If you’re not satisfied with a standard Evo or want to make it even better, the good news is there’s a world of tuning and modifying options available to you. In fact, a standard Evo is a rare sight and tuning and modifying also gives you the opportunity to create your own unique Evo that performs exactly the way you want it to. There’s a huge industry that has developed over the past few years that can provide you with any parts or services you need to create your perfect Evo.
Warranties, Insurance and Modifications
Before you start modifying your Evo, think about your insurance and any warranty.
Modifying your car can render your insurance void or at least increase your premium,
so always check with your insurer about planned modification before you carry them
out.
Modifications are also likely to render a warranty void. Minor modifications, carried
out by Ralliart dealers may be permissible with an official Mitsubishi UK manufacturers warranty. However, that doesn’t stop many owners of new cars modify their cars and it’s one good reason for buying a new import that doesn’t have a warranty in the first place.
Power:
All Evo engines respond well to tuning and being turbo charged it’s relatively easy to
find extra power. The later the Evo, the more power it can handle before you start
running serious risk of engine problems.
Safety First!
Whilst Evo engines are very tuneable, there are a few basic steps you should always
consider when carrying out any performance enhancing modification to help ensure
nothing that can potentially damage the engine is unknowingly occuring.
Fuel Cuts – One very common problem when carrying out any performance modification are fuel cuts. Fuel cuts are a safety mechanism of the standard ECU, but prolonged fuel cuts can engine cause damage. Put basically, fuel cuts occur when the standard ECU detects too much air flow into the engine and cuts power.
There will be a violent cut power as you accelerate. This is designed to prevent the car over boosting and damaging the engine. All power modifications will increase engine air flow, but unfortunately there’s no set formula for when fuel cuts will occur, but it’s generally around 1.2-1.4bar of boost pressure. If fuel cuts do occur, the best course of action is an ECU upgrade although fuel cut defencers can be fitted to eliminate fuel cuts.
Boost Gauge – If you’re planning any engine modifications it’s highly advisable to fit a boost gauge to monitor boost pressure. It’s easy to over boost a car and either cause fuel cuts or worse too much boost that can damage the engine or turbo.
Other Gauges – Any other gauges you can add when tuning an engine will prove beneficial. Gauges such as oil temp/pressure or an exhaust gas temperature gauge can all help you spot a potential problem before it’s too late. There are a huge range of different gauges to choose from in different styles from different manufacturers.
Knock Gauge – Another problem that can cause serious engine problems and is detonation or knock. Detonation will occur when too high combustion chamber temperatures cause the fuel and air to ignite prematurely. This should be avoided at all costs. Knock gauges such as the KnockLink are a sensible additional to hopefully warn you if detonation is occurring.
Fuel – As you increase the performance of the engine, it will become more important to use the best fuel possible in order to prevent detonation and potentially serious engine damage. If you are not sure, Shell V-Power will provide the best detonation protection being a 98ron petrol. Octane boosters can also help. Never run any Evo on normal unleaded petrol, always use a super unleaded. If a car has been heavily
modified it may well of been mapped for a specific petrol or race fuel.
Air/Fuel Mixture – One absolutely critical factor to measure when tuning an engine is the air/fuel mixture. Even just adding an air filter or exhaust could cause a car’s air/fuel mixture to become too lean. A car running
too lean is likely to destroy pistons and/or turbos. However, equipment to measure the air/fuel ratio accurately is expensive and therefore is normally checked professionally. Most tuner’s or rolling road companies can provide this service. It’s best to check before and after any modification. Most cars have their air/fuel mixture set by a tuning company when the car has any ECU modifications or remaps using the tuner’s own wideband air/fuel sensor and gauge.
There are issues with installing a wideband air/fuel sensor mainly around cost longevity as well the need for it as the air/fuel mixture should not change when set unless problems occur elsewhere. This has meant that permanent air/fuel sensors and gauges are rarely installed, but with the cost of the equipment falling this is starting to change.
Exhaust
Changing all or part of the standard exhaust system will release power. The bigger and straighter the exhaust the more power can be released. Exhaust systems for Evos are normally sold as full systems or cat-back systems and usually made in stainless or mild steel. Certain Evo models come fitted with aftermarket exhausts like some of the FQ range of cars.
