chrisp@oliven.UUCP (Chris Prael) (06/13/84)
To: Jeff Buchanan Peter Barbee and anyone else who finds this subject entertaining: Both of you seem to be in need of doing some homework on the subject of handling. I would suggest Costin and Phipps as a starting point, even though the book is getting a bit long in the tooth. A more recent, and very good book is Fred Puhn's on improving production car suspensions. You would also find the article on driving technique in the latest Road & Track instructive. Next, you might both note that LOGIC is totally useless on the subject of handling and how to get it. Five years of messing around on the track in SCCA did a thorough job of rubbing my nose in that. The only valid question is "what works?". (The same rule applies very well in mucking around computers, by the by.) In essence, the art of getting more grip boils down to maximizing the area of the tire contact patches at all times. With modern tires and no aero effects the primary considerations are minimizing camber change and maximizing compliance. These two factors involve a large number of complex compromizes. When you add aerodynamic effects a whole new set of parametric compromizes are required. While some rules of thumb are generally available, they only provide "best guess" starting points from which to develop. And develop means try lots of variations and MEASURE the results. Ditto combinations of variations. Finally, you might both of you check your facts. As an example, Peugot has not been involved in "Grand Prix" racing since World War I. Their first attempt at competition of any sort in the last 25 years is an entry in the world rally series, based on the 205 series car. If you had either of you been paying any attention to Formula 1 lately, you would know that the cars ride like buck boards at present. This is because body attitude and ride height are the most important factors in developing grip by aerodynamic downforce. Chris Prael
roger@fritz.UUCP (06/19/84)
[] Chris Prael recently mentioned Formula 1 suspensions being very harsh. This is quite true, though less true than it was in 1982, the last year that ground-effects were legal. Since the ban on skirts, airfoil underbodies, etc., the drivers have all said how much more pleasant the cars are to drive, with the softer suspensions. I believe that "pleasant" is a relative measure here. For example, I watched the Canadian Grand Prix on ESPN recently, and was interested to here the announcer comment that Brabham was running much softer suspensions than any of the other teams. This was evident on one part of the course, where the camera angle was ground-level. Early in the race, with full tanks, the Brabham of Nelson Piquet would bottom out; a flash of sparks the evidence. Later in the race, as the fuel was consumed, no more sparks. The drivers may believe it is an improvement, and I'm sure it is, over ground-effects Formula 1 cars. But "pleasant?" Roger Webster
dxp@pyuxhh.UUCP (D Peak) (06/25/84)
I noticed Marion mentioned the port injection to be used on the '85 Corvette.
This reminded me of a discussion I had a couple of weeks ago with a friend
within GM and this port injection (by Bosch) is supposed to add another
44 bhp to the already reasonably healthy power of the 'vette.However with
the introduction of the injection you're going to be hit with a 11-13% price
increase. That means instead of paying approx $25,000 it's going to cost
somewhere around $28,000 which is somewhat more than a Porsche 944 and
closing in on the bottom line of the 911 series.It looks like Chevy is
definately going after the Porsche sales market.
--
Dave Peak (pyuxhh!dxp)
" The bare necessities of life : Food,Clothing and a blonde ! "
- W.C. Fieldshakanson@orstcs.UUCP (06/29/84)
<betcha can't eat just one>
In the June issue of Road & Track, in Miscellaneous Ramblings, is a fairly
extensive article on the improvements to the '85 Corvette. The "weaker"
suspension includes the following changes:
Base suspension: Front ride rate reduced from 125 to 100 lb/in.
Rear ride rate reduced from 170 to 120 lb/in.
Z51 suspension: Front ride rate reduced from 160 to 120 lb/in.
Rear ride rate reduced from 220 to 160 lb/in.
To retain the same overall roll stiffness, the front anti-roll
bar diameter has been increased on both suspensions.
Shocks revalved front & rear to reduce ride harshness. Bilstein
shocks now come automatically with Z51, free option with base.
These supposedly help tune out minor road disturbances.
To reduce "dartiness," improve directional stability and
returnability, and to slow down the steering a touch, caster
has been increased from a nominal 3 degrees to 4.
The Z51 gets 16x9.5 inch wheels at front and rear ('84 had 8.5"'ers
up front) -- better directional stability and braking stability.
According to GM, the improvements are worth 3 counts on their ride-harshness
scale. According to the editor, "On rough surfaces where the '84 Z51 would
shake your teeth out, the '85 Z51 rattles them and the '85 base suspension
introduces just a mild case of chatter." So it apparently isn't "Wimp-City"
for the new '85 Z51 suspension. In fact, it is predicted that it will have
as good or higher (i.e. "better") numbers in the slalom and on the skidpad
as its '84 counterpart. It's an exceptional balance between ride and handling
that they are shooting for.
To give you an idea where I stand on the issue of handling, I will quote the
editor again and say that I agree wholeheartedly:
In a sense, it [the '84 Z51 Corvette] is a race car for the
street. [Some] will say it's a little too racy. Without
disputing the Corvette's incredible handling characteristics,
I would argue that its exceptional handling numbers are of
little use if you can achieve them only on the rather artificial
confines of a mirror-smooth proving ground.
With that, I will point you to the excellent article for discussion of the
other improvements (port injection, better brakes), and give yet another
plug for the magazine by suggesting that you who are interested check out
the March, May, June, and July issues of R&T -- they contain an enlightening
series of articles in which the authors and editors attempt to define the
notion of a sports car. Happy driving....
Marion Hakanson CSnet: hakanson@oregon-state
UUCP : {hp-pcd,tektronix}!orstcs!hakanson