The Saab B234R is regarded by many hardcore Saab fans as the greatest engine ever produced by the Swedish manufacturer. That is, of course, all subjective. However, there’s a reason why so many people that really know their stuff praise the engine. In fact, because of junkyard availability the Saab B234R is actually becoming a relatively popular engine for swaps. Why is that? Well, let’s get started.
The Saab B234 is a member of the ‘H’ family of engines first developed in the late 70s as a successor to the Triumph derived B engine, which was reaching its technical limits (especially with the advent of turbocharging). When the H engine first appeared, it was fitted into the new Saab 900 at the very beginning of the 80s. The problematic in-block water pump was replaced with a simple belt driven external unit, and a single cam sat on top. CIS fuel injection was used, which generally was an excellent system, and plain old Bosch ignition powered up the distributor. The new engine would be known as the B201, signalling the beginning of the iconic H engine family that would eventually continue on to 2009 in the 9-5.
A second camshaft was added in 1984 and the newly DOHC was renamed the B202 (two liter, two cams). The B202 was Saab’s first quintessential production engine, and made it’s way into both the wildly popular Turbo Saab 900, as well as the freshly introduced Saab 9000 in 1985 where the strange slant block was configured to drop into the engine bay transversely.
The B202 struggled to make the 9000 a worthy adversary for some of the noteworthy competition such as the BMW 5-series, Mercedes 190, and Audi 100, so it was time to get a fresh engine.
The Saab B234
Launching somewhere between 1989 and 1990, the H engine got a huge revamp. Displacement was bumped to 2.3l by means of increasing stroke length to 90mm, up from 78. The block was also taller in order to accommodate the longer stroke without shortening con rods, but bore stayed the same at 90mm. That made the B234 perfectly square. Balance shafts were added to give it a more luxurious feel, and oil squirters were added to cool the bottom of the pistons. The compression ratio on turbo engines ended up at 9.25:1, while NA motors got over 10:1 CR’s. Normally Aspirated versions of the B234 made it into the NG900 as well. The basic Saab 16v cylinder head stuck with only minor changes being made.
Connecting rods in the B234 were forged, as was the crankshaft. Combined with the closed deck iron block, this created a very stout motor. It would have to be, too, because Saab was about to bolt a large turbo and make the most powerful production engine in company history.
In 1993, Turbo Saab 9000’s were now shipping with Trionic engine management, allowing for a very precise electronic control of fuel, ignition, and boost pressure. With the harmonious union of the very strong torquey B234, a special Trionic 5 engine map, and a larger turbocharger, Saab punctuated a new chapter in it’s book “How to design a sleeper” The B234R was born.
Automatic transmission cars were limited in power output, but if you were the type of person that preferred to shift yourself, you got the full 225hp and nearly 300ft/lbs of torque. In 1993, this was a huge amount of power for a boxy four-cylinder front wheel drive sedan. Even the top trim Porsche 993 turbo supercar only made around 50hp more at the time.
The turbocharger used was a Mitsubishi TD04HL-15, and charge air was cooled with a reasonable sized intercooler. From the factory this setup still had miles of headroom, and it’s not uncommon for people to make big reliable power with only a few small modifications.
Because of this, it’s an extremely popular engine to swap into other cars, as mentioned above. I know people that have picked up running B234’s for under $200. I’m not just talking about people souping them up and putting them into other Saabs. A cursory google search reveals successful swaps into Miatas, Subarus, BMW‘s, a whole variety of Opels, and more. Our friends in the Saabs of Anarchy Lemons team even swapped its 2.0l brother (the B204) into a YJ Jeep Wrangler. I personally know of a Mercedes 450SL that’s having its heavy smokey V8 replaced with a very cheap B234R.
Due to the low cost of purchase (unfortunately most Saab 9000’s these days can be found in recycling yards rather than on the road), the B234R has made it into several very successful LeMons racing cars, including an extremely successful Saab powered Nissan 300zx. Someone even mounted a pair of B234R’s into a speedboat. I think someday I personally would like to build a Volvo 142 with a B234R driving the rear wheels, due to the availability of custom bell housings to mate them with T5 gearboxes….goals.
If you have an engine you think is really cool, really interesting, or just plain weird, leave it in the comments below. Maybe it will be featured on the next edition of “Get to know an engine”!