Mitsubishi Magna 1996 - 05 with 6G72/74 SOHC 24v engine.

Dummies Guide to Vehicle Modifications!

The Mitsubishi Magna 3.0 / 3.5 models were a major upgrade for Mitsubishi owners. Replacing the TR/TS 4 and 6 cyl old 2 valve per cylinder engines, these produced much greater horsepower, fuel economy, handling with stronger and more varied transmissions. Triptonic automatic transmissions, 5 speed manuals it had it all. The TE – TH models came out with the 3.0 145kw engine, the TH – TL models came out with the 3.5 litre 163kw engine with its greater torque. There was a TJ Mode Ralliart 180kw engine was very popular with improved engines, LSD and suspension.

The TJ AWD 157kw model which again, was not adequately designed with the same engine horsepower now spread through an AWD platform and auto, reducing acceleration, but having great handling. The TL and TW model magna was released without Ralliart enhancements, but unfortunately the looks of the front was horrendous and lost the interest of many potential users, despite it being internally, the best magna range of all. This was the final magna model which was replaced with the new 380 Model. Despite all this, the magna is a great model to modify, and retains is benefit of being a cruise car with great torque and reasonable handling. They can go very hard and produce surprising times.

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. The brakes on the Magna have always been disappointing under any reasonable braking. 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 – we will be breaking this into sections to provide a well balanced vehicle. Additionally the modification package will be set-up 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.

RPW does not take any responsibility for people performing these modifications on there car without professional involvement. Check with your local government regulations before modifying your car as these items may not be legal in your country.

Updated Information – whilst much of this document is still relevant, our primary recommendation when modifying all versions of the Magna is to now perform the 3.8L 6G75 SOHC 24v engine conversion which is rated at 193kw on average. With our recommended bolt on additions etc, this engine easily exceeds 220kw at the flywheel on stock internals. This is a very easy conversion and is particularly effective in the AWD range which transforms them into an excellent vehicle.

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 drive ability.

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.

1. Quick Shifters

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 RPW Modified 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. Auto Transmission Cooler

We cannot preach this enough on Mitsubishi vehicles. If you have an auto, any model, this should be one of the very first things done to the vehicle. 99% of Mitsubishi transmission failures are as a direct result of the oil being overheated by the lack of factory cooling on the transmission oil.

Regular changes every 20,000km should be done regardless on these vehicles. Fitment of an after market transmission cooler, of virtually any design, will improve transmission life and responsiveness by over 100%.

The vehicle will shift more consistently, be more reliable and cost a lot less to repair in the future. This is a very easy thing to fit and as you modify the vehicle more, becomes extremely necessary. They are usually mounted in front of the radiator, although RPW has been using the B&M fan cooled units a lot more which have there own thermostatically controlled fan to further improve there reliability.

3. Air Filters & Cold Air Induction Kits

The factory air box system on these vehicles, is partially restrictive. There are several ways to free them up – we recommend two main options

  1. Fitment of a K&N Factory Replacement Air Filter for those wanting the Stock look, with improved air flow and throttle response.
  2. This vehicle utilises a MAF – Mass Air Flow Unit which measures air volume and records back to the ECU as the primary referencing source for all ECU management. Fitting universal air filters creates many idling, running rich and other issues with drive ability. Utilising the K&N Specific K&N Ram-pod filter that is oval shaped with an oval shaped adapter. This way we ensure that you do not have any ECU tuning issues.
  3. Cold Air Induction Kit – We manufacture a polished stainless steel system with that show car quality looks, and price. Only available for manual model vehicles, this kit relocates the unit down in to the front bumper with 3″ tubing for constant cold air feed. Cannot fit auto models as there is not enough clearance around the auto transmission to get the piping past.
  4. We recommend also fitting one of the K&N Pre Filter Charger Kits that provides additional filtration and resistance to water

This should produce an approximate gain of around 1 – 2kw with improved throttle response and torque.

4. Fuel rail Upgrades

Like most Mitsubishi models, Mitsubishi is very conservative with the accelerator pump setting in an effort to provide reasonable fuel economy. This has the effect though of robbing power and inducing flat spots on acceleration. The magna throttle body design is such that this is amplified by the stock throttle body requiring large amounts of movement to let significant air flow through.

The second issue with the vehicle is an unequal distribution of fuel supply to every injector due to the small adapter which joins the two fuel rails and the feed system coming in one rail, and being fed out the other side of the second rail.

A duel fuel rail feed kit – replaces the single feed into one fuel rail, coming around the back of the motor into the 2nd fuel rail, then out to the fuel pressure regulator. This twin unit has a feed into each fuel rail, and a return line out of each up to an after market fuel pressure regulator.

