re: How to adjust Konis on Milano

[Scott Fisher <sefisher@domain.elided>]

In ad#798, Doug Sedon writes:

> normally, shocks don't affect oversteer/understeer wery much, their function is
> to control the rebound of the springs/torsion bars.

For the 95th-percentile driver, you're correct.  However, when I was
competing regularly in SCCA autocross events, I found that dialing the
relative stiffness of shock absorbers had a noticeable effect on
*initial* over/understeer, at least in a class where shocks were some of
the only allowed changes.  

How come?  Rebound is only one aspect of the car's suspension action
that shocks control -- there's also jounce (that is, compression, either
as the wheel goes up or as the car comes down).  A shock that could be
adjusted for extra resistance in jounce acted like a stiffer spring,
though only for a second or so.  However, we found that on tight
autocross courses, that was enough to change the car's dynamic handling
in the all-important corner entry phase.  It also makes a big difference
in the way the car felt on the street.

> konis, being able to be
> adjusted quite stiffly, mite affect the cars dynamic a bit tho.  

That's just what we found out.  I was using Tokico Illuminas, which at
the time were easily adjustable, included both jounce and rebound, and
even had a lifetime warranty. :-)  They had settings from 1 to 5, with 1
the softest and 5 the stiffest.  The car was a 1984 VW GTI, in a class
(E Stock) where the only allowed modifications were shocks and tires,
basically.  (Oh, right -- you could use any oil filter you liked, too.
:-)

> however, i'd
> try stiffening up the front, not the rear, if your car is understeering. 

We found that exactly the opposite -- rears two clicks stiffer than the
front -- worked the best.  I used to run the Illuminas at 1 in front/3
in rear for the street, and 3/5 for competition.  (We tried it once at
5/5 and the front was so stiff we skittered over bumps on the course and
were actually slower.)  

The extra dynamic roll stiffness at the rear acted like a rear sway bar
during corner entry, increasing the rear slip angles and helping point
the car's nose when I was braking and starting my turn-in.  Then, once
the car's attitude was set for a mild initial oversteer, the suspension
settled out and the weight balance/spring rates took over and the car
was stable in the middle of the corner; finally, when I'd get on the gas
again and transfer the weight to the rear, the slip angles went up at
the rear again and I would exit the corner in a very controlled 4-wheel
drift.  I ended up 2nd on points that first season, losing only to a
*very* good driver (regular Nationals competitor).  Then I got seriously
stupid and bought a road-racing car the next year and am just now
recovering financially. :-)

The one case where Doug's comment may well be correct  -- and I don't
know the Milano's front suspension geometry well enough to say yes or no
- -- is if the understeer is coming from a camber gain curve that goes
positive under body roll.  I know this to be true for older British
sports cars, not sure about torsion-bar Alfa chassis.  If the outboard
front wheel tilts away from the car under body roll, then reducing body
roll at the front will improve front-end stick -- just the opposite of
what Fred Puhn and Carroll Smith will tell you.  However, don't forget,
they're talking about racing cars with suspension geometry designed for
the track, not about production vehicles for the general populace.  

One final comment for Glenn's "understeering" Milano: I found that the
GTI handled its best when I had about 1.25 degrees of negative camber
dialed in at static ride height.  That was a big part of getting the
front end to hook up.  Again, the books will tell you that such settings
will wear out the inner edge of the tires quickly; when that became my
wife's car, that was the case and we corded all four tires (two fronts,
rotated the rears forward) in about 12,000 miles.  However, when *I* was
driving the car, I still corded the outside edges first.  You might want
to choose a balance point that gives you good grip and reasonable tire
life, or you might just enjoy the cornering feel so much that it's worth
buying new tires every year or so.  Your mileage -- and in this case
budget -- may vary. :-)

Oh, and not to knock Glenn's Spider (or mine) in any way, but if you
*really* want to feel what an Alfa is capable of in the handling
department, drive a 105-series Coupe.  It's got the same basic balance
as your Spider, but it has the Alfa factory chassis stiffener installed
- -- that big piece of sheet metal over the passenger compartment.  It
works even better than Don Ereminas' oughta-be-patented bedframe.  :-)

Best,

- --Scott

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End of alfa-digest V7 #801
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