4-LINK setup

[lvsalt]

DCWATERJET Z, car has been 220mph
weight 3600lbs - weight with driver
LF - 817lbs
RF - 811 lbs
LR - 1027 lbs
RR - 945lbs
600lbs of ballast

 4LINK
instant center length 62.75" instant center height 13.07"
600 lb springs

 Car steers where you point it but could use some help hooking up, we have plenty of power were not using.
 4 link setup ?
more weight on rear ?
any thoughts ?

 Thanks GARY

[Sumner]

DCWATERJET Z, car has been 220mph
weight 3600lbs - weight with driver
LF - 817lbs
RF - 811 lbs
LR - 1027 lbs
RR - 945lbs
600lbs of ballast

 4LINK
instant center length 62.75" instant center height 13.07"
600 lb springs

 Car steers where you point it but could use some help hooking up, we have plenty of power were not using.
 4 link setup ?
more weight on rear ?
any thoughts ?

 Thanks GARY

A thousand more pounds, but keep the front/rear balance the same as it is now if the car goes straight when you spin the tires.  If the back is coming around then put more in the front.  Of course this is just a guess without knowing more about the car,

Sum

[jl222]

    Ivsalt
   The 222 camaro has a four link also. The top bars are mounted in the very top holes the bottom bars in the very bottom this results in an instant center in front of the car.The rear springs are 110lbs. ProChassis didn't want us to change from 88lbs. but we added a big intercooler tank and water tank. the two weight boxes are full of lead,maybe to much.The car weighs 4680 lbs,3000lbs on rear 1680 on front.We have gone 288 mph at bville with a 279 exit speed and several times over 267+ We hold the AABGALT at El Mirage at 229 mph. I bought new 800/820 tires for it last year because i thought the old ones were getting to old, but get this, they still had the tits on them. We also run a 10 inch spoiler but almost flat which helps downforce. We can spin the tires in low gear but once in second it hooks up.
  As i've posted before if you want to spin the tires, mount the rear end solid, or install a four link or other type of suspension with the instant center in the wrong place with too heavy springs.
  You can view the car in build diarys [Getting ready for bville]
                                 

[lvsalt]

So your suggestion would be lighter springs and move instant center in front of car
for a starting point ? we dont have alot of places to put more weight but we could
probably fit a couple of hundred more pounds.

 Thanks Gary

[Sumner]

   ..............................The rear springs are 110lbs. ProChassis didn't want us to change from 88lbs. ......................The car weighs 4680 lbs,3000lbs on rear 1680 on front......................

Hi John, good stuff and I've talked to others that keep the rear soft for better bite and like that approach.

I do have a question with 3000 lbs on the rear, 1500 a side let's say and with 110 lb/inch springs it would seem like you would be into coil bind unless the springs are really long.  I would think that you would compress a 110 lb spring something like 13 1/2 inches with 1500 lbs on it.  I'm interested as we are maybe making new spring choices for Hooley's Stude.

Thanks,

Sum

[jl222]

  GARY
  It works for us. With 600lb springs it would take 1200lbs to compress them 1" pretty high wheel rate. If you push down on the rear of the car it probably does't move.I would run some weight in the rear to make sure the car doesn't have lift at high speed.
  correction on still having the tits on the goodyears, the old tires had raised nubs on them about the same size has the wear holes,thats what i was talking about.The new goodyears are different.

[jl222]

  Hi Sum
 Yea it doesn't add up but i got out my Alston book to check the spring rates part #181614 110lbs 12'' long  blue. 21/2 inside diameter. Looks like we have them screwed up to around 111/2 ''
  When we push on the rear of the car it moves down with little effort and the front comes up.
   How is that lakester coming? Hope to see you at Bville
   You keep me on my toes and back,had to jack up the car and check things.

                                   JL222

 

[hitz]

  Hi Sum
 Yea it doesn't add up but i got out my Alston book to check the spring rates part #181614 110lbs 12'' long  blue. 21/2 inside diameter. Looks like we have them screwed up to around 111/2 ''
  When we push on the rear of the car it moves down with little effort and the front comes up.
   How is that lakester coming? Hope to see you at Bville
   You keep me on my toes and back,had to jack up the car and check things.