This kit provides more stable fuel supply to the injectors and much better throttle response. No ECU retuning or modifications are required. This system has easily powered our Twin Turbo magnas in excess of 600kw.

5. Cat Back Exhaust Systems

The Magna vehicles have quite a good system from the start. The 3.0 model vehicles, run a 2 1/4″ mandrel bent system (In effective diameter) whilst the 3.5 models run an effective 2 1/2″ mandrel bent system. We say effective, meaning that in some points it can be slightly smaller, in other area’s slightly larger. The cat converter on these are a good flowing unit as well.  At this point you must reach your first major decision on where you wish to go with the vehicle – in summary we recommend the following options

  1. 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 a rear muffler upgrade only. Lukey manufacture a bolt on replacement rear muffler kit for the magna vehicles, quieter, direct fitment and is worth on average 5 – 10kw by itself depending upon which model magna you have.
  2. 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, a replacement 2 1/2″ diameter replacement exhaust with a new  resonator and choice of canon or oval shaped muffle design. Mandrel bent design is mandatory.
  3. Naturally Aspirated – Haltech EMS – okay you are an extreme modder. Larger throttle body, camshafts the list goes on. In this case a complete 2 1/2″ mandrel bent system or a 3″  mandrel bent system, again with with the addition of a high flowing cat converter system.
  4. Naturally Aspirated with 6G75 3.8L Motor Conversion – we recommend going with a 3″ system which our tested twin 2 1/4″ muffler system at the rear of the vehicle. Fitted up with a high flowing cat converter. Suitable for Naturally aspirated and Supercharged variations.
  5. Turbo Charged – no more need be said. A 3″ mandrel bent system, high flow cat converter are more than you will ever need. Keeps the car quiet, no droning and has a great sound. Going larger than 3″ for any vehicle producing less than 600hp at the flywheel will not produce any further improvements other than to make more noise.

These can produce small gains with the basic systems of around 5 – 10kw at the wheels, with increased rev-ability and torque.

6. 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. In this situation the following

  1. Replacement of stock springs with some lowering units – Lovell/King Springs 30mm or 50mm lowered units depending upon how low you want to go.
  2. Fitment of a White Line rear sway bar. Reduces body roll without reducing drive-ability.
  3. Fitment of a White Line strut brace. Reduces the tendency of the vehicle to float on the road and makes it less sensitive to changes in road camber, resulting in less need to constantly adjust the steering wheel to keep the car driving straight. This is highly recommended for the magna vehicles, as it dramatically reduce the tendency of the vehicle to wander on the road.

This package will proved a well balanced vehicle, capable of handling corners at higher speeds, will feel safer 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 Naturally Aspirated and going a little more extreme
  2. Looking to turbocharge / supercharge the vehicle

1. Extractor Upgrade

Not all extractors are equal. But fit a badly designed set and you can lose more than you can gain. We manufacture three different designs for the magna vehicles, depending upon your application and how you drive the vehicle. Our units are mostly bolt on systems, requiring around 2 hours to be fitted.

The stock manifolds on the Magna models are quite restrictive, especially in there flex pipe design which joins at a 90 Degree intersection, and is not a tuned length system. This means the rear bank has a shorter length to the front manifold.

All of our header systems, are tuned length meaning that from the header flange to the point at which the two separate header lines merge together, pipe length is identical to produce the same signal strength and air flow equally for both cylinder heads.

  1. RPW 3-1 Street Design Long Tube Headers – partial bolt on system. These require welding and adapting to the stock flex pipe. Long tube 1 5/8″ diameter headers, primarily suited for all 3.0 and 3.5 model vehicles, auto models which do not plan on having serious modifications. The smaller diameter piping produce strong torque gains at low rpm, strong mid range but will suffer at top end horsepower with more aggressive modifications to the engine. The use of the longer header design, amplifies the scavenging effect with less interference between engine cycles.
  2. RPW 3-1 Street Design Short Tube Headers – these are a bolt on system. Designed for Manuel model vehicles with a tendency to mid to high level modifications. This design primarily focuses on mid range and top end horsepower. With 1 5/8″diameter headers, this maximises air flow with virtually no restrictions. A tuned length design, it does not quite produce the same signal strength at low rpm compared to long tube headers, but has superior air flow at higher rpm levels. Manuel model vehicles will find that this design is there best option for all out performance.
  3. RPW 3-1 Race Design Long Tube Headers – these are a bolt on system. These are a long tube header, with pipe diameter increased to 1 5/8″, the same as our short tube headers. Designed primarily for the 3.5 and 3.8 engines, Auto models utilise these to retain low rpm and midrange torque with improved high rpm breathing due to the larger pipe diameter. For supercharged etc vehicles, these work extremely well in channelling high volumes of gases and producing strong scavenging effects to help improve throttle response off boost. These are used with the 6G75 motor conversions which do not require any sump pan modifications like other brand headers.

