Mirage/Lancer CE - 4G15 SOHC 12v Vehicle Performance Modification Guide
The Mitsubishi Lancer - Mirage 1.5 model is the base range model and was more commonly known as the GLi model until the recent introduction by Mitsubishi of the GLi 1.8 model for greater power. The 1.5 engine is very much your economy engine with only 64kw - 67kw of power depending upon your location. It can be modified easily and with surprising results. It is never going to be a V8 eater unless you go the turbo route, but the results of minor modifications can be very satisfying and for the majority of car owners, using these cars as mobile sound factories and body kits, this suits them perfectly.
The naturally aspirated packages also work extremely well with many new options now available, whilst the low boost turbo systems of course always give there large cousins something to be concerned about. The most commen upgrade we now do for these models is the DOHC head conversion which is worth by itself, 8kw but requires no computer modifications at all, working on the factory SOHC 12v computer.
Utilising this as a baseline, we are now seeing the humble 4G15 engine go from 65kw up to around 110kw in naturally aspirated form and around 150kw with some medium level turbo boosting. Not all mods are for power though, there are many area's of braking and suspension that any stock car can always be improved with. Along with other drive line upgrades, you can have a smooth reliable car, with improved handling, and provide that little bit of sporty power to keep most people satisfied.
This section is to be used as a guide in your modification - I will be breaking this into sections to provide a well balanced vehicle. Additionally the modification package will be setup so that as you increase the power of the vehicle, your alternative items like brakes etc are matched to your new power level. This guide has also been done in an order which provides successive gains from the modifications power wise. Jumping say to number 20 first, may result in a LOSS of power until you have done other items to match its effect. ============================== Group 1 Modifications The group 1 modifications are designed for the every day driver, wanting improvements across the board without sacrificing road comfort, fuel economy or driveability. These are also the baseline modifications for the more extensive Group 2 Modifications. Standard horsepower for the vehicle is 65kw on average at the flywheel. ============================== Group 1 Modifications
1. Quick Shifters (MANUAL)
The Mitsubishi gear shifter system is one of the better ones on the market. But that does not mean that people do not want to improve them. This is one of those modifications that can be done at any time. The units suit most people who want something to reduce the long throw and give a more precise feel to where the gears are located. For those performing any level of competition work, or just want something a little more extreme, the Rally Spec Unit reduces overall movement by as much as 65% over stock.
2. Air Filters & Cold Air Induction Kits
The factory air box system on these vehicles, is quite restrictive. There are several ways to free them up - I recomend two main options:-
i. Fitment of a K&N Factory Replacement Air Filter for those wanting the Stock look, with improved air flow and throttle response OR
ii. The Cold air kit relocates to the front bumper, pulling cold air especially where utilised with a aftermarket front bumper. Of course a K&N large pod filter is used.This should produce an approximate gain of around 1 - 2kw with improved throttle response and torque.
3. Fuel Pressure Upgrades
This is the one thing I believe that these vehicles should always have fitted regardless of how little, or much you modify the vehicle. Quite simply the factory vehicle has been tuned for maximun Economy. This has resulted in a fairly large flat spot off idle when accelerating hard from a standing start of from a cruise mode situation. The reason for this is Mitsubishi has tuned very lean on the accelerator pump settings, resulting in the lack lustre performance on throttle, but excellent fuel economy.
Fitment of the Fuel Pressure Regulator kit eliminates this flat spot, whilst only marginally reducing your fuel economy. Without going into huge detail, trust me when I say, flat spots are eliminated, your car will actually accelerate properly without hesitating and your fear of being run over at stop signs will diminish rapidly. This is an easy bolt on kit and can usually be done in around 1 hour maximum. Increases the fuel capacity within the fuel rail. This enables upon acceleration, a greater volume of fuel to become available before leaning out. This also reduces the tendancy to pulse the fuel and create disturbances in the fuel flow, providing a smoother transition to power.This will not produce any HP Gain, but will provide an approx 10ft/pd torque improvement at low rpm off idle.
4. Exhaust System Upgrade
Okay you have done the easy mods, now time to do something about the exhaust. Contrary to what many people believe, without any form of induction work or fuel work, fitment of exhaust upgrades are only marginally beneficial. The stock system on these vehicles is usually an Asmathic 1 5/8" system.
