AHC/WI: Successful Chevrolet Corvair

[Delta Force]

To date, the Chevrolet Corvair is to only air cooled rear engined vehicle to have been produced in the United States. The Corvair engine was unusual for General Motors in being a flat six cylinder design, featuring extensive use of aluminum. The same rear engine and rear wheel drive configuration was and is used by the Porsche 911. Unfortunately, Ralph Nader (a public safety advocate before running as President for the Green Party in 2000) singled out the Corvair as being the most deadly car in the United States in his 1965 book Unsafe At Any Speed, focusing on the alleged vulnerability of the Corvair's suspension "folding over" under extreme conditions. Ironically, at the time the book was published the Corvair was on to the second generation that featured an anti-roll bar, and a 1972 study found that the first generation Corvair was no more dangerous than other vehicles of its era under extreme conditions. The Corvair also had an automatic transmission featuring a layout closer to modern standards (reverse after neutral on the bottom of the transmission, although there was no park gear), while some vehicles had a more dangerous configuration with reverse being at the top of the transmission, after low gear. Nader's book still contributed to a dramatic loss of sales for the Corvair, the end of anything other than legally mandated upgrades for the second generation Corvair, and the cancellation of the third generation design.

I'm not that familiar with Nader's book, but could the Corvair have potentially been lauded in his book as a safe design if it had featured the anti-roll bars starting with the first generation? That would have eliminated Nader's primary complaint about the Corvair, and the safer configuration of its automatic transmission might have been praised. At the very least could the Corvair have avoided Nader deeming it to be the most dangerous car in America, with an entire chapter of Unsafe At Any Speed devoted to it? If the Corvair avoided the title of most dangerous car in America, might the proposed third generation vehicle have been developed and entered production?

Here's some photographs of a 1967 Chevrolet Corvair Monza coupe, a second generation Corvair design.

 

[TFSmith121]

Sporty little car

Nader was an activist, and his work was a polemic; the reality that the Corvair was a reasonable design in comparison with its peers, and certainly was a step in the right direction regarding fuel efficiency and what was going to happen to fuel prices in the '70s, all fell by the wayside.

More of a Mustang type myself, but still - neat little car.

Best,

 

[Kevin Renner]

Based on the Gen1 Corvair chassis you had. Two and four door sedans. The Monza hardtop. A wagon. A ragtop. Plus a van and pick-up. Plus with a total of 1.8M vehicles sold was it really a failure? In some ways IMO Nadar killed innovation in the US auto industry.

 

[TheMann]

The Corvair was far beyond many of its peers in terms of design, but Nader singled it out because of its quirks. It was a rear-engined car with swing-axle rear suspension, not a good combination owing to the fact that swing-axle cars are very prone to big changes in camber in their suspension if you hit a bump or change your throttle amount mid-corner. The rear anti-roll bar would have helped that, but the better option would be a complete independent rear suspension with that anti-roll bar, which would have reduced many of the handling quirks.

Unsafe at Any Speed was Nader effectively saying that Detroit didn't care about the dangers of their cars, and considering that most Detroit vehicles of the time had very poor suspension designs, terrible brakes, sloppy body fabrication and way more power than grip, he did have some points. But as mentioned, the book was a polemic, and while Detroit needed a wakeup call, that wasn't it. What it really needed was intelligent engineers at the head of GM, not accountants and financial guys. Nader didn't help that, he just redirected its attention.

 

[Delta Force]

The van and truck were produced from 1961 to 1965 as the Chevrolet Greenbrier. The Volkswagen Transporter used a similar configuration as the van and was derived from the Volkswagen Beetle. I'm not sure if anything with a configuration similar to the truck was ever produced, but it's certainly an interesting location for an engine.

 

[modelcitizen]

The Corvair was a contemporary of the Porsche 911. So many similarities: Sporting intent, flat air-cooled six, available turbo, etc.

I think a Corvair evolving along a similar path could make for a very, very entertaining car.

 

[modelcitizen]

There are some articles with information about the plans that were canceled for the third-generation Corvair.

