' in the low 1.50's last year I have not ran it with the adjustable uppers yet...
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Old 05-01-2013, 09:46 AM   #11
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Default Re: Position of instant center effects on chassis

The trans will make most guys comments from autos 180* from what you need, Clutch issues are a balancing act, how you launch it will make a lot of diff
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Old 05-01-2013, 11:03 AM   #12
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Default Re: Position of instant center effects on chassis

I understand. From what I see anti squat well over 100% is needed with a small tire stick car.
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Old 05-01-2013, 11:18 AM   #13
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Default Re: Position of instant center effects on chassis

I VERY GOOD SHOCK IS NEEDED
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Old 05-01-2013, 11:19 AM   #14
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Default Re: Position of instant center effects on chassis

I'm assuming my s/a strange shocks won't cut it...
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Old 05-01-2013, 11:35 AM   #15
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Default Re: Position of instant center effects on chassis

I don't think so, the Hit at the start is going to be very hard and the harder you make it hit the more the tire is going to want to basketball back up, your going to want to curb the hit to start then hold it till you shift, then it starts over, this to changes if you have a adjustable "slipper" clutch.
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