If you're starting to think that means bad news, think again. The new engine is completely aluminum, netting a weight savings of 27.5 pounds over the 4G63, not counting intake and exhaust components. On top of that, it's aimed the other way around, with the turbocharger against the firewall and the intake on the radiator side. This allows for a 10mm lower engine mounting position (the exhaust doesn't have to go underneath it), which results in a lower center of gravity.
The pistons, fully floating and made by Mahle, sit inside cast-iron cylinder sleeves. In addition, bore and stroke are now equal, at 86mm for both. This is as opposed to 85mm and 88mm, respectively, in the Evo IX. Up top, MIVEC does its work on both camshafts (MIVEC was only on the intake cam of the previous car), and direct valve actuation means that there are no rocker arms. The manufacturer says that this alone is responsible for a 1kg reduction in engine weight.
The Evo X will have an ignition coil for each of its four cylinders, as opposed to the twin-coil system used on the Evo IX, where two cylinders shared one coil. This time around, the cylinder head and block use separate cooling chambers, resulting in more reliability and importantly, less mess when you turn the boost up too high.
The 4B11 isn't even loosely based on the 4G63. A timing chain replaces the belt of the Evo IX and there are no balance shafts in the new engine. A new aluminum short port intake manifold has an electronically controlled throttle body mounted further upstream-a first for any Evo. And don't bother with your gigabuck stainless steel manifolds, either; this thing's already got one. On top of that, the downpipe, which is much shorter, is now 65mm instead of the Evo IX's 60mm pipe.
Mounted in between that sweet stainless steel manifold and the big downpipe is the sweetest turbocharger Mitsubishi has yet to offer on the Evo. This one's entirely aluminum-oh, and titanium. It's still based on a TD05H, but this one's called a TD05HA-152G6C-12T. A big part of the reason it's in place is the higher compression ratio of the new engine (9.0:1 compared to 8.8:1). For those nerdy enough, the Evo IX used a TD05HRA-155G6C-10.5T, and the Japan-only Evo X RS uses a TD05H-152G6-12T. That RS turbocharger has an Inconel turbine wheel (as compared to the titanium-aluminum wheel we just mentioned).
Getting The Power To The Systems
You're wondering why Mitsubishi decided to use a twin-clutch transmission in its high-end Evo MR. We all are. The only statement we could get out of product planner Ryugo Nakao was, "...it offers the convenience and effort-saving qualities of an automatic transmission."
The thing is we're not sure if you should be giving a damn about convenience and effort-saving qualities if you're out buying Mitsubishi Evos. Nevertheless, if you're going to buy a "flappy paddle" gearbox, this just might be the one to buy. Here's why.
For one, it's got two clutches so it shifts as quickly as say, an Audi or VW equipped with their "DSG" transmission. So the good news is that this close-ratio box couldn't be more different than irritating systems, like BMW's "SMG." How does it shift so quickly, you ask?
It's a rather innovative solution-rather than have every gear on one input shaft, the dual-clutch SST places odd gears on one shaft (that's one, three and five) and even gears (two, four and six, geniuses) on an additional shaft. Each of the two shafts has its own wet clutch to feed torque to the output shaft. Say you're driving in an even-numbered gear. The computer monitors vehicle speed and throttle position, and pre-selects either a higher or lower odd gear. The transmission then disengages the even-numbered gear clutch and engages the odd-numbered gear clutch.