The Evolution is going through more changes. True to its name it is evolving into a car that capitalizes upon its starting point and is becoming more of what it is. So what is the Mitsubishi Evolution? Its heart and soul is that of a rally car. About thirty years ago Mitsubishi crafted a Lancer into a very competitive rally car and continued the evolutionary process through today.
Mitsubishi had some very successful years with their rally cars and in the late nineties they won the WRC four years in a row. It also produced a street version of its rally car and named it the Lancer Evolution. Versions I through VII were never sold through the dealerships in America, even though they were in Europe and Japan.
In 1999 I spent a few months in Scotland and enjoyed being able to view television coverage of rally competition as well as read the car magazines’ reviews of the Evolution VI and VII, never dreaming that an Evolution would be offered in the US. A year later and the new came out that Subaru would be bringing the WRX to these shores. That was Subaru’s version of a rally car for the street. It was soon followed by the STi version with even more power and handling. In 2003 the eighth iteration of the Evolution was finally delivered to Mitsubishi showrooms in the U.S. In 2005 the MR version was added to the lineup of Evolutions and I snapped one up.
That year an active center differential (ACD) was added to the suspension technology that included all wheel drive (AWD), front and rear limited slip differentials (LSD), and aggressively tuned spring rates and shock valving. The brakes were incredible Brembo calipers on huge rotors at all four corners. The brakes have four “pots” on the front calipers and two on the rear. These “pots” are the pistons that push against the brake pads. Typical disc brake systems will have calipers with only one “pot” or piston that presses on one side’s pad and the other side is forced together much like a “C” clamp does as you screw in the one side. This single piston design is very efficient and economical to produce, but when braking capability becomes critical, having direct pressure on both sides of the rotor is far more effective.
The Evolution was shod with some very sticky tires, too. Mitsubishi chose to design their street suspension around the Yokahama Advan tires that provide fantastic grip as well as precipitous wear. Most Evo drivers are lucky to get 12,000 mile out of a set. While they erase away their tread they are certainly having the time of their lives.
The Evolution is unibody construction, which means that it doesn’t mount the body on a separate frame, but designs the body as a frame itself. This means that the car is far lighter than it would be if it had a separate frame. Typically car manufacturers will spot weld these unibody structure together and the Evo is also spot welded. It is just that the Evolution line is welded a whole lot more than the Lancer would normally be. Structural stiffness is therefore multiplied which translates into far more precise handling.
The suspension is designed to keep the tires in the best contact with the road possible. That is critical to taking corners briskly and being able to control braking. They chose McPherson struts on all four corners with multi-link suspension. The control arms and suspension links are forged aluminum for strength and to save weight. If you put a ping pong ball in your hand and waved it around you would find it easier to do than if it was made of lead. By keeping the weight of the linkages down the suspension components can move faster and provide a more responsive driving experience.
The MR version came with Bilstein struts (spring dampeners for those of you from the UK). The Bilstein folks have been designing struts and shock absorbers for decades and are known for the highest quality and engineering. They did a fantastic job with the design used on the MR. It provided a more comfortable ride than the standard Evo (the GSR) and yet turned better lap times than the more aggressively sprung GSR.
Aluminum is used on more than the suspension. The front fenders and hood use this light weight material and the MR version gets an aluminum roof to contribute to a lower center of gravity.
Great, you say, so why change a good thing? Perhaps it is a sick compulsion of mine to constantly see an opportunity to tweak a good thing into a better thing. Believe it or not I do restrain myself. There are Evolution owners out there that have really gone over the top. There are at least a half a dozen Evolutions in the U.S. that have over 1000 horse power to the wheels. There are several in the area that are in excess of 500 hp and are probably more suited for track use than commuting to work in.
