rear panhard bar tech

[redracersmod]

Ok guys I was talking with a fellow racer yesterday about panhard bars and adjustment he said he searched the forum and found lots of conflicting info on adjustment and was left with even more confusion. So maybe someone with more knowledge then I do can help make all of us more informed. Let's start by looking at what each adjustment does individually. What does it do (tighten or loosen and where) if you only raise the panhard bar on the frame? What if you lower it? What about if you only change it on pinion up or down? Lastly both together up or down. Thanks guys

[let-r-eat]

http://www.afcodynapro.com/afco-tech-tips

[Anonymous24]

The panhard bar dictates rear roll center. If running a balanced setup, rarely should the panhard bar be adjusted in anyway.(RARELY!). Keep in mind each track has its own unique setup that is required. I have learned that if you must adjust the panhard bar, it should be equally adjusted on the pinion plate and chassis mount. Adjusting only one side WILL change rear roll center location. Rear roll center should be paired with the front roll center so the chassis rotates upon the same axis.

[redracersmod]

So your saying put it at the recommended height and location and never touch it because it will be right? There is a reason its adjustable its to adjust it. What I'm asking is what affect does it have if you move the frame side up and leave pinion alone. Does it tighten the car does it loosen the car? Does it affect middle or entry or both? What happens if you just move pinion side up?

[Anonymous24]

Yes I am saying once configured correctly, for that specific track, yes leave it alone. As I stated above, the panhard bar dictates rear roll center, and you want the front and rear roll centers paired. Its adjustable because each track requires a specific setup. Flat tracks require roll center placement more to the left than a high banked race track. Adjusting the panhard bar in the manner you are describing may help handling issues, but in reality, your setup may(probably) have a flaw in another area. Panhard bar should NOT be adjusted to correct handling issues.

[Anonymous24]

Also recommended heights are all just educated GUESSES. Every car is different. Base set up sheets are for racers who haven't taken the time to learn vehicle dynamics. They are provided by chassis builders so the racer can be relatively fast without proper education and understanding of how every component works. Balanced setups are CRUCIAL. I have yet to come across a base setup that is truly balanced.

[redracersmod]

Ok so then how do you adjust it to find the correct placement?

[propit21]

would you not want to adjust from heat to main where the track drys out and more roll is needed in the car to help gain rr traction?

[let-r-eat]

Why does NASCRAP make panhard bar adjustments throughout the night? They haven't dialed in their front and rear roll centers?I don't agree with Anonymous24. The front and rear roll centers and their placement is an important tuning tool.

[Anonymous24]

No. As I stated above, the panhard configuration is setup specific per track that you are running. If you need more RR for the feature, you also need more RF. Its crucial to keep the setup balanced. I recommend adding ballast to the right side of the chassis for both the RF and RR in optimum locations to achieve more side bite. There are a few other adjustments that could be made, but adjusting the panhard bar isn't one of them. If you would like more detailed information, please PM me, and we can go from there.

[Anonymous24]

QUOTE=let-r-eat;1807003]Why does NASCRAP make panhard bar adjustments throughout the night? They haven't dialed in their front and rear roll centers?I don't agree with Anonymous24. The front and rear roll centers and their placement is an important tuning tool.[/QUOTE]Its OK to disagree with me. I went to college to work NASCAR or NHRA. I have obtained the education those fellow racers have. Mechanical Engineering specializing in Vehicle Dynamics. I was unable to finish college due to having children. Full time work/full time school/racing every weekend 2-3 nights don't mix. I'm sharing knowledge that is accurate and track tested.

[MasterSbilt_Racer]

I love this thread!

[MasterSbilt_Racer]

would you not want to adjust from heat to main where the track drys out and more roll is needed in the car to help gain rr traction?

Why is more roll needed to gain traction? Do you want more rr traction on exit?

[Anonymous24]

Why is more roll needed to gain traction? Do you want more rr traction on exit?

Excellent question MasterSbilt_Racer. I look forward to the upcoming responses regarding your question.

[redracersmod]

Actually from what I have read is body roll doesn't permote more traction on the RR tire. Correct me if I'm wrong.

[washeduptoo]

IMO body roll doesn't have to create side bite, but side bite does create body roll. Again, JMO and best of luck.

[Anonymous24]

Actually from what I have read is body roll doesn't permote more traction on the RR tire. Correct me if I'm wrong.

No correction needed.

[let-r-eat]

I'm glad you have such high credentials. Could you divulge into the mechanical concepts that justify this? Why would we want to restrict the placement of the rear roll center when we don't have to? The rulebook isn't limiting us?I see no reason to couple the front and rear roll centers in anyway. Providing optimal slip angles for the intended configuration doesn't require us to limit our adjustability.. I'll let Chad Knaus and Chip know they might as well weld up those adjustable mounts. Is their an optimal position for a particular slip coefficient? Sure. Does it change constantly? Sure.I'll take adjustability.

[propit21]

I enjoy these thread great learning, am going to go ahead and take the bait. We found by adding angle in the j bar when the track went dry and slick, it helped with side bite in on entry and middle, considering your panhard bar/j bar doesn't have much effect on exit.

I didn't go to college to become a engineer or do I think I know that much about chassis dynamics so am just going off what the driver have told me and what we have done and seems like it helped. I would love to know other adjustments to make.

What I've have heard or read is that the angle in the bar works as leverage of weight from left to right. You can also move statically your rear roll center up or down or left to right depending on where you mount you bar, angle, or how high or low it is. (Other things also play a part as well) So an easy adjustment for us if we need more "side bite" is just just add angle in the bar whether right or wrong we feel we get good results from that adjustment, it's also easier then moving ballast for us.

[redracersmod]

I moved my panhard up on the frame and left the rear end location the same it seemed to loosen my car.