                                   JL222[/color]

John,

  I'll probably catch hell about this but here goes:

  As you screw up on your springs, your car will lift. The space at the spring will stay the same with the weight of the car on the ground If you angle the shock away from perpendiular, it will lower the car and make it softer. It you want to make the suspension stiffer at the same height with the the same shock position, you put stronger springs in. IMHO

  Harv

[Sumner]

  Hi Sum
 Yea it doesn't add up but i got out my Alston book to check the spring rates part #181614 110lbs 12'' long  blue. 21/2 inside diameter. Looks like we have them screwed up to around 111/2 ''
  When we push on the rear of the car it moves down with little effort and the front comes up.
   How is that lakester coming? Hope to see you at Bville
   You keep me on my toes and back,had to jack up the car and check things.

                                   JL222

Thanks, what is your front spring rate (on you back time again??  )??  Are your front springs carrying some of the rear weight??  I didn't understand the "screwed up to around 11 1/2"?  Do you have them compressed 1/2 inch with the tires off the ground??  What was the compressed height if you remember?? Don't get under there again!!

I'm back to working on the lakester every day.  I'll keep on it, but don't see it running in August.  Maybe up there to get teched if I want to spend the money on the gas for that.  Hopefully maybe running in Sept. or Oct. with the stock 750 motor.  I'll be at Speed Week for sure with Hooley and will look for you guys and hopefully see you run well over 275 this year.  You have put a lot of work into that car and it is time for 2 good runs.

c ya,

Sum

[jl222]

  Hi Sum
 I was just getting ready to clarify the spring height when i read your post. The spring lenght of 11 1/2'' is with the car jacked up by the rear bumper and the rear end in full droop.Any how i got to thinking that could be missleading,so i jacked up under the rear end this time and measured the compressed length of 7 1/2'' that gives 4'' settlement. You got me worried about coil bind so i grabbed an end wrench that fit just right between the coils 10 coils x .230'' thickness of wrench= 2.3 '' of compression left. Some of the springs at the top and bottom were to tight to get the wrench in so their is at least 2.5'' before coil bind.
  Hope this clears things up
                                            JL222                   

[Sumner]

  Hi Sum
 ......................You got me worried about coil bind ............ JL222 

Don't worry I worry enough for the both of us and a few more  ,

Sum

[jl222]

  Hi Hitz
   Your right about raising the bottom spring pad will raise the car, our shocks are adjustable so when we tighten them it raises the car, it also shortens the spring and gives it more spring rate. Picture a bolt and nut as you tighten the nut the distance gets shorter.
   Shock placement does make a difference,our shocks are mounted in front of the rear end giving more leverage on the springs.While i was checking things out to day,measuring at the fenderwell and center of tire i got 3.5'' of travel before the tires cleared the floor, but the springs compressed 4'' due to the motion ratio.
  Were's Anderson CA                    
                
                                                 JL222

[lvsalt]

Hi John

 Thanks for the info. I know every car is different but how far in front of your car is your instant center?
We will probably try some softer springs and weight also

 Thanks Gary

[jl222]

   Gary
 You got me thinking on spring rates and i came across alston's basic way to find them. Take the total rear weight and subtract the unsprung weight [ 100% of the rearend- tires- brakes and 50% of the shocks -springs-4 link bars and driveshaft -track locater.any thing that's attatched to the chassis] and divide by six.
   1972lbs-385lbs=1587 divided by six =264.5 lb springs. 385 lbs estmated from his example in book.
He also said this is for Alston chassis using koni shocks with 12'' springs.Any how 264.5 x 6=1587lbs.
 Using your 600 lb springs times six=3600 lbs.
 These rates don't add up for our car but using a softer spring lowers the car and gives a softer hit to the tires.
  Hope this helps and hope to have instant center info soon. I located the 4 link heights and lengths so hope to scale it soon.

                                                       JL222

[lvsalt]

Thanks John

 Im In Gardnerville NV, And our car is in Las Vegas at my dads, I dont remember the name of it but i will find out. We have a software program for the 4-link where you put in the numbers and it gives you the IC and IC height. I think it was $80, saves alot of time so you dont have to draw out your setup on the ground. We use Afco coil overs in the back I think there  12" X 2 1/2" springs. They have a large selection of springs on there website so we should be able to pick up some more springs.

 were you involved with the ZIP CODE top fuel car?

 Thanks Gary