M140i / M240i

BMW M140i / M240i

WG Motorworks Tuning Guide

The *40i BMW engine range are equipped with the B58 engine, a 3.0 single twin scroll turbocharged straight six, equipped with dual Vanos, Valvetronic (Variable cam lift) with direct injection

The engine is quite frankly is a little gem, producing maximum torque under 2500rpm yet still able to keep peak power at the top end of the rev range. Usually paired with the equally impressive ZF8 automatic gearbox which makes gearchanges effortless, removing all negativity we would usually associate with automatic gearboxes. Released with official figures of 340hp by the manufacture, this is rarely the case on the dyno - with most companies including ourselves regularly seeing 360-370hp prior to tuning.

The straight 6 engine is part of BMW's modular engine family (B38/B48). The B58 is the one which you will find installed in most of the current models (3 Series, X3, X5 etc) this post is also relevant to almost all models equipped with this engine.
With no real common weak links yet apparent, the main limitation will come from inlet temperatures as the charge cooler is built into the inlet manifold as a one piece unit. Currently there are only upgrades for the charge cooler radiator available to improve cooling.

B58 Engine ECU tuning can be offered across two options, our custom tuning with its proven calibrations - which have been Dyno, Track, and also importantly Road tested. Alternatively, and preferably we can offer Map switching software over MG Flasher platform which allows to offer 4 different maps. TCU (Transmission) tuning can also be offered on the ZF8 Automatic gearboxes by XHP, for the perfect combination.

For the power-hungry folk or those who simply want to improve their soundtrack - plenty of upgrades can be offered from MOT legal exhaust systems and full track system (not road legal), along with Hybrid turbochargers and engine cooling upgrades. Click here for Performance Upgrades

For those Track Addicts, Nurburgring goers, or simply for those who have increased their power and want a chassis to match, we can offer simple upgrades from high-performance pads/brake lines to full suspension Coilover systems, with various Rollbar and bush upgrades. Click here for Chassis Upgrades

Stage 1

The first step with extracting power from the B58 engine requires no hardware changes, this is a software-only upgrade. The ECU software follows the linear torque delivery of the stock ECU tune through the low to mid-range while in the higher rpm range, where the standard power curve starts to flatten off, we keep the power climbing, holding the peak power right up to the limiter where as much as 450HP can be seen, Petrol Particulate Filter (PPF) typically see slightly lower results.

We retain this flat torque delivery for driveability reasons, most of the 40i models do not come equipped with an LSD, with this in mind additional torque moments or spikey delivery can provoke unwanted wheel spin, and show up chassis limitations. Another reason for limiting the torque is to ensure we do not have any fuel rail pressure drop, typically we run 450-460lbft, although slightly higher levels can be seen we would rather not run the fuel pump at 100%, and leave some headroom for pumping losses over time.

With our 'Stage' software upgrades the following features are included:

  • Vmax Removal (Speed limiter removed)
  • Sports Displays recalibrated to suit new outputs
  • Enhanced over run (Optional)
  • Stock Power on the ECO mode

Expected Results, based on our Dyno Dynamics rolling Road:

430-450HP
450-460LBFT

Stage 2

An additional step towards improving restrictive exhaust flow of the stock exhaust is the removal of the catalyst in the downpipe, upon removal of the standard catalyst it is recommended to install a sports cat to retain MOT legality, or a full de-cat pipe can be utilised for optimal gains if the vehicle is to be for track use only. With the free-flowing downpipe installed fueling can be optimized and new lambda targets set, and boost levels and ignition timing can be optimised, taking into account the less restrictive exhaust system.

The standard cat-back with or without PPF filter can be still retained, we do highly recommend removing the PPF Filter, however. The stock exhaust is not deemed to be overly restrictive at this stage due to its large bore design, improvements can still be made with replacement with free-flowing bends.

Low-end response is improved and turbo lag is reduced which will be noticeable on the road, the torque curve will be held similar to stage 1, with an extra 10-15LBFT  however power at higher RPM will increase by 10-15hp. With the limiting factor at this level of the tune being the limitation of the fuel pressure system - this is upgraded as part of a plus stage.

