RA28 stering rack conversion (need advice)

[barned01]

does the rear sump (not mid-rear but full rear) go far enough back to sit behind the ke70 crossmember still?
would need the measurement of the rear sump 1g.

[willwal98]

it may do but I don't know if it would leave enough room for the rack again then. Anybody actually using a rear sump 1g?

[BigWorm]

I'm currently in the process of carrying out the TA23 to K/AE71 crossmember & rack & pinion conversion, and here's a pic of the 2 setups side by side.





I can confirm the lower control arm mounts of the xE71 crossmember are a total of 30mm wider, giving 15mm either side, and the total crossmember width of the xE71 is 40mm wider, front & rear, so it needs 20mm carved off either end, new holes drilled & a bit of reinforcement.

Thanks to Blue RA28 Joel for the idea of this, it certainly becomes the best option if you have a 4A that can now use standard 4A RWD engine mounts & has standard sump to crossmember clearance, something I was never completely happy with the old setup.

If any other measurements are needed let me know, I'm home all day & have the tape measure handy.

[TA-022]

can 1 not fit [red cicles] outer rods to KE [blue arrows] inner rods to bring the length back to std?

and if their different threads what if you could find a same thread part to achieve this with.


if this can be done then one would assume track can remain std.

[BigWorm]

I'm not sure I get what you're saying??

The steering arms are completely adjustable for length so these don't need modifying, and it's the lower control arms that deterimine the track (in this instance).
For the track to remain standard the LCAs would need shortening or their brackets relocated/slotted.

[TA-022]

aight now i understand why there are track issues.

mixing control arms shouldnt be too hard to keep track std.


look forward to seeing your results!

[MWP]

aight now i understand why there are track issues.
mixing control arms shouldnt be too hard to keep track std

Problem is that when you change the control arm lengths for the KE70 xmember, you screw up the bumpsteer and ackerman as the tie rod piviot points are not in the correct places.

[willwal98]

unless of course you change the lenght of the rack to suit, but that kind of goes against the whole point of moving to the KE70 x-member

[Major Clod]

I think you would honestly be better off going for the extra 15mm either side, it isn't really that much and can easily be correct by finding the proper offset wheels or getting your guards rolled, etc... It's going to be less hassle than trying to work out all new steering geometry.

[TA-022]

im thinking more about rta regs. track cannot be increased/decreased by more than 25mm.

[Major Clod]

In QLD, we can increase the wheel track by 26mm. This is measured from the center of each tire, so with the correct offset wheels you should be able to keep the wheels in the same spot as stock. If I remember correctly TurboRA28 was using wheels that were similar to a silvia offset with his KE70 crossmember, plenty to choose from there, and it matched perfectly with his F series rear end. Just a thought.

[MWP]

In QLD, we can increase the wheel track by 26mm.

Same in SA.
But thats track... so thats 13mm per side.
Not a lot to play with.

Oh... and my engineer said i could go over that, but it would mean more theory/testing for him to do for rego complience = more $$$s.

[barned01]

steering noob question:
is thhere an issue with mounting that cross member the other way around?
ie the rack is now facing the front of the car.
you would have to turn the rack around so the part that connects to the steering wheel is on the correct side again, and you have to redrill holes in the crossmember to get it too fit anyway.
please don't hurt me profusely if this is stupid.

[TurboRA28]

Yeah I found the MKII F series rear end with a KE70 rack made the front and rear track equal. Then using +34mm silvia offset wheels moved the track back in a bit so there is no scrubing.

[MWP]

steering noob question:
is thhere an issue with mounting that cross member the other way around?
ie the rack is now facing the front of the car.
you would have to turn the rack around so the part that connects to the steering wheel is on the correct side again, and you have to redrill holes in the crossmember to get it too fit anyway.
please don't hurt me profusely if this is stupid.

Nope, not stupid.
Plenty of cars use a rear sump and mount the rack at the front of the engine xmember.

Of course, you should always talk to an engineer before trying to do such radical things though.