ziperhead

Well it finally got around 60 degrees here so I thought I would go out through my car into a couple of on ramps.

When I turn hard left my car feels like thedrivers siderear is trying to lift up and the steering gets a little lightfor a second until I peddle the throttle . When I try and turn hard right the rear feels flatterand or normal.I toke a quick measurementon how my rear axle is centered using the tire to fender technique and I am off 3/4 inch more away from the tire on the drivers side then on the passenger side.Will axle centering help me correct this feeling I get when turning hard left?

LCA's pointing down towards the front
Roush lowering springs all around
Koni Yellow'sall set to 180*
UMI adjustable panhard baron my to do list to install
Stock 17" tires at 32 psi cold

One other question, does it make sense to run different rebound (Koni adjustment) on the front versus the rear since I added more weight to the front on Kenne Bell install?

Appreciate any feedback and or suggestions. Learned quite a bit from this forum

2007GT/CS

Yes. Having your rear now off center at your new ride height (courtesy of the stock PH bar) is definitely causing your rear to be squirrely. Put on that adjustable ASAP

I run the same adjustment on my Konis front and rear even with the S/C.

Stoenr

I would think you would want to get those LCA's level again. But lets wait for our forum professionals to reply.

Sleeper_08

Until they do you might want to have a look at the end of this link http://www.cherod.com/mustang/HowTo/LCA%20_adj.htm

F1Fan

Hi ziperhead,

That is just the jacking effect that all Panhard bar cars have. It's worse at low speeds and tight turns and as you lowerthe rear roll center. Nothing you can do to your Panhard bar setup can change this feeling. If you really want to get rid of that feeling you canachive this by replacing thePanhard bar andbracewith a Watt's link. The jacking effect is one of the reasons I switched to a Saleen PJ Edition Watt's link which solved the jacking problem and also made the car handle so much more consistentlyunder power. I thought my car was working prety well and indeed it did until I drove a Saleen PJ Edition 302 and even with the slightly offdamperand spring rates, stock Panhard bar, LCA's andUCA I could feel the difference in rear end behaviour.

HTH!

Norm Peterson

Like Chip said, it's (at least mostly, here) caused by the asymmetry of a PHB. But I think that roll center vertical migration is a larger effect than jacking of the sprung mass. If you're noticing a difference in rear end ride height, left side vs right, you might have noticed that the handling was a little tighter turning one way vs the other (I won't tell you which way so that I don't influence your memory/thoughts/future testing).


I'm not picking up the measurement method very well here. Are you telling me thatthe axle has shifted toward the passenger's side? BTW, there should be some body control holes underneath that would be much better points of reference if somewhat more difficult to use. I don't have my FSM loaded on my work computer, but I'm pretty sure I saw that info in it.


Yes, but I'll qualify that by adding "at least theoretically". The effect that damping has on vibrations (which is all that suspension movement really is) is a function of both mass and spring rate. Increase either and in order to maintain the same damping effect you need slightly more damping. In this respect, damping is a SQRT thing, so increasing the front weight by 5% is only looking at wanting~2.5% more damping. You, individually,might or might not notice that small of a difference. Most folks probably wouldn't, and I'm not at all sure that I would.

You might play with staggered damping in order to affect transient handling, and changes there would be larger than changes made to suit a relatively small weight increase.


Norm

ziperhead

Thanks to all for the feedback. Learning a bunch on this forum. I will install my new adjustable panhard bar and have a four wheel alignment,then start messing with the shock adjustments.

Sam Strano

Having the axle off center by so much is a bad thing. That's the problem, not the fact the car has a PHB. The car had a PHB before and was not doing this, that hasn't changed, and fwiw the longer the PHB the less arc is sees through it's range. There are also some really, REALLY fast cars that use PHB's for rear axle location all the way up to Nextel Cup cars (which while we can make fun of, are not slow around a road course especially given the weight and the tiny tires).

I'm sure when you adjust the PHB to center the axle things will be just fine.

F1Fan

Hi ziperhead,

So what happened?

Cheers!

ziperhead

Waiting on my Rhino Ramps so I can get my handsome self under the back of my car. New UMI adj panhard bar going in this weekend I hope.