The turbocharged V8 is a common sight in the engine bays of today’s luxury cars. All the big 3 German automakers have them, and Cadillac made one for about ten seconds before GM realized they were making a good decision. These motors make a lot of sense today. Emissions regulations are getting tighter, fuel economy must improve, but the demand for performance hasn’t gone away.
Turbocharging is an accepted reality of engines today, but it wasn’t always so common. Turbocharging started out being used in aircraft engines, with their popularity really picking up steam during World War 2. They were used to increase performance and or deal with extra altitude. Once you begin to learn about turbocharged aircraft engines, you may also fall into the seemingly endless rabbit hole concerning “turbo compounding”. Next thing you know you haven’t left your house in several days–you’re trying to find ever-more detailed diagrams of the Napier Nomad in all of its configurations. Ask me how I know.
Like a hot Cutlass through… Uhh…
The second production car ever to be turbocharged (the first was a Corvair) was the Oldsmobile Jetfire–a high-performance version of the Cutlass. It contained the boosted V8 in question, a modified version of Olds’ 3.5 liter V8 called the “Turbo-Rocket”. This engine (in all of its various trims and displacements) is actually extremely common. Several other GM brands used it, and it even ended up across the pond in many different British cars. The first one was made in 1949, and the last one was bolted into a Land Rover in 2004. As far as my research tells me, it actually still remains in limited production in the United Kingdom. The turbocharged version was the least common, for reasons which will become apparent.
The Turbo-Rocket used a small turbocharger manufactured by the Garret AiResearch Corporation (sound familiar?). They had some experience in WW2 building various systems for aircraft–including intercoolers–and worked with Oldsmobile to create the turbo in question; the T05. The T05 was a small (I was not able to find the exact size of the exhaust turbine), a relatively slow-spinning unit with an integral wastegate. At 2200 RPM, the strengthened Olds 215 would provide enough exhaust for it to reach a peak boost pressure of 5 PSI. A few thousand RPM later, power would peak at 215 ponies. At one horsepower per cubic inch, this was considered impressive at the time.
A little help from Messerschmitt
One problem all turbocharged engines suffer from is an increase in inlet air temperature. There are various ways to solve this, including the use of intercoolers–or pulling back on the motor’s compression. Another way is water or alcohol injection.
The BMW M4 GTS is one of the most well-known modern cars to use water injection. It helps squeeze another 68 horsepower out of the already intercooled S55. This idea isn’t new, though. Many boosted aircraft in WW2 used the same sort of system. The system on the Messerschmitt BF 109 used a mixture of water AND methanol. To be precise, it was a mixture of 50% methanol, 49.5% water, and .5% corrosion inhibitor.
Oldsmobile took notice of these sorts of systems and decided to put them to use in the Jetfire. When the engine was under boost, some of the pressure would be plumbed off into a tank of “Turbo-Rocket Fluid”. This pressurization, in concert with a venturi in the inlet track, would draw the ‘TRF’ up behind a side-draft carburetor and into the mouth of the turbocharger.
The TRF would evaporate, cooling the intake charge and effectively boosting the octane rating of the fuel by two whole points. This was what allowed the reasonably high compression ratio (10.25:1) and the aforementioned increase in performance. The Turbo-Rocket Fluid’s secret formula that allowed these sorts of gains was 50% methanol, 49.5% water, and .5% corrosion inhibitor.
An Interesting Find
By some miracle, the original video given to dealerships to help move Jetfires out the door has been saved, and although the film clearly needs to be restored, it’s on Youtube.
The whole video is really funny. If you’re at work and feel like taking a 14 minute-long restroom excursion, this video would be a good way to fill that time. I think that’s an F-106 Delta Dart at 1:17. I like how GM just got a fighter jet to buzz some suburban area for the sake of a dealership-only promotional film. It definitely beats the Chevy Volt song and dance routine.
Probably the funniest part of the whole video happens at 6:09. “Your wife will love your boosted V8! Look how happy she is!” I think that’s the only positive reaction I’ve ever seen a non-enthusiast woman have to a turbocharger. I speak from experience, of course.
Breaking up under Boost
When the tank was full and everything was all hooked-up, the system worked as intended. The intake charge was cooled, the horsepower went up, and you could continue your 1960s sort of life; doing things like chasing the big truck that fogs your cul-de-sac with doubtlessly toxic insect repellent. The issues began to arise when the juice ran out.
First of all, the car would pull 4 psi of boost pressure when it was out of TRF. This was to prevent engine damage when the much-needed go-juice wasn’t available. People would wander back to the dealerships, wondering why their new Jetfire was lacking its usual thrust. The answer was simple: you were out of TRF and the only place to buy it is here. This may have been reasonable if the TRF lasted a fairly long time, but it didn’t. It could last as little as 1-2 tanks of gas.
The Jetfire itself was also not really a “sporty” car. This was done on purpose, with Oldsmobile’s chief design engineer saying that the car was, “a hot-performing street job, not a high-speed race car”. This was a mistake. The Jetfire was not a sports sedan, but it was priced like one. It’s MSRP of just-below three thousand dollars put it up against other vehicles that were more powerful and handled better.
Oldsmobile had a Genius Solution
“Wow. It seems like this whole turbocharger thing didn’t really work out. What do we do?”
“Don’t those things just bolt on?”
“You got a wrench?”
Oldsmobile decided the best course of action to solve the whole turbocharger issue was to just get rid of them. They told all the owners that they should bring their cars to the dealership so it could be uninstalled. It would be replaced with a four-barrel carburetor and dual exhausts to gain back some of the lost power. If owners decided that they wanted to keep the turbocharger, that was too bad. Oldsmobile also stopped making the Turbo-Rocket Fluid. Before the age of the internet, people just didn’t know what else to put in the tank.
As a result of this program, nearly all of the 3,765 Jetfires had their turbos taken off. Today, it’s likely that less than a hundred factory turbocharged cars still exist. That means none of us will probably ever get to experience what driving one was really like. That, however, does not mean there isn’t a low-quality Youtube video of a man (who appears to live in the middle of a cornfield) bang-shifting one.