This article has jpeg copies of an image-heavy article very worth looking at,
http://blog.hemmings.com/index.php/2010/04/25/sia-flashback-corvairs-for-the-70s/

I don't know how many of the images I ought to place here, here's an example, they're accessible by way of the above link,

 

[modelcitizen]

I'm attaching a pic in case the linked image goes away. The article page files are too big to attach.

 

[TFSmith121]

Nice design

Vette and Camaro/Firebird with a little Mustang, looks like.

What might have been

Best,

 

[Kevin Renner]

I do remember seeing Transporter based pick-ups in the '60s. One reason the Corvair was not as profitabnle as say a Chevy II was parts interchange. GM in the early '60s was actually pretty willing to innovate. Consider the small aluminum V-8, early attempts at turbo charging, Corvair's flat six. IMO one of the Corvairs problems was it was different. It was out of the norm of what most Amerrican consumers wanted. One other problem is early Covairs to compensate for over steer issues was differing front and rear tire pressures. Naturally the owners and most service station attendants/mechanics who "knew better" would inflate the tires to the same pressure. As far as the swing axle rear end. VW Bugs used the same thing plus various other imports. The Triumph Spitfire comes to mind

 

[marathag]

Naturally the owners and most service station attendants/mechanics who "knew better" would inflate the tires to the same pressure. As far as the swing axle rear end. VW Bugs used the same thing plus various other imports. The Triumph Spitfire comes to mind

Most of the Beetles didn't have enough power to worry about high speed handling where that would be an issue.

Bugs were far more dangerous than most folks realize. Porsche 356s had enough power to be as squirrelly as the Corvair

 

[Delta Force]

There are some articles with information about the plans that were canceled for the third-generation Corvair.

The designs look very similar to some of the Corvair concept cars. As the article mentions though, not much information on the engines and other mechanics of the vehicles, it was more general design.

I wonder if the Corvair could have become something of a smaller complement to the Corvette in the General Motors performance car lineup?

 

[Cash]

I owned a 1965 Corvair convertible with the turbocharged engine. Still consider it one of the top three cars I ever owned. With the top down it it resembled a Camaro. Never felt the car was unsafe, but the turbo engines had a tendency to blow oil seals, which happened on a memorable trip to Boston in 1971. I sold it to a Corvair fan who rebuilt the engine, replaced the ragtop, and was still driving it five years later.

ETA: I read Unsafe and still feel it was a hatchet job by a "consumer advocate" who was looking to make a reputation on an easy target. The Corvair had its faults in its early iteration but was nowhere near as bad as other, more popular vehicles.

 

[Riain]

How would a 3rd generation Corvair go after the 1973 oil crisis, was it hard on fuel? How would the flat 6 go with al the pollution controls added?

 

[DD951]

The designs look very similar to some of the Corvair concept cars. As the article mentions though, not much information on the engines and other mechanics of the vehicles, it was more general design.

I wonder if the Corvair could have become something of a smaller complement to the Corvette in the General Motors performance car lineup?

I've seen another article or two on what would have been the abortive 3rd-gen Corvair after doing some research on Google for another car thread, & IIRC, it would have been a 1970 model, and it would have been the first instance of the "Colonnade" styling that would be used on the 1973-77 A-bodies. (Although there were no pics, former insiders said to think of a somewhat shrunken '73 Chevelle with such tweaks as necessary to accommodate being a rear-engined car to get the general idea of what it would have looked like.)

Mechanically, there wouldn't have been a lot of changes. Engines would have remained largely the same at first. Some refinements would have been made to the suspension, and there was talk of making front discs standard. The big news would have been with the transmissions, as the 3-spd manual would have been dropped, as would be the Powerglide 2-speed AT, the latter being replaced with a 3-speed automatic transaxle.)

As for trying to market it as a performance car, GM did try to push the turbo models as one, without much luck, as the sort of performance enthusiast who that sort of car would appeal to tended to prefer buying imported sports cars, while efforts to promote it as a direct competitor to the Mustang fell utterly flat, as beyond the knocks on the Corvair as "too unconventional," getting smoked by 289 Hi-Po Mustangs in drag races was a real drawback in that particular market segment- I don't think that the sales collapse following Nader's book was the only factor in not only the car's demise, but the sudden & total abandonment of any performance efforts after 1966, once GM had the Camaro & Firebird to play with in the performance market.

