Why flip rear pivot blocks on X-5?

Fiddybux · #1 03-02-2009

Hi,

I've heard people mention this, and seen setups (e.g. Ellis Stafford), where the rear pivot blocks are flipped over, and out of necessity have been ground away to make room for the outdrives, as the natural left block goes on the right and vice versa. But I wonder what is the point in this? What does it achieve?

I've had a think about it, and as far as I can tell it would raise the chassis in relation to the rear wishbone / suspension arm by about 3mm, or however tall those little lugs are on the pivot blocks are. But what I don't know is what effect this would have on the handling.

Can anyone shed any light on this for me? I'm sure others are wondering the same thing too.

Thanks in advance.

ashleyb4 · #2 03-02-2009

It raises the hingepins and allows the car to go though the bumps better.

A

bigred5765 · #3 03-02-2009

and alters the rear anti squat,

Lee · #4 03-02-2009

I think Ellis or Elvo will be able to give you a technical answer to this but ill try to do my best.

What you are doing is lowering the wishbone pivot point in relation to the chassis. this means that you are raising the roll centre, the rear of the car will roll a bit more in the corner but it should be better over bumps and just feel that bit more planted.

We used to play about with raising wishbones when i raced on road and moving them up by 0.5mm made a massive difference to the handling of the car.

ashleyb4 · #5 03-02-2009

Surely arent you raising the wishbone pivot point compared to the chassis as you are raising the hinge pin?

A

elvo · #6 03-02-2009

Inner hinge pin goes UP in relation to the chassis - if everything else stays the same - roll centre goes UP, rear end rolls LESS.

But I think the plantedness comes from having the wishbone and camber link closer together.

BTW, the little lugs should be filed/Dremeled off.

Fiddybux · #7 03-02-2009

Quote:

Originally Posted by bigred5765

and alters the rear anti squat,

How does it alter the anti squat Carl? We talking more anti-squat, like more than 4 degrees or something?

I don't suppose you can have less than zero anti-squat...'cos this would be pro-squat. He he, anti anti-squat.

Dunno, just rambling now.

Fiddybux · #8 03-02-2009

Quote:

Originally Posted by elvo

Inner hinge pin goes UP in relation to the chassis - if everything else stays the same - roll centre goes UP, rear end rolls LESS.

But I think the plantedness comes from having the wishbone and camber link closer together.

BTW, the little lugs should be filed/Dremeled off.

Oh right...cool advice...and I would have left the little lugs on which would have properly ruined the whole mod!

Cheers.

elvo · #9 03-02-2009

2° anti-squat block flipped = 2° pro-squat = not what you'd want. To be remedied with lots of spacers under the front 2 screws.

Using the 0° block is probably easier.

Fiddybux · #10 03-02-2009

Quote:

Originally Posted by elvo

2° anti-squat block flipped = 2° pro-squat = not what you'd want. To be remedied with lots of spacers under the front 2 screws.

Using the 0° block is probably easier.

Right okay...that's handy as I've got loads of 0 degree blocks cos I never use them.

Would I need to stick washers under the rear screws to put me back near 2 degress?

ashleyb4 · #11 03-02-2009

Put washers under the front screw to bring you back up to 2 degree.

A

Fiddybux · #12 03-02-2009

Isn't that only if you use the 2 degree blocks though Ash?

If you use the 0 degree blocks then surely you put the washers under the rear screws?

bigred5765 · #13 03-02-2009

wrong way round russ,under the front gives you anti squat, under the rear gives you pro squat

GRIFF55 · #14 03-02-2009

Any links to pics of this mod please?

ashleyb4 · #15 03-02-2009

an ok picture at the bottom of the page of ellis's mod at the bottom of the page on his xx4.

http://www.oople.com/rc/photos/reviewxx4/ellisxx4.html

A

GRIFF55 · #16 03-02-2009

got ya. cheers ash

Fiddybux · #17 04-02-2009

Quote:

Originally Posted by bigred5765

wrong way round russ,under the front gives you anti squat, under the rear gives you pro squat

Cheers Carl.

Fiddybux · #18 04-02-2009

How many anti squat shims are required under the front to bring it back to 2 degrees?

I have loads of anti squat shims left over from my XXX and they would be ideal to use I guess.

bigred5765 · #19 04-02-2009

we use to use one of the xxx shim for 2%

Fiddybux · #20 04-02-2009

Cheers Carl.

So tell me, do you have an issue with there being a gap between the bottom of the rear shock tower posts and the pivot blocks?

I'm just wondering if I will make a gap when I file off the little lugs on the pivot blocks when I flip them.