At this point you must reach your first major decision on where you wish to go with the vehicle - in summary I recommend the following options:- i. Naturally Aspirated - Stock Computer - You are only after mild improvements to make the car sportier, but don't intend to do any real serious mods. This being the case stick with replacement of the stock exhaust with either a rear muffler upgrade only 2" Lukey Ultra flow oval shaped unit, or complete it with a 2" press bent exhaust system with new muffler and resonator. Cat converter should remain stock. Any larger on the system would not provide without sufficient more expensive mods, any real gains.
ii. Naturally Aspirated - Piggy Back ECU - you are after mild to medium improvements to make the car sportier, with slightly more than average vehicle modifications. This being the case, we recomend a 2 1/4" diameter replacemenet exhaust with a new lukey resonator and muffler. No need to go mandrel bent unless you have money to throw away. This setup will handle the majority of modifications we have listed short of turbo systems
iii. Naturally Aspirated - Haltech EMS - okay you are an extreme modder. Twin throttle bodies, DOHC Head Conversion, camshafts the list goes on. We recomend in this case either a 2 1/4" mandrel bent system or a 2 1/2" press bent system, again with lukey units. Only real difference is addition of a 2 1/4" or 2 1/2" cat converter depending upon how extreme you are going
iv. Turbo Charged - no more need be said. But don't go throwing your money away on a 3" mandrel bent system. A 2 1/2" press bent system, cat converter with Lukey units are more than you will ever need. Keeps the car quiet, no droning and has a great sound. Mandrel bent on the 2 1/2" system could be done but honestly, you don't need it.
These can produce small gains with the basic systems of around 2 - 5kw at the wheels, with increased revability and torque.
5. Suspension Upgrade - Level 1
Suspension Package? Level 1? What is this. Basically at this point you are still have a midly modified vehicle and want to just improve the looks slightly and handling.
I recommend in this situation the following:-
i. Replacement of stock springs with some lowering units - either Lovell 30mm or 50mm lowered units depending upon how low you want to go.
ii. Fitment of a White Line rear sway bar. Reduces body roll without reducing driveability. iii. Fitment of a White Line strut brace. Reduces the tendancy of the vehicle to float on the road and makes it less sensitive to changes in road camber, resulting in less need to constanty adjust the steering wheel to keep the car driving straight.
This package will proved a well balanced vehicle, capable of handling corners at higher speeds, will feel safter at higher speeds especially above 100km/hr. The steering will feel more precise and you will have overall more confidence in pushing the vehicle harder. ==============================
Group 2 Modifications Okay the basics are done and you have a plan. The following mods require you to decide, which of the following ways you are going which will be:-
1. Staying with the 1.5 SOHC Cylinder head assy for some further mild tweeks mostly in braking and suspension. OR
2. Upgrading to the 1.5 DOHC Cylinder head conversion, with more medium to extreme tweaks. OR
3. Looking to turbocharge with either the SOHC or DOHC cylinder head assy
First decision - SOHC or DOHC cylinder head? We can only say one thing here - go the DOHC every time. If you don't want to do this then skip the next option and move on.
1. DOHC Head Conversion Package
The DOHC head conversion is quite simply the best option if you seriously want any more power from the vehicle. A Naturally aspirated tweaked DOHC package will outperform any SOHC variation short of turbocharging. Its superior flow characteristics cannot be beaten. By itself with the stock 1.5 SOHC computer this is worth 8kw at the flywheel with an increased working RPM range. This is a one day conversion which can be performed by simply swapping the cylinder head and other minor components. Usually supplied with new timing belt, tensioners and all appropaite manifolds. Also comes standard with a 51mm throttle body.
You need to decide at this point because any extractor / turbocharger route requires a specific manifold / extractor for the specific cylinder head model which cannot be swapped across to the alternative. This package upgrades the vehicle from 65kw on average to around 76kw on average at the flywheel. With above mods as recomended the vehicle should be close to around 80 - 83kw at the flywheel.