Removing the catalytic converter (or converters for an Evo 8 260) and fitting a decat pipe will remove a major restriction of the standard exhaust system and is a cheap performance improvement. However, this will almost certainly cause the engine exhaust emissions to rise beyond the legal limit. Whilst some increase in peak BHP will occur, a loss in torque is also likely. Releasing the full potential of a decat can only be found by an ECU remap.
Another reason to change the exhaust system is for sound. The standard factory exhaust on any Evo is quite quiet and most owners prefer a louder sound on an Evo. Be warned that some systems (such as the Blitz NUR Spec) are so loud they can cause problems with sound levels on trackdays. Expect to pay anywhere from £300 for a cheap cat-back system to well over £1,000 for a high quality full system.
Air Filters and Induction Kits
By making an Evo engine breath better it will produce more power as more air can enter the engine, particularly important when higher boost levels are introduced. One very popular modification is to remove the standard air filter and replace it with an aftermarket one or complete induction kit. One important factor to consider is that the engine will respond better if you feed it with cool air rather than hot air from in the engine bay. Therefore, also fitting a cold air box or relocating the air filter to a location where cold air is available will achieve the best results.
Aftermarket relocation and cold air boxes are also available for this purpose. There are a massive range of aftermarket air filters available costing anywhere between £30 and £200.
Dump Valve
Many owners change the standard dump valve to an aftermarket one, but this will not increase performance unless there’s a fault with the standard one or more than about 1.7bar of boost is being run. The main reason for changing the dump valve is for the sound effects you get if you fit a vent to atmosphere (VTA) dump valve rather than a recirculating one like the standard dump valve. Aftermarket dump valves can cost anywhere between £75 and £350.
Fuel Pump
The fuel pump is the main limiting factor when trying to increase engine power beyond a mild increase and for safety reasons is always a good to change when you carry out any engine modifications. As the engine power is increased the more fuel it will need and the amount that can be provided is limited by the fuel pump. A fuel pump that cannot provide enough fuel will cause an engine to run too lean (see above).
Upgraded fuel pumps to replace the standard one are available for around £100. These replacement fuel pumps are needed from around 350bhp on later cars, but as you near 500bhp these will also run out of steam. Larger, external fuel pumps are then needed and many of these also require additional fuel lines and swirl pots.
Boost Controllers
The easiest and quickest way of achieving significant power gains is to simply raise the boost the turbo is running. Be warned, increasing the boost too much will cause fuel cuts and the fuel pump may need to be upgraded (see above) on a standard car and therefore these issues should be resolved first. There 2 basic approaches for raising and controlling boost. The first is to raise it with a manual boost controller and the second is to use an electronic boost controller.
Manual Boost Controllers - Mechanical boost controllers normally use a valve, of some sort, to alter the boost levels. They are, generally, a lot cheaper than electronic controllers and also easier to setup Disadvantages with mechanical controllers are that the majority of them are ‘under-bonnet’ applications and, as such, cannot easily be altered on the move. Also, mechanical controllers will not compensate for changes in atmospheric conditions i.e. when the intake air temperature drops the boost level will rise due to the denser air in the intake but the boost controller will not be able to take account of this and drop the boost back to the desired level. Manual boost controllers can cost as little as £25.
E
lectronic Boost Controllers - Electronic controllers are a modified version of the standard control setup with a few more features. They use an electronically controlled solenoid(s) to allow the alteration of the amount of air bled from the system. Because they run independently of the main ECU, they can be programmed to have a wider range of features than the standard setup. The advantages of electronic controllers is that they are in-car adjustable and can normally handle several different boost settings. You can also, generally, modify the shape of the boost curve in some way i.e. provide a high peak boost and then settle out to a lower level, map the boost level to particular engine revs or gears etc.
Electronic boost controllers cost anywhere between
£100 and £350
Manual Boost Controller and Electronic Boost Controller
ECU Upgrade
Upgrading the ECU will allow the full potential of any modifications to be released and with some types of ECU give you complete control over how the engine runs. There are 4 basic types of ECU upgrades available:
Plug and Play – Plug and play ECU’s are designed to swap directly with the standard ECU and provide features like fuel cut removal and slightly more aggressive mapping. However, they contain a generic map that will work with any car and therefore not fine tuned to the modifications a particular car may have. The most popular Plug and Play ECU is the Ralliart Sports ECU available for the Evo onwards. Plug and play ECU’s cost around £500 to £700.