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 5 – 7kw at the flywheel with increased torque and improved upper acceleration and rpm range.

3. 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 6G72/74 SOHC engine is 65mm. The unique design of this unit is such that, although it is 65m in diameter, there are restrictions which do not allow air through the unit until you actually reach 25% throttle. Then it begins allowing air to move through it. This results in a feeling of a lack of “Throttle Response”

  1. We provide an exchange throttle body system for these vehicles. High Flowing of the unit reduces the point at which air flows through the unit from 25% down to 12% throttle position. This significantly improves throttle response, requiring less throttle movement for more fine control over acceleration and movement. There are multiple throttle body designs varying in vacuum line fittings 1 or 3, cruise or non cruise control and traction control. These also vary Manuel to auto as well. The fitment of this unit does not require removal or machining of the intake manifold.
  2. Whilst this work is being done, we recommend fitting 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 temperatures by 25% overall resulting in improved combustion, fuel economy and throttle response. The thermo block kit replaces the gaskets between the upper and lower intake manifold, as wll as the throttle body gasket. No modifications required.

This package adds 2- 5kw at the flywheel, but does improve throttle response and low rpm drive ability. The thermo block kit reduces heat soak and this allows the engine to maintain maximum 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 Magna is a 276mm single piston calliper package with 260mm rear brakes. Ralliart and AWD modes come out with the larger 295mm Twin Piston Calliper font brakes, 284 vented rear brakes. All model magnas suffer from warpage of the brake rotors and severe brake fade after repeated braking applications. RPW Has several upgrades here we highly recommend.

  1. For those wanting something marginally better, and are not planning on doing ANY MAJOR Horsepower mods, then minor upgrading of front brakes only. Retaining stock callipers, fitment of some Performance brake pads and slotted Rotors is very beneficial. Braking by around 10% with better feel and dramatically less brake fade. Brake warpage is eliminated. For all Ralliart and AWD models this is the only option except for the Brembo Upgrade.
  2. For those wanting something a little better, upgrading of the front brakes to a Twin Piston Calliper package, dramatically improves pedal feel and increase brake clamping force. Utilised with EBC Green Stuff Brake Pads, this is a major upgrade without going extreme.
  3. For those wanting something without going to extreme levels, fitment of a 295mm Twin Piston front brake package is the final step. Guaranteed no brake fade and this large rotor will fit very nicely inside of any 15″ or larger rim. This package will handle any repeated braking short of consistent track use.
  4. Next a Rear Disc upgrade package. This replaces the 260mm rear disc package with a 284mm vented rotor package.  Fitted with optional EBC Black or Green Stuff brake pads, slotted rotors, 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.
  5. For the ultimate upgrade, Mitsubishi EVO Brembo four piston caliper setups front, twin piston callipers rear are optional as well, but require a minimum of a 16″ rim to clear the larger rotor sizes. These fit with very minor modifications and we cannot praise this system enough – this is the only upgrade option available for AWD and Ralliart owners.

5. Suspension Modifications – Level 2

Okay ready to take the final plunge for power and hit that turbocharger or camshafts with computer. Wrong. Lets take a look at your suspension again. Factory shock absorbers will incresae 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

Shock Absorber Options – three choices here with standard type strut assemblies

  1. Fitment of KYB Excel-G replacement units for the more budget conscious. Retains improved handling over stock.
  2. 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. Well proven, we have run these for many years and found them to be an excellent product.

Coil over Strut Assemblies

  1. There are now several brand of coil over strut assemblies for the magna vehicles and they provide significant benefits in handling, height adjustment and wheel alignment etc. If you have the funds and want something to handle on the road like a race car with comfort, then this is the way to go.

The final items we recommend to improve your suspension is as follows

  1. Fitment of a 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.
  2. 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 center of balance, to provide a reduced tendancy to “Lift” the front of the car upon accelerating. Requires a wheel alignment straight away.
  3. Fitment of a Whiteline rear strut brace (In Coupe Models Only) for additional reduced body movement.
  4. Fitment of a Whiteline improved front sway bar for reduced front roll.

RPW Does not recommend replacing the balance of the vehicle rubber mounts with Polyurethane ones for any street going vehicle unless being used for competition use. This results in a very very harsh vehicle on the road with much increased road noise and vibration. We feel the packages we have recommended provide that best balance of street vehicle and performance without sacrificing drive-ability.

