Re: turning circle, Ferrari (more Alfa content)

[George Graves <gmgraves@xxxxxxxxxxx>]

I had an opportunity to live with an Alfa 147 GTA for two weeks this 
past May in Italy (Check the September issue of "Sports Car 
International" for my "road test" of that puppy). The power steering is 
incredibly quick at 1.25 turns lock-to-lock, and while it took a few 
klicks to get used to it (as the previous poster said, it doesn't take 
much of a lapse in concentration to have one heading for the ditch 
-especially at autostrade speeds) I found that it made the car 
wonderfully "tossable" with very little effort and that made my high 
speed "tour" of the old Targa Florio circuit in Sicily extremely 
enjoyable. The downside was that  here we have a car that's about the 
same size as a Ford Focus, and it had a turning circle of 12.1 meters 
(39.7 feet) between curbs, which made U-turns on two-lane roads a bit 
of a chore. Wouldn't stop me from buying one if they were available in 
the USA though :->

On the home front, I recently installed a power steering setup from a 
Milano to my GTV-6 (the steering of which is very much like that of an 
old, front-engined Ferrari such as a 365 Daytona). Anyone who's ever 
driven one of these Alfas will tell you that the slow (4.5 turns 
lock-to-lock) heavy (takes two men and a boy to parallel-park a GTV-6) 
factory steering on this car, while fine at any highway speed that the 
car is able to accomplish, makes spirited driving on two-lane roads a 
very wearying and somewhat harrowing, experience. The power steering 
setup reduced the steering effort and the steering ratio from 4.5 to 
less than 3.5 turns lock-to-lock while managing, somehow, to maintain 
all the road feel of the old, manual rack. The car is now much more 
pleasurable to drive around town and especially on two lane roads. I 
recommend this modification highly, just be sure that you fit a rack 
that doesn't leak.

George Graves
GTV-6 3.0 liter


On Tuesday, August 19, 2003, at 10:53 AM, alfa-digest wrote:


> Date: Tue, 19 Aug 2003 09:52:17 -0400 (EDT)
> From: Sonny <maxid@domain.elided>
> Subject: Re: turning circle, Ferrari (some Alfa content)
>
> The discussion of Ferrari turning circles got me curious, so I poked 
> aruond a
> little. A Ferrari Maranello has a 13.8 steering ratio and a 39.3 
> ft/12.2 m
> turning circle. A ratio of 13.8 means that to turn the road wheels 1 
> degree,
> you have to turn the steering wheel 13.8 degrees. This is one of the 
> quickest
> steering racks on a production car. My casual observation indicates 
> that
> ratios from 15-19 are common on contemporary cars with power-assisted 
> steering
> (non power-assisted cars generally have higher ratios). Alfa 156 and 
> other
> modern Alfas have some of the quickest ratios around, in the same 
> range as the
> Ferrari. Custom racks with even quicker ratios are available from 
> tuners, but
> they are unsuitable for road use, as a brief lack of concentration may 
> land
> you in the ditch, or worse. In my opinion, steering ratio is a more
> informative number than turns lock-to-lock because it directly 
> reflects the
> steering feel of a car. Turns lock-to-lock is influenced by the limits 
> of
> wheel travel (~turning circle) in addition to quickness of steering.
>
> For a number of years, variable-assist power steering has been common; 
> i.e.,
> the amount of assistance decreases with engine rpm or vehicle speed 
> with the
> intent of stabilizing the car during highway travel. More recently,
> variable-ratio has also become common; the ratio of the rack varies 
> between
> the center and either extreme. When only one number is given for the 
> steering
> ratio of such a car, it is the ratio at center.
>
> Older Ferraris without power steering may have had slower steering to 
> offset
> high steering input demands due to large tires, but I don't think 
> Ferraris in
> general have particularly slow steering. It appears to me that other 
> sporty
> cars have surprisingly large turning circles (Subaru WRX STi and Mitsu 
> Lancer
> EVo come to mind; both have _quick steering_ though), but it is my 
> guess that
> the large turning circle is mandated by technical consideratins of 
> some kind,
> not including the manufacturer wanting "to limit the number of turns
> lock-to-lock"...what would be the value of that?
>
> Sonny
> 91 164 S
> Baltimore
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided