Along with the new turbo Regal, Buick introduced a second turbocharged model for 1978: the full-size Buick LeSabre Sport Coupe. Unfortunately, buyers weren’t very interested, although the turbocharged Buick V-6 could outrun the 350-cid V-8 and returned much better gas mileage. Let’s take a look at how the turbo LeSabre compared to its V-8 counterpart.
Like other GM B-body and C-body full-size cars, the Buick LeSabre was completely redesigned and downsized for 1977. In coupe form, the new LeSabre actually looked even smaller than it actually was, due mostly to a relatively short 115.9-inch wheelbase. Seeing it in isolation, you might assume it was only a little bigger than the also-downsized 1978 Buick Regal, but the LeSabre was actually over a foot and a half longer and 5 inches wider. I find the downsized LeSabre coupe better-looking than the downsized Regal, although the Regal’s more upright formal roof offered better packaging efficiency.
Despite its still-ample size and weight, the downsized LeSabre handled noticeably better than before, especially the Sport Coupe, which came with a firmer suspension with front and rear anti-roll bars and big GR70-15 tires, plus faster-ratio power steering. (The latter ended up being the subject of a recall.) Car and Driver editor Patrick Bedard, who among other things was a licensed racing driver, thought the LeSabre Sport Coupe had the best chassis of any of the downsized B-bodies, better even than the F41 Chevrolet Caprice, with which C/D was also quite impressed. When properly equipped, these cars were very capable for their time, which the car magazines found a welcome change from most past Buicks.
This newfound sportiness faded somewhat inside. Buick didn’t offer bucket seats on its full-size cars in 1977 or 1978. In mid-1978, Oldsmobile tried the full-size buckets-and-console routine again with its Holiday 88 Coupe, but Buick didn’t follow suit until 1979, and interest proved to be very limited. In 1978, you could order the LeSabre Sport Coupe with a cloth 55/45 split bench, which was at least less slippery than vinyl, but this car has the standard vinyl notchback bench.
There was no instrument package either, even as an option, and the only available transmission was a column-shifted Turbo Hydra-Matic.
Although a normally aspirated 3.8-liter Buick V-6 was standard on the base LeSabre and LeSabre Custom, over 90 percent of buyers ordered a V-8. The most powerful engine available in 1978 was the L80 Oldsmobile 403-cid V-8, which had 185 net horsepower, but it wasn’t very common. For most LeSabre buyers, the choice was between the L27 Pontiac 301, with 140 hp, or the L77 Buick 350-4V, which had 155 hp. Since the LeSabre still weighed about 4,000 lb and V-8 cars were usually saddled with a sleepy 2.41 axle ratio, performance was leisurely with the 301 and only okay with the 350. Car and Driver‘s 350-powered 1977 LeSabre Sport Coupe needed 12.2 seconds to hit 60 mph and ran out of breath at 96 mph flat out.
The 350 was still optional on the LeSabre and LeSabre Custom for 1978, but the 1978 LeSabre Sport Coupe now came with the new turbocharged version of the 3.8-liter Buick V-6, also available in the 1978 Regal Sport Coupe. Today, the Buick turbo V-6 is most strongly associated with the Regal, which it eventually transformed into a latter-day muscle car, but Buick offered the engine in most of its RWD cars at one time or another, including the B-body LeSabre. In 1978, the standard engine in the LeSabre Sport Coupe was the milder one-year-only two-barrel version of this engine, but most turbo cars had the optional LC8 four-barrel version, which had 165 hp and 265 lb-ft of torque, accompanied by a more assertive 3.08 axle ratio.
Installing a ’70s-tech turbo six in a full-size car might sound like a very dubious proposition, but in some ways, the turbocharged 3.8 made more sense in the LeSabre than it did in the Regal. For one, the turbo LeSabre got meaningfully better gas mileage than the 350. In the Regal, fuel economy was basically a wash — the turbo engine’s EPA ratings were so similar to the LG3 305 V-8 that it didn’t even help Buick’s Corporate Average Fuel Economy (CAFE) calculations — but the turbo LeSabre had a useful 1 mpg edge over the L77 350. Thanks to Buick’s Electronic Spark Control system, the turbocharged V-6 didn’t need premium fuel, so it was cheaper to feed than the 350.
The turbo car was also faster. I found an interesting assessment in the February 1978 Road & Track, which compared two LeSabre Sport Coupes, one a 1977 with the L77 350 V-8, the other with the 1978 LC8 turbo V-6. Here’s a summary from the text and the above graphs (which show the 350 V-8 on the left and the turbo V-6 on the right):
| Performance | 1977 L77 350 | 1978 LC8 V-6 Turbo |
|---|---|---|
| 0 to 30 mph, sec. | 3.5 | 3.6 |
| 0 to 40 mph, sec. | 5.2 | 5.2 |
| 0 to 50 mph, sec. | 7.7 | 7.2 |
| 0 to 60 mph, sec. | 10.9 (est.) | 10.0 (est.) |
| Quarter mile | 18.1 sec. at 76 mph (est.) | 18.0 sec. at 79 mph (est.) |
(I gleaned the “est.” figures based on the graphs, since R&T didn’t include a table of acceleration times, and neither the 0 to 60 nor the quarter mile times were stated in the main text.)
This was generally consistent with Buick’s claims, which showed that the V-8 would pull ahead by a slight margin off the line and then fall behind at higher speeds. Road & Track noted, “The turbocharged V-6 reach 90 mph 2.4 sec sooner and was easily pulling away from the V-8.”
On the road, the R&T editors found the turbo car’s automatic upshifts “were a slight bit sluggish,” but thought that “otherwise the feeling was very much like driving a car equipped with a V-8.” The TH350 transmission’s higher-stall torque converter did a fairly effective job of masking the engine’s turbo lag, and didn’t hurt gas mileage. Over more than 4,000 miles of driving in both cars, the V-6 turned out to have a much bigger edge in real-world fuel economy than the EPA numbers suggested: Road & Track averaged 16.5 mpg with the V-6 turbo car, compared to only 13.5 mpg with the 350 V-8. Considering the turbo car’s higher numerical axle ratio, that was a pretty decisive advantage.
Associate editor Thos L. Bryant also took the turbo LeSabre on a road trip through Arizona, Colorado, and New Mexico to see how it performed at altitude. The original rationale for “turbo-supercharging” was to give aircraft engines better altitude performance by compensating for lower air pressure, and sure enough, Bryant found the turbocharged V-6 did well up to about 7,500 feet. At even higher altitudes, it would still pull long grades, but if you lost too much speed, it took a while for the V-6 to get back into the meaty part of its torque curve.
Road & Track unfortunately didn’t comment on the comparative handling of the V-8 and turbo cars, but even with the turbo hardware, the V-6 was lighter than the Buick 350. With the same suspension and less weight on the nose, the turbo Sport Coupe likely handled even better than the V-8 version.
All this seemed to make a solid case for the turbo V-6. In the LeSabre, it was close to a second quicker to 60 mph than the 350, had better passing power, and returned significantly better gas mileage. True, the turbocharged engine was a bit lazier than the L77 350 at around-town speeds, but almost 75,000 ’78 LeSabre buyers chose the Pontiac 301, which wasn’t any great shakes in that department either. Nonetheless, LeSabre Sport Coupe sales were dismal: only 8,139 cars for 1978. Buick buyers just weren’t interested.
Some customers may have been wary of the turbo engine, which was an unknown quantity in terms of reliability. The earliest versions were buggy — at one point, the Road & Track test car’s Electronic Spark Control system took an unexpected tea break, which didn’t inspire confidence — and prone to plug fouling and cracked exhaust manifolds. However, I think to a large extent, people buying full-size Buicks just expected a V-8, even if it was a small and underpowered one. The normally aspirated 3.8-liter V-6, which was standard on the LeSabre and LeSabre Custom, made for pretty sluggish going in these full-size cars, and only about 21,000 1978 LeSabre buyers chose it.
Buick had started to worry by this time that their median buyer age was getting awfully high (“They’re getting older every year,” lamented general sales manager John D. Duffy Jr.), but if they were expecting the LeSabre Sport Coupe to help them attract younger buyers, they were out of luck. The 1979 model had more power than the ’78 and some detail refinements, including the availability of bucket seats, but sales fell by more than half, to 3,582 cars. Buick sold a mere 1,277 more for 1980, after which the turbo LeSabre was dropped for good.
The turbo Regal survived through 1987 and still has a small but fiercely loyal following, but the turbo LeSabre is very rare, and seems to have be mostly forgotten except by hardcore Buick fans. This one has popped up for sale at least four times in different states since 2018; when Unique Classic Cars sold it for $17,900 four years ago, it still had fewer than 40,000 miles on the odometer.
