Car Unloading Off The Line.
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From: SPRINGFIELD MISSOURI
Car Unloading Off The Line. My car is comming off the line good but then the suspension is unloading and then breaking loose. QA1 Rs in the front and QA1 in the rear. F. set at 2 and the backs at 6 and 7 275lb springs in the front . TArm set at -2 ET slicks at 12lbs with tubes 28x10.5. any ideas on what im doing wrong. Here is a vid of it comming off the line. http://media.putfile.com/john1030 this one I hooked but was squirly out of the hole. here is another race you can look at. http://s177.photobucket.com/albums/w...t=DSCF1040.flv 
Last edited by dnkynrbk; Feb 8, 2008 at 02:22 PM.
On The Tree
Joined: Mar 2002
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From: Northern Kentucky
Try going with 1 in the front, and loosen the rear shocks up a notch at a time.
What kind of torque arm and rear sway bar are you using? I noticed the car squats a bit, excessively on the right side.
I usually keep the pinion angle at -3 degrees as well for a hard hitting track setup.
What kind of torque arm and rear sway bar are you using? I noticed the car squats a bit, excessively on the right side.
I usually keep the pinion angle at -3 degrees as well for a hard hitting track setup.
opposite, tighten up the shocks. you're unloading because the shock is topping out too quicking and taking all the weight off of the back tires before you have enough wheel speed not to spin. also throw some air in those tires
On The Tree
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From: Northern Kentucky
The shocks are designed with a fixed firm compression. Only the rebound is adjustable. With the rebound loosened up it'll come up quicker, but because of the fixed firm compression it stays up and keeps weight over the rear tires. With the standard F-series shocks the shocks come down just as fast as they raise up, they're not the best track shocks. Good point with the air pressure too, that could help. I typically don't run mine below 16 lbs.
I still think the problem is in the rear suspension. A properly built rear suspension wont squat hard (or at all) on launch. It should plant the rear tires hard enough to at least stay level, if not raise the rear end a little on launch. The car is also not staying level out back when it launches and I think a stiffer sway bar would be a big help.
I still think the problem is in the rear suspension. A properly built rear suspension wont squat hard (or at all) on launch. It should plant the rear tires hard enough to at least stay level, if not raise the rear end a little on launch. The car is also not staying level out back when it launches and I think a stiffer sway bar would be a big help.
it doesnt matter how tight the front compression is, once the shock tops out the weight transfer is over.
I'll agree with ya the car is a mess though and prolly needs more than a shock adjustment, thats just a good start
I'll agree with ya the car is a mess though and prolly needs more than a shock adjustment, thats just a good start
On The Tree
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From: Northern Kentucky
The car is accelerating, the weight transfer is still there, obviously not as much as right off the line though. I still don't think transfer is the real problem. Loosening the shocks would be more of a band-aid anyway.
I see a couple things happening. The car is rolling over, I dunno what you ahve on there for a swayber, but get a good on the car first, that will help a good bit, a wolfe, spohn, bmr extreme, or that new trz unit would probably do the trick. This will get the car leaving evenly.
I don't know what you have the tires aired at, but try them at 12 or 13, if you're any lower then that it's definately not helping. Your pinion angle is o.k. Try putting the front shocks at 3 and the rears at 4/5, that is where I have mine (same shocks, same front springs) and it seemed decent the first time out. Where is your tq arm mounted on the front, and do you have relocation brackets, if so what hole are they in? If you have the rear arms pitched too much it will cause some of what you are seeing, try them in one hole down from stock if the car is slightly lowered (like just the rear spring rubber's removed which is how mine is) or if the car is stock height, you may even want to try them in the stock holes, pitching the arms down is good for slower cars, but once you get into the low 10's and faster it starts to cause some problems, some like what you are seeing.
Also, how is the track prep? How are other cars running that are making similar power, good, bad? is anyone hooking and running in the low 1.3 to 1.2 60 foot times there? if noone is, then you may also have a track prep issue and you're trying to overcome that as well.
I don't know what you have the tires aired at, but try them at 12 or 13, if you're any lower then that it's definately not helping. Your pinion angle is o.k. Try putting the front shocks at 3 and the rears at 4/5, that is where I have mine (same shocks, same front springs) and it seemed decent the first time out. Where is your tq arm mounted on the front, and do you have relocation brackets, if so what hole are they in? If you have the rear arms pitched too much it will cause some of what you are seeing, try them in one hole down from stock if the car is slightly lowered (like just the rear spring rubber's removed which is how mine is) or if the car is stock height, you may even want to try them in the stock holes, pitching the arms down is good for slower cars, but once you get into the low 10's and faster it starts to cause some problems, some like what you are seeing.
Also, how is the track prep? How are other cars running that are making similar power, good, bad? is anyone hooking and running in the low 1.3 to 1.2 60 foot times there? if noone is, then you may also have a track prep issue and you're trying to overcome that as well.
