In 1980 the 301T emerged as a possible way for Pontiac to maintain some semblance of performance in an age where gas prices had driven people to down-size and down-perform. Pontiac, still working with a 10 year old car and thus a 10 year old philosophy, had to think of something to keep buyers coming back for the “outdated” Firebird and have it work in favour of CAFE regulations: a 12 mpg 400 could no longer be the weapon of choice. What’s a good way to maintain some fuel economy, while still having a V8 (nobody’s going to settle for a Trans Am with a four-banger!) with some punch? Why, forced induction, of course! Slap a Garrett AiResearch model TB0305 turbocharger, good for 9 psi of boost, onto the existing low-deck 301 with an 800 cfm Quadrajet, and what do you get? 210 hp @ 4000 rpm and 345 lb*ft of torque @ 2000 rpm. Well, you say, that horsepower isn’t that great – no, not by today’s standards, but compared to the 150 hp of the basic 301 it isn’t too shabby. Besides, a turbo T/A was still able to pace the Indy 500 with only a rear end gear swap and removal of the A/C equipment.
Despite the fact that GM had high hopes for the 301T, it didn’t receive all that many accolades at the time of its introduction. People seemed to think (partially due to GM’s propaganda) that the 301T was going to be the second coming of the vaunted and legendary SD 455. Well, that’s just dumb. A quick review of the numbers show you that the 301T is not up to the standards of Poncho’s most revered mill. However, for its day, the 301T was (on paper at least) the meanest engine you could get in almost ANY GM, including ‘Vettes!
However, because it wasn’t the tire-burner that those in rose-coloured glasses inexplicably expected, and because the technology wasn’t quite yet fully developed, the automotive press was, and has been, less than kind to the 301T. While the last years (’79-’81) of the 2nd Gen Firebirds (1970-1981) are generally well-regarded from a styling standpoint, there are many people who ripped the 301T out to replace it with a more easily souped up 305, or, back in the day (when they were more plentiful) a 400.
I know what you’re thinking: What? Replace a Poncho mill with a Chevy one? Sacrilige! It is, but it’s also what has happened to a lot of cars, and not every ’80 and ’81 Turbo-hooded car has a real, working 301T under the Screaming Chicken. However, Faust does!
What Goes With a 301T?
Besides just bolting on a turbo, some other parts of the engine were strengthened to withstand the boost: extra material was added to the block’s bearing webs and top deck, and main-bearing-cap bolts were increased from seven-sixteenths to one-half inch in diameter. Crankshaft fillets received a pressure-rolling treatment to make this part more fatigue-resistant. Pistons are cast-aluminum, as in regular 301s, but they were redesigned (along with the wrist pins) for greater strength. The compression ratio was also lowered to 7.6:1 (for 1980). The turbo engine was given the same special, low-drag water pump as the base 301; however, a robust 70 psi oil pump was specified to keep the TB0305 happy and functional. To better assist this pump, an oil pan with more baffles was added.
Snazzy new styling to compliment the new power plant was restricted, of course, by the existing body and facias. However, “Turbo Trans Am” decals were applied to the spoiler and an entirely new hood was created: replacing the hallmark shaker scoop was a one-piece unit with an off-center “bulge”. I have seen numerous references that say “the bulge was needed to make room for the turbo”. This is true, but I dislike this wording, as it implies that the turbo resides under the bulge, which it does not. The turbo unit is on the opposite side; the bulge actually makes room for the air cleaner, which sits higher due to the turbo components. A new, giant “screaming chicken” decal, complete with flames licking up the bulge, graced this hood (although this was an option – $120 in ’80 and $125 in ’81, American dollars). “Turbo 4.9″ decals on the sides of the bulge told everyone what you had and an array of lights on the back of the bulge told the driver how much boost was in use.
Note that turbo light availability appears to have been somewhat inconsistent; Faust doesn’t have them, and he was built in Dec. 1979.
What Does the 301T Look Like?
I have been to many car shows where people exclaim they’ve never seen a 301T, and it generates considerable interest among younger automotive enthusiasts, for whom turbocharging is a much more common “trick of the trade”. Regardless of age, the general reaction when I pop the hood is one of honest, and utter, disbelief. The “old boys” have never seen one or haven’t seen one intact for ages, and it looks a lot different from the Hemis and 454s they’re used to. The “new boys (and occasional girl)” are blown away by the size of the turbo, since new units are much smaller. The really freak out when I tell them there’s no intercooler! (Nice work, GM…)
Oh, one other thing; almost NOBODY who isn’t a T/A nut seems to believe that the turbo is stock! I have had all kinds of people ask me about “where did you get your custom engine”, etc. It’s quite entertaining, actually! My favourite instance was at a car show that was basically all new import tuner-types, and me. I had a crowd of younger tuner people looking at the car and one guy goes ” Is that legit?” I didn’t know to what he was referring… He then asked about the turbo, and what the numbers after it were. I told him: “It’s a 4.9 Litre turbocharged, carbureted V8. ” He still didn’t believe me until I popped the hood. Then he believed it!
As mentioned above, the 301T option offsets the air cleaner and carburetor, creating a distinct visual impact. Everything in the engine bay looks like it’s shifted sideways! Add to that the armoured, heat-resistant plate designed to prevent the turbo from peeling the paint off the hood, and you have a very interesting technological orphan on your hands.
Because it seems that the 301T is of more interest now than when it was made, I have some pictures of it below; now you can see what Pontiac was thinking back in the late 1970′s. For better or worse, it was the cutting edge of powerplant technology, insofar as performance and economy were concerned!
What Can the 301T Do?
It should have been obvious that we weren’t getting a reincarnation of the SD-455, to be sure. Magazines at the time varied HIGHLY in their recorded times for ¼ mile and 0-60 runs.
Car and Driver 1980 turbo T/A test: 0-60 in 8.2 seconds, ¼ mile in 16.7 seconds
Road & Track 1981 turbo T/A test: 0-60 in 8.7 seconds, ¼ mile in 16.0 seconds
I’ve also heard of some magazine test that required over 9 seconds for 0-60! Apparently, every car is unique – for better or worse!
Keep in mind, too, that a turbo Trans Am (or Formula) tips the scales with a curb weight of almost two tons, and has a mild 3.08:1 rear end ratio in the name of fuel economy.
As an update to these numbers, the October 2000 issue of High Performance Pontiac features a drag test of a basically-stock turbo T/A. The numbers aren’t terribly impressive: the ¼ mile was done in 16.27 seconds @ 87.04 mph. The article goes on to point out that, while the car’s acceleration was slow, it was very consistent: 6 different runs yielded very similar times. This consistency, combined with the well-balanced nature of the turbo T/A, make these cars excellent bracket racers. The owner of the featured T/A had already won 2 Pro-Class championships, in fact! Slow and steady really does win the race – you just have to choose the right type of race!
More esoterically, Faust’s 301T whistles like a jet engine crossed with a banshee under hard acceleration, especially if the secondaries on the carburetor open up! Even under mild stomping, though, Faust’s 301T will emit a nearly supernatural shriek from the front end, and muscle car rumbling from the back. I call the turbo sound “ghosting”, because it sounds like a ghost. There’s also no blowoff valve on the 301T, so you don’t get that annoying popping sound as pressure builds up. Experts inform me that could be because of a sticky wastegate actuator, and lower restriction exhaust. If you hear a 301T doing that, it isn’t necessarily in bad health; Faust has always done it since I got him (in 1999), and he runs fine.
However, 301Ts can get noisy in a bad way, too. If the impellers on the turbos are damaged, then they will run very loudly. If you hear one doing that, then it’s best to tell the owner that it’s time for a turbo service! Normal, stock, healthy 301Ts are very quiet, even under acceleration.
Electrical and Vacuum Diagrams:
Since many of the 301Ts out there have self-destructed or been replaced, finding good wiring diagrams and vacuum illustrations can prove to be a problem.
Here they are for the 1980 301T installation: