General question

[Rob M.]

All techies,

What is supercharged ? I've seen this label put on more than one car recently and also read some vintage articles where this phrase was mentioned. I've seen some pictures of replacements of carburators with an alternative setup which was labelled a supercharger but on what principle was this based ? Where there more than one supercharger for C1 Vette's ?

greetings,
Rob.

[Joe C.]

Re: General question

All Corvettes are and always were naturally aspirated. They were never supercharged.
A supercharger is a mechanically driven pump, which pressurizes the intake plenum, thereby increasing the charge into the combustion chambers. External superchargers are normally driven by belts, taken off of the crank pulley. There are also internal superchargers, like Mazda uses on their very powerful 2.2 liter six. This is also referred to as a "Miller Cycle" engine.
Turbochargers use the same principle, although they are turbine/pump units, driven by exhaust gas.
Far as I know, Buick was the only domestic brand to use a supercharged engine.

That is the simple answer.

Joe

[Dave Suesz]

Supercharging

As above, a supercharged engine has the intake gasses pressurized either by a belt or gear driven pump, or, in the case of turbosupercharging, by a turbine using exhaust gas.

USA domestic cars have a long history of supercharging. The '57 Thunderbird was available with supercharging, as was the '63 (I think) Oldsmobile, the Corvair Spyder and Corsa models were offered with turbocharging, the '66 Shelby GT 350S had a Paxton supercharger (similar to the '57 T-bird), the 80's Mustang Turbo and Mustang SVO were equipped with a turbocharger, the Thunderbird Turbo Coupe was turbocharged, and the later Thunderbird SC was supercharged. Pontiac has offered a supercharged coupe for over ten years.

I owned a Corsa and a Tbird SC. The Corsa had a 180 hp turbosupercharged aircooled six cylinder, a great handling road car similar to the Porsche up to about 100 mph. The Thunderbird SC was a phenomenal road car, with a V6 equipped with an Eaton M-90 supercharger, up to 13psi boost (15 in the later models) progressive steering, self-adjusting shocks, 8-way power leather seats with power adjusting bolster, and more. Rock steady, car would cruise comfortably all day at high speed.

Installation on Corvettes has been going on almost since Chevy started building them, certainly in the late 50's when Paxton started offering kits. They probably still sell them.

[Joe L.]

Re: General question

Rob-----

Joe and Dave have pretty much answered your question. I'll add this: the term "supercharger" usually refers to a belt or gear driven device to boost manifold pressure. The term "turbocharger" usually refers to a device which uses exhaust pressure to boost manifold pressure. Actually, both devices are "superchargers" with the latter being a turbosupercharger. In the vernacular, though, the nomenclature distinction between the 2 types of devices is as I described.

Although Corvettes as delivered from Flint, St. Louis, or Bowling Green were never equipped with a supercharger or a turbocharger, some Corvettes as delivered to dealers were. These were the Callaway Corvettes of the later C4 series. These units used turbochargers or dual turbochargers in combination with other engine mods to achieve very high power levels.

Although they are very efficient, I don't like turbochargers. One problem is a momenetary lag in the delievery of power (called "turbo-lag") which results from the need of the turbine to react to the exhaust gas. Better technology has reduced this, but it's impossible to eliminate it, altogether.

Another problem with turbochargers is potentially very high maintenence costs. These devices spin VERY high RPM and they run VERY hot. Both factors create high susceptibility to deterioration. Rebuilding, repair or replacement of turbochargers is very expensive.

I have a 2004 Pontiac Grand Prix GTP which is equipped with an Eaton supercharger and 3.8 L engine. This is a very sweet car to drive. The nearly instantaneous surge of power when the supercharger comes on makes me smile every time. There's nothing like it. The 3.8 L engine, although ancient, has been refined to a high degree and in combination with the supercharger really makes for a great overall driving experience.

[Clem Z.]

joe i had a SC GTP for a rental car in fla.

and it ran great. national lets you pick your car in the garage so they had impalas,non SC GTPs but when i saw the SC emblem on the deck lid i grabbed it.

[Clem Z.]

PS joe,if i decide to keep my C-6 for more than

a couple of years i most likely install a SC on it because that is the way to make HP without effecting mileage or emmissions

[Ralph Harlan]

Re: General question

Studebaker also had a "factory" supercharger available back in the mid/late 50's through the early 60's that was essentially a Paxton

[Rob M.]

Thanks all for explaining! *NM*