My experiences from modding my pan-hard

[Sam-Q]

I thought guys might find this interesting as people rarely seem to talk about the importance of the pan-hard.


Now first up all of this is with the following:

ae86 with 4.9kg front springs/4kg rear

whiteline anti-roll bar


I used to have a problem where around any long or short corner with any sort of load on the car the back end would squat down and feel like it was having huge tyre roll, like having 80 profile tyres back there. This would then cause it to have unstable oversteer and felt like the back of the car was doing it's own steering into the corners exagerating any steering input I gave it.

I had a custom modded to be adjustable pan-hard with the original hard to remove rubber at the body end and a two piece polyurathe bush on the diff end.

I tried a selby anti-roll bar in the back, put the poly bushes back in the top left trailing arm (had a drilled out rubber bush) and went to the 4kg springs at the back- it helped it a bit but it was clear it was just covering something else that was wrong.

So I changed both the bushes on a stock pan-hard to a harder one piece type from AJPS which was then installed. This made a noticable improvement in stabilising the back even though my bushes where already relatively stiff.

So with this progress I bought a 20mm rod end and fitted that to the diff end of the pan-hard. On testing this has made the rear so stable and flat that it now pushed the front to give it much more understeer than before. I find this amazing as this is a drastic difference just from going from a stiff polyurathe bush to a hard bush and it's exactly what most people seem to be using already.

So next on the agenda is modding the bar again. I am considering making a new bar that's either made from scratch that's stiffer all round with rod ends in both sides or I impliment a 5/8" rod end into my existing bar. I am likely to go for the later with some bracing. I originally never wanted to have a solid joint on both ends but it looks like there is to much to gain from it for the noise/vibration that will come from it.

I will also try removing the top left hand trailing arm, removing the anti-roll bar in place of the original with my own custom bushes and links and also lowering the front of my car another 5 to 10mm.

I couldn't find them in time but I do also need to fit a rubber boot over the rod-end as I don't want it to wear any quicker than it has to.

I posted this thread here as even though it's not a technical question I thought people would find it insightful, perhaps in the technical articles would be a more appropriate area. Peoples own opinions are also welcome.

[keiichi]

how does adding solid bushes in the rear push the front?
also, where do you get your rod ends from?

[keiichi]

also, we need someone on here to test anti-squat... i really want to build a boxed in 4 link for my corona and test different setups and see how much improvement one can get for drift in an underpowered car. although im selling said car cause i cant work on it anywhere :S

[keiichi]

oh and my experience modding my panhard was back in '05. i fitted a ke70 diff to the rona cause i didnt knwo how to weld the rona one but the panhard was too long so a put a 45deg bend in it. it wasnt very stable.

[Pidgey]

My only experiences with panhards are having to bend back/ fit new panhards to my friend's Nissan Patrol, from hitting gutters and the like. Patrols love being sideways.
But, I didn't think modifying/ putting stiffer bushes in would have such a profound effect.
Will definitely be going adjustable with decent bushes on the skyline.

[Sam-Q]

how does it make it understeer more? good question as the two seem unrelated and while it's easy to understand on how it it feels it's harder to explain.

What I could feel before is the back would lean and grip more however in an unpredictable fashion. I don't fully understand why because just the theory of the diff moving either way should not account for the change.

Now it feels like the back is much more flat on the road and has had more or less the same effect as stiffer rear springs.

I better add this isn't just a little bit of a feeling on what's going on, just going from the poly bush to the rod end has had such a drastic effect that I am sure a non car person would be able to feel it in the passeneger seat if they had been through this corner a few times before and after. I will also add this is all at only about 50km/h through some tight bends and the effect would be much more pronounced at higher speeds, I just have not had a chance to test it better yet. Sounds like the main dog-leg at Winton racetrack needs a revisit.

I purchased my rod ends from "Bearing wholesalers" in Bayswater Vic for only $20 inc GST which is strangely cheap considering their 14mm size is $22 each and they are $26 off ebay with some serious postage cost. The thread is 20 x 1.5mm and they look quite well made. The rubber boots where sourced through ebay but they have not been fitted yet.

I am going to check how much my pan-hard flexes compared to a 25 x 1.6 ERW pipe and if it's simular I might go for that to make a new one up. This way if I don't like the effect of two rod ends I can go back to what I have now.

[Sam-Q]

also, we need someone on here to test anti-squat... i really want to build a boxed in 4 link for my corona and test different setups and see how much improvement one can get for drift in an underpowered car. although im selling said car cause i cant work on it anywhere :S

I tested it about 4 years ago before these bolt on kit's became available, the effect is only relevant off the line and is irrelevant to drifting as there wouldn't be any torque reaction off some wheels that are already spinning. Besides I woudl of thought you would want more squat geometry in a drift car.

For me I lowered the diff mounts about 50mm, this helped me get more traction from a standing start but no-where else. Now being the way I am I want to push the limits as much as practially possible. So what I have in mind is I use some 5/8" (15.8mm) rod ends for the diff end lower trailing arm joints which should have a smaller outer diameter than the original tubes and bushes off the arms. From here I would extend my brackets once again so that the bottom of the rod ends are about 105mm off the ground. So still legal height wise but with the greatest amount of anti-squat.

I will make this the nominated pan-hard tuning thread.

[spoon]

sounds like what ive been putting up with in my KE - kindve snap oversteer - might be worth looking into, my panhard is due for an upgrade! keep us posted on progress!

[Sam-Q]

yes it does feel like that, and very uncontrolled at that.

For once I will have more updates.

[shift_rook]

same you forgot to mention the most important thing, when talking panhard length don't forget to say your spring lengths :)

[keiichi]

I tested it about 4 years ago before these bolt on kit's became available, the effect is only relevant off the line and is irrelevant to drifting as there wouldn't be any torque reaction off some wheels that are already spinning. Besides I woudl of thought you would want more squat geometry in a drift car.

For me I lowered the diff mounts about 50mm, this helped me get more traction from a standing start but no-where else. Now being the way I am I want to push the limits as much as practially possible. So what I have in mind is I use some 5/8" (15.8mm) rod ends for the diff end lower trailing arm joints which should have a smaller outer diameter than the original tubes and bushes off the arms. From here I would extend my brackets once again so that the bottom of the rod ends are about 105mm off the ground. So still legal height wise but with the greatest amount of anti-squat.

I will make this the nominated pan-hard tuning thread.

yes in theory having full anti-squat would be worse for an underpowered drift making harder to spin the wheels, i also thought that maybe it would actually have the effect any throttle input seeming more responsive... but not tested though.

i also wanted to test a full equal length and parallel setup in both links and panhard so there is no left/right movement and turning of the diff.
i think , for grip, you want the top links pointing up so you get the effect of all wheel steer as you go round the corner.

but this is a panhard discussion, dont have much to contribute i'm afraid. you should check what angle your panhard is and if it isnt level try getting it level and see if that makes the rear end even more stable.

bit off topic sorry but i also always wanted to know, how low can you lower a car before it becomes pointless and detrimental or is it all correctable and an overall better thing because of a lower center of gravity?

[assassin10000]

Sam, you want anti-squat as the weight of the car shifts back and pushes the body downwards, having anti-squat forces the cars suspension to leverage against that weight and pushes the tires even harder into the ground gaining more traction, to an extent. Plus the anti-squat effect keeps the cars attitude more level when on the gas lightly through corners helping prevent from unloading the front end which can lead to understeer where you don't want it to happen.

This is good for BOTH grip and drifting. That's why I prefer traction brackets on my car, even when the tires are spinning it allows more stable overall grip and acceleration which can be used.


Going back to the panhard and stiffer pivot points helping... I think of it like this, the softer bushings allow the diff to move left/right more. That movement will change the articulation of the 4-link itself to a certian degree and causes the diff to 'twist' more when loaded in a turn, which I think causes the outside tire to unload some. Due to the shorter unequal length upper 4-link/control arms. It's effects may even oscillate during the turns if the panhards pivot points load/unload due to grip level of the tires changing/skipping/etc, leading to an unstable feeling. Removing that sideways movement prevents that additional twist/side load on the 4-link and allows the rear to stay more level/planted in both feel and mechanical grip.

Andrew

[Sam-Q]

ok I am finally back

keiichi: my pan-hard is level as it is. It appears that in standard form the bar leans down to make the bar level during suspension compression. You can correct the front of a car from any level of lowering if you keep adding thicker roll center adjusters however you need to run bigger diameter wheels to fit them. As for the struts they need to be shortened to allow for the damper valving to still be in the ideal position. The back is harder and unless you chop into the floor your limited as to what you can do.

Assassin: thanks for having a go at explaining what I couldn't. Your description sounds accurate of how it feels and it did feel unstable in an unpredictable way when driving. I now have lowered the front of my car 5mm lower to compensate for the lack of 'rear steering' I had and it seems to be a good set up so far. It is however going to take a lot to get used to as my previous driving style would be such that I have a sharp turn in and then ease it off when the back moves by itself- I guess I was almost using a drifting style of steering without wheel slip to go the fastest.

