Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 (Tek) 9/28/84 based on 9/17/84; site hammer.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!vax135!cornell!uw-beaver!tektronix!orca!hammer!doncr From: doncr@hammer.UUCP (Don Craig) Newsgroups: net.auto Subject: Re: How to turn a Saab? Message-ID: <1308@hammer.UUCP> Date: Thu, 6-Jun-85 05:39:27 EDT Article-I.D.: hammer.1308 Posted: Thu Jun 6 05:39:27 1985 Date-Received: Sat, 8-Jun-85 02:51:33 EDT References: <13200026@hpfcla.UUCP> <435@tymix.UUCP> Reply-To: doncr@hammer.UUCP (Don Craig(steveg)) Organization: Tektronix, Wilsonville OR Lines: 169 Summary: Re: How to turn a Saab (170 lines) I rallied for a number of years at the Canadian National level, both as co-driver and driver, and owned a Mini Cooper S (fwd!!) which I drove 'spiritedly' in Montreal winters. I have been hauled out of ditches twice in the same afternoon during a blizzard in the Eastern Townships of Quebec, and have rolled three times while rallying. Be warned. Practice the following in an EMPTY parking lot with a wet, snowy, or icy surface. Professional rally drivers reach their peak twenty years after they start competitive driving (if they make it). Handbrake turns were much favoured by rally drivers in the fifties and sixties, when speeds were lower. They are used today only in emergencies, because they are difficult to accurately control, and tie up a hand better used to shift gears. They will give more oversteer (i.e., a tendancy to spin) than almost anything else you can do while driving. Used in the street, where speeds are much lower (even for Roger Ramjet) than in competition, they are good for abrupt 90 degree and 180 degree turns of the car body. They do NOT alter the original vector of the car when properly applied. That happens after the car body has turned and the tires have a new slip angle (the difference between the direction in which the tire is pointed and which the road is moving). If the road is dry asphalt, handbrake turns are also noisy. Handbrake turns require that the handbrake operate on the rear wheels of the car. This unfortunately excludes the Saab, whose handbrake operates on the front wheels. If the car is rear handbrake, front wheel drive, handbrake turns are fairly easy. Start the car into the turn so that the suspension compresses on the outside. You should be understeering at this point (it doesn't look like you'll make it). Pull on the handbrake (with the release depressed!) the right amount (:-) (relatively violently) and the car will suddenly(ish - depending on its polar moment (tendancy to resist doing this)) oversteer/ start to spin. Start to steer into the potential spin immediately. Also release the handbrake at the right time (:-) (relatively soon). The length of time the handbrake is applied and the promptness with which the driver turns into the potential spin control the amount of turning the car body actually does. The extra trick (which requires some practice) for rear wheel drive cars is to dip (depress) the clutch for exactly the duration that the handbrake is applied. I last saw handbrake turns used as a regular high speed technique at the World Rally Championship level by the great British driver Roger Clark when he visited Canada in 1977 with the Ford of England team. The rear brake discs had twin sets of calipers, one set operated by the footbrake, and one set operated by the hydraulic handbrake. And at every service stop (every 1 - 3 hours of competitive driving), his mechanics would change the handbrake pads. I believe his Ford Escort (the old European kind) finished third overall. And now the Saab. A very interesting but somewhat eccentric car capable of high performance indeed. Handbrake turns are not available because the handbrake works on the front, but other things can be done. The world expert in Saab driving is the Swede Stig Blomqvist, who won the world rally championship in 1984 (although that was in the somewhat similarly handling (can understeer like a pig) Audi Quattro). Stig rallied a Saab in Canada in the summer of 1978, and was the first man to win a Canadian National Rally in a production class car (only safety modifications allowed from stock). (The American John Buffum (Vermonter actually) is the only other man to have done this, he did it in a Volkswagen GTI.) I did one not very successful rally as co-driver (tells the dummy behind the wheel what to do) for the Canadian Saab factory team. Blomqvist's style in car handling makes sure he NEVER gets caught out by understeer. He does this by entering the tighter corners in an attitude of gross oversteer (near the limit of the steering gear to turn into a potential spin). As the