2. Extractor Upgrade Not all extractors are equal. But in reality, any half decent designed unit will be an improvement over the stock manifold on the vehicle, get a 4-1 race design kits which bolt up to the factory cat converters without any modifications required. Increased throttle response, torque and horsepower all result from this. If you have the DOHC cylinder head you will find the results are even more impressive due to the higher flow characteristics of the DOHC head.
If your plan is to go turbo, then save your money and jump ahead several more levels. This is not for you. For everyone else, this will complete the balance of your exhaust system modifications.
This package adds around 5kw at the flywheel with increased torque and improved upper acceleration and rpm range.
3. Single Throttle Body Upgrade / Thermo Block Kit Time to look at improving throttle response again. Now if you are wanting to go a little more extreme, to a twin system then you need to wait a little longer. For everyone else, time to start looking at improving throttle response, even if you are going turbo.
The stock throttle body on the 4G15 SOHC engine is 46mm and the DOHC engine is a 51mm (Not convinced to go a DOHC yet?).
I recommends for the majority of owners to do the following:-
- For all SOHC owners, upgrading the stock to a bored out 51mm or a 55mm is very beneficial. To be quite honest, on the SOHC models, anything with the stock manifold and cylinder head over 55mm is really just not effective. The cost V gain ratio is just not optimal for anything larger than a 55mm unit.
- For all DOHC owners, upgrading to our bored out 55mm is extremely beneficial.
- For DOHC owners with upcoming computer mods (Piggy back ECU) then a 60mm is also very beneficial if you are remaning Naturally Aspirated and don't plan on going to a twin system. If you are going to a turbo, then stay with the 55mm.
Whilst this work is being done, I recomend fitting at the same time a Thermo Block Kit. Consider this an extension of the cold air induction kit be reducing heat soak into the intake manifold from the engine and the throttle body which have hot water running through them. This drops the average intake tempatures by 25% overall resulting in improved combustion, fuel economy and throttle response.
This package adds 1 - 2 kw at the flywheel, but does improve throttle response and low rpm driveability. The thermoblock kit reduces heat soak and this allows the engine to maintain maximun ignition timing with max throttle response.
4. Brake Upgrades - to suit all future modifications
Before doing any further power or suspension modifications, brakes now need to be seriously looked at. The stock brakes on the front of the lancer is a 235mm single piston caliper package with drum rear brakes. Atrocious and disastrous is one of many words used in relation to the Mitsubishi brake system on these vehicles.
Below in increasing order is the packages I recomend. (The stock brakes run a single piston 235mm rotor package)
i. For those wanting something marginally better, and are not planning on doing ANY MORE Horsepower mods, then minor upgrading of front brakes only. Retaining stock calipers, fitment of some EBC Green Stuff brake pads and slotted Rotors is very beneficial. Improved braking by around 25% with better feel and dramatically less brake fade.
ii. Next package recomended is to replace the rear drum brakes with a Rear Disc Conversion package. This fits a Mitsubishi 260mm rear disc package with EBC Black Stuff brake pads, slotted rotors, handbrake cables etc as a complete bolt on kit. This in combination with the above brake package, will suit all but the most hardcore modifiers. Great for looks as well. Braking is improved by around another 10% with much reduced brake fade again, especially as the speed of the vehicle reduces and the rear brakes become more effective.
iii. For those wanting the final level of brakes, fitment of a 276mm Twin Piston front brake package and brake master cylinder upgrade is the final step. This part is absoloutly necessary for anyone wanting to turbocharge their vehicle in order to enable it to be permitted by the Police to be licensed with a turbocharger conversion. Guaranteed no brake fadeand this large rotor will fit very nicely inside of any 15" or larger rim.
5. Suspension Modifications - Level 2
Okay ready to take the final plunge for power and hit that turbocharger or twin throttle body with computer. Wrong. Lets take a look at your suspension again. Factory shock absorbers will increase your braking distance, especially if they have been running inside lowered springs for 10 - 20,000km. They are marginal at best when new.
Time to go for more extreme options.
