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 Post subject: Rear Spring Rates
 Post Posted: Mon Aug 16, 2010 7:39 pm 
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Location: nw ohio
So I was wondering what rear spring rates everyone runs. I have 110lbs on the rear of the nova and i am thinking they might be too stiff. 1225 lbs on the rear. would like some opinions.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Mon Aug 16, 2010 8:01 pm 
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Location: Shepherdsville, KY
What you have sounds about right to me. I have 110s on the rear of mine with about 1200 rear weight and just uner 2,300 total. I had some lighter ones on it before (I think 95s) but found they were too light.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Mon Aug 16, 2010 8:46 pm 
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Location: Benton, KY
I got about 1120 on the rear and run 85lb springs


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 Post subject: Re: Rear Spring Rates
 Post Posted: Mon Aug 16, 2010 10:00 pm 
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My car is around 1250lbs on the rear tires and I had a severe handling problem with 95lb springs on it. I got like a 125 or 130lb CE spring on the back now and the handle problem went away. What was happening was the rear wing was loading the springs so much down track that by the time I got to the 330 timers the shocks were bottoming out. After the spring change I had .5 to .750 from the shock hard stop.

Studebaker weighs 1860lbs on the rear tires and it's got 150lb springs in it.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Mon Aug 16, 2010 10:31 pm 
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1175lbs on rear tires, total 2400lb whole car. 175 lb/inch sometimes and other times 200lb/inch springs on rear.


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 Post subject: Re: Rear Spring Rates
 Post Posted: Tue Aug 17, 2010 3:34 am 
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Location: Tell City, IN
1100 lbs on the rearend and have #130 springs. Have tried 95 and didn't work at all for me.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Tue Aug 17, 2010 5:22 am 
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One thing I found out is you can run a lighter spring if you have longer shocks. =;
Another thing is it also has to do with how your 4 link is set up also. With more anti squat you don't need a lot of spring...IMO anyway but if you disagree tell me #-o

Same as Chuck 110's on the rear......

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 Post subject: Re: Rear Spring Rates
 Post Posted: Tue Aug 17, 2010 8:06 am 
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Rear weight on the dragster is ~1300# and 110# springs (11 or 12") and it had 110# 14" springs when I bought it and the rear weight would have been ~1500# with the BBC it had previously. Talk about a bitch, try taking 14" springs off a 12" shock.

When a fast car launches, the entire weight ends up on the rear tires so static sitting weight is only part of it. 4-link settings like Barry mentioned should carry part of that weight. What the anti-squat pct is will change how much weight the bars are "lifting" during the launch.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Wed Aug 18, 2010 1:56 pm 
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Barry and Rick got a handle on this. There is something else involved. How far from center line of chassis the springs are mounted has some effect also, depending on roll center. Springs that are in farther from tire center line have a softer spring rate at the tire. This is mostly for street driven cars but air buffeting at higher speeds can set up an oscillation problem, if the spring is too soft. The oscillation can increase/decrease wheel weights from side to side. Don't forget, spring rates are not spring rate at the wheel. Example Front spring on a GM car is way higher than a Ford to get same wheel rate. Because of where the spring is mounted on the control arm. A spring on top of rear axle or in front of is softer at the wheel than one mounted behind rear axle. You can use math to figure this precisely. Roll center height also effects spring rate to some extent. It has to do with the angle of force on the tire. This is much the same as your instant center, only side ways. Just something to think about.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Wed Aug 18, 2010 5:14 pm 
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thanks for the info guys. it just seems like to me the car is bouncing off the line and not really hooking so to speak. im getting lots of tire spin. gonna have to do somemore research i guess. it acts like the springs are too stiff.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Wed Aug 18, 2010 8:01 pm 
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If it's bouncing at the hit then it's unloading the tire. Stiffer shock settings might help and also different IC on the 4 link to slow down the hit.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Thu Aug 19, 2010 5:57 pm 
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thought it might be better to just watch it lol \:D/ if you listen you can hear the rear tires spinning still at the end of the video until it goes into high gear. thoughts? (click on it to play the video)

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 Post subject: Re: Rear Spring Rates
 Post Posted: Fri Aug 20, 2010 10:12 am 
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My personal thoughts is your ic is too long and low. It just not lifting at the front at all , its trying to and then it just gives up and unloads and spins. Unless you have it tied down in the front I would suggest an ic or anti squat (what ever you want to call it ) =; change.

I have been through this myself with my car here is some video of it doing about the same thing and then after the ic was moved.

edit I just saw your slow mo videos and you have not got hardly any separation at all your ic is way to long or shocks are set way to tight.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Fri Aug 20, 2010 4:56 pm 
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thanks for the videos. you can really see a difference in the way your car leaves. i'm gonna play with the shock settings a little this weekend if it doesn't rain again and see if i can get any improvement. im thinking you guys might be right i will probably have to change the four link some though. On a side note, what did you do to pick up 4 tenths like that? \:D/ im running 5.60's now spinning like your first video lol. my car is set up for 1/4 mile though.

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 Post subject: Re: Rear Spring Rates
 Post Posted: Sat Aug 21, 2010 1:58 am 
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Location: Benton, KY
Those are different engines a 466 and a 533 the extra power made the car work better. The best it ever ran with the 466 was a 5.51. It did work better after moving the 4 link some and I think there probably was a better setting that it could have worked better at , but the 533 came along =; .


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