With our 'Stage 2' software upgrades the following are included:

  • Vmax Removal (Speed limiter removed)
  • Sports Displays recalibrated to suit new outputs
  • Catalyst code removal to avoid EML lights
  • Cold start delete (removal of high / loud idle) (optional)
  • PPF delete software (If applicable)
  • Enhanced over run (Optional)

Expected Results, based on our Dyno Dynamics rolling Road:

440-465HP
460-470LBFT

Stage 2+

The final hardware change for maximising the standard turbochargers efficiency range, which allows up to ramp up the mid-range boost to gain optimal airflow is a fuel pump upgrade. The issue of the standard fuel system becomes clear if attempting to run much higher torque than 470-480lbft, then the fuel pressure will drop - this can cause limp mode or worse engine damage from lack of fuel pressure. To resolve this and to run greater torque levels (with requires more fuel volume) an upgraded high-pressure fuel pump is installed (HPFP) this allows more fuel volume per camshaft stroke (camshaft driven pump) thus allowing more fuel volume without pressure drop.

When upgrading the fuel pump there are a few options, and we advise you to think about the future plans if any - if planning to run over 550HP on pump fuel, or even with ethanol blends an aftermarket pump is recommended, otherwise for the base upgrade we use a 'TU' fuel pump from the later B58 models (Z4 / Supra)

Now the fuel system is up to the standard we have two options of tuning. either run a flat ~500lbft or curve upwards to 540lbft. We would highly recommend a LSD is installed for the latter level of power delivery, otherwise, we would suggest running a flatter delivery to keep wheel spin down.

With our 'Stage 2+' software upgrades the following are included:

  • Vmax Removal (Speed limiter removed)
  • Sports Displays recalibrated to suit new outputs
  • Catalyst code removal to avoid EML lights
  • Cold start delete (removal of high / loud idle) (optional)
  • PPF delete software (If applicable)
  • Enhanced overrun (Optional)

Expected Results, based on our Dyno Dynamics rolling Road:

470-490HP
500-540LBFT

Stage 3

The stock turbochargers are the limiting factor when it comes to the next stage of performance, with compressors/turbines limiting any more flow. With larger compressors and turbines installed into the stock turbo housings, these 'Hybrids' allow much great flow of airflow, and exhaust gas turbine flow. High flow downpipes are a must at this state of tune, and with a cat-back system advised for optimal gains.

Charge temperatures start to creep up when increasing the boost pressures - so depending on target HP and usage we would advise a charge cooler radiator upgrade as well. Water Methanol would also be a recommended upgrade when looking for maximum output. We have seen good gains from installing a Port Meth system.

With our 'Stage 3' software upgrades the following are included:

  • Vmax Removal (Speed limiter removed)
  • Sports Displays recalibrated to suit new outputs
  • Catalyst code removal to avoid EML lights
  • Cold start delete (removal of high / loud idle) (optional)
  • PPF delete software (If applicable)
  • Enhanced overrun (Optional)
  • Switchable map modes (MG Flasher Licence needed)

Expected Results, based on our Dyno Dynamics rolling Road:

530-680HP
550-650LBFT

Stage 4

The next level. Once the Standard Hybrid or bolt-on turbo route has been exhausted, although we deem this more than enough for most people - there are those who want to send it to the moon!

At this level of tune, it is worth thinking about much more than just the powerplant upgrade, but everything else also - from upgrading Gearboxes, engine mounts, engine internals, inlet manifolds, etc! With this in mind, these are not cheap upgrades, and pricing requires us to know your exact goals/budgets and requirements.

We offer motorsport turbochargers with beautiful hand made tubular exhaust manifolds to high flowing Cast turbo's

Expected Results, based on our Dyno Dynamics rolling Road:

700-900HP
650-750LBFT

OUR SERVICES INCLUDE

Dyno Testing

All ECU remaps are carried out on our State of the Art Dyno Dynamics Dynotech rolling road, which can accurately read upto 1200HP

Data Logging

Each car is hooked up to a Wide band lambda sensor to ensure correct air to fuel ratio, along with data logging tools to ensure Boost, Ignition timing parameters are all incheck

Diagnostic Check

We carry out a pre and post tuning ECU diagnostic trouble code check (DTC) to ensure no faults are present before or after tuning