Mitsubishi Colt Ralliart Turbo R&D Test Vehicle

The plan - turn this show stopper into something ultimatly crazy !!

Technical Specifications

  1. Mitsubishi 2006 Ralliart Colt also known as the CZT Colt in Europe
  2. 4G15 1.5 Litre DOHC 16 valve Turbocharged Mivec (Mitsubishi Innovative Valve Timing and Lift Electronic Control) engine with electronic ignition
  3. Factory Power Output : 113lw @ 6000 rpm / Torque : 210Nm @ 3500 rpm
  4. 5 Speed Manuel Gearbox
  5. Four Wheel Disc Brakes

RPW has been “Lent” this vehicle by one of our long time customers. Over the upcoming months this vehicle will be subjected to many hours of labour, more than a dozen dyno runs and a lot of modifications. From its stock state – it will be initially have every form of RPW bolt on modifications fitted to it. During the whole event various dyno runs will be done to catalogue the various gains.

We anticipate a lot of response and some great results out of this engine. Below our our plans in rough order and as we progress through them – we will update this page with data sheets, photos and dyno print outs etc. We trust everyone will enjoy this.

All Dyno tuning will be performed on the Dyna Pack Hub Dyno. The reason being that this eliminates any variations in tyre slippage, heat in tyres etc. This is a mechanical hub connection to the wheels and whilst the numbers may be slightly higher over a normal roller dyno, the gains are 100% confirmed between runs with no variations to worry about other than mild temperature variations which we will be attempting to minimise.

Plan of Attack

  1. Get Vehicle to RPW Workshop in Stock Trim, visually inspect vehicle and roll eyes, so much to be done – completed
  2. Run vehicle on dyno to prepare baseline power outputs to compare future modifications to compare comparative results – completed
  3. Remove stock gear shifter assembly – fit RPW Rally Spec unit to vehicle – In Progress
  4. Perform exhaust work – fitment of 2 1/2″ system with new expansion chamber resonator and Lukey Ultra flow muffler and tip
  5. Dyno vehicle to compare gains of exhaust system on stock vehicle
  6. Manufacture on vehicle RPW Replacement Front Pipe / high flow cat converter & Turbo outlet.
  7. Remove Factory Boost Restrictor Pill and dyno test
  8. Manufacture and complete Under Drive Pulley Kits and dyno test
  9. Install K&N Panel Filter and / Pod filter setup and compare gains on dyno
  10. Dyno vehicle to compare comparative gains
  11. Install and fit Haltech Interceptor, retune vehicle with increased boost.
  12. Finalise re flashing of Factory ECU, retune vehicle
  13. Manufacture and fit RPW Turbo Manifold Upgrade
  14. Manufacture camshaft and valve spring upgrades.
  15. Develop drive train improvements – Quaife ATB, Clutch and Flywheel
  16. RPW Front Mount Inter cooler Upgrade
  17. Turbocharger Upgrades
  18. Haltech Elite Computer Upgrades
  19. Stroker Crankshaft and piston Kits

Job 1 – Get Vehicle to RPW Workshop in Stock Trim – 1st November 2007

Vehicle received by RPW and inspected. In completely stock trim – quite impressed with its starting package. Vehicle drives very nicely and looking forward to modifying it. Driving the vehicle we were impressed with the torque response, throttle response and general willingness to accelerate. But we know we can do better.

Suspension was very soft, and brakes felt good. Overall very impressive car – impressive because we know how much we can do to it. Nice light clutch, and the shifter feels good but once you are used to a RPW short shifter, they just plain feel yucky and vague. The turbo kicks in very nicely, strong torque range. Car is very zippy to drive around, but you can feel the power drop off as the boost tapers off very fast. Have organised for the start of the work to be done on the vehicle immediately.

Job 2 – Run Vehicle on Dyno for Baseline Power Run – 108kw / 211nm factory output.

RPW will be placing the vehicle on our dyna pack hub dyno unit, and performing three power runs to produce our baseline. Once done, this will be shown here with a report on the vehicle in its stock form.