6. Drive Line Upgrades

There are three main driveline upgrades whch can be done, which go a long way towards improving the reliability of the engine as well as drive-ability.

  1. Clutch Kit – At some point your clutch will need upgrading. Two options available – for naturally aspirated drivers a standard cover plate 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 strengthened by an additional 25%. This provides slightly increased pedal effort and more tendency to be shuddery on take off’s but will handle the higher torque characteristics of a turbo.
  2. Lightweight Billet Flywheel – this has two benefits being increased strength over stock units and also make the semi ceramic clutch units more drive-able by not allowing them to shudder as much. Second benefit is that they are lighter and enable the engine to reve easier, faster with less reciprocating weight. No loss of torque but more willingness to rev quicker and harder.
  3. Manuel model Magna’s are known for there weak differentials. Upgrading to a Limited Slip Differential has many benefits including increased gearbox strength, increased traction, reduction of wheel tramp, better road feel and handling. Quaife units are the only units we have found that not only provide improved traction, but strengthen the gearbox and are a direct fitment. On normal driving this acts like a normal stock differential – until you accelerate.

Group 3 Modifications

Now we are down to the serious modifiers. You are usually plan 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. Reflash Factory ECU or replacement EMS System.  But We like to think of it this way.

  1. If you are still budget conscious (And your at Group 3?), then stick with either a reflash.  This is more than suitable for everything except the most hardcore engine modifications except for turbo-charging / supercharging.
  2. An After market EMS is the only option if you plan on going for heavy naturally aspirated modifications or forced induction.

Re-flashing the factory ECU is only available on some models, and for the majority of owners except for those going forced induction, this is the best option for tuning. This is the cheapest long term option and our preferred tuning option where possible. We can remap factory fuel and ignition curves as well a reprogram Automatic Shift patters on AWD models. Compatible with low boosting supercharger systems as well.

Haltech and Link EMS systems are what RPW specialises in. We make our own plug and play ECU packages which means we can have your car running in around 15 minutes with a Haltech EMS system on there.

2. Intake Manifold Upgrade / Twin Throttle Body Conversion

The stock intake manifold on the V6 engines is like most manufacturers, a limited unit.  RPW has manufactured several options, that provide significant gain. All of these require ECU upgrades to get the most out of the engine for performance. Horsepower is not our only goal, Torque is what people want and that is what our manifolds are designed to do.

  1. First you can go for a single throttle body RPW Performer Intake Manifold with Internal Ram Tubes. Massive throttle response, looks without extreme levels of tuning required. Significant torque improvements and can be utilised up to a single 65mm throttle body.
  2. The same Performer Series manifold, minus internal ram tubes is available for forced induction vehicles. The massive 100mm plenum chamber and smoothed internal runners provides significant air flow gains at low rpm, but the larger chamber with curved walls, provides a smoother path of air when being forced in and produces significant torque gains an aids in bringing boost on sooner.
  3. RPW Also manufacturers a twin 40 and 50mm parallel butterfly set-up for the magna vehicle, with or without internal ram tubes. The large Holley throttle body (Manuel vehicles only) has an inbuilt NOS nozzle, and provides quite significant air flow gains.

The twin / single manifold upgrades in n/a form can take the car with tuning up as high as around 200 kw at the flywheel. Twin units produce much stronger mid range acceleration, single units much broader torque from a lower rpm range.

3. Turbocharger / Supercharger 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.

  1. Anyone believing they can effectively fit a turbo or Supercharger kit on there car safely, properly and legally for under $5000.00 AUD$ is just plain dreaming.
  2. These engines in stock form will not handle above 1 PSI boost without after market 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.
  3. 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.

  1. For boost levels up to 10 psi can be done safely on the stock head gasket dependent upon tuning and inter-cooler efficiency.
  2. Do not boost above 7 psi on the stock piston / conrod set-up otherwise you will learn what a smashed piston looks like.

The 6G74  SOHC engine at around 7 psi is good for around 230kw at the flywheel at the extreme. With forged components you can go up to as high as 450kw reasonably at around 20 psi boost

The 6G75 SOHC engine at around 7 psi is good for around 300kw at the flywheel. This is one the reasons why this is our preferred reasons why we do this motor as a transplant.

Our final advice – if 180kw is not enough for you – the finish reading this page, and instead either look for another car or look to do a engine swap to a larger Mitsubishi engine.

Did you like our guide? Something did not make sense. Please let us know and we will try to update this with more relevant information etc. We hope this helps you plan your vehicle modifications in a more informed manner.