Vintage Motor Trend Road Test: 1962 Corvair Monza Spyder – “Chevrolet Has A Problem With The Corvair Turbo”

As I read more of these old Car Life and Motor Trend magazines, my appreciation for Roger Huntington increases steadily, especially since I just found out that he was paralyzed from the chest down. He wrote for some 15 magazines, including road tests for Motor Trend and others. Apparently he didn’t do the actual driving, but the very detailed testing, which was an important element back then, not just oohing over the latest entertainment software.

This review was something of an eye-opener for me, as Roger’s methodical testing brought to light the limitations of the rather primitive turbocharging that was employed in the new Monza Spyder. As to the specific problem he called out—and is quoted in the title—it all boils down to one word:

Lag, as in turbo lag. It was severe, and it substantially impacted the ability to take advantage of the 50% boost in power as promised by its 150 hp rating. Just how bead? Read on.

That’s not to say the Spyder didn’t also bring a number of positives to the equation; quite a few actually. In addition to the turbo engine, mandatory options included a badly-needed heavy-duty suspension sintered-metallic  brake linings, a lovely instrument panel with nice round gauges, the four-speed manual and a 3.55:1 axle ratio. Plus a few badges, of course.

The combination of all these turned the Spyder a genuine sports car, in a liberal definition of the term, and cemented its growing image as being a “poor man’s Porsche”.

The Corvair engine was beefed up to withstand the additional power, had a lower 8.0:1 compression ratio to help minimize detonation, a plastic cooling fan to reduce belt loads at higher rpm, and heavy duty clutch.

As to how it performed, Roger preferred to put the numbers out here first and then do the explaining and the qualifiers. 0-30 in 4.0 sec., 0-60 in 12.1 seconds and the 1/4 mile in 18.5 @ 77 mph was deemed “certainly ‘adequate’. It is by no means quick in this day and age. You may consider it acceptable for a compact sports coupe in this price range. Or you may not. I don’t”

He didn’t pull any punches there. But it’s true; by 1962, 10 seconds for the 0-60 was becoming the dividing line between slow and quick, although in case of imported sports/sport cars, that number was still often somewhat higher.

As a point of comparison, the results of Car Life’s test of a 1961 Monza four-speed with the 98 hp engine were:  0-30: 4.0 sec, 0-60: 15.5 sec., 1/4 mile 20.3 @68 mph. The same to 30 mph, slower to the higher speeds, but not all that much slower. The gap between the Spyder’s 50% power boost and its acceleration numbers were significant.

Here comes the bad news: very serious turbo lag. The large 3″ turbo took way too long to spool up and provide proper boost. This drastically impacted its utilization except in high speed cruising, where the turbo was already spinning pretty well. But in acceleration from a stop or at lower speeds, it might as well not have been there. In fact, it never was able to provide any boost in first gear, and only a bit of boost at the very last moment of having to shift from 2nd to 3rd. In third gear full boost finally arrived just when it’s time to shift into 4th. That explains the acceleration numbers.

Even while driving along in third gear at a pretty high 56 mph (4000 rpm), it took 4.5 to 5.0(!) seconds for the turbo to spool up and provide full boost. Of course, one could put the brakes on while doing that, and the boost would then be right there, but that’s not exactly practical.

Huntington took accelerometer readings to calculate the amount of hp generated at 4000 rpm in each of the gears during full acceleration. 1st gear: 91 hp. 2nd gear: 96 hp; 3rd gear: 103 hp. 4th gear: 112 hp, but probably not yet at full boost due to the track not being long enough. That 112 hp probably corresponds closely with a gross rating of 150 hp.

“How might Chevrolet have licked this turbo response problem? It’s not easy.” The Olds Jetfire turbo didn’t have this serious lag, because they used a by-pass system (waste gate), which also allowed them to keep a high 10.0:1 compression ratio. But that also necessitated an alcohol injection system to prevent detonation. Olds also used a smaller 2.5″ turbo, unlike the 3″ turbo on the Spyder, which increased the Spyder’s turbo rotating inertia by 2½ times. Of course the Jetfire’s system turned out to be a nightmare, and many had to be “de-turboed” by dealers for unhappy customers. Meanwhile, the Corvair’s crude system, which just relied on exhaust back-pressure to limit boost to about 10 psi, ended up being quite reliable and was used for a number of years, through 1966.

Huntington does point out some positives: fuel economy is essentially unchanged, if the boost is not utilized much. It’s silent, and the tone from the low-restriction muffler was fine.

There were situations where the boost could be utilized and savored, as in shifting down into 3rd and running it out to 70 at full throttle. Or in 4th gear, when it’s floored at about 50 or 60; it takes a few seconds, but when the boost comes on, “it surges in and pins you right back. It’s great great between 70 and 90 in high”. Which makes it a fun car, on the highway especially, but it might as well be a non-blown version around town.

Other reviews of the turbo Corvair do mention the lag, but not nearly as succinctly as does Huntington, with his accelerometer reading to confirm just how bad it was.

It seems to me that most of the turbo lag issue could have been resolved by teaming the engine with the Powerglide automatic. In fact, it seems like it would have been a terrific solution: one could spool up the turbo from a standing start by applying the brakes, as was so commonly done with automatics on the drag strip. And once spooled up, it would be one continuous surge of boosted power. So why not?

Ate Up With Motor wrote that such a combination was tried, but that during the moment the automatic shifted from Low to High, there was substantial overboost due to the lack of a wastegate, which then caused “catastrophic engine damage”.  Too bad; the more I think about it, the more I like the idea. Automatics were widely seen as a way to significantly to reduce the turbo lag issue in the early turbo cars of the eighties.

Huntington found no fault in the Corvair’s new heavy duty suspension and brakes. “They have a beautiful compromise between ride and handling…We noticed especially a reduction in oversteer tendency. Much of this is due to the front anti-roll bar, rather than the stiff springs” (this is the “$4 unit” Chevrolet decided to leave off at the last minute). The Corvair now understeered more at lower speed, transitioning to neutral, and eventually to oversteer near the limits of adhesion. “If you spin out it will undoubtedly be the rear end that goes first!”

This heavy duty suspension also included a lower ride height to increase negative camber on the rear wheels as well as “limiter straps” to prevent severe tuck-under. My ’63 Monza had this suspension, and I never once experienced a truly scary moment, despite a lot of high speed driving on curvy mountain roads.

All of this goes a long way to explaining why Chevrolet developed the 140 hp 4-carb version for 1965. It did need plenty of revs to make that additional power, but it certainly didn’t need 5 seconds for the boost to come on.


Related CC reading:

Curbside Classic: 1963 Corvair Monza Spyder Convertible – The Turbo Revolution Started Here

Curbside Clairvoyant: 1962-63 Olds Jetfire — With Turbo Rocket Fluid! — GM’s Deadly Sin #36