1975 Toyota Corolla SR-5 Archive Test: Longer, Wider, Slower

From the July 1975 issue of Car and Driver.

The “Longer, Lower, Wider” philosophy of car design is up for grabs. Detroit has reluctantly had to give up that approach or suffocate in its own padded bulk—and who should take over the well-used ploy but Toyota, the company we’ve come to know as small-car specialists.

As incriminating evidence, we have the 1975 Corolla—long­er, wider and a prime example of Detroit’s old gambit of mod­el maturation. From most standpoints, this new Corolla is a better car: more civilized, roomier, even better looking. But the crime Toyota has committed has to do with the cost of it all—and not just the list price, although that has taken a fat hike as well. What is most worrisome is a generalized soften­ing of the Corolla’s metabolism: In maturity, it has become a substantially slower car.

That is especially tragic in the SR-5 version. Here is an arrow from Toyota’s quiver aimed right at the heart of the driving enthusiast. It bristles with a five-on-the-floor (just like a Lotus or Porsche), fat tires, fender flares and enough instru­ments to monitor a space launch. Past Corolla SR-5s left their mark as rare have-your-cake-and-eat-it cars: cheap to buy, fun to drive, and remarkably efficient with fuel.

But a lot of the fun is gone for 1975. Even with the old optional 1588-cc four-cylinder engine moved up to standard duty, there is a severe horsepower deficiency. The basic de­sign hasn’t been changed; it’s still a pushrod cross-flow hemi with an aluminum head. The camshaft has lived in the cast-­iron block from inception, and this engine got along just fine with such a handicap. Formerly it was an undisputed over­achiever, strong right up to the redline, pumping out nearly one horsepower per cubic inch in spite of its pushrods. But now it seems old age has set into the Corolla’s hemi. Its health chart lists a horsepower peak down a debilitating 13 hp since the 1973 SR-5, and in the current California version (subject of this test), the atrophy is even worse at 15 hp.

The problem stems from the techniques Toyota has stooped to for a clean exhaust. Valve sizes remain the same but intake passages are sized down in the head and intake manifold. In addition, the carburetor’s air-flow rating is down by three percent compared to 1973, so high-speed breathing is off accordingly. Low-speed snap is wilted by a centrifugal spark-advance curve that waits until 5200 rpm to deliver full advance. Exhaust timing has been shifted for more overlap, resulting in a natural EGR (or incoming-charge dilution by spent exhaust gases) for NO_x control. A large thermal reactor plenum-type exhaust manifold is new for 1975 for external combustion of pollutants. To feed it with substantial volumes of oxygen, the air pump drive ratio has been geared up. This all combines to sap 12 to 15 hp from the little engine, in which the only change beneficial to power output is a compression ratio bumped from 8.5 to 9.0 to one.

Compounding this decline in engine-room productivity is the car’s escalating weight. With a wheelbase longer by 1.4 inches and overall length stretched 1.7 inches, curb weight has increased by 200 pounds since last year. It’s the same obesity that has crept up on most domestic machinery. In the Corolla, the result is a 10-percent weight gain with a softer engine to pull it down the road. Quarter-mile times are off a full second from the SR-5 we tested two years ago, and that makes the Corolla fair game for anything on wheels.

You can almost stomach that slowdown if you don’t let yourself notice the SR-5’s five-speed transmission. The basic pleasure of a car like this is meant to be mechanical harmony: an eager power-generator up front matched perfectly to its task by an able driver and their trusty gearbox. The tight ratios of a five-speed are essential to smoothly slice off speed while spiraling down entrance ramps, and with such a small motor you need a constant handful of gears on the exit side to keep the revolutions up for whipping into the straights.

But none of this clicks together if the engine is as soft as the ’75 Corolla’s. When you nail it, first gear is reasonably energetic, but as you slide the shifter into second, the fun starts to fade. Above 40, it takes so long for the engine to crawl up its rev range that you aren’t snicking through the gears any more but just sitting back waiting—and hoping to squeeze out a few more rpm.

The sagging acceleration curve effectively deflates the Co­rolla’s aggressive character. It’s no longer the scrappy pocket rocket that used to love being driven flat-out. Now it’s a young adult, complete with a few correspondingly more mature apti­tudes. Instead of the old bouncy SR-5 ride, the Corolla now rolls down the freeway with poise. Its response over bumps and dips is smooth and supple—good enough to comfort for­mer owners of big American cars through the trauma of switching to compact transportation.