The baseline run has been done on our Dynapack Hub dyno with standard SAE correction for temperature factors. We compared the power figures to another stock Ralliart Colt and found them to be nearly identical, although there were some subtle variations in the air/fuel ratios. Our analysis of the stock setup showed that it peaked on boost very early, and then drops the boost level quite fast as the rpms increase. The air fuel ratio drops straight down into the 11’s and even 10’s in some cases which we find quite amazing for a stock vehicle to run this rich. Power and torque is good, producing 108kw at the hubs with 211nm of torque.

Interesting is that peak horsepower was produced at 6000 rpm, and still increasing, whilst peak torque was produced at 3000rpm and then drops off quite rapidly. With good tuning, increased boost the torque and power levels should rise considerably. Since dyno figures of other mods compared to stock are listed below, check those for the standard dyno results.

Job 6 – RPW Dump Pipe Housing Package (Completed November 2009) – Part 2

Further inspection and removal of the factory exhaust revealed the dump pipe housing off the back of the turbo is also very small in both shape and design.

As mentioned above, it only has a 1 3/4″ diameter outlet which is a severe restriction.

RPW has manufactured a replacement unit, designed for better flow, as a bolt on item with a 2 1/2″ diameter outlet.

This will be based on an EVO design for maximum performance. Below are photos of the stock units and replacement units.

This used in combination with the new dump pipe kit will maximise flow on the vehicles for maximum performance and boost response.

The photos do not do this product justice. The prototype was successfully fitted to the test vehicle and was an easy direct bolt up without any modifications required.

The gained the following results which were inline with our expectations

  1. We gained a 5hp improvement at the hubs, with 3 – 5 ft/pd torque improvement. Minor leaning out of AFR ratio’s which is a good thing.
  2. As has shown on all exhaust mods to date, the boost level has dropped by another 2kpa on average overall as the stock ECU system remains at maximun wastegate duty cycle.
  3. In a nutshell, we gained horsepower and torque with a reduction in boost level. This can only mean good things.
  4. On the road the car accelerated a lot more smoothly and hit the rpm limiter very very quickly. Throttle response was massively improved and the exhaust note can only be termed as “Sweet”. No increased noise or droning.
  5. Below are some links to specific feedback from customers who have tested this particular modification. Nothing speaks better than customer feedback
  6.  Owner of Test Vehicle Feedback from Ralliart Colt Forums –
  7. More feedback from someone who also test drove the vehicle –

These units are now in mass production, manufactured in stainless steel.

Be warned though, there are some cheap knock off’s which stainless steel designs, but do not flow the same as our units which are a true 2 1/2″ internal diameter.

Job 7 – Factory Boost Restrictor – Completed 11th November 2008 

Research confirmed that the factory vehicles utilise a Boost Restrictor Pill inside the boost control solenoid which bleeds off boost pressure to the Factory Turbo Waste gate. Below is a photo showing the restrictor (Photo taken and modified from the 3000gt application).

Removal of this restrictor increases boost by approx 3 psi across the board. This will retain the Mitsubishi Factory curve on the Colt with its high peak and reduction as RPM’s increase, simply increasing the values by approximately 3 psi.

For those wanting that extra boost, or in the case, fitment of a full exhaust system, this is a highly recommended modification. This is a common situation from all Mitsubishi turbocharged applications and is something that anyone can do with some basic tools and around 1 hour of time.

Below is a dyno graph showing the results of the boost restrictor removal, showing the boost curve increase and power increase. Obviously with more exhaust work etc, the gains will be greater, especially with tuning. The dotted line shows before removal, solid line after removal. A nice solid 15+kw gain in power at the wheels.

Note that this is completely separate to the secondary boost restrictor pill which is located in the vacuum hose near the turbine which is responsible for increasing the boost level before being bled off by the solenoid valve.

Job 8 – Under Drive Pulley Kit – Completed 11th November 2008

Racing Performance Works has completed fitment of our new Under Drive Pulley kits onto the vehicle. This replaces the larger heavier unit with a light weight aluminum unit. The diameter is approximately 2/3rd of the factory and reduces the rotation mass of the balancer.

