panhard bar

[malibu43]

hi guys,i wonder if anybody can give me a hand in this topic.
i do race my 80 malibu as road course,and i want to improve the handling ,in the rear end do i need a panhard bar for this kind of race,my rear end its all stock,.
thanks for any help

 

[83LSWagon]

http://www.pro-touring.com/forum/showthread.php?t=46556&highlight=watts+link+g-body
This would be your best bet, but I say run a panhard and see how it does.

 

[Norm Peterson]

You could run a PHB or the Watts link that Marcus at SCandC.com now offers.

BUT . . . you need to keep all OE rubber bushings in the existing UCAs (no poly) AND you need to locate the PHB or WL pivot up at approximately the same height as the UCA ears on the pumpkin.

Failure to do so will put the PHB/WL in conflict with the OE 4-link in roll, and the combination will generate additional roll stiffness just like bolting on another rear sta-bar would do. This is a progressive effect, where being "off" by a little in setting the height (within ~1" of ear height) probably doesn't matter, while being 6" off is asking for trouble (likely in the form of snap-oversteer).

IOW, the only reason for adding a PHB/WL to the converging 4-link is to limit the amount of lateral axle movement under cornering load that you'd get with the OE rubber bushings in the UCAs. Attempting to lower the rear roll center or reduce the amount of rear axle roll steer via an added PHB/WL is unlikely to give you the desired overall result.


If you don't mind me asking, what category do you race/time trial/open track/HPDE the car in? In most forms of sanctioned racing, suspension mods tend to bump you up-class, but open-tracking is still "run what ya brung". I'm also a little curious as to where this might be at.


Norm

 

[malibu43]

Thanks NORM,but am still dont get something right,i´ve read that the panhard bar, can only work with parallel 4 links, not like ours malibu they have triangulated 4 links and its no necessary to have a panhard. am ok in this or its something also that i dont know about this car?.
i will tel you,that i race my bu as road course racing,i have lots of problems with the rear suspension,because the spring cannot be cut to get the desired height,so i swap them for a nissan springs, they are light then oem,and it can be cut,but they are still to soft,my car weight total its 2.797 lbs, very light,my mayor problem its when i make fast left hand turn the rear right wheel its spinning i asume thats why i dont have posi unit,thats why i want to run a panhard bar.do you have pics and how to install in it.
my bests regards from the last country of the world CHILE.

 

[malibu43]

NORM asking your question,its a asphalt road race,the engine its a 350 goodwrench,600 cfm single pump carb,#520 heads iron,1.95 valves,3 angle seats job,local market flat top piston,metal heads gasket,oem hei ignition,home made headers,12 bolts rear end, 4:11 gears from a c-10 light truck,dunlop 225/50zr/15 front,295/50/15 rear.ride height its about 7 inches. what also do you need to knw for help me?.

question,what do you mean "pumkin",snap oversteer,.
thanks again
jorge

 

[malibu43]

hoo i forgot,what is hpde,open track ,sorry am english to basic,just to keep a regular conversation.
thanks again

 

[Norm Peterson]

pumkin - the big casting in the middle of the rear axle that the differential gears, posi, and the gear oil goes into. The UCAs attach to ears that are cast into the top of this thing.

snap oversteer - oversteer that suddenly occurs in the middle of a hard turn. There are a number of possible causes, but trying to use too much throttle is NOT one of them.

hpde - high performance driver education, running on a road course under the guidance of an instructor who is also in the car, at much higher than a street driving pace but not as hard as all-out race driving would be. This also includes the various NASCAR-oriented driving experiences where you follow the instructor who is in the lead car.

open track(ing) - similar to hpde but also includes driving solo (no instructor on board).



Norm

 

[Norm Peterson]

Thanks NORM,but am still dont get something right,i´ve read that the panhard bar, can only work with parallel 4 links, not like ours malibu they have triangulated 4 links and its no necessary to have a panhard. am ok in this or its something also that i dont know about this car?.

You have that correct as far as the geometry requirements go. Four links that aren't all parallel in plan view are all you need, so it's still best to avoid having the uppers end up fighting with a Panhard Bar or Watts link especially when you're driving at race levels. However, a street car that still has all the rubber bushings in the rear suspension and driven moderately hard may benefit more from better lateral location of the axle than it gives away by having too many links trying to do the same job.

Let me emphasize the "moderately hard" part, as autocross or track driving or racing normally exaggerates the flaws without improving the benefits.


BTW, four parallel trailing links plus a PHB is still not a good arrangement for cornering (the four links will argue with each other when the car tries to roll). It's strictly a drag strip suspension arrangement.

i will tel you,that i race my bu as road course racing,i have lots of problems with the rear suspension,because the spring cannot be cut to get the desired height,so i swap them for a nissan springs, they are light then oem,and it can be cut,but they are still to soft,my car weight total its 2.797 lbs, very light,my mayor problem its when i make fast left hand turn the rear right wheel its spinning i asume thats why i dont have posi unit,thats why i want to run a panhard bar.do you have pics and how to install in it.
my bests regards from the last country of the world CHILE.

I would have expected the right rear to spin on a hard right turn before it would on a hard left. Does it also do this? I would investigate the corner weights before trying a PHB. Something has to be way off in order to spin the outside rear tire, whether you have a working posi or not, and needs to be fixed first.

Have you tried to get springs from any of the US circle track supply houses? There is quite a variety of rates and lengths available, and you'll know that two springs with the same part number will be closer to identical than you're likely to get by cutting.

A PHB would be a custom-fit sort of thing in this chassis, but any picture of a 3rd or 4th Gen Camaro/Firebird or a 2005-up Mustang would be a place to start. You do need the brace that's above the bar itself. One other thing - PHB's used for road courses normally attach to the right side of the axle and on the left side of the chassis, which is opposite to circle track use and also the way the above cars are built at the factory.


Norm