In fact, the Corolla SR-5 now has the capable handling that was the single failing of earlier models. Track width is up two inches in front and 1.6 inches in the rear, and the tires are upgraded one size to 185/70HR-13s. It’s enough to make the Corolla SR-5 the best-handling Toyota ever. Since there is no grinding understeer at the limit (as there is in the Celica), steering effort needed is moderate. You can pitch the SR-5 into a tight bend, get way over your head, let the tail swing wide and hold it there with your foot flat on the throttle. The car hangs on like a racer, its body roll well in check. Since there is plenty of front tire grip left in reserve, you can dive toward the inside for a quick pass if necessary. If the bend is tight enough, inside rear wheel spin limits forward progress to an extent, but this is nowhere near the speed limiter it was in the old narrow-tire Corolla. So if you enter this SR-5 exclu­sively as a downhill racer where tire-smoking torque is not a factor, you should have an even shot at the competition.

Part of your unfair advantage will come with late-braking techniques. It’s an easy edge to develop because the Corolla has the finest stopping equipment in its class. Proportioning is adjusted so that the front tires lock first—as they should—and pedal feel through the vacuum boost system is first rate. Good brakes are not only a valuable speed advantage but a comforting safety device as well. If you jump into a turn really over your head, the front disc/rear drum system will haul you down without twitching the tail around or catapulting you off into the hostile wilderness.

The blend of performance attributes you get in this new Corolla SR-5—soft acceleration but great handling and brak­ing—means it is no longer the vibrant street-racer it once was. The engine is not a willing partner when you feel like a hard run. But if you work hard and guide the car with a deft hand, keeping the revs in the high range and not losing an ounce of speed to excessive tire scrub or premature braking, the Corol­la can be quick on a twisty road. It’s low on cheap thrills when you stand on the gas, but it can still deliver fun.

At least it’s a good deal easier to live with when your needs are strictly transportation. The new body carries its five-mph bumpers without the tacked-on look of last year’s cars, and frivolous trim has been stripped away, leaving the well-propor­tioned body clean and functional. Even the accent items have been given a purpose: The black mesh hood vent exhausts heat from the engine compartment while similar grilles on each rear fender duct interior air out of the car.

The real justification for the new body, according to Toyota, is a roomier interior. But the gains are small: an extra inch of elbowroom front and rear, and 1.5 inches of additional front headroom. The latter comes largely through the use of a molded headliner, which unfortunately adds no rear head­room over last year’s car. Somehow, the product planners in Japan also forgot about a hatchback body style for the Corol­la, which may turn out to have been a big mistake in today’s highly competitive little-car market.

The instrument panel may be the nicest part of the Corolla package. Toyota has always been the master of the plastic interior. There is no pretense: no attempt to emulate mahogany, engine-turned aluminum or sewn leather. Just straightforward molded plastic. There are no phony seams to waver out of alignment or fake stitching to challenge your detection. From the steering wheel forward, every contour is smoothly cloaked in a molded skin. When automo­tive plastic finally becomes respectable, the SR-5 will be eligible for an industrial design award.

Furthermore, the panel is efficient to use. The driver is clearly given top priori­ty: an array of seven dials sweeps be­fore you with the information needed to keep all systems on line. Nothing is hid­den behind the wheel rim, and crucial speed and engine rpm readouts lie directly ahead. Controls are moved off the panel, so you operate the wipers, wind­shield washer and headlights from fin­gertip stalks on the steering column.

All of this is proof of the careful thought lavished on the new Corolla to make it a good transportation device­—and, of course, primary evidence of the Longer, Lower, Wider philosophy. The LLW reasoning admittedly works well if you focus on the basic Corolla. It starts out as America’s least expensive auto­mobile and also enjoys the distinction of 24-mpg fuel economy (in the Car and Driver Mileage Cycle). Once that bottom line is nailed down, you can afford to yield to the pressures of the LLW theory, which serves to flesh out what might otherwise be stark transport. It does so at a price, though: less fuel economy, compactness and performance.

If you’re after the feisty secret-racer image the SR-5 signifies, however, LLW just won’t do. If more room is the plan, there are efficient front-wheel-drive packages. If creeping weight is a prob­lem, there are plastic/aluminum radia­tors, alloy engine blocks, and whole new families of high-strength materials. If old engine designs resist emissions control, there are stratified-charge approaches and Mazda’s rotary record of annual emissions cuts along with performance boosts. Technology, not the LLW stra­tagem, is the ultimate salvation of per­formance cars like the SR-5.

Source: Reviews - aranddriver.com