SAAB B234 represents a journey from a borrowed design to what is generally accepted as one of the best four-cylinder engines built in recent history. At the very minimum, the B234 rates as one of the best engines SAAB have ever made.
Our goal with this short guide is to introduce the B234 to those who aren’t familiar with it and explain just how important this engine is in the grand car modding scheme.
SAAB’s Ticket to the Engine Hall of Fame
The so-called engine hall of fame is packed full of awesome designs from all over the world. Every or almost every manufacturer has contributed to this legendary roster that grows each year.
What makes an engine worth such high praise?
The answer to this question varies from person to person; however, most will say it’s some combination of reliability and performance. But wait, things get even more interesting. A small group of engines stands out, even from the other hall of fame members.
We’re talking about engines that aren’t just popular for their power or reliability, but also their versatility. Engines such as the K20/24, the mighty LS, and of course, the B234 from SAAB.
All of these have in common that people swap them into all kinds of vehicles. SAAB’s B234 has always been a popular swap option, but it is becoming even more so now that donor cars are abundant.
What exactly makes the B234 so suitable for swaps and tuning? Let’s find out!
Building Upon a Solid Foundation
The story of B234 starts way back in 1968. Back then, Triumph Motor Company designed the first H pattern slant-4 engine. They’ve used the original 1.7-liter version in their Triumph Dolomite 1850 and later models.
At this point, you’re probably wondering what does SAAB has to do with Triumph? Back in the day, while Triumph was designing the slant-four engine, SAAB was also trying to build a motor of their own.
The company was putting together the SAAB 99, and they needed something to power this new model. After some time and several failed attempts to build something that met their needs, the brass at SAAB realized that building an engine from scratch is neither easy nor cheap.
Fortunately for them, they had Harry Ricardo’s consultancy firm working for them. It just so happened that Ricardo was well-informed about what Triumph was building. His idea was to have SAAB adopt the engine because it was simply better than the 1.2-liter motor they were unsuccessfully putting together in-house.
That is precisely what happened. SAAB took the slant-four and used it in a variety of models. The original Triumph motor was later used as a foundation for the B series engines, which is where B234 originally comes from.
The Slant Design
Slant engines are a rarity these days. So much so that even some of the most hardcore car enthusiasts don’t know they exist. However, the fact that they are rare doesn’t mean that they are bad. On the contrary, slant engines were known for a few fairly important benefits.
The slant engine differs from a standard inline design in cylinder orientation. With the slant design, you’re looking at 45 degrees of angle from the crankshaft to the combustion chamber. Such structure may come across as odd, but you’re getting more room for both intake and exhaust manifolds, and they allow the engine compartment to be thinner altogether.
Most importantly, slant engines are easy to make, which is why both Triumph and SAAB kept making them for a long time.
B202 – The Prelude
To reach the B234, we have to first go through the B series and then the famous H series, which has spawned the B234. SAAB didn’t just use the Triumph slant four engines as a crutch to bridge a technological gap.
No, they’ve pretty much leaned on this engine hard, perfecting it through various iterations until they reached what is now known as one of the best turbocharged engines in the world.
Getting there wasn’t easy. SAAB had to jump a few hurdles to get the engine to work reliably with a turbocharger. For one, they had to get rid of the in-block water pump that caused all kinds of issues.
The redesigned version had the pump moved outside the block and chain driven. Not only was this solution easier to make, but it was far more reliable and simpler. The B series and H series were installed in everything ranging from the SAAB 99 to 9000, and 900.
Before B234, there were the B201 and B202. These were 2-liter versions of the H engine fitted with the new water pump, SAAB’s CIS fuel injection system, and a BOSCH distributor. The B201 was a 2-liter engine with a single overhead camshaft, while the B202 added another one, hence the altered designation.
The B202 was introduced in 1984 and was the powerhouse behind the SAAB 900. When they tried to push the 9000 series with it, things didn’t end so well. In fact, the 9000 wasn’t capable of going against the equivalent BMW or Mercedes-Benz of the era. Something new had to be devised.
B234 is Born
The need for something more powerful has put SAAB in a very peculiar position. They could either build something new or just keep doing what they were doing up to that point. Naturally, they went with the latter option.
The new B234 features a larger displacement, being a 2.3-liter package, unlike the standard 2.0-liter B202. Instead of messing with the bore, SAAB simply increased the stroke to gain those .3 liters of displacement. The addition of some 12 mm to stroke gave the B234 a boxy, square appearance.
They went on to add balance shafts because there were excess vibrations without it. The addition of balance shafts gave the whole package a more refined feel. Next, SAAB introduced a set of oil squirters to keep the bottom end of pistons cold. Where SAAB really went a step further was adding forged connecting rods and a forged crankshaft.
What they’ve basically done is created a perfect stock platform for all kinds of tuning. Forged internals were capable of cranking out much more horsepower than the stock block had to offer. Combined with their standard 16v head, the B234 engine was ready to make history.
The boosted version delivered 9.25:1, while the naturally aspirated models got over a 10:1 compression ratio.
The Trionic Engine Management
When SAAB introduced the Trionic engine management systems in the 1993 SAAB 9000 series, they’ve essentially built the final piece of the B234 puzzle. Trionic computers were capable of making very fine corrections both to the fuel/air mixture and boost. The resulting engine got to be known as the B234R.
Paired with the capable manual transmission in the 9000 Aero, you could get 225hp out of one of these, as well as 300ft/lbs of torque. Those figures don’t look like much these days, but keep in mind that we’re talking about the early ’90s.
SAAB was one of the few brands that could deliver such power from a four-cylinder engine. For comparison, the next best thing was the Porsche 993 that made only 50 hp more. To make that additional 50 hp, Porsche had to use almost anywhere from 1.3 to 1.5 liter of additional displacement compared to the SAAB 9000 Aero and its B234R.
It didn’t take long before enthusiasts realized just what kind of weapon this engine really is.
The Unsung Hero
Although the B324 engine’s story is obscure on its own, the Mitsubishi TD04HL-15 turbocharger they’ve used is talked about even less. The setup SAAB had put together includes this massive turbo, paired with an equally massive intercooler.
Such a combo did two things for the car – it provided tons of cold air, and it gave the engine miles of headroom. Headroom that would later be used to squeeze out crazy horsepower figures from stock engines. Oh, remember those forged internals? They added to the whole headroom situation as well.
Popular Engine Swap Choice
The tuning potential of both B234 and B202 engines has made them a popular choice for all kinds of swap projects. Today, in 2020, the situation is even more hectic since you can get your hands on a B234R 9000 Aero for dirt cheap. There are running motors out there for $200 or less.
Because of that, you’ll see all kinds of Miata projects, franken-BMWs, and other cars being running H series turbo engines.
Quality SAAB Parts
If you’ve got a B234R or any version of this engine, sooner or later, you’ll have to change a worn-out part. We offer one of the largest catalogs of Genuine, OEM, and aftermarket parts for SAAB vehicles.
To find the parts you’re looking for, simply head over to our online store and select your vehicle in our navigation tool. Our system will crunch the data and give you a list of parts that match. Additionally, you can always use your VIN to get even more accurate results.