Related Reading
Vintage Review: 1977 Buick LeSabre Sport Coupe – Gran Sport By Another Name (by GN)
Curbside Classic: 1977 Buick LeSabre Custom Coupe – Mellow In Yellow (by J P Cavanaugh)
CC Outtake: Buick LeSabre Coupe – The Prettiest B-Body Of Them All (by Rich Schwartz)
COAL: 1978 Buick LeSabre Custom…The One I Should Have Kept (by Len Peters)
Vintage R/T Review: 1979 Buick Riviera S Type – The “S” Stands For “Sharp,” Not “Sporty” (by me)
Aaron thanks for this one. After you were showing bucket seat full size cars, my mind immediately jumped to this Buick even if it didn’t have bucket seats.
The magazines were certainly high on them. At the time I was graduating college and was considering a regional technical sales position requiring travel by car and looked at these really hard. I ultimately decided to stick with design engineering and didn’t buy one The styling had that Ferrari 400 roofline and was clean for the period and not brougham like.
Another way to look at a turbo’s advantage besides barometric pressure is the difference in oxygen level. My understanding is that for each additional thousand feet above sea level there is a 3% loss of oxygen. For this reason athletes can gain an edge by training at high altitude to improve pulmonary efficiency. Has it helped the Denver teams? That’s debatable.
If Jim Klein had been 10 years older, he might well have bought one of these instead of the ’88 LeSabre T-Type:
https://www.curbsideclassic.com/cars-of-a-lifetime/coal-1988-buick-lesabre-t-type-a-young-man-buys-an-old-mans-car/
A buddy of mine in college had a ’77 LeSabre coupe with the 403. I don’t remember it being an acceleration demon but it cruised effortlessly.
I’m not surprised they didn’t sell well. Turbocharging was a very immature technology, and Buick buyers in the era tended to be a very conservative lot.
I have driven most iterations of B Body, but I have never driven a LeSabre with the turbocharged engine. Buyers were wary of the complication of the turbocharged engine and stayed away. I think GM’s diesel debacle had something to do with it, as GM got a lot of bad press on that, which may have affected sales of their turbo models.
A LeSabre with heavy duty suspension rode and handled very well for the time.
I worked on these cars when they were newer.
The 5.7 diesel came out in late ’78 in the Buick’s (If my memory serves correctly) and it wasn’t until late ’79 when when the 5.7 starting showing how much of a POS it is/was. I believe the diesel was not a factor in the lack of success with the turbo 3.8.
I actually had some customer interaction involving the subject of the turbo engine. I also had a buddy who was salesman. The following is what I recall: Those that owned them loved the power (for the time) and fuel mileage, but were wary as to how they would hold up in the long run. When asking others about if they considered the turbo 6, they mostly responded with “A Buick needs a proper V-8”.
So you were correct about the apprehension of the technology, but I really don’t think the 5.7 diesel had any real effect.
Glad you wrote the LeSabre Sport Coupes up. I thought they were very nice looking cars for the time.
…but Buick offered the engine in most of its RWD cars at one time or another, including the B-body LeSabre.
It was also available in the ’79 to ’85 FWD Riviera. Unfortunately, it was dropped when the 500-pounds lighter ’86 Riviera was introduced. Had they kept it on the options list, it would have been a far more interesting car than it ultimately was.
Yes, I added a link to the end to the Road & Track introductory review of the 1979 Riviera S with the turbo engine.
These are my favorite of the 77-79 B bodies, funny enough I was expecting a weird bucket/console combination I didn’t know existed like other recent featured Bs and am slightly disappointed there wasn’t a truly ultimate obscure LeSabre sport coupe with it. Nevertheless the bodystyle has a great profile, it’s no comparison with the Regal that to me looks way too stubby(the 81 restyle made those substantially better as far as I’m concerned). The minimal instrumentation is disappointing too, as the dash and round gauges that are there are nice looking
The thing that catches my eye regularly with these early Buick turbos, and I suspect the point, is the bright red intake system looks both home made and finished with Krylon spray paint. The late 70s were not good times for well dressed factory engine compartments, with their miles of hoses and lines, bulky ever more standard AC systems, smog pumps and what have you and the disappearance of colorful divisional blocks and chrome lids/covers on sporty setups, but Buick was proud enough of this system to make it stand out under the hood where they could
Price may well have played a part in the reluctance to embrace the Turbo V6.
Another thing is turbo lag. It’s obvious in the acceleration chart. You can see the V8 car initially accelerates much better than the V6 despite the almost absurdly long final drive ratio. Turbo lag can be fun in the right car and frame of mind but most want their full-size to go when they tell it to and not have to wait a second or two for it to get its act together and get moving.