Mitsubishi’s 4B11T engine is the successor to the legendary and heavily praised 4G63 engine. The 4B11T had a lot to live up to, considering the vast success of the 4G63 engine. But against all odds, the 4B11T engine might even have come out on top as it has proven to be a very capable engine.

As the 4G63 engine grew older it started having difficulty complying with emission regulations, and as the engine turned 15 years old it was discontinued as it no longer was compliant with emissions standards.

Mitsubishi’s 4B1 Engine Lineup

The foundation of the 4B11T starts with the 4B1 engine lineup and is made up of four different engines.

• 4B10 (1.8L 4 Cylinder NA)
• 4B11 (2.0L 4 Cylinder NA)
• 4B11T (2.0L 4 Cylinder Turbo)
• 4b12 (2.4L 4 Cylinder NA)

These are all-alloy straight-4 piston engines and were not only used by Mitsubishi, but Chrysler, and Hyundai too. The basic design of the cylinder block is shared through all the engines, but the specification such as exhaust manifolds, intake, and exhaust ports to engine tuning was always individually developed by Mitsubishi themselves.

As all the engines share the same engine block, the difference in displacement is due to different stroke and bore.

All engines utilize double overhead camshafts (DOHC) as well as Mitsubishi’s variable valve timing, MIVEC.

4B11T Usage and Specifications

The 4B11T engine was exclusively used in the 2007-2016 Mitsubishi Lancer Evolution X and the 2008-2015 Mitsubishi Lancer/Galant Fortis Ralliart, although the latter was slightly detuned and with a smaller turbo.

Due to the gentlemen’s agreement, cars in Japan were limited to a maximum of 280hp. Thus, the Japanese actually got the least powerful version of the 4B11T engine. Both Europe and the U.S. drew the longer straw out of the stack on this one.

The United Kingdom got themselves some one-off models, the Evolution FQ400 and Evolution FQ440. These were the most powerful road-legal Mitsubishi Evolution ever produced.

Evolution FQ400 and Evolution FQ440

It’s hard to tell why the UK got these one-off models, but it might have to do with them being right-hand drive, and because they weren’t limited to the gentlemen’s agreement. This meant that Mitsubishi really could show off without being limited by some agreement.

These models we’re the top-dog trim level of the Evolution X lineup. The 4B11T in these models was heavily revised. They got high-flow fuel injectors, a new hybrid turbocharger, an improved intercooler, a 3-inch high-flow stainless exhaust, and a completely remapped Engine Control Unit (ECU). The result is over 400 hp in the FQ400 and 440 hp in the FQ440.

These modifications were enough to power the FQ400 from 0 to 62 mph (0 to 100 km/h) in 3.8 seconds and the FQ440 in 3.6 seconds. That is completely bonkers for a Japanese sedan that is more than 13 years old.

But the engine department wasn’t the only thing revised by Mitsubishi. The entire chassis and suspension got a full rework. The suspension was lowered with Eibach springs and Bilstein shock absorbers. A wider and more lightweight 18-inch nine-spoke alloy wheel was fitted with Toyo Proxes R1R tires.

The body kit was lightened by using carbon-fiber elements and composite side skirts. The styling design we’re improved to look more aggressive and to increase aerodynamics to improve grip and handling. A brand-new Vortex Generator and carbon fiber diffusor were also mounted to the FQ400 and FQ440.

Mitsubishi didn’t back out on safety either, both the FQ400 and FQ440 got a full 5/5-star safety score by the Euro NCAP’s independent crash tests.

It is safe to say, the Evolution X, the last Evolution to ever be produced, went out with a bang.

Specifications

4B11T Reliability

In stock form, the 4B11T is quite a reliable engine, apart from some fairly weak factory connecting rods there is nothing really that’s considered a weak point.

When you start modifying the 4B11T there are a few things you’d want to consider in order to not ruin your engine. The reliability between the predecessor 4G63 and the current 4B11T starts to be noticeable when you increase the horsepower figures. The key difference is that the 4G63 uses a good ole iron block in comparison to the 4B11T’s aluminum.  This means that the aluminum block in the 4B11T won’t be able to handle as much power as the 4G63.

How Much Power Can Stock 4B11T Handle?

The restricting factor of the 4B11T is the aluminum block. In stock form, the general saying is that if you keep torque figures between 350-380 lb. ft you should be fine. If you go over this, you risk damaging the engine, and in the worst case blowing it all together. However, the tune is also a major factor. If you have a smooth tune, you’ll be able to up the figures a bit further. A rough tune will certainly make the engine work harder than it needs to. So try and find an experienced tuning shop, preferably one with experience with Evo’s.

A general safe haven for a stock 4B11T is around 400 hp and 340-360 lb. ft. More than that and you’d be looking at upgrading the internals without having to worry about ruining your reliability.

4B11T Swap Examples

Generally, the 4B11T is not particularly common for engine swaps as the 4G63 is. For most, the 4B11T is considered more difficult to work with as it’s more advanced and cramped. With that said, for the people that work with these engines on a daily basis, most claim it’s just a learning curve. And that once you’ve learned the ins and outs of the engine really isn’t any more difficult to work on than the 4G63.

There are a few individuals which have seen the large potential in the 4B11T engine, I’ll mention one of them. If it is of any interest, I could make a complete stand-alone post about 4B11 swapped cars.

4B11T 800HP Engine Swapped Ford Fiesta

This is not your typical engine swap. The owner of this Fiesta, Mariusz Stec ditched the Ford engine for a fully built 4B11T to be used for hill climbing. In this form, the Evo engine produces about 800 hp and 850Nm and thanks to its 4WD system (also taken from an EVO) it can do 0 to 62 mph (0 to 100 km/h) in close to 2 seconds!

Even with the 4WD system, this Fiesta only weighs in at about 1,050 kg (2,300 lbs) which allows it to handle on a dime. The flame-spitting side exhaust is also a nice touch.

I’ll leave a short 2-minute compilation of one of its hill climb sprints.

4B11T Conclusion

The 2.0L Turbocharged I-4 4B11T engine is an overall good engine and was used in the Mitsubishi Evolution X (10). People tend to mistake it for a downgrade from the infamous 4G63 engine. But according to us is just misinformation from people trying to figure out how to work on the 4B11 engine.

While the aluminum block of the 4B11T doesn’t allow for as much power and torque as the stock 4G63 iron block, it still is very reliable if power is kept within the 400hp~ and 360~ ft. lb. of torque, just make sure to use a smooth, and high-quality tune.

The 4B11T power delivery is generally a lot smoother than the 4G63’s, and if modified has the same power potential as the old 4G63 engine. Mitsubishi’s created two one-off Evo’s for the UK market, the Evo X FQ400 and FQ440 which both had various suspension and chassis upgrades, including over 400 hp which could catapult them from 0 to 62 mph (0 to 100 km/h) in less than 3.8, and 3.6 seconds.