In the world of high-performance four-cylinder engines, there are a few names that pretty much everyone knows. B16, K20, SR20, EJ, EA888, and more.
In previous articles we’ve gone in-depth on the Mitsubishi 4G63 and the Mitsubishi 4B11, but today we’re going to put them head to head to find of out which one is the better engine.
- Bore: 85mm vs 86mm
- Stroke: 88mm vs 86mm
- C/R: 7.8:1 – 8.8:1 vs 9:1
- Block: Cast Iron vs Cast Aluminum
- Head: Cast Aluminum vs Cast Aluminum
- Valvetrain: DOHC 4V vs DOCH 4V
- VVT: MIVEC on intake cam on last-gen Evo vs dual MIVEC
- HP: 210 – 280HP vs 276 – 403HP
Both the 4G63 and the 4B11 follow the basic idea, which is taking a dual-overhead-cam, 2.0L 4-cylinder, and cramming a ton of boost in it. Both of these engines were developed and built with performance in mind, and they’re both very well known for outputting decent amounts of power with minimal modifications.
The 4G63 is part of Mitsubishi’s Sirius engine family, which started back in 1976 and continued in production up to 2013. The 4G63T, specifically, didn’t hit the US market until 1989 in the first DSMs.
The 4B11, on the other hand, is part of Mitsubishi’s 4B1 engine family, which is within the Global Engine Manufacturing Alliance. The 4B1 family started in 2005, but it wasn’t until 2007 when Mitsubishi used the 4B11T in the Evo X.
The 4G63T features an 85mm bore, 88mm stroke, dual overhead cams, a cast-iron block, and a cast-aluminum cylinder head. From the start of its life, the 4G63T was designed as a race engine, and the first 4G63T in the US came about from Mitsubishi’s participation in rally racing.
Compression ratio for the 4G63T was anywhere from 7.8:1 to 8.8:1 depending what year and model car it came from.
It’s also important to note the only version of the 4G63T which was variable valve timing was the Evo 9’s 4G63 and it only featured MIVEC on the intake camshaft.
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 is semi-closed which is pretty strong. Up top, you’ll find dual overhead cams with Mitsubishi’s MIVEC system on both the intake and exhaust camshafts.
One of the obvious advantages of the aluminum block is weight savings. The 4B11 weighs about 26 lbs less than the 4G63, and the superior thermal efficiency of aluminum increases heat transfer to the cooling system.
This results in cooler piston and oil temperatures improve engine durability and longevity.
4G63T Bottom End
Looking more closely at the bottom end of the 4G63 shows some pretty interesting features. The 6-bolt engines use massive and thick connecting rods, very wide and beefy rod and main caps, an insanely low 7.8:1 compression ratio, and a forged steel nitrided crankshaft.
The pistons are cast, but with a very strong design and had low and wide rings for extra strength.
The later 7-bolt engines had a higher compression ratio, lighter rods, narrower bearings, redesigned pistons rings, and other changes. The changes made the more efficient, but also made it slightly weaker.
4B11T Bottom End
While the 4B11’s 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.
The 4B11 features four-bolt crank caps, which isn’t something you’ll typically see on a modern small inline engine. The pistons are forged and use a fairly low 9:1 compression ratio. The connecting rods are also pretty strong.
Both the 4G63 and the 4B11 bottom ends are safe to push around 400-500whp. I’m sure many people have pushed further on a stock bottom end, but 400 to 500whp is a pretty safe number.
4G63T Cylinder Head
The design of the cylinder head is one of the keys to making big power, and Mitsubishi did a pretty good job with all versions of the 4G63’s head.
The earlier 1G intake ports are huge and it’s often argued that the 1G head is better than the 2G head because of the port size, but there isn’t a whole lot of validity to this claim. The 2G head does have smaller ports, but with a straighter design which ultimately provides better air velocity.
4B11T Cylinder Head
On the 4B11’s head you’ll find a reversed intake layout that puts the exhaust side toward the rear of the vehicle, compared to the 4G63T where it’s on the front.
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 bucket-over-valve design eliminates the hydraulic lifter and rocker arms that were used on the 4G63 head.
As far as stock power output, the 4B11 is the better engine, but that isn’t saying much considering it’s newer and features a dual MIVEC head and other advanced features.
Throughout the years of the 4G63T, Mitsubishi used a few different turbochargers, but most of them cant push more than 5psi past their stock output. For a decently powerful streetcar, the stock turbos can provide enough power and provide decent throttle response as well.
The 4B11T uses a version of the TD05H 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 a little bit more than that of a bolt-on and tuned 4G63, but the 4B11T makes way more low-end torque than the 4G63T.
The increase in low-end torque is created by the dual MIVEC system, more efficient stock turbo, and several other factors.
Pretty much anytime you’re talking about the 4G63, someone brings up the whole crankwalk issue. Early 7-bolt engines have gained a reputation for excessive thrust bearing wear, which over time allows the crankshaft to walk back and forth in the block.
Eventually, this problem will destroy the crank position sensor and shut the engine off.
The reasons for crankwalk have been debated since the issue was first reported, but the problem has been somewhat blown out of proportion. Luckily, Mitsubishi was aware of the crankwalk and it’s not an issue which plagues the 4B11T at all.
At the absolute peak of high-horsepower cars, it would appear the 4G63T is the better engine. With a massive aftermarket backing and decades of testing behind it, the 4G63 simply has more backing and has proven itself more times than the 4B11T, but that doesn’t necessarily mean it’s the better engine.
As I discussed in the 4B11T article, it never really got the same amount of love or aftermarket attention, mostly because it was only used in the Ralliart and Evo X for a short period. Simply put, there were fewer applications and less 4B11s out there compared to the 4G63T.
Which One is Better?
Back to the original question at hand, which one is better. The 4B11T is arguably the better street engine because of the dual MIVEC system and more efficient turbocharger, ultimately allowing it to produce more usable low-end power than the 4G63.
That being said, it’s very easy to argue the 4G63T is the better engine at the limit because of its vast aftermarket support compared to the 4B11.
To avoid starting world war three with Mitsubishi fans, I’m going to let you guys decide which one is better down in the comments. Drop down there and let me know which engine you think is better and why, with some specifics!