mlc asked:
>So, I have a couple
>of questions that I'm hoping the MR2 experts in the crowd can help with
>(and you know who you are!).
>
>1) Have you ever switched a car from manual steering to power
>steering?
>Are there hideous things to know about such a swap (like there are with,
>say, the air conditioning which wraps and winds around suspension pieces
>and such)?
>
I had a '94 MR2 Turbo with PS, a '91 Turbo with manual steering, and a '93NA
that was switched from power to manual steering. The MR2 has EHPS
(electro-hydraulic power steering) which uses an electric pump mounted up
front so you don't have to worry about plumbing back to the engine. It also
has variable assist controlled by a computer, and the assist varies with
steering angle and vehicle speed. To install the EHPS you need the power
rack and pinion, the pump and reservoir, the computer, and the plumbing.
You might also need a steering column sensor (I believe this varies with
model year). To mount the pump you will have to cut some sheet metal next
to the spare tire well since the non-ps cars don't have this area cut out.
>I understand that power weighs more (but don't care). I also understand
>that the ratio is quicker with power. Most importantly, I've been
>lifting weights since we bought this thing, and I still fight pretty hard
>with it in tight corners.
>
I personally preferred the ps in the MR2. The quicker ratio means much less
steering input in slaloms which I really liked. The assist isn't a lot and
it gives good feel. As a matter of fact, when I first bought the '94T I
wasn't sure if the ps wasn't working. However, the top national MR2 drivers
all seem to have manual steering.
One thing you can try is to dial in less positive caster. This should
lighten up the steering effort a bit. Caster is generally good since it
gives dynamic camber, but you can get plenty of camber on the front of an
MR2 anyway (with crash bolts), so I think you can tune caster for steering
feel without giving up handling. (Note: Caster is not adjustable on the
'93+ MR2s).
>2) Other MR2s I've been in (and now it's been several) seem to have
>more
>low-end power and less high-end power than mine does (and folks who >have
>driven ours tend to agree). Since in autocrossing, lots of times you're
>needing the low-end relatively more often, it seems as if investigating
>legal means to improve the low-end would be a valid use of off-season
>time (no cracks about "what off-season?" from you, Randy Chase). Any
>ideas?
>
Are you using the same exhaust that the other guys are using? Most folks
just put on a straight pipe for autox. The MR2NA has a nice torquey engine,
and they generally run out of breath at higher rpms, so yours does sound a
little backwards. I have heard that getting the injectors done helps low
end torque a lot, but I have never done it personally. I know a Celica
driver who got his injectors done and he said the low end improvement was
significant. Also do all the usual tune-up stuff like plugs, plug wires,
distributor cap and rotor, timing, etc.
Brad Burns
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