Mitsubishi Lancer CJ 4B12 Mivec

R&D Project Vehicle

Technical Specifications

  1. Mitsubishi 2008 CJ Lancer
  2. 4B12 2.4 Litre, DOHC 16 Valve Mivec (Mitsubishi Innovative Valve timing and lift Electronic Control) Engine
  3. Power 125kw, 170 HP EEC @ 6000 rpm, 226Nm @ 4100 rpm
  4. 6 Speed CVT Transmission
  5. Four wheel Disc Brakes

RPW has been “Lent” this vehicle to work our magic on. 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.

Final point – please note that even though our dyno graphs show the readings as Flywheel Horsepower / Flywheel Torque figures, the calibration option is set to a Factor of 1, which means that hub and flywheel horsepower ratings are identical. Hopefully this will clear up some confusion people have with the results from the dyno print outs.

At various stages the vehicle will be taken down the quarter mile strip and run again to catalogue some results and see what the improvements are there as well. At this stage we will not be doing any specific suspension / braking upgrades as part of this R&D project, but that may change as time goes on.

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. Download ROM off ECU and prepare OpenECU Definition Files for re flashing – completed.
  3. Run vehicle on dyno to prepare baseline power outputs to compare future modifications to compare comparative results – completed
  4. Remove stock gear shifter assembly – fit RPW Rally Spec unit to vehicle – completed
  5. Install K&N Panel Filter and / Pod filter setup and compare gains on dyno
  6. Perform exhaust work – fitment of 2 1/2″ system with new expansion chamber resonator and Lukey Ultra flow muffler and tip including high flow cat converter and dyno test.
  7. Manufacture on vehicle RPW Replacement Extractor packages & Dyno Test
  8. Retune vehicle utilising OpenECU Re flashing technology
  9. Manufacture and fitment of RPW Stage 1 camshafts
  10. Retune vehicle and see final results

Job 1 – Get Vehicle to RPW Workshop in Stock Trim – 25th June 2009

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. This vehicle was the first CVT vehicle we have driven, CVT being Constant Variable Transmission. It was not as bad as we thought, with it holding a steady 5000rpm on acceleration.

We could manually enable the gears via a triptronic setup, which enabled us to rev it out, but once you hit the 6000+ rpm range, the vehicles drive by wire throttle body control was very slow to allow rpm’s to drop. First thing first, put it on the dyno and see what it does.

Job 2- Reflash ECU – 25th June 2009

The first thing we did, as part of our plan was to download the ROM off the ECU, and to ensure we could reflash the vehicle in the future. We have decoded around 50% of the ECU Rom data file, and are now finalising the maps for the variable camshaft technology and drive by wire throttle body control.

This is extremely important as many modifications will invariably end up with a CEL check code, usually by a check routine of throttle load V Desired Torque V Air Flow Volume. With our ability to reflash, these problems will be easily solved as we change the appropriate maps to give us more flexibility.

We now have enough of the factory ROM file to be able to do normal reflashing of the main fuel maps and ignition maps. Interesting the vehicle uses a factory Knock Sensor for sensing both Octane Level and using two maps, a High and Low Octane map for fuel, ignition and variable camshaft timing.

We will for our purposes, only be modifying the high octane maps, leaving all low octane maps factory for added safety. Since these usually run quite rich and low on ignition timing, these will be safe to leave untouched.

Job 3 – Run Vehicle on Dyno for Baseline Power Run – 101kw factory output.

We placed the vehicle on our dyna pack hub dyno unit, and performed several baseline runs.

This took a while until we could find the right combination of gearing and method to allow us to get a stable power run. The vehicle was run in 4th gear, using the triptronic option and setting it to 4th gear.

The results were pretty much what we expected, in line with the factory outputs of Mitsubishi, with there consistent very rich fuel ratio’s. As can be seen, once the vehicle hit over 3000 rpm, the air fuel ratio’s dropped down into the 11’s.

Different dyno runs sometimes touched the 10’s. Power was fairly smooth but as can be seen, is a little bump. Interesting is peak power was produced at 6500 rpm, but the factory ecu in normal mode holds the vehicle at 5000 rpm on hard changes.

Peak torque was produced at 4000 rpm and tapered off (This can be seen on future graphs). With the ability of this vehicle with its variable camshaft timing and variable throttle body set-ups, this is an area for certain can be radically improved.

Mitsubishi Lancer CJ 4B12 Stock 1DBT988

Job 4 – Upgrade Gear Shifter Assembly.

