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Dennis · Post by **Dennis** » Wed Apr 20, 2005 3:58 am

I'm about to get my deDion worked over for negative camber and toe-in, but I was wondering about moving the center watts link down.

Is there a formula to determine how much mm it should move down or is it no exact science?

Let me know what you think!

gtv11636 · Post by **gtv11636** » Wed Apr 20, 2005 12:24 pm

Good question Dennis!

I'll add one more question to the above:

Does the lowering of the center pivot position compensate Lowered cars? I know the best thing to do when lowering the car is to shorten the watt links ( is it ?) so does the lowering of the center pivot compensate this so one can stay with the original watt links ?

SamW · Post by **SamW** » Thu Apr 21, 2005 3:36 am

I think it is mainly there to keep the rear centered, as the suspension moves up and down, the center watts linkage rotates. There are a few places that sell adjustable spherical watts rods if that will help you.

Dennis · Post by **Dennis** » Thu Apr 21, 2005 3:56 am

Hi Sam,

I know about the rods (have them), but the center is on top of/above the triangle. I know it's best to lower the center (or pivot as you will) of the linkage, but by how much. I just wanted to know if there is a formula to determine HOW MUCH it should be lowered.

Mats · Post by **Mats** » Thu Apr 21, 2005 5:55 am

As per usual it depends on what you are trying to do and what you have done.

The rear roll centre is located in the pivot point and by lowering the pivot point you move the roll centre. Is that good? maybe... Depends on what the front end is doing and where the front roll centre is located.

So there is no easy answer or a formula, read a book about chassis engineering and you will know what you are doing.
Much better then listening to opinions that usually are just echoes of what people have heard is 'the mod'.

My opinion is that you should look at the front suspension instead as it is the failing end, the rear is miles ahead.
But this is of course my opinion...

gtv11636 · Post by **gtv11636** » Thu Apr 21, 2005 6:29 am

From what i remember speaking about this with Joe Benica I think he once told me the front and rear should be lowered together.
at the rear the pivot should go lower and at front the axle studs should be replaced by longer type wich has the lower ball joint seats lower then original position, the question remains - how much should the rear center pivot go lower ?

BTW - Does the SZ uses some bearing at the center pivot or some bushing?

Jim K · Post by **Jim K** » Thu Apr 21, 2005 6:42 am

All this talk about lowering the rear pivot is fine....did you try to figure out how LOW (close to the ground, that is!) the center crank will be??
Mats is right about roll-center math and its worth looking at it just from an exercise point of view. The "Advanced race car suspension development" book is good informative reading and very uncomplicated.

Jim K.

Micke · Post by **Micke** » Fri Apr 22, 2005 12:53 am

LOWERED TOGETHER???

The front should be raised - not lowered!!!

gtv11636 · Post by **gtv11636** » Fri Apr 22, 2005 5:07 am

Micke wrote:LOWERED TOGETHER???

The front should be raised - not lowered!!!

Sorry, I ment to lower the bottom suspension balljoint, not the hole car.

Micke · Post by **Micke** » Fri Apr 22, 2005 5:20 am

OK, still doesn't make sence though.

Front or rear mod helps separately too.
However, in both cases you need to consider what it does to the suspension setup and modify springs/AR bars accordingly.

gtv11636 · Post by **gtv11636** » Fri Apr 22, 2005 7:01 am

Thanks
I Know that.

Dennis · Post by **Dennis** » Fri Apr 22, 2005 7:16 am

Hi Micke,

Thanks for the input, but you've already told me that

I think I'll follow Jims tip and buy the book. Altering the front-end is WAY more complicated.........

Micke · Post by **Micke** » Sat Apr 23, 2005 11:24 am

While we're on the subject of books....

Besides buying the one from Jim (which is a MUST), also buy all books from Carroll Smith i.e. Tune To Win, Engineer To Win, Prepare To Win, Drive To Win (I think you got the point by now)

Lower rear watts link