corner progresses he unwinds the steering wheel until the front wheels are more or less lined up with the direction the car is pointing. If the corner tightens up, he doesn't unwind the wheel. To achieve the oversteering entry attitude several things can be done. On any front wheel drive car, lifting your foot from the throttle will provoke oversteer. If you do this violently, you will get a lot of oversteer, especially if the suspension is already compressed on one side of the car from having started a turn. Turning into the potential spin immediately controls how much turning you get. The other technique that oversteers a front wheel drive car is 'left foot braking'. Most low performance street machinery has what is known as a front brake bias. Usually about 60% of the braking force of the footbrake is applied at the front wheels and the remaining 40% is applied at the rear. This promotes understeer under braking, so that Aunt Millie in a panic skid will not spin, but will tend to go in a straight line towards her impending doom. More sophisticated drivers want to be able to turn sharply while braking hard, and are prepared to turn into a potential spin to retain control. This requires at least a neutral brake bias (50 - 50) and preferably a rear brake bias (say 40% front, 60% rear). A fully prepared rally car has brake bias adjustable from a lever beside the handbrake, so the driver can vary the amount of rear brake bias (never saw anyone set it for front brake bias), depending on the road tightness and surface condition. I would guess my RX-7 SE has about 55% rear bias and 45% front. My Mini Cooper was permanently set up with 70% rear and 30% front (ho ho ho). Brake bias can be adjusted by replacing or modifying (or removing in the case of the Mini) a device that sits somewhere in the hydraulics and is known as a 'proportioning valve'. Do not see your dealer for this modification, unless he is very understanding. For cars that cannot be modified due to various rules (competition, insurance, safety), a similar effect can be achieved by putting a softer brake lining on the rear shoes or pads, and by putting a harder (so-called competition) brake lining on the front pads. Stig Blomqvist's production cars always had the hardest possible linings on the front, the softest possible on the rear. (His full blown cars usually had the proportioning valve hard over for rear bias.) With brake bias to the rear, a driver can set his car up in an oversteering attitude by depressing the foot brake once the suspension on the outside of the turn is compressed. If he depresses the brake with his left foot, his right foot is available to depress the throttle, and he can balance the angle of the car's body by playing his right foot against his left. This works because applying throttle while braking significantly reduces the effect of the front brakes, provoking even more rear brake bias. It even worked on my father's fwd Pontiac, which has about 70% FRONT brake bias, but it gets the front brakes and engine very hot, and the car handled so badly I was probably wasting my time. To get a feel for this in an EMPTY parking lot with a slippery surface: Approach the turn at a reasonably rapid pace. Start to turn in for the corner, compressing the suspension on the outside of car. With power in but good, sharply rap the brake pedal with your left foot. When the car starts to oversteer (if you did it right) be very ready to turn into the direction of the potential spin. And practice practice practice if you intend to try it anywhere else. The sooner you get hard pads on the front, and soft shoes/pads on the rear, the easier you will be on your drive train. To sum up, lifting your right foot will always give you oversteer on a front wheel drive car. If you do this violently, you will get a lot of oversteer, which you can then balance and control. If you want to oversteer while braking, either adjust your brake bias to the rear, or apply power and brakes at the same time which achieves the same effect. Stig Blomqvist uses all of these tricks and then some. In competition, front wheel drive cars are typically faster in the tight and twisty sections than rear wheel drive cars, but somewhat slower in the fast corners. This is because a front wheel drive car can only get oversteer while slowing down, but a rear wheel drive car can get oversteer while speeding up as well. This is if ALL other things are equal, which they never are. Driver ability counts for a lot. (Last year's production class world rally champion was driving a Golf GTI, fwd.) Fast driving of four wheel drive cars (Quattros, Peugot 205's, Lancia Delta's, funny RX-7's) is another subject.