My goal was to take advantage of opportunities inherent in the Evolution to increase power and handling without destroying the car’s street manners. In the UK dealers are able to offer versions of the Evolution beyond what comes out of the Mitsubishi factory in Japan. These are cars with more horse power and extra handling tweaks. They are called the FQ series. FQ stand for, well, Fucking Quick. There is the FQ320, FQ340, and in 2005 came the FQ400. This version was made famous on the British television series called Top Gear where the FQ400 trounced a Lamborghini Murcielago. This was one very impressive Evolution, but it was not practical for daily driving as the clutch was more of a trigger and it consumed petrol and tires at an astounding rate. The following year the same developers came out with the FQ360. It was still an impressive performance version of the Evo, but far more practical as a daily driver.
So my goal was to convert my Evolution VIII MR into a U.S. version of the FQ360. I wanted to enhance the handling and take advantage of the power potential lurking behind all the stock bits. I say U.S. version because the American Evolutions were not imported with active yaw control (AYC) as the British and Japanese versions were. While that gives me a slight disadvantage, there were plenty of opportunities to enhance despite that missing piece.
First off I researched the suspension modifications that would make sense. The Evolution is a very popular vehicle for tuners so there are all kinds of suspension upgrades out there to choose from. Not all of them are improvements and often one change that shows potential can actually end up having a negative effect.
I was particularly concerned about the effects of springs that would lower the car’s ride height. Normally you would consider lowering a car would be of benefit since it lowers the center of gravity, and it does. But it also results in changes in the angles of the suspension links and lowers the roll center of the car at the same time. The roll center is a point where the suspension angles converge and forms the basis for the roll axis, or the point on which the car’s body rotates as it leans going around a corner. If this point drops too low it can even be below ground level and then bad things happen. Even though the center of gravity is lower the car will handle with understeer and “push” its way through a corner instead of gliding around in a balanced fashion.
I first settled on springs made by a company called RSR that were made of a light weight titanium alloy. They provided a modest lowering while keeping the unsprung weight to a minimum. Unfortunately there was a problem with the distribution channel and they suddenly became unavailable. Fortunately there was another option by Swift Springs. They are another light weight spring that lowered the car 1.4″ in the front and 0.8″ in the rear.
In order to be certain that the lowered stance didn’t cause me problems with the roll center being too low I ordered up a kit from Whiteline that brought the roll center up by replacing the lower ball joints and outer tie rod ends. I also installed a bump steer correction kit for the rear of the car. Bump steer occurs when the car goes over a bump and the direction of the tire is forced by the suspension geometry either in or out instead of staying parallel to the centerline of the body. The Whiteline folks are out of Australia and have many fine suspension products.
Tires are a key component to any car’s handling. The Yokahama Advans were too noisy and wore quickly. I decided to check out my options on Tire Rack’s site and found Bridgestone Potenza RE-01R to be an excellent replacement. They are very sticky and far quieter. I’ll let you know about the wear as time goes on.
I had previously added an adjustable rear anti-roll bar as well as additional chassis bracing in the form of a rear strut tower brace as well as a trunk bar both from Mitsubishi.
With the suspension bit on and a proper alignment it was time to see what kind of power was lurking in the engine. Mitsubishi has already out together a very potent 2 liter engine right out of the box. This engine, known as the 4G63, has been around for enough years that its power secrets are well known. Like most turbocharged engines it responds to freeing up the intake and the exhaust with more power.
I had previously gone to a “cat-back” exhaust from Greddy early in the car’s life. The Greddy item was all titanium so that meant it was very strong and very light. It is so light that the 49 pounds of parts that it replaced now only weighed 9 pounds. To further enhance the exhaust I replaced the downpipe with a larger diameter unit by Tanabe that I purchased from Road Race Engineering when I was out in California last June. Between those two pieces I replaced the stock catalytic converter with a high flow version. I wrapped the downpipe with exhaust wrap to hold the heat in and muffle the sound some. It is beneficial to keep the heat in so that the flow out of the exhaust system maintains its speed.
