<VV> Comfort Speeds

[Brent Covey]

> >In terms of steering and stability alone, Corvairs without a front
> >spoiler/air dam "feel" light" over 60-65mph.

I think most people would be hard pressed from the drivers seat to tell if a
car had the spoiler fitted- I think its mostly intended for appearance
issues. Spoilers do seem to help a bit with crosswind sensitivity, but the
Corvair is very insensitive to crosswinds if its set up correctly, the whole
car blows over as one peice rather than the nose being buffetted off course,
and the roll steer built into the rear suspension tends to self correct the
cars course against buffeting from the side, the rear suspension steers
itself towards disturbing forces. The high caster of the Corvair front
suspension helps also, you probably have noticed if you wag the steering
wheel back and forth and wag the tail of the car, or hanging the tail out on
a slippery surface, just releasing the wheel during a cycle the car will
sort itself out very rapidly all on its own.

Corvairs are very sensitive to some tire/alignment situations, even the
slightest rear wheel toe-out really upsets things, and the front to rear
track difference makes them climb the truck ruts on bad highways if the
tires have stiff sidewalls, such as the original bias ply tires. Radial ply
tires are far less sensitive to ruts but the bias belted type also kill
about 90% of this behaviour while retaining the very soft ride and pleasant
handling of the bias ply tire. Bias Belted tires are by far my favourite
tires on a Corvair because they have the snappy steering response, excellent
lateral stiffness and soft ride of the original bias ply tires without some
of the twitchy rut running behavior of a bias ply or the rubbery sloppiness
of the radial. The smooth breakaway of the bias ply and bias belted tires is
nice in contrast to the somewhat more ragged behavior of radial ply tires at
the limit also, drifting around a freeway cloverleaf at 75 mph is much
easier and more controllable on the bias ply/bias belted tires, as example.
There arent many bias belted tires availible now, only real ones I am aware
of is reproduction Firestone Wide Ovals in D70-14 which probably would fit a
late Corvair OK but are a little on the large side.
>
> My 66 Monza has essentially a new front end and actually feels more
> comfortable/stable above 60 mph than below and is fine at the 70 mph limit

This has been my experience also pretty much- the late Corvair chassis seems
to really settle down and hug the road around the 100 mph point. I have seen
speeds close to 130 mph running 140HP cars full throttle down steep grades
(belt breaks at 6400 every time) and the car felt extremely stable and safe.
Late model brakes with good linings are very capable, but some linings (like
glazed factory installed ones) wont even stop the car once properly from 70
mph. Good brake linings will haul you down from 110 mph no problem, and
still not be too hot to lock the wheels immediately after with normal pedal
pressure. I had good success with some very inexpensive Wagner riveted
linings I bought in the late 1980's that were biscuit coloured with little
brassy looking flakes in the material.

> It does have (relatively) modern but narrow/tall 185x80x13 radials
> There is a bit of vagueness to the steering between 35 and 45 but is solid
> above 60.

I have noticed theres a lot of differences between various manufacturers
tires for 'feel' in 185-80R/13's...some of the nicest tires I have used were
very cheap (K Mart brand Hankooks, as example) but seems to flatter the
Corvair suspension better than others. Considering a late Corvair on 175/185
radial ply tires at stock low pressures can outcorner the oil in the sump,
gas in the carbs and Powerglide fluid on a long corner leaving you in
neutral, with a dead engine with the oil pressure light on, its not
neccesary to have very large tires on a Corvair. I would expect 205's is
about the point of diminishing returns for handling on dry roads in an
unmodified Corvair, the narrow tires seems much nicer on any wet or loose
surface however, and will save fuel.

I find the slop in late axle yokes aggravates the sloppy lateral flexibility
of the radial ply tires and makes the car feel a bit wobbly on high crown
roads at high speeds and would suggest extra attention to shimming the nut
next to the spider gear shaft to correct this. Keep your worn spider shaft,
the worn flat part on the spider shaft will provide a bearing surface for
the yoke nut and the rate of further wear diminishes as the shaft develops a
flat side where the nut touches it. The yoke nut is shimmed to force it into
closer contact with the shaft, watch you still have enough spline engagement
to retain the yokes however. Very slight positive camber on all four wheels
and one third a degree extra positive caster on the right front wheel with
pretty decent rear toe in and pay attention to getting the rear track struts
(trans x member to trailing arm) having slight tension at curb so they can
do thier job make straight line stability much improved.

I would suggest anyone replacing springs consider using the F41/Z17 type
rather than the original stock front springs if they are planning on using
radial ply tires. The stock standard rate front springs have a natural
resonance not far off what a radial tire carcass has and tend to drum and
vibrate with radials. The harder F41 springs kill this off and force the
front tires to work a little harder and overall are a little nicer, less
twitch thru the steering wheel on expansion joints, slab freeways etc. Rear
springs do not need the F41 type as much, the rates are very slightly
different in the rear, so changing them makes no drastic difference. F41
cars came from the factory with a softer shock absorber than regular
suspension cars to offset the harder springs. If you have the full F41
spring setup and aftermarket shocks, your kidneys will find the bucking of
the rear suspension very punishing, you may need to experiement a little to
discover a shock that works well for your particular car without making the
ride too harsh. I am a fan of tall ride height, and do not like doing things
that reduce suspension travel. Getting the car poised up on its springs has
some nice handling advantages, such as killing bump steer and reducing
crosswind sensitivity and usually just generally improving ride quality. GM
raised ride height on the '73 Grand Am  over the other A Bodies for much the
same reasons. Giving the suspension space to work can make the car more
pleasant on bad roads, and generally diminishes handling glitches.

Most Corvairs have shockingly poor wheel alignments, even looking at a
picture of a bunch of them parked at a Convention you can see tires leaning
every which direction and all kinds of odd tire combos that probably would
create issues. The usual late Corvair with a so-so steering box, bad pitman
bushing, screwy rear wheel alignment, sloppy diff yokes, overside and
non-complimentary tires, heavy mag wheels, worn out stock (or worse, cut)
front springs and lousy brakes would not be a very satisfying car at high
speed or on a bad road, but the cure for this situation is fairly obvious.
If everythings in good shape and pointed the right direction and the
wheel/tire combo is flattering, the Corvair is a very delightful car at
speed.

Hope this is food for thought,
Brent Covey
Vancouver