Why flip rear pivot blocks on X-5?
 

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.

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

A

and alters the rear anti squat,

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.

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

A

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.

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.

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

Cheers.:D

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?

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

A

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?

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

Any links to pics of this mod please?

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

got ya. cheers ash

Cheers Carl.

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.

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

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.

Pleanty of threadleft in the tower just tighten the screws more.

A

It's not that at all....it is because the inside of the tower meets with the top of the rear diff cover and dremeling the inside too much weakens the tower loads. I expect I will have a gap as I can't physically get the tower to sit any lower without removing more material from inside.

put a washer on top of the rear pivot block mine seems to be fine.

A

I'll try it, thanks.

Ash, you don't run an X5 as far as I'm aware though. The tranny tunnel profile is different.

Bux, do you mean at the front? You really want it to sit down as much as possible and all be clamped down properly. If it's not there is chance the toe in block can move up and down and your antisquat will actually change during the run. You can take some material out of the top of the diff cover to gain some more clearance.

Actually have you deliberatly threaded out the toe in blocks? As if not you'll often tighten up in that thread so you can't pull the tower down far enough.

Yea i know the tunnel is diffrent and you have to remove some of the material from the shock tower for it to fit it should clamp down the washers where just a suggestion.

A

I actually drill out the toe block holes so that it only tightens to the tower.

Just dremel more from the tower to get the 2 to meet. You can take some of the housing but may as well do it off the tower.

There is a brace available from X Factory (by some clever E Speed guy :p) that you can put on the front of the tower to beef it up for when it is dremeled.

E.

Thanks Dan and Ellis...that is much clearer. :)

Do all of you that run upside-down-blocks put washers back undeneath to get 2 deg anti-squat?

I tried the mod with 0 degree blocks and didn't like it because it made the car unpredictable (would dive off sideways over bumps), but now I'm thinking I forgot to add washers :blush:

I just run the 2° and cut of the pimples and stick them on the car, don't really play with the squat too much on it as I never feel I need to and don't have any washers under them.

E.

Well I'll let you know after Sunday! I'm running the 0 degree blocks with XXX Anti-Squat shims under the front screws between the chassis and the blocks. The blocks are visibly angled backwards now (higher at the front).

I had to take a lot of material off the blocks though because they were fouling on my outdrive savers.

I've kept the 2 degree ones to one side and will whip them back on in the event of unpredictability...but at least on the bench the 0 degree flipped ones feel lovely and means I have a greater range of useful movement in the shock, i.e. they're threaded into the middle of the shock now whereas before they were almost fully tightened down.

I only run 2 deg blocks with a thin washer under the front.

Personally I'm a 0 deg man, pimples cut off, sometimes with 1 washer under the front if I want some antisquat but often not and so 0deg.

Interesting, might give it a go but im not sure it will have the stability i like. O yeah, i cut the pimples off too.

Remember that if the shock tower is not in the correct location (up and down) you are changing the entire suspension geometry. While this might be advantageous, considering the legendary quality of the xx-4 suspension, that's not likely. I suggest doing what is necessary to maintain the same assembled height as standard.

Hey dudes, ive been reading this thread, and i dont know if im confused or other people are confused, so this is what ive gleaned from my own knowledge of this and whats in this thread, my understanding is that flipping the blocks would not affect anti squat, the 2 deg or 0 deg block refers to the amount of toe-in the block gives the arm (right or wrong?) Ashley brings up a good point and its backed up by young chazz, as soon as you've filed something away on the block, the tower, if screwed all the way down to meet the blocks against the chassis, will then sit lower than it previously would (that could all be very small amount of difference) a spacer in between the block and the tower would restore tower height and should also then avoid the need to dremel more off the tower to get it to fit over the belt tunnel

Not quite,

We're all talking about the worlds (CR) toe in blocks which are all 3 deg toe in. The 0 or 2 refers to the amount of antisquat the block has when the right way up. Personally becasue of my concern that a 2 deg block reversed should give 2 deg pro squat, for ease I always use the 0 block so it's easier to then washer up the front edge to generate antisquat as required.

The pips you trim off are very small, I wouldn't worry about tower height being effected, however becasue they are amall I wouldn't want them as the low face you clamp down hard against the chassis.

ahh, thanks Dan, now i understand it all, im assuming the result would be the same if using the old blocks also ( as in changing the height of the hingepin), im not an anti squat user either. Did i miss the meeting where everyone decided to run the cr rear blocks?lol are you guys therefore running cr rear arms and hubs. I like the old school setup, but i was going to toy with 0 deg toe-in and 1 or 2 deg toe in at the hubs

3 deg inboard come on the xx4 WE? It's xx CR not the newer XXX CR.

The 0 deg inboard and toe outboard was from the original XX/XX4, the only person I know that used that was Cree who liked it with the 2 1/2 deg hubs. I have the bits for it but tend to stick with the 'norm'

As it happens though I am now using the XXX CR wishbones and hubs for for different reasons, there is no forced compatability.

Well I said I'd come back on comment on the car with 0 degree blocks and anti-squat shims under the front screws to bring it back to 2 degrees of anti squat.

It was freaking awesome! Never have I felt the X-5 so planted and predicable to drive fast. This was on an indoor circuit at the Southport GP. Two carpet types, jumps, bumps / ripples and slippery tarp. I'm certainly sticking with this mod.