As you might already know, the Mitsubishi 4G63 is one of the most legendary 4-cylinder engines of all time. Just like any engine, though, Mitsubishi ended up replacing the 4G63 because it was struggling to meet emissions standards that get stricter every year. The replacement for that engine was the 4B11, and although it might not be as internet famous as the 4G63, the 4B11 is a fantastic engine.
The 4B11T is part of Mitsubishi’s 4B1 engine family, which is within the Global Engine Manufacturing Alliance. While most versions of the 4B1 are roughly similar, the 4B11T is the only turbocharged engine in this family from Mitsubishi. Other engines within the global engine manufacturing alliance are turbocharged, including some from Hyundai and Chrysler.
The 4B1 family started in 2005, but it wasn’t until 2007 when Mitsubishi used the 4B11T in the Evo X. On the outside, the 4B11T might seem like just another turbocharged 4-cylinder engine, but it’s what’s on the inside that makes it special.
Inside the 4B11T you’ll find an 86mm bore and an 86mm stroke, making this a square engine. It features an aluminum block and an aluminum head, which is different than the 4G63 which used a cast-iron block. The block uses a semi-closed design which is pretty strong. Up top, you’ll find dual overhead cams with Mitsubishi’s MIVEC system on both the intake and exhaust camshafts.
The only cars to use the 4B11T were the Mitsubishi Lancer EVO and Lancer Ralliart. Between the two the 4B11T is nearly the same, other than a slight detune and a smaller turbocharger on the Ralliart. As a whole, the 4B1 engine family is used in a bunch of different vehicles, and other cars that use the Global engine manufacturing alliance platform include brand new cars like the Kia Stinger, however, the 4B11T was only ever found in the two aforementioned versions of the Lancer.
Interestingly enough, the 4B11T is pretty much better than the 4G63T in every way when you compare them stock to stock, but a lot of enthusiasts never came to love the 4B11T because it was used in the Evo X, which was much larger and heavier than any other Evo model before it.
Before you go down in the comments flipping out that I called the 4B11T better than the 4G63T, just know I was referring to completely stock form, meaning not modified in any way. One of the most notable design changes of the 4B11T was the all-aluminum design which made it 20 to 30lbs lighter than the 4G63T while also having much better thermal efficiency.
What Makes it Great?
What makes the 4B11T such a good engine is what’s on the inside. While the basic specifications might make it sound like just another the four-cylinder, the square bore/stroke ratio, dual MIVEC, efficient turbocharger, and most important the strong engine internals are what makes this engine so great.
To put it simply, the bottom end of the 4B11T is well known for being very strong and being able to withstand pretty big power numbers, however, it’s not quite as strong as the stock bottom end found on the 4G63T.
When the 4B11T first came out a lot of people were worried the aluminum block construction and semi-open deck design was going to be a weak point. While the block might not be as insanely strong as the block of the 4G63T, it’s still very strong and can easily withstand a high horsepower street application.
Another notable feature of the 4B11 is the four-bolt crank caps, which isn’t something you’ll typically see on a small inline engine, however, it’s pretty common to see on V style engines. The pistons are forged and use a fairly low 9:1 compression ratio. The connecting rods are also pretty strong. On a stock bottom end, the 4B11T is capable of withstanding upwards of 500 horsepower or more pretty much fine.
One of the most notable issues of the 4G63 was crankwalk, although, that problem has mostly been blown out of proportion on the internet. Luckily, Mitsubishi was aware of the crankwalk and it’s not an issue that plagues the 4B11T at all.
Another interesting thing to note is that 4G63 was fitted with balance shafts, which were used to eliminate vibration. Many modified 4G63 engines had to have their balance shaft removed because it became a nuisance when tuning the engine. The 4B11, on the other hand, doesn’t come equipped with balance shafts. Overall, the engine itself is cleverly designed so that vibrations are nonexistent even without balance shafts.
As far as the stock turbocharger goes, the 4B11T uses the TD05H152G6 turbocharger, which is quite a bit more efficient and makes more power than any turbocharger found on the 4G63. With some bolt-on parts and tuning, a stock turbo 4B11T can make anywhere from 350 to 400 horsepower, which is similar to that of a bolt-on and tuned 4G63, but the 4B11T makes way more low-end torque than the 4G63T.
The massive gain in low-end torque is thanks to the much more efficient stock turbo. On top of making way more low-end power, the 4B11T’s turbocharger is also very responsive and provides much better throttle response than any turbo found on the 4G63T.
The reversed intake layout puts the exhaust side toward the rear of the vehicle, compared to the 4G63T where it’s on the front. The manifold is designed for the traditional twin-scroll turbo and is made from stainless steel. The front pipe never extends across the oil pan, which minimizes oil temperature problems.
On the head, the dual MIVEC control allows for a wider range of duration and valve overlap to promote turbo spool up and helps the engine produce more power. The direct-valve actuation design eliminates the hydraulic lifter and rocker arms that were used on the 4G63 head. The bucket-over-valve design decreases the chances for failure at high-RPM operation.
To wrap all up, it’s easiest to just remember that the 4B11T is part of 4B1 engine family which is within the Global Engine Manufacturing Alliance between Mitsubishi, Chrysler, and Hyundai. It’s fundamentally different than the 463GT before it, however, in stock form it’s more efficient and makes more power.