I am familiar with the anti-squat concept which is why I want to push the limits and get the most out of as I ca. The effect is subtle though even from a large adjustment such as mine so I don't believe that you will feel it unless your in first or second and with a lot of grip, or else I just don't think you can get enough of a torque reaction to do anything.

I am in the process of making/getting made another pan-hard but this time made from scratch and with twin rod ends. It will be on car adjustable with a 20mm rod end for the diff side and a motorsport 5/8" for the body side. I took a chance and have 5 at once on the go for anyone else I meet who wants one if it works out.

[Sam-Q]

time for an update:

I have now gone to a double rod end pan-hard and it works amazingly well. Before I still had a little bit of rear end wobble under high load and now it's just the tyres that squirm a little. I wish I would of done this years ago.

Sometimes the tyres also slide a small amount however it feels completely controllable and stable, I am now looking into my next step of rear camber.

[Jacobxxx]

rear camber? interesting...

[timbo]

rear camber how? is it floating hub or axle i forget... or bend you whole case?

[Celica RA45]

also you make the panhard rod adjustable so it can go up and down in different positions .std its in the center of the diff ,but by dropping it 20mm lower you change the rear roll center which also makes the rear springs seem softer you have 2 go this both ends thou
also on most race cars they either use no rear sway bar or just keep the factory bar and adjust this to suit /on my race car i use std rear bar celica and rear panhard rod is 30mm lower than std with rose joints on both ends spring rates are much lower than what you guys run
from memory my fronts are 300 lbs and rears are 220

[Sam-Q]

crap I made a post and lost it. Now where was I:

glen you make some good points and the blunt reason why I have not tried is because I don't know what I am doing and I would rather go for a watts link anyway. Currently my bar sits level. As for spring rates I am not with the trend of most of the people on this forum who think less lean must mean faster and better. I am using a 4.9/3.2 (375/225) combo which is working well for me

As for the rear camber how to I want to discuss that in another thread

[jimmy19650]

I wonder if by using the solid mounted rod ends, the panhard rod is binding and using the diff and panhard rod as a giant torsion bar. We used to change the angle of the trailing arms in some race cars under qualifying conditions with soft rubber, so they would work against each other. By this I mean changing the arms from being parrallel to intersecting. This used the diff as a giant torsion bar and gave more rear grip. Could not do this for long as the stress on the diff would result in cracks.

[Sam-Q]

Jimmy I would say yes but instead the floor and the mounts cop it instead, here have a read of this:

My "3.5 link" suspension (http://www.ae86drivingclub.com.au/forums/showthread.php/25766-My-quot-3.5-link-quot-suspension)

[jimmy19650]

First time I have read that article. But you are 100% correct. As I mentioned in my post, we only used this setup for qualifying. The last I remember was an AU supercar in about 03-04. The diff lasted 4 laps at bathurst and had to be repaired.

[Sam-Q]

wow ok, I didn't expect it to be that drastic in it's effect. However thinking about it on the ford it had chunky rod ends and the mounts would been reinforced by the roll cage right? If so this would of meant there was no give anywhere else and the diff copped it.

The funny thing is I never heard of it this problem till I was thinking about the geometry of my diff one day and thinking there was a contradiction in it's movement. I posted my thoughts on toymods about 5 years ago and some agreed.

[KE70]

Interesting Sam, i am currently thinking if I should replace my rear suspension rubber bushes with std rubber or polyurethane. Its welded so it might be poly.

At the same time I am thinking of cutting and shutting my pan hard rod about 10mm or roughly what is required to get my diff back in the middle.

[Sam-Q]

I don't suggest rubber bushes to be put back in for even a stock car. Having a welded center also puts a lot more forces on the trailing arm bushes.

[Frak]

. I am using a (375/225)

I have been using 380lb/in front, 225lb/in rear for years, I find it works REALLY good, I don't know how many times 'drifters' have asked spring rates then screw up their face and say something along the lines of, "bit soft hey"

[Sam-Q]

mines a 275 front, so pretty soft compared to most people on here

[Grant #2]

I'm 6.7kg/mm front, 5.1kg/mm rear on my coupe. I find that it's about the upper limit for a reasonable daily driver on real roads. There is some extra roll compared to other cars with 8/6, so for an all out track car it's not ideal. I have a TRD front roll bar and a stock GT-S rear.


Sam,
I went from cusco heim jointed lateral rod to a poly bushed whiteline for comfort and I didn't notice much, if any handling downgrade. If anything, it was overall better for me because I have stock rubber LCA bushings up front, and it made the car seem a little more balanced in quick transitions. I did appreciate the solidness of the heimed bar, so I can appreciate what solid bushes all around woudl be like, but not for a daily driver :)