As well the air conditioning and alternator load is reduced on the engine. This improves the acceleration, torque and overall power of the vehicle Below is a dyno sheet showing the improvement of approx 2kw and 2 – 3nm of torque with no other changes, no tuning. We were quite pleased with the results of this.

The dyno graph below  shows the minor improvements on the dyno but the real results aer shown on the road when accelerating.

Job 9 & 10 – Comparison of K&N Panel Filter V Pod Filter setup – Completed 19th March 2008

Racing Performance Works did our test comparison earlier in the year to compare on the dyno the difference between the K&N Panel Filter and K&N Filter charger Kit. Below is an excerpt from discussions we made on the Ralliart Colt Forums. Rather than provide a clinical description, we have chosen to leave this information instead as we feel this is a very honest way of explaining the results.

Okay first results, on the back to back tests on filters – I think people will be very surprised.
I will put a more detailed report on our website. I hope K&N don’t sue me……

1st comparison factory air filter Versus K&N panel replacement filter

HP Gain – maybe 1kw
Air/Fuel ratio – leaned out nicely definitely would be better for fuel economy, throttle response
Boost level – increased slightly
Repeat-ability – after three power runs there was a slight decrease in power as the air box heated up slightly by around 3kw

2nd comparison K&N panel filter versus Pod Filter in engine bay

HP gain – loss 4kw
Ar/Fuel ratio – leaned out further slightly, but on 3rd power run richened up slightly, overall matched panel filter for end result air/fuel ratio curve.  Slightly better throttle response
Boost level – same increase as panel filter
Repeat-ability – after three power runs there was a marked decrease in power as it started sucking the hotter engine bay air.  Power change between 1st to 3rd power run by around 8kw

Overall results – analysis

The pod filter has the most potential, but in both circumstances showed that no matter how much more air we allow the motor to suck in, it just can’t get rid of it fast enough, even with leaner air/fuel ratio’s and slightly more boost, overall hp didn’t increase which means the car just can’t get rid of the exhaust gases yet. No surprises there.

Heat soak is a big issue, and basically where the pod filter is let down. K&N have supplied some extra piping to pump the air up to the filter, but in my opinion it will do bugger all. I am going to put the car on the hoist tomorrow and see if I can re-adapt the kit to convert it to a proper cold air kit, Ie relocate filter to one of the guards. I think this is a job for where you have a FMIC unit, and you can open up the guard on the passenger side to mount the filter. This would be the perfect scenario for the pod filter.

Meanwhile, personally, I recommend the panel filter Unless you are doing the FMIC unit.

The ram pod kit is a nice kit, nice adapters although the bracket is a pain to fit up. I think of it as the ram pod kit has much much more potential than the flat panel filter. But its one of those “Future” mods where you are aware that its not being used to its full potential. But stop – its not all bad. I believe this test is not fully developed yet. Once the dump pipe is fitted, and the air can then push more air out, with more boost, its going to want more air in. This is where the ram pod I believe will start to shine and probably exceed the panel, even with heat soak.

Okay more detailed report than what I anticipated, but will update our website in the next day or two with detailed report and dyno sheets.

In Summary, heat soak is a major issue with the vehicle, and any pod filter set-up sitting inside the engine bay, especially with the stock inter cooler, is just making the car work harder. The factory ecu picks up the hotter air and retards timing slightly for protection. In our opinion, any exposed pod filter is not recommended. RPW will be investing in further research for a proper cold air feed set-up as one of our next priorities.

Job 11 – Installation and Tuning of Haltech Piggy Back Computer – Completed 17th April 2009

After 18 months of research, RPW has finally enabled the use of a piggy back ecu to enable retuning of fuel, ignition and boost curves on the vehicle. We now have the fuel and boost curves working perfectly, ignition tuning is just around the corner with some final data logging and scanning to be completed by Haltech with some software changes.

This system worked perfectly until we hit a snag – we produced too much torque improvement, and hit the factory ECU Torque limiting levels and produced a Check Engine Light. We have now stopped all work on any piggy back system on the colt and have instead proceeded with sourcing a 2nd hand Ralliart Colt ECU to provide reflashing of the factory ECU. This will be done via OpenECU / Openport 2.0 technology. Once this is available more information will be provided.

