ALFAGTV6.COM

Micke · Post by **Micke** » Fri Oct 21, 2005 3:16 am

Warum?

U know something that we don't.....

Mats · Post by **Mats** » Fri Oct 21, 2005 4:54 am

Well, for starters you will get a stiffer front suspension while breaking. That will transform the balance in pretty unpredictable ways.

Why do you want anti-dive anyway?

Micke · Post by **Micke** » Fri Oct 21, 2005 6:04 am

To keep the front spoiler from self destructing for starters.

Getting a stiffer front while braking is the entire idea of anti dive or am I wrong? That's the good side. I know having too much is not very sound.

Andrew.b · Post by **Andrew.b** » Fri Oct 21, 2005 6:17 am

My ex-rouse gtv6 has anti dive lower arms from the IMSA 75 turbos.

I'll see if i can post a pic.

Make the front end of the car quite 'twitchy' and it's you loose a bit of 'feel' at the point of locking the wheels under braking.

What i mean is, it's easier to lock the wheels, as you get less warning.

Mats · Post by **Mats** » Fri Oct 21, 2005 8:38 am

I thought the idea was not to get the front down...

The stiffness is just the unwanted sideeffect.

Anyway, stop driving on motocross tracks and add some spring (both front and rear) instead.

Maurizio · Post by **Maurizio** » Fri Oct 21, 2005 10:25 am

thought it was something like that.... but never knew you had to tilt the a-arm forward.

Anti dive: I had an idea on that one too but went into the bin when going to coil over. Not enough room on the standard upper arm. You need to frabricate one.

My idea was to move the castor rod mounting on the upper arm, downward. When breaking there will be a small compound of the forces on the castorrod upwards to help lift the chassis. The nice thing about it is that you could shim it out for more anti dive. So you could play with it.

Mats · Post by **Mats** » Fri Oct 21, 2005 1:42 pm

eh? no. That won't work, only the placements of the joints itself matter. The link can be approximated by a straight line between the rotation points in the joints so it won't matter how many shims you add.

Maurizio · Post by **Maurizio** » Sat Oct 22, 2005 12:04 am

yep, have had a longer thought about and your right mats won't work

You have to move the front attachment point.

Andrew.b · Post by **Andrew.b** » Sat Oct 22, 2005 3:44 am

Maurizio wrote: thought it was something like that.... but never knew you had to tilt the a-arm forward.

Anti dive: I had an idea on that one too but went into the bin when going to coil over. Not enough room on the standard upper arm. You need to frabricate one.

My idea was to move the castor rod mounting on the upper arm, downward. When breaking there will be a small compound of the forces on the castorrod upwards to help lift the chassis. The nice thing about it is that you could shim it out for more anti dive. So you could play with it.

The correct way to get anti-dive is to move the lower wishbone mounts.

You can ONLY do this with coilovers as you cant bend the torsion bar!

I'll find the pics.... this will explain well

MD · Post by MD » Fri Jun 23, 2006 1:48 am

Relocated posting about transposing lower control arms and use the ball joint the "wrong way" up....

Hey Barry, the back to front upside down twice around your neck and up you date for a stopper formula is one we have been kicking around as well.

Like all the comments others have made, the repositioned ball joint goes from being under pressure to under tension and there is a risk it will pull out. ( OK I know all you advanced engineering types know this, it is for the "don't try this at home folks crowd").

However, this is such an exquisitly simple and valuable modification, I think we should collectively work on it until we nail it. For instance, my first thoughts are to figure out some way using the existing ball joint in the top position and create a clamping effect around its seating collar. The "clamp" should encircle the joint and form a back up tensioner to prevent the ball coming out of its socket.

The next problem is to hold the "tie down" in position and with sufficient force to do the job. Needs more thinking.... perhaps finding a ball joint designed to be under tension instead of compression would be a good start.

A note for the OZ crew, be warned. I have just spent a week beating the feat around a swag of machine shops to have just this modification made. In polite terms they all told me to piss off and and don't come back. The reason has to do with the insurance and liability freaks that have got them all sacred shitless. You know modifying front ends, what if there is an accident, what if this and that. What a wank !! Anotherwords, you wanna do this ? you're own your own.
_________________
Alfa Romeo moves my world.

Dennis · Post by **Dennis** » Fri Jun 23, 2006 2:01 am

I was thinking along the lines of a tubular chromoly lower a-arm with nascar ball-joints. These are relatively cheap, screw-in, all parts can be replaced, strong enough and fully adjustable.

If these things hold up on nascar cars, I'm not to worried they'll do the job in my racecar.

have a look:

Micke · Post by **Micke** » Fri Jun 23, 2006 2:33 am

Before even thinking about using the stock ball joint upside down, please make the effort and try in a bench how much forve it withstands before failing. If it's less than 2 tons I'd forget it right away.

And before starting to modify the stock unit, just search for a suitable piece from another car or something.

Maurizio · Post by **Maurizio** » Fri Jun 23, 2006 4:36 am

I'm not sure where I read it, but in my memory fade it says take for horizontal loads 20G and 8G as total load....

Someone who can confirm that number?

Jim K · Post by **Jim K** » Fri Jun 23, 2006 6:35 am

You guys are about to get some poor mucker killed here! Whats all this shit got to do with everyday road use, potholes, gravel roads, cobblestones etc??? Even if the std clamping force is sufficient, would you want to repeatedly put it in a random vibration environment while the joint is constantly under (separation) tension of ~400-500kg????? I don't know if I'm missing something here, but if this 'mod' fails in the wrong place and time (as usual!)it won't be 'hahah, guess what happened last night!!??'. You want to do this right, go for something like Dennis shows, there's plenty of ideas in a Summit Racing or Speedway catalog, but think out a bulletproof design, not just a Sunday race job for a smooth track and 900kg car!!
There I said my bit, now I'll take all you got!
Jim K.

Dennis · Post by **Dennis** » Fri Jun 23, 2006 7:47 am

That's why it's under "Race cars and track prep", Jim. You're completely right that's completely insane to try something like this with parts not designed for this application.

I would hate to it failing on me, that's why I've chosen to use the nascar parts. If they hold up on 180 mph Nascars, they'll hold up with me.