With our test vehicle, being a Auto model, we sourced separately a new Mitsubishi Gear Shifter Assembly, and like our previous designs for other lancers, we have manufactured our renowned Short Shifter Kits.

We have managed to shorten the throw by our typical 60% over factory.

The short shifter kits are now available on exchange for all Manuel model owners.

Short Shifter Late Plastic Base

Job 5 – Upgrade Cold Air Induction Kits

These vehicles utilise the Mitsubishi new style Hot Wire MAF sensor. These vehicles, as we know run very rich from factory. There have been a lot of DYI customers fitting CAI (Cold Air Induction) and SRI (Short Ram Intake) kits to there vehicles with mixed results. As can be seen from our own efforts, this is understandable when you look at the dramatic differences it makes to the Air Fuel Ratio’s of the vehicle.

We first after doing our back to back test on the baseline dyno run, fitted a K&N panel replacement air filter to the vehicle. We did not include a dyno printout, because essentially, we got no increase or decrease in power from the unit. We explain this, by the sheer fact the stock air intake box set-up, is quite restrictive in factory form.

It has a very small opening at the front, with holes drilled into the base around 1/3rd the way back as it sucks air from within the engine bay, and is also heated up by its proximity to the radiator. The size of the set-up is virtually fixed in the amount of air it can pull at one time. The K&N panel filter, whilst it can flow better is being hampered by the fact that it cannot get any more air being pulled through the factory inlet setup.

The next step was to manufacture a new complete cold air kit for the vehicle. We did this by utilising the K&N Apollo Cold Air kit. We replaced the factory piping, with a new 90 degree silicon elbow which utilises smooth piping. We then cut out of the factory air box the piping that the MAF sensor screws into, giving us an easy 30cm of length of smooth piping.

This was cleaned and buffed, making it a very easy DIY job. This was fitted into the silicon elbow, and we then placed the enclosed K&N air box onto the end of this. At this point we know have either a SRI system for those wanting that type of system, or can add the additional K&N piping to pull cold air from the front bumper location. We did both systems, and surprisingly, found that both the SRI and CAI set-up produced the same horsepower levels. Below are the dyno graph printouts.

As can be seen, there was a dramatic difference in the Air Fuel Ratio’s, with the system leaning out from rich 11’s up to mid 12’s. Remembering, for tuning our goal is to actually reach 13.2 – 13.3 AFR under full acceleration. This leaning out and increased air flow, led to a 6kw gain at the wheels and 15nm torque improvement. Interesting to note is that from 4250 rpm onwards, the gains remained fairly consistent. We can only say that with further tuning, and smoothing out of the AFR ratio, these gains would be easily amplified.

Below are also some photos of the kit fitted to the vehicle, although better photos will be provided soon as well.

Job 6 – 2 1/2″ Exhaust System

The next step is fabrication of a 2 1/2″ mandrel bent exhaust system utilising a new Metallic cat converter, Muffler and Resonator package.

We specifically went for a 2 1/2″ system with factory styling of middle resonator, and the choice of two rear muffler designs.

The single tip muffler retains factory style design and noise levels.

The twin tip system has a much smaller muffler design for greater noise levels and has the Mitsubishi Ralliart Lancer spec centre to centre clearances on the rear tips.

Job 7 – Extractor Packages

The final part of our exhaust work will be installing extractors to the vehicle.

The factory system utilises a traditional short manifold with a small straight pipe bolting up to the cat converter. RPW will be manufacturing three designs for these vehicles being

  • RPW 4-2-1 Street Design System – this will be primarily for the CVT Transmissions where the factory setup on shift changing at 5000 rpm, requires focus to be placed on lower rpm torque and horsepower.
  • RPW 4-1 Street Design System – utilising a 4-1 manifold setup, this was essentially for the 4B11 models and was our first prototype design.
  • RPW 4-1 Race Design System – utilising a 4-1 manifold setup, this will fit all models focusing on producing superior torque and power across the whole rpm range, but specifically focusing also on rpm above 4000 rpm.

Due to difficulties sourcing another 2.4 litre engine we were unable to provide back to back dyno printouts.

But reports from customers outside of Perth who have purchased these units have reported large increases in throttle response and midrange acceleration, with improved top end performance.

Job 8 – Reflash ECU

We were finally able to source a vehicle, Manuel model this time, to perform a tuning comparison to the CVT Model and finish our research.

The vehicle is complete stock other than fitment of a HKS Air cleaner, Ralliart Air Intake Snorkel and a RPW 63.5mm rear muffler.

The vehicle had a before/after dyno report done with the flash tune to show the real results gained.

As always the results were impressive. The fuel economy if nothing else should be the largest gain.