Japanese engine parts manufacturer JUN and tuning legends Cosworth are bringing out a host of parts for Mitsubishi’s all-new performance engine, the 4B11. Cosworth are in the midst of development of a high-flow head for Mitsubishi’s brand new four-pot, which promises a revised combustion chamber design and provision for larger intake and exhaust valves. Not to be outdone, JUN have released a full set of valvetrain parts as well as what is perhaps the most desirable upgrade for the 4B11 - a 2.3-litre stroker kit.

Combine all three and I’m sure you’ll have one beast of an Evo X (or Lancer Ralliart, given the two have virtually the same long-block), however even in isolation each of these parts should provide a measurable gain for your Mitsu’. JUN’s stroker kit will put a sizable dent in your hip pocket (&yen 472,500 is the price of entry), however those 300cc extra should bump up the torque output by a similar amount. Besides, it’s hardly the most expensive stroker kit I’ve ever seen, and at least all the parts you’ll need to install it are included, like the new crank, pistons, conrods and oil jets. You will, however, need to budget for getting the block bored out from 86mm to 87mm, as the JUN kit utilises wider pistons. Mitsubishi says the cylinder liners aren’t serviceable and that boring out is a no-no, but then again it’s only 1mm of meat you’ll be losing.

Click on these links for more information on the JUN stroker kit and camshaft kit. If you want to learn more about what Cosworth’s got in store for the 4B11’s head, then check out Eric Hsu’s blog here.

[Source: JUN, Beyond The Dyno]
[Image courtesy of Mitsubishi]