Job 12 – Reflashing Factory ECU (Updated 13th October 2010)

RPW has successfully worked with EcuFlash and Evoscan to enable the stock ECU to now be re flashed. Below is an outline of just some of the things we can do

  1. Adjust the fly by wire throttle maps to improve throttle response / smoothness of power
  2. Re-tune the fuel and ignition curves to maximise power
  3. Modify the mivec changeover point to maximise torque / power
  4. Alter boost levels by use of pills / restricters or allow use of after market boost controller
  5. Play with torque request maps to remove CEL check codes
  6. Removal of CEL Codes

There are more than just the above, but we think everyone will get the point. Once this is finalised we are able to do a lot of modifications to the vehicle very easily.

Updated news 13th October 2010

We today did our first successful read / write to the ECU,  the car had several minor modifications which worked perfectly without any issues. We are now be doing some advanced tuning and producing stage 2 level tunes.

Finally we can now drive a colt like we wanted to.

Below are dyno sheets showing our new test car.

This test vehicle had the following modifications

  • RPW Front pipe kit Version 1
  • RPW Exhaust System 2 1/2″
  • RPW Version 1 Dump Pipe Housing
  • XR6T inter-cooler with partial RPW Inter-cooler Pipes
  • K&N Panel Filter inside stock air box
  • Fitment of GrimmSpeed 3 Port boost control solenoid

A baseline run was done with the stock tune on the car.

A 3 port boost control solenoid was fitted, and the vehicle tuned.
The results are impressive to say the least and there are now many threads dedicated on the RColt forums regarding this set-up.

Job 13 – Turbo Manifold Upgrade – completed

RPW has manufactured our first replacement turbo manifolds for the Colt vehicles. We are tested two designs, one being a Stainless Steel unit for those wanting show quality looks.

The other is our Premium Steam Pipe manifolds which utilise even longer pulse driven runners, more shaped direction of flow and of course, the thickness of 3mm steam pipe.

This will never break, crack or have any failure. The benefits of steam pipe are also retaining more heat to drive the turbo, ceramic coating of the unit to reduce heat soak inside the engine bay.

Our tuned length design with longer primary pipes and more shaped pathways was our preferred design and has proven itself to be better design.

This will be superior in terms of horsepower compared to the unequal length design, but will be slightly laggier.

But for higher boost levels above consistent 15 psi, this will produce gains which won’t be matched by the stainless steel or varied length manifold.

This manifold has been made available to suit both the factory TF03 flange or the Mitsubishi TD04 series turbochargers.

The first unit was fitted to a customers vehicle being the stainless steel design.

The vehicle showed excellent results with test vehicle gaining on average 5hp across the board with a 3 ft/pd torque improvement.

Most interesting is again, there was a slight variation in boost levels, a minor drop as well as a definite leaning out of the AFR ratios prior to peak Boost point, with the vehicle leaning out dangerously to around 14 : 1 AFR.

This test was done with a RPW Full exhaust on the vehicle including Dump Pipe Housing, Front Pipe and cat back system, with under drive pulley and K&N Filter.

The side effects of the stainless steel unfortunately is the excess heat now being generated inside the engine bay and the concern over the long term reliability of the stainless steel welds.

Job 15 – Camshaft and Valve Spring Upgrades 

RPW has completed manufacturing of billet performance camshafts and valve spring upgrade packages now for the colt.

These have been successfully independently tested by other firms and clients.

We have fitted to a customers vehicle, a stage 1 profile onto a 1600cc stroked engine package, which produced excellent results in smoothness of idle and low rpm drive ability.

This proved our case that bigger is not always better. We now have a wide range of camshafts profiles available and some of the most powerful colts in Australia run our Camshaft Billets and Valve springs.

We also now have available vernier camshaft gears for the exhaust camshaft, allowing full tuning options for all camshafts upgrades.

Job 16 – Drive Train Upgrades

RPW has worked with Quaife to match up a bolt in differential. This has been successfully done and has been fitted into a colt vehicle.

This has advantages over current Cusco / Ralliart units by retaining the stock feel with no grinding, noisy or jerking of the steering wheel.