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to add to JL's questions, what is the weight of this car? and this is off a footbrake correct?
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On The Tree
Joined: Mar 2002
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From: Northern Kentucky
I see what you're saying, it may help some but I still don't see this being a transfer problem.
It looks like he's leaving on the foot brake. The car is squatting hard on the right side and wanting to walk. I'm betting a beefier rear sway bar would help or adding preload to keep it level if he already has one.
Still curious about which torque arm too.
It looks like he's leaving on the foot brake. The car is squatting hard on the right side and wanting to walk. I'm betting a beefier rear sway bar would help or adding preload to keep it level if he already has one.
Still curious about which torque arm too.
oh yeah, I agree I think an anti-roll bar will definitely help. I just didnt comment on it due to the fact I have no direct experience with them. I'm still rocking a Hotchkis 1" bar 
On The Tree
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From: Northern Kentucky
I've been using the Wolfe single bar for a couple years on my Formula and I like it. When I swap rears on it I think I'm going with the BMR or Spohn. I need something that's a little less in the way and removeable.
The car needs an antiroll bar for sure. The control arm angle also has alot to do with the weight transfer, if they're too steep it will transfer a ton initially, which would also cause alot of the unloading that I am seeing happen.
First thing to do, get the front shocks to 3 or 4, rears at 4 and 5, rear tires at 12 psi and put a good anti-rollbar on the car, and try again. I guarintee that gets the car a Ton better off then it is right now.
First thing to do, get the front shocks to 3 or 4, rears at 4 and 5, rear tires at 12 psi and put a good anti-rollbar on the car, and try again. I guarintee that gets the car a Ton better off then it is right now.
fwiw, video in my sig, that's with the front shocks @ 5, rears ar 4/5 12 psi in a set of 28x10.5S et drags, 275 lb springs on the front, r series front shocks, 12 way rears, wolfe drag bar, bmr stock lenth tq arm, -2 pinion angle. It still has a bit left in it, I was spinning off the transbrake some, and that was at 3500 lbs... I suspect coming out this year at 3200 lbs and going from a 4.10 to a 3.73 gear will help it hook better, transbrake goes to 5400, a little much for a 480 rwhp+100 to 150 hit of nitrous, but it's working o.k. IMO considering that video is only the 4th run on the jug.
...and going mid-10s?? Impressive. A little risky for my blood, I want my **** straight off the line.
I've been using the Wolfe single bar for a couple years on my Formula and I like it. When I swap rears on it I think I'm going with the BMR or Spohn. I need something that's a little less in the way and removeable.
I've been using the Wolfe single bar for a couple years on my Formula and I like it. When I swap rears on it I think I'm going with the BMR or Spohn. I need something that's a little less in the way and removeable.
Make sure you dont have something going on with a LCA bushing or the like. Maybe the angle of the camera and the wheel offset but the rear end almost looks crooked in the car. Do some measurments from the lower rear of the doors on the car to the front of the front of the rear tire, along that bodyline with the tires aired up to 25 psi or so.
Also make sure the rear is centered in the car side to side.
If all that is good. Air the rear tires up to 14, put the rear shocks on max firm, the fronts on 5 and work from there. Loosen the fronts up one click a pass if needed. Do a GOOD burnout.
Mine is on slicks now, 28x10.5W, with 14 psi, no tubes, leaving at IDLE! I went a 1.55 60ft last night, only got one pass, all the rednecks blowing up ****.
My car runs 10.90 all motor at 3800lbs....it runs straight as an arrow with 14 psi in the tires and no tubes.
I have a stock rear swaybar.
David
Also make sure the rear is centered in the car side to side.
If all that is good. Air the rear tires up to 14, put the rear shocks on max firm, the fronts on 5 and work from there. Loosen the fronts up one click a pass if needed. Do a GOOD burnout.
Mine is on slicks now, 28x10.5W, with 14 psi, no tubes, leaving at IDLE! I went a 1.55 60ft last night, only got one pass, all the rednecks blowing up ****.
My car runs 10.90 all motor at 3800lbs....it runs straight as an arrow with 14 psi in the tires and no tubes.
I have a stock rear swaybar.
David
Last edited by FASTFATBOY; Feb 2, 2008 at 07:46 AM.
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From: SPRINGFIELD MISSOURI
sorry guys been a away to response. Just put a wolf rollover bar on this last month and havent got to test it out. I have a UMI chasis mount torque arm. and running 28.10.5 et slicks with tubes at around 12lbs of air. This is probally the best 60ft I have had at a 1.48 with this run. Track prep there sucks too. Foot braking at 1800rpm if I foot break any higher the car just breaks loose and spins. Seems like the car raises then feels like a good launch then it unloads and the car breaks loose.
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From: SPRINGFIELD MISSOURI
also I have deleted the sway bar off the front. too. I will post a pic of my car on the lauch from the front tonight. I have r series in the front and think F in the back on the shocks.