TA22 + rack and pinion

[TurboRA28]

Not if you design a good steering system..

RCA's only help when the control arms and steering arms are not in a perfect paralelogram.

Most cars have bump steer built in - mrs smith is driving down the road and dog runs out she jumps on brakes, bump steer cause front wheels to toe in, car feels stable and doesn't dart around but goes in a straight line.

Then mr racer lowers the shit out of the car and for one changes the position of the control arm/steering arms and puts the geometry into a different area of the bump steer. Also mr racer doesn't like the feeling of toe changes over the suspension travel..

So RCA's are good here and also help with roll centre.

[takai]

Aye, RCAs will only help with dynamic changes when lowered. They basically reset the bump steer close to factory.

On the other hand if you have designed toe out on bump into your suspension setup you have so little hope its not funny.

[TurboRA28]

Ha we don't need to talk about that.. Thinking back to my first attempt at rack n pinion.. Hmm 20mm toe in under full droop, 20mm toe out at full compression..

[takai]

Ouch.......

["Z" UTE]

Ha we don't need to talk about that.. Thinking back to my first attempt at rack n pinion.. Hmm 20mm toe in under full droop, 20mm toe out at full compression..

MATE that is awesome, please do tell, so that we never go down that road !!

cheers Chuck.

[TurboRA28]

That was the result of a rack that was wider than the control arm pivot points.

["Z" UTE]

Top stuff Joel, that is the type of info, which will help a newbie, BIG TIME.

cheers Chuck.

[TurboRA28]

Yup no worries.. Probably been mentioned earlier in this post.. But take note of the offset of the steering knuckle between where the hole for the balljoint is, and the hole for outer tie rod..

I think RA28 is around 10 - 15mm offset (the outer tie rod sits inbound 15mm more than the balljoint.. So that means the rack has to sit 15mm inside the control arm pivot.

I just chucked a KE70 rack in mine, which sat 15mm or so outside of the control arm pivot.. So add that to the extra 10 - 15mm on the knuckle, and you have a rack that is 25 - 30mm too wide (each side).

[takai]

Yeah, but thankfully that is fixable

[TurboRA28]

Exactly.. In that instance I welded some plate to where the control arms bolt on, and redrilled the holes in the correct spot..

Probably illegal, but awesome steering and good camber.

I also drilled the holes offset to assist with caster, so the bushes didn't have so much pressure on them.

[merc-blue]

So whats the go? has anyone actually done on recently enough to be able to say what they used and the results?
im considering getting my Xmember a AE82 rack and going nuts until it all fits

[takai]

Yeah, im probably goign to start thinking about this one more in a few weeks. Some stuff to do before then

[vanman]

If the big issue with this is that the steering needs to match the control arms, Why couldn't you just use the complete front end setup from the AE71? Track width between the front tyres is only wider by approx 50mm, the standard wheels wouldn't even sit out of the guards. This would also set the car up with 4A mounts already set up as if standard, and make any AE71/AE86 brake conversion available to you.

If you wanted it to be the same track width, you could always cut-n-shut the xmember and rack at the same point to keep the geometry correct. Would obviously need a custom steering shaft to connect between TA22 column and the AE71 rack in either case

Does the KE70 setup have the bottom end of the struts the same distance apart, or would there be problems with the camber on the wheels?

My 2c, cos cut-n-shut AE71 was my original plan - any feedback would be helpful

Cheers
Vanman

[WDE_BDY]

From memory (pics were posted here somewhere) the KE70/AE71 crossmember is way different in how it bolts to the body. Engineering a cut up crossmember would probably be interesting as well.

Callum

["Z" UTE]

I will shortly, when time permits, visit my friendly suspension expert, and see if we can find a rack that is a little shorter than the KE70, something along the lines of Torana/Escort, which would have been similar in track to a TA22.
This will be an ongoing project for me, so do not expect quick results. The car has to be stripped, and painted, on the original rolling gear. Then the engine conversion, and suspension work begins .

A staggered cut and shut, with plates top and bottom, would do the job nicely, if you wanted to reduce the width of the crosssie.

cheers Chuck.