 

[Delta Force]

How would a 3rd generation Corvair go after the 1973 oil crisis, was it hard on fuel? How would the flat 6 go with al the pollution controls added?

The article mentions that the flat six was difficult to modify for compliance with emissions controls relative to other designs at General Motors. I don't know if that's inherent to the flat six design, or if other engines were easier to modify because General Motors was more familiar with them.

 

[NothingNow]

The article mentions that the flat six was difficult to modify for compliance with emissions controls relative to other designs at General Motors. I don't know if that's inherent to the flat six design, or if other engines were easier to modify because General Motors was more familiar with them.

It's probably more closely related to how the engine was packaged. Longitudinal RR is a much tighter fit than a FR or FF design when you try to squeeze a catalytic converter in there. Transverse RR will at least give you space to squeeze it in aft of the engine.

 

[TheMann]

It's probably more closely related to how the engine was packaged. Longitudinal RR is a much tighter fit than a FR or FF design when you try to squeeze a catalytic converter in there. Transverse RR will at least give you space to squeeze it in aft of the engine.

The Corvair could easily enough IMO use the Porsche 911 (and Lamborghini Countach and Diablo) layout of having the gearbox forward of the engine. Ideally, a rear-engined car like this would have the engine as far forward as possible with the gearbox ahead of it, which is largely the case on the Porsche 911. The Diablo and Countach had the driveshaft run through the sump, and with a flat-six engine with the cylinder heads on the sides of the motor, you could easily design an oiling system where the sump is on below the cylinder heads, where the oiling system could use a gear-driven double pump to effectively have two separate oiling system. Using this arrangement with an air-cooled flat-six is not a bad arrangement because the liquid weight would be low down and the center of gravity would be quite low down. Transverse RR design is effectively the same as transverse FF in terms of design, but the problem is that the Corvair would either have the engine ahead of the rear axle or have grossly-unbalanced drivetrain design. You could have the gearbox below the engine, but that has its own issues with center of gravity. Using a transverse RR also makes exhaust installation more tricky, as one bank of cylinders is gonna be against the forward firewall whereas with longitudinal RR you have exhausts on either side of the engine.

If GM wants the best power from the Corvair, they need IMO to go a little nuts. Longitudinal flat-six, twin turbos (one for each bank of cylinders), and special carburetors with one for each cylinder (Fuel injection would be better, but in the late 1960s this is bordering on ASB), with four-valve heads, air-to-air intercooling and the design I set out above. The exhaust ports are on the bottom, and feed into the turbos mounted to the engine in a vertical arrangement, with the turbine on the bottom and compressor on top. The top of the engine has the intercoolers integrated with the intake manifolds, with the carburetors blow that. Small turbos and short intake piping would result in fast throttle response, and the lower center of gravity. Intakes for the engine would be from a cowl behind the rear window (like the second-generation car) through a pipe over the car. The camshafts would be driven from the front of the engine via a gear between the engine and clutch, with twin overhead cams for better valve control. As much of the top of the engine cover would be open and the cover would include four electric fans wired to the ignition. Ignition timing would be set from the camshafts, while a serpentine belt would be on the back of the engine to run the alternator (which would hopefully be a much bigger one to work with the electric fans) and air-conditioning compressor, while gears off the back of the block would drive the oil pumps. Designed properly, the while arrangement could be attached to a subframe in the rear and lifted into the car. The XP-873 design above would have too small an engine back to make the engine sit right at the rear, but if you have the engine over top of the rear axle and most of it forward with the driveshaft under the engine, you get better weight distribution. (Design the diff for it and you could have the driveshaft spinning the opposite way to the crank, which could be enormously beneficial for NVH purposes, too, and having the turbos attached to the engine and having them be counter-rotating could help this further.) This would be an expensive solution and not all that easy to work on, but the distributors would be at the back of the engine bay (making adjusting ignition timing easy), and when emissions come about, you put the catalytic converter at the back and feed the exhausts into it.

 

[Riain]

Was the engine a pushrod or did it have overhead cams?

 

[Delta Force]

Was the engine a pushrod or did it have overhead cams?

Wikipedia says the Chevrolet Corvair engine was a pushrod.