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Author Topic:   No Forward Bite or Sidebite...Help!
mod7
Member
posted June 24, 2003 10:53 PM
Just wanting to get some help. The car is a DW-8 with short arms and short panhard bar. Springs are 150rr, 200lr, 750rf, 650lf. Shocks are 92's on rear and 75rf and 74lf. The pull bar has a 700# spring. The car has zero forward bite and gets in a drift in the middle of the turns. I raised the ride heights on all corners for fear of the track being rough due to all of the rain. The ride heights are 5 1/2 lf, 5 3/4 rf, 6 lr, 6 1/4 rr. Just my thinking, maybe the ride heights are to high and not transferring the weight to the rear? Had 50# ballast and full of fuel. The track had semi good bite in it and with the short bars and short panhard bar, I figured this would be a rocket. But I went from the front to the back FAST. This is was my first week on the short bars. Help! Thanks for the replies and help it is greatly appreciated.



rocket36
Member
posted June 24, 2003 11:14 PM
I'have zero experience with modifieds (late models only) but here goes...
Lifting the ride height is actually a bigger deal than most think and I learned the hard way too. By raising the ride height you will be changing everything. Your front end alignment (camber, toe) will change dramatically (as well as your roll centre) so you would need to reset that.
By screwing weight adjusters down (equal distance on adjusters) your corner weights (cross %) will change because of the different weight springs. And the rear panhard bar angle will change as will the roll centre. So you may have opened a can of worms.
Reset your ride heights to manufacturers specs so that all the suspension geometry is correct.
You may need more angle in your panhard bar... that should help in the middle which will obviously effect the exit.
could also try lifting the right top rod (if its a 4-bar) at the frame.
Maybe a little more cross weight (but not sure)
I should have asked this earlier, are you sure the problem is in the middle, if your experiencing the problem (loose) while in the middle, the problem may actually be on entry?
Your rear shocks seem extremely soft. You would think to the advantage but it might be producing inconsistancy.
Let us know what you try and how it goes.

[This message has been edited by rocket36 (edited June 24, 2003).]

uforacing51
Member
posted June 25, 2003 02:14 PM
Rocket is right,
Be in the mood for a long haul, I spent 3 evenings or a total of 16 hours scaling my car. If you don't have scales, get access to some because the percentages are as important as the springs and shocks as well as the rest of the stuff you talk about.


wfoondirt
Member
posted June 26, 2003 02:27 PM
Reset you ride heights to dw's specs. A 1" change in ride heights makes a huge difference in suspension geometry (mostly for the bad in this case), especially with the short trailing arms. Did you scale the car when making the changes?
As a side note, higher center of gravity increases weight transfer.

WIthout further details this is about all i can say

mod7
Member
posted June 26, 2003 02:42 PM
No I didn't rescale the car after I raised the ride heights. Usually I do, I was just pressed for time. I have lowered them back down to the recommended heights and rescaled it. The numbers that I have now will work. They are 52 cross, 59 rear and 65 left rear. I think when I raised the ride heights that is where the problem was. After I thought about it, I not only changed the heights, I changed trailing arm angles, pull bar angle, panhard angle and front end settings, too. Guess that was one of my bonehead moves this year!


dluna
Member
posted June 26, 2003 07:23 PM
We had the EXACT same problem with the 4 wheel drift. Running on a REALLY rough track so we raised the ride heights all 1". The car had NO side bite at all. Every turn we had to just wait until it finally stuck enough to get back on the gas, then go. I don't understand exactly why the side bite would go away because it puts MORE angle in the panhard, which should increase side bite by lowering the rear roll center? Perhaps the change on the front roll center is the main reason??? Also with the higher CG, wouldn't that stick a lot of weight on the RR with the increased weight transfer, making the RR stick more? Sorry guys, still learning here!!! Thanks


WPP
Member
posted June 27, 2003 11:51 AM
I run a dw and i also raised my ride heights 1 inch last year i ran what dw calls for but if you run ump tires you need to set the ride heights about 3/4 to 1 inch higher i lowered the rear control arms down 1 inch and the panhard bar a 1 inch lower on the pinion but i have notice the car was a little bit loose going in i may try to lower mine a 1/4 to see if there is a change how the car enters the corner but i run a 4 -bar lr spring behind and a z-link right rear with spring hooked to the birdcage in front with a 700 rf spring and a 650 lf i have been reading the post about a stiffer lf and i have thought about running a 750 on lf but the car is good except going in


dirtbuster
Member
posted June 27, 2003 12:45 PM
Bar angles do not change if the only thing you change to affect ride heights are the tires. As long as you dont turn the jacks the suspension will be in the same relationship just a little higher off the ground with the bigger tires. If you set the car up to DW specs with imca tires then swap to the hoosiers the car will be 1/2-3/4" higher only bacuse of the difference in tire diameter.


WPP
Member
posted June 27, 2003 05:12 PM
I see what your saying i only use ump tire so i set my height with ump tires i also set the control arms lower because i know my ride heights are higher i do this because were i will not bottom out the shocks plus the arms are short but i would like to have some imca tires to set the ride heights


MOD75D
Member
posted June 28, 2003 11:47 PM
I could be wrong but would'nt adding a little lead or just moving some lead higher in the rear help the side bite?


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