Thread: P11 Auto-X Setup help

my opinion is that it is not 1:1. Possibly the .87 is closer. even with the 600lb, the car feels like the front dives a bit still. I feel this is because of the roll centre vs centre of gravity points are moving further away when lowering the ride height. Same thing happens to r32 Skylines and 300zx which they fix by using loner ball joints.

I am going to be making some custom LCAs using some spare oem arms I have. Replacing most of the bushings with bearings and the ball joint with 3/4" spherical bearing and bolt. that way I can have a solid setup with adjustable roll centre.

Now with panhard if you lowered the roll center in the back enough it shouldn't overload the front as much anymore. Less weight transfer to front should reduce front dive.

Btw How low are you?

Got any links to the R32 or 300zx's with extended ball joints? Just curious .

Don't get me wrong, the car feels great now with the panhard, I guess I just got used to it now and the mid corner push is more apparent. and then again, the car rotates so easy now that if I come in with more speed and turn in fast at the apex then there is little to no push. sucks that there hasn't been any events since the install because I am sure that I would be a lot more competitive. The only cars that are quicker on auto-x are 4wd cars, and just barely if at all, they always made up the time with the launch.

My car is not physically low from the ground because of the 17" wheels and big tires but my LCAs are at a angle. I would have to measure to be honest. I will get that for you later.

Here is a link to gtr Canada about the roll centre of the gtr which using the third link design p11 use. not exactly the same but very identical. Don't see why we cannot use the same principles they apply with great success. Our ball joint are obviously not the same as gtr as they just use a spacer between the ball mount and the attachment point, where we would need a longer rod to get the same results.
Frankiman's street/track GTR project - Page 44

What are your current alignment settings? i did not read through the whole thread.

But i do see a fair amount of front outer edge tire wear. I'd suggest at minimum 3 degrees camber in front, and definitely do the front roll center correction. I'd also add more caster if u can adjust it.

You should measure if you are bottoming out the shock in front as well, i'd almost say you can go with more spring if your shocks are valved to handle it. If you compete on high grip concrete surfaces more spring will reward you. if its low grip asphalt, i'd stay around the 550-600 front 650- 700 rear rate. if you are on high grip concrete i'd stay around the 700-750 front and 800-850 rear rate. on my pulsar which has similar to b13 suspension if not identical i run 600 front 700 rear on low grip asphalt.

At what speeds are your autox at? i would almost suggest a front splitter and rear wing depending on the speeds you hit since you are likely not running on classing due to the extensive modifications you have. as silly as it sounds it does impact autox sweepers at around the 80-100km/hr speeds.

I honestly do not know the values of my alignment, I made my UCA to be 12mm shorter than stock which should bring me to the 2.5-camber.
My springs a 600lb front and rear. The tire wear is because I rotated the tires from right to left as it actually wears the inside due to some toe out that was dialed in at the time. I am now at 0 toe since there are no event currently happening.

I place small red zip ties on the shafts of each shocks which gives me a good indication of my travel. I still have about a 1/2" to go before bottoming out.
We would be lucky to hit 50mph, I would say we average 30 to 40 mph.

Thanks for the link for the GTR roll center fix. It makes sense, I remember the thread on Gnet about extended ball joints too (which got no where).

As for motion ratios found this thread. I'm gonna measure mine when I get back home, now curious enough to actually do it.


Drove the car up a mountain, wasn't too impressed, but something else is not sitting right, it's been like this since I rebuilt it, I figured it was stock suspension, but now I think it might be something else like bushings, can't think of a way to explain it though. Maybe it's just too bouncy because I left the shocks on the softest setting.

I might try swapping the rear springs to the front and see how the car drives then. But first I need to do LCA caster bushings and UCA camber arms.

10/8 k setup sounds like it would work well. Are you running any swaybars front and rear? Also, try not to lower it too much. 2" would be the lowest I would go with stock ball joints. I feel when I go too low the car rolls more for sure. Maybe try raising it a bit.

I turned up the rebound/dampening to be 10 clicks instead of 1 click as before, and it feels a good bit better. Taking a turning hard I can hear my wheels chirping, not sure if it's front or rear though (too cold for having windows down still).

I'm lowered 1" exactly front and back, car looks great with 1" drop, don't need any more. Heck I might raise it up more still. I'm planning on doing 17" rims, so that would allow me to go back to stock height and not look like 4x4.

I still need to do my caster bushings and cusco camber arms. At 10psi I'm already having a hard time keeping traction in 2nd gear with 0 camber as is...

Just figured I would bump this thread back to life. Not much has happened to suspension since the rear panhard bar, but just to lay it out setup is below which most of it is in this thread somewhere:
Tein Coilovers with 600lb eibach springs front and rear( tein dampers are now dead)
Shorten UCA (12mm if i remember)
Panhardbar conversion
20mm spacers front
LCA brace

Tires are currently Continetal Extremecontact DW 340 TW front 255/40-17 and Continental sportcontact 245/40-17 rear

This current setup is extremely capable and there is still room for improvement, LCA are using oem bushings which may need replacing soon. Here is my results from this weekends event.



Unlimited vehicles are mostly using Toyo R888 so I feel i did very well and the results speaks for itself. Now discussions are starting to push me up to unlimited class.
If that is the case then it is time to level up!

That's awesome! How big of a difference do you think the panhard alone was? I'm thinking about picking up the conversion again.