ECU Chip - Fitting an ECU performance chip will allow a standard ECU to be altered with a new set of parameters that release more power from the standard ECU, but these will be generic and not car specific.
Unichip make a chip for the Evo 7 onwards for approximately £400. This is fitted to all FQ-340 cars.
ECU Reflash – Another option for upgrading the standard ECU is to reflash or reprogram it or fit an ECU performance chip. Reflashing the standard ECU will allow any parameter to be customised and a map loaded that is designed to suit a particular car. The only form of ECU reflash available (for the Evo 5 onwards) is EcuTek. A reflash will cost around £600.
Mappable ECU – A mappable ECU is a completely programmable ECU that replaces the standard one. Every engine parameter can be completely customised and far more advanced features are available compared to the standard ECU. This should result in a map that is maximising the potential of the
engine. Mappable ECU’s are beneficial if a car’s engine specification is regularly changing and re-maps are required to maximise the performance. Popular ECU’s for all Evos are made by Autronic, MoTec, AEM
and GEMS. A mappable ECU will cost anywhere between £800 and well over £2,000.
Cams - A lot of development work has been done over recent years by a range of companies to develop cam shafts to increase the performance of an Evo engine. Some cams are designed for torque and response and other for outright power. Fitting performance cams (particularly to cars earlier than the Evo 8 MR) can produce good results, but there are a massive choice of different cam profiles available and selecting the right ones are critical. Other modifications, such as turbo, will affect the choice of cam.
The Evo 9 has a variable inlet cam that can be controlled by the ECU and cannot be replaced without changing the engine head. Aftermarket cam shafts can cost between £800 and £1,500.
Turbo
A standard Evo is fitted with a very efficient turbo charger that was upgraded to a twin scroll unit from the Evo 4 for extra response. However, there’s a limit to the extra power the standard turbo can supply (around 400bhp or 1.5bar at peak power). Upgrading to larger turbo can produce almost limitless power (some current Evo engines are producing almost 1,000bhp). However, it comes
at a price and that price is turbo lag.
The decision to upgrade to a larger turbo or not is usually about whether more outright power is wanted or a more responsive engine. The choice normally comes down to how and where the car will be used. This is the dilemma of a turbo charged engine, although using NOS and anti-lag can be used to reduce turbo lag.
Most turbos are sold as kits complete with an upgraded exhaust manifold, pipe work, wastegate and other components.Upgraded turbo kits cost from £2,500 to £4,500.
Another turbo option is to modify the existing turbo, creating a hybrid turbo that is more responsive than standard and able to produce a bit more power at higher RPM. Hybrid turbos can be built in a number of ways, such as fitting a ball bearing core to standard turbo, to suit certain applications. Hybrid turbo conversions cost from £500.
Intercooler
The big problem of running higher boost is the hot air it creates from the turbo and then passes into the engine. The hot air will reduce the amount of power that the engine can produce. All Evos are fitted with a front mounted intercooler that cools the air from the turbo before it enters the engine. With higher power cars (400bhp+) it is normally desirable to fit a more efficient intercooler to further cool the intake air.
Fitting a larger can result in more turbo lag and therefore should only really be fitted to cars that need it.
Upgraded intercoolers cost from around £500 to £1,000.
Big Power!
As mentioned above, as much as 1,000bhp can be produced from an Evo engine. However, this is very specialist work and requires a whole host of additional changes to those outlined above. Expect to pay many tens of thousands of pounds for a seriously high horse power engine!
Engine Internals
When looking for big power (over approximately 400bhp for Evo 6 onwards) or reliability, it’s time to upgrade the engine internals. Stronger pistons and con rods are often fitted whilst the crankshaft is normally only upgraded for very big horsepower or stroker cars. An alternative when fitting different engine internals is to‘stroke’ the engine with a stroker kit which increases the stroke of each piston with a different crank, con rods and pistons. This effectively increases the capacity of the Evo engine from 2ltr to as much as 2.4ltr. A stroker kit will result in an engine with more torque and able to power a larger turbo at lower revs. Expect to pay £5,000+ to have engine internals upgraded.
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