As well it comes with a lifetime warranty against breakage, and will dramatically improve traction on the colt without any side effects. We look forward to updating results on this.

The results were immediate with improved road feel, increased traction and the end result, faster acceleration in both straight line, but especially on corners. There are no side effects and the job can be done from start to finish in the same day.

Other upgrades are a billet flywheel and stronger clutch which no doubt many colts are going to be needing soon.

Clutches are now available in both stock and a Heavy Duty Option. Flywheels are also now available in conjunction with the Heavy Duty Clutch Upgrade.

Experience has shown that the stock clutch / flywheel package starts to fail once the vehicle starts producing any reasonable horsepower with full exhaust modifications and tuning.

Job 17 – Inter-cooler Upgrades

The factory inter-cooler is a very small unit and has been proven to be both restrictive once boost levels are lifted above the 14 psi levels, as well as creating heat soak. Testing was done between several designs including

  • Front Mount design mounted beneath the front bumper bar insert
  • XR6T Falcon units mounted behind the front bumper insert.

We decided to stay with the Front Mount universal straight design due to not being restricted on air flow as well as inter-cooler gets a greater amount of airflow across its face.

The additional benefit is that the pipe work is simpler with this design. The only side effect is that it does involve the removal of the factory Mesh Material across the face of the front bumper.

Testing showed tremendous gains with the inter-cooler, with any inter-cooler in fact compared to the factory design.

Below are some photos of our design fitted up as well as a dyno graph showing a vehicle tuned more heavily and the results you can achieve with good tuning.

Job 18 – Turbocharger Upgrades

The factory turbocharger on the colt is classed as a TF035-10T unit. This is a very small turbo and maxe’s out at 205hp on average at the hubs on our dyno.

Even with the upgrading of 3 port boost solenoid and upgrade waste-gate actuator, the turbo is unable to hold boost levels in excess of 15 psi above 5000 rpm on average.

There are now several choices of bolt on turbo upgrades being

  • TF035-15T – essentially a larger intake wheel. Direct bolt on and good for around 240hp max on our dyno
  • TF035-15T/TD04 – this is a hybrid turbo developed by RPW which has the 15T intake wheel, but a larger exhaust wheel. This turbo is good for up to a maximum of 300hp on our dyno
  • TF0035-16T/TD04+ – this is the same turbo as above but has further machining work done to have a larger intake turbine. This turbo is good for around 330hp on our dyno.

There are always the choices of the Mitsubishi TD04 turbo range which match the same wheels as our hybrid turbo’s, but these would require custom front pipes, turbo outlet pipes etc.

With our hybrid turbo’s you can retain all of your existing modifications and.

Below is a dyno graphs of vehicles tuned with all our tested bolt on modifications with the TF035-15T/TD04 Turbo range.

Job 19 & 20 – Haltech Elite Upgrade with Stroke Kit

With the recent release of the Haltech Elite series of ECU’s with drive by wire control, RPW decided to get one of our vehicles, in this case a Stroked 1600cc full forged motor with stage 1 camshafts, springs, and of course, our TF035-15T / TDO4 turbo.

The Haltech was wired up and work is now in development in producing full plug and play kits to completely replace the factory ECU. This has several advantages over the stock ECU, being live time tuning, fuel flex E85 duel mapping, more advanced boost control, launch control to name but just a few.

The stroker kits were developed to reduce turbo lag, enable larger turbo’s for more top end and to improve throttle response and acceleration.
This design does not involve any modifications to the engine block and RPW has now built several of these with great success.
Below is a dyno printout of the vehicle that essentially took into account all of these modifications we provide for the colt.

RColt Stroker Package with Haltech

Final Words

We hope you enjoyed reading the results of this project. We updated this page with our new website to reflect some of the latest developments and results but have tried to keep the “Historical” development for which we now take for granted when working on the colts that now seems very obvious.

There has been lots of other research done including inter-cooler pipes, waste gate actuators, cold air induction kits and more advanced head work. We have developed stage progressive performance packages which have been very successful in producing a lot of modified colts Australia wide.

We would like to thank those customers who worked with us over the years in enabling us to test things on there vehicles, especially in the early years.