5a. Shock Absorber Options - three choices here with standard type strut assembies
i. Fitment of KYB Excel-G replacement units for the more budget conscious. Retains improved handling over stock.
ii. Fitment of KYB AGX units. These are externally adjustable and are perfect for the all round street / strip / circuit car. You can set them soft when your on the road, hard when your driving hard. Adjustment takes less than 1 minute
iii. Fitment if Koni Sports Inserts. These are similiar to the KYB AGX units, but are serviceable and provide that little bit more control. They are a more precise unit, externally adjustable on the front only, internally adjustable on the rear. For the more sports conscious person these could be the better choice.
5b. Coil over Strut Assemblies
I recomend the Tien units specifically manufactured for Malaysia Conditions. To put it quite simply, many Japanese units are set very very hard, so even on there softest unit the car is very harsh, hurts kidney's and actually has worse handling as it skips all over the road. The hardest setting on the Tien units, are equal to the softest setting on the japanese normal imported units. I cannot recomend these enough - they are simply fantastic with the ability to set your road heigh, rebound levels etc. These Tien Units are also available to be eletronically adjusted on there rebound rates via up to one independant controller per corner, or one controller on all four units as an example. Mostly for extreme racing only.
The final items I recomend to improve your suspension is as follows
i. Fitment of an Upgraded front engine mount. This polyurethane improved unit, reduces axle tramp and engine movement. Increases traction and reduces the vehicle ability to get that dreaded engine bounce especially on wet roads. Any serious drag racer would feel the benefits of one of these straight away.
ii. Fitment of a Whiteline Anti Lift kit to the front lower control arms. In essence, this increases the caster of the front lower control arms and lowers there centre of balance, to provide a reduced tendancy to "Lift" the front of the car upon accelerating. Requires a wheel alignment straight away. Highly recomended.
iii. Fitment of a White Line rear strut brace (In Coupe Models Only) for additional reduced body movement.
I do not recomend replacing the balance of the vehicle rubber mounts with Polyurethane ones for any street going vehicle unless being used for compeition use. This results in a very very harsh vehicle on the road with much increased road noise and vibration. I feel the packages I have recomended provide that best balance of street vehicle and performance without sacrificing driveability.
6. Drive Line Upgrades
There are three main driveline upgrades whch can be done, which go a long way towards improving the reliabilty of the engine as well as driveability.
i. Billet Lightweight Front Under Drive Pulley - this unit reduces both the moving mass of the front harmonic balancer, as well as being physically smaller by around 25% diameter over the stock unit. Helps to make the car rev faster, spins up faster and higher. The reduction in drive ratio's means that the power steering and alternator are turning less at higher speeds further reducing engine load. This is just small enough to reduce load without reducing the effectivness of the operation of the alternator and power steering units. Highly recomended and very easily fitted.
ii. Clutch Kit - At some point your clutch will need upgrading. Two options available - for naturally aspirated drivers a standard coverplate with a semi ceramic five pucker clutch disc package. This will increase clutch efficiency by 50% without any extra pedal effort required. For turbocharged vehicles, this is upgraded to a Heavy Duty unit with the cover plate strengthend by an additional 25%. This provides slightly increased pedal effort and more tendancy to be shuddery on take off's but will handle the higher torque characteristics of a turbo.
iii. Lightweight Billet Flywheel - this has two benefits being increased strenght over stock units and also make the semi ceramic clutch units more driveable by not allowing them to shudder as much. Second benefit is that they are lighterand enable the engine to reve easier, faster with less reciprocating weight. No loss of torque but more willingness to rev quicker and harder.
Group 3 Modifications
Now we are down to the serious modifiers. You are usually DOHC head converters, with plans on going turbo or serious Naturally Aspirated Twin Throttle body packages. Comfort and driveability is usually second to engine performance and speed is your goal. These next levels are also the most expensive ones, but be warned, if you have not done any of the Group 1 or 2 Modifications yet, you are WASTING YOUR TIME AND MONEY. Finish them first.
1. Computer Modifications
Okay two choices. EMS or Piggy Back. Pro's and Con's. But I like to think of it this way.
i. If you are still budget conscious (And your at Group 3?), then stick with the piggy back. Don't run more than 12 psi boost or go more than say a twin 46mm throttle body package and definitly don't do any camshaft work. You will be fine. ii. Your not budget conscious within reason. Then EMS is the way to go. Much more advanced tuning, with options like shift lights, in built boost controllers, many many more mapping points, much finer tuning if your going over 12 psi boost or doign cam work etc this is the ONLY choice. Additionally the stock ECU even with a piggy back is unable to cope with any camshaft changes at all.
