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The designers at Mitsubishi decided to use a
reciprocating ball steering gear box in their flagship
sports car. This severely effects steering feed
back and introduces un wanted play into the steering.
Another problem with these units is age. I
replaced my leaky unit with another that also leaked.
All that leaky fluid caused paint to peel off the frame. |
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Here is an animation of the play in the steering wheel.
Yup. That's sitting still and it no... even with
all that movement the wheels don't move. It is not unusual for a StarQuest to have
some steering play. This isn't necessarily due to
the gearbox, but it does need addressing. |
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My search for a donor rack was pretty short. Lots
of hotrods use Pinto/ Mustang II racks for some reason. These
are available through most parts catalogs. But
parts catalogs are for new things. I can't afford
new things so I am getting one off of a 240. The
reason I chose this one is because it will be compatible
with the power steering pump of the SR. Then again
there's probably not even a difference between the
gearbox pump and this... but whatever. |
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I measured a 240 rack and it just
happens to be the 20" from ball-joint to ball-joint that
I was looking for. I have been trying not to screw
with the steering geometry of the car. I am no
engineer so I don't want to screw up the geometry that cost
Mitsubishi millions to develop 20 some years ago. |
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Here is a diagram I've made to show the left - right
movement of the rack. It moves (A)
47/8". I'm looking for a
rack that will come close to this. I'm settling on
the HICAS for now. It's
A measures XX" (coming
soon). |
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In this photo you see the measurements I took off the
stock Starion rack. Both tie rods (A)
are 15" long. B is
the length of the rack, 20". From what I measured
on a 240 the B section is
20" inches as well. But then again I might have
that wrong because I measure like a drunk retard.
I'm still looking to find out how long the tie rods are
on a 240 (S13). I'm now looking into HICAS
steering racks from 240s. Should be the same
dimensions as a regular rack but with a quicker ratio
(14.9:1 vs. 17:1). It's also less turns lock to
lock (2.6 vs. 3.1). The Starion's steering was 2.8
turns lock to lock so 2.6 will be a small upgrade. |
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I
got my rack today! |
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Look how close the lengths are to each other! It
does look that I'll need to max out the threads on the
tie-rods to make them the same as the HICAS rack is a
tad longer. I'm actually surprised I even got
everything from tie rod end to tie rod end. Now to
get it all mounted and safe. Here's the plan: |
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That's where I plan on mounting it. I'll
have to knock off the 2 stoppers on the cross-member and
weld on some brackets. From the distance away from
the frame rail holes, it looks like I'll have enough
room for the steering column. Now I need to line
up some U-Joints for this. |
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This is more of a difference rather than a problem.
The shorter tie rod on the HICAS rack will lead to more
bump steer than the Starion Rack. This is all
theory of course. I'll get measurements for
A and
B when its light again. Also note how
measly the 240 tie rod is. Part of this is due to
the fact that the Starion tie rod had to experience more
than just tension and compression, it had to deal with
the strains of that curve located above
B. I don't see this
to be a problem although I'll see how well it works
after a few rallycrosses and drift events :-D. I
do have the option of upgrading to Moog inner and outter
tie rods. Might be a good investment. |
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This is one thing I'll be having trouble with. The
bolts on the tie rod ends are different thicknesses.
The HICAS rack's bolt is larger (A<B).
I'm going to have to bore or drill the knuckle. |
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