On the intake side there was not a lot to be done with the stock air filter box other than replace the filter element with a K&N drop in element. Some Evo owners have gone to a larger cone filter, but that has some drawbacks. The stock air intake is designed to ensure that the engine inhales cold air from outside the engine compartment. A cone filter would have to be isolated from the heat pouring out of the radiator and the engine compartment. Due to the increased turbulence generated by a cone filter the mass airflow sensor (MAS) is often confused and provides the wrong information to the engine control unit (ECU).
The next step was to upgrade the cam shafts. This can be a tricky proposition as the wrong choice can result in an engine that only performs in an rpm range that is not suited to a daily driver. I researched what options were out there looking for cams that would provide excellent mid-range power so that the car would not be torture to drive in urban traffic, yet would come on like gang busters when it was needed. My choice was a set from GSX Power Division. They are out of Charleston, SC, and offer a stage one set that did just that. It didn’t require an upgrade to the valve train either. By upgrade I mean the valve springs and retainers, which often must be upgraded with high performance cams.
Finally I decided to upgrade the front mount intercooler as well. The factory unit is basically very large. It is far larger than any intercooler that was offered on Mitsubishi cars prior to the Evolution. Since I live in a part of the country that gets mighty hot in the summer I decided to give my engine every advantage in terms of a cool intake charge of air that I could. Greddy makes a much larger front mount intercooler that bolts up in the stock location and doesn’t require any cutting or welding. It also comes with larger diameter piping that ensures that boost pressure is not lost.
A couple of weekends ago a friend of mine and I tackled the job of putting on all of the power mods. Since the car has about 45,000 miles on the odometer it was a good time to replace the timing belt, balance shaft belt, and associated pulleys. This normally is scheduled for 60,000 miles, but it made sense to do it early. I also replaced the serpentine belt that drives all the accessories.
While Doug tackled the timing belt and cams I worked on the intercooler and exhaust parts. Thank goodness Jim’s Garage has a lift. It makes life easier for everyone.
The front bumper cover came off as well as the pan under the engine area. Then the bumper itself was removed. While Doug worked on the cams I rolled under and removed the downpipe and catalytic converter as one unit and worked to install the new downpipe and cat. Stainless steel metric bolts were used to connect up the exhaust system and then, when it was all tight, a second nut was added to each bolt to ensure that vibration didn’t loosen things up.
Doug is not only very experienced with 4G63 engines, he is also very methodical, which is why I was fortunate to have his help. We took our time and over a twelve hour period we swapped out the old cams for the new ones, installed cam gears and cam seals, installed the balance shaft belt, timing belt and new pulleys, and put the engine all back together. There was a bit of drama when oil leaked out of the bolts that held the tensioner to the engine block. That was remedied with the application of thread sealant on the bolt threads.
Then the new intercooler was fitted and the bumper re-installed. With the Greddy intercooler kit came new piping including a replacement for the pressure side of the turbocharger. The new pipe omitted a small tube that the old pipe had so that pressure could be monitored. This monitor point was used by the car’s ECU to control how much boost pressure was applied. The Greddy folks supplied additional tubing and a new place to hook the monitor to that was off the tubing that controlled the boost recirculation valve (often called the BOV or blow off valve). Later, on a test run with the car I discovered that the turbo wasn’t producing much more than half a bar (about seven pounds) of boost. A quick check of the old short piece of vacuum hose showed that it contained a small orifice in it. Once the metal orifice was moved to the re-routed hose the ECU was able to produce normal levels of boost pressure in the 1-1.5 bar range (19-22 lbs.).
The ECU also received a re-flash that we got from one of the best tuners around, called Jestr (yes, that’s how it’s spelled) Tuning. The changes ended up a success. The handling is fantastic and the power is unbelievable. While we haven’t had it on a dyno it is likely at least 360 hp to the wheels and plenty of torque to match.
This has been a lot of fun and it is especially fun when things turn out as you hope they would. With a little more tuning of the ECU we should be ready for some track time as well as some road trips.