Haltech Interceptor / Greddy Emanage systems - provide a great unit for baseline tuning.
i. The Haltech - I recomend for people who have gone all the through the Group 1 & 2 level modifications, but don't plan on going any further.
ii. Greddy Emanage - I recomend if you are going for a turbo / twin throttle body conversion due to its ability to be able to tune with larger injectors and tune properly (To a degree) with boost.
Haltech EMS systems can be plug and play and can have your car running in around 15 minutes. There is the E6X for those wanting something simple, or the Haltech E8 for those wanting the best. With the inbuilt boost controllers, and hosts of other functions, these are way ahead of trying do piece together a piggy back with seperate boost controllers, shift lights, guages etc. Note that I do not recomend plug in pre programmed computer chips. These are not tuned in real time on a dyno to suit your individual car. As you modify your vehicle you move further away from the standard average formulae of your engine output. This requries significant tuning and can only be done in real time, not on a computer 3000miles away from your car.
The interceptor units usually provide around a 5kw gain at the flywheel, with improved driveability and torque. The full EMS units provide a little more at this point, but really show there benefit later with more extensive modificaitons.
2. Intake Manifold Upgrade / Twin Throttle Body Conversion
If you are remaining Naturally Aspirated you have several options.
i. First you can go for a single throttle body Performer Intake Manifold with Internal Ram Tubes. Massive throttle response, Haltech piggy back system great looks without extreme levels of tuning requried. Significant torque improvements and can be utilised up to a single 60mm throttle body OR
ii. Upgrade utilising stock manifold, modified with fitment of a second throttle body - twin throttle body conversion. Either twin 46mm or twin 51mm throttle bodies work very nicely for a progressive throttle response and great top end rush of power. This system is fantastic and highly recomended if insurance premiums are a worry. Requires a Greddy Emanage to run this effectivly. OR
iii. The third option is a combination of a Performer Intake Manifold and twin throttle body. Massive plenum chamber, improved air flow, progressive throttle response, this is nearly equivelent to a qaud throttle body kit without the side effects and all of the benefits. Massive air flow and the ability to tune with a piggy back or EMS system. Not turbo compatible of course.
The twin / single manifold upgrades in n/a form can take the car with tuning up as high as around 110 - 115 kw at the flywheel. Twin units produce much stronger mid range acceleration, single units much broader torque from a lower rpm range.
3. Turbocharger Conversion Package
What more can we say other than your a horsepower and boost Junkie. Welcome to the rest of the world. This combines extreme levels of torque and power, with neck snapping acceleration. It comes at a cost though, increased fuel economy, higher insurance and lots of money. But lets get something clear first.
Anyone believing they can effectively fit a turbo kit on their car safely, properly and legally for under $5000.00 is just plain dreaming. These engines in stock form will not handle above 1 PSI boost without aftermarket computer management despite what people believe. 25 : 1 rising rate fuel pressure regulators, larger injectors, moving the distributor to retard timing all these tricks - none work. Don't skimp. 5th Injector systems are something that came and died in the 80's. Quite simply this does not distribute fuel properly to all cylinders, and still does not provide ignition timing adjustment
Do the job properly and although it may cost more, it will last longer, provide trouble free maintenance and be everything you want it to be.
i. For boost levels up to 10 psi can be done saftley on the stock head gasket dependant upon tuning and intercooler efficiency. ii. For boost levels up to 14 psi requires an upgraded decompression head gasket which RPW manafactures. iii. Do not boost above 14 psi on the stock piston / conrod setup otherwise you will learn what a banana conrod looks like.
The 4G15 SOHC engine at around 12 psi is good for around 130kw at the flywheel at the extreme. The DOHC engine for the same boost is good for around 150kw at the extreme. With forged components you can go up to as high as 180kw reasonably at around 20 psi boost
My final advice - if 150kw is not enough for you - after you finish reading this page, it's either look for another car or look to do a engine swap to a larger mitsubishi engine.
Along Wiraje : Crefit to http://www.rpw.com.au