To tune a car several things need to be checked to know were the limit is instead of exceeding it while adjusting the calibration. Before we tune a car we first make logs (live recording) of all relevant engine parameters and check if the factory given performance output is reached. Components like a MAF(Mass Air Flow sensor), turbocharger, injectors and so on might not be OK. A list of parameters that will be checked if available can be seen below.

• Vehicle acceleration
  Is stock acceleration/performance within factory tolerances?
• AFR / Lambda (air to fuel ratio)
  Is the fuel-air mixture within the right area?
• Air consumption
  Is the consumed amount of air correct? (MAF failure?)
• Injection duration
  Is the injection duration according to calculations?
• Ignition timing
  Is the ignition timing currently set according to calibration? Deviations or ignition retards can indicate interuptions from the ECU (knock retard/control).
• Manifold pressure*
  Is the desired boost pressure maintained? If not, turbocharger or other components can be not within the right working range.
• Turbo/Super charger PWM control*
  Like boost control/manifold pressure, is the mapped PWM (Pulse Width Modulation [%]) value close the actual value? If not turbocharger problems might be the case.
• Engine roughness(acceleration of the crankshaft per cylinder after igniting/injecting)*
  Large deviations can indicate problems with injectors, spark plugs/coils, cylinder pressure loss.

If deviations are observed during the investigation of your engines health or if you desire or we recommended, we can perform the following measurements to check engine health before starting to modify engine torque & power output.

• Cylinder leak test
  A leak test indicates if the pressure in the cylinder is moving towards other areas not meant (leaking intake/exhaust valve(s), piston ring sealing NOK and head gasket leak).
• Cylinder compression test
  A general check if all measured cylinders are within factory specification.
• Valve clearance*
  Wrong valve clearance can give rough idle, more noise (when set to large) and (exhaust) valves can overheat when set to small. It is recommended to check valve clearance if adjustment is possible.
• Throttle body synchronization*
  If the throttle bodies from an engine with individual throttle bodies are not within specification rough idle, … can occur.
• Smoke test
  A smoke test can be performed to see vacuum/pressure (intake side) or exhaust leaks (exhaust side). These leaks cause problems to an engine. It is possible that a certain amount of air is not entering the engine but blown outside.

Once the stock parameters and engine health of the vehicle is observed and inspected to be OK, the calculating can begin. On petrol and diesel engines several components of the engine need to work within specification to guarantee that the component doesn’t failure due to exceeding the limits of the specification (durability). A list of components and specifications that are checked can be viewed below.

• Engine (bottem end, crankshaft, conrods, pistons, cylinderhead, valve springs, …)
  Can engine components handle the torque, power and maximum engine speed?
• Turbocharger
  Compressor: how much pressure can the compressor handle?
  How much air flow/consumption it can give?
  What is the maximum permissible turbine rotor/compressor wheel speed?
  Turbine: What is the maximum turbine inlet temperature?
  Petrol applications this can be from 900 – 1100°C.
  Diesel applications with variable geometry 800-850°C
  Intercooler: Is it able to cool down the amount of air before entering the cylinder(s)?
• Electronic components / Air & fuel components
  MAF (MassAirFlow sensor): how much mass air can it measure?
  Injectors & fuel pump: Are they able to supply the amount of fuel desired?
  Ignition system: Are sparkplugs, ignition coil(s) able to supply enough energy for good ignition?
• Gearbox
  What is the maximum permissible torque input for the gearbox?
  In some ECUs the torque per gear can be adjusted. In low gears the maximum torque can be lowered to avoid damage to the DMF (DualMassFlywheel), transmission, drive shafts and differential.

Once these parameters are observed the tuning/remapping or re-calibrating can begin. Before we start to remap we calculate and investigate the logs (live recordings) which we have measured before to analyze the current operating conditions of the engine. On NA (Naturally Aspirated) petrol engines the most benefit can be made on ignition timing, fuel mixture (AFR or lambda) , variable intake systems like intake length or chamber (BMW DISA or resonance valve) and variable systems like camshaft angle adjustment. Of course if these systems are installed.

Once a turbocharged or any other kind of charging systems is installed on an engine a detailed look on that system can be placed. Most of these charging systems are not operated at theirmaximum air flow capacity. This gives us the ability to use the reserve margin that the manufacturer of the engine didn’t use. You would ask yourself why doesn’t the manufacturer use the reserve margin? Several reasons can be placed.

• The manufacturer has kept the reserve margin for altitude margin. When vehicles are operated in high altitude conditions (mountains) the ambient pressure drops. On a NA engine this would lead into performance decrease. If the charging system of the engine has a reserve margin over the normal operating line(at regular ~1013mbar altitude) the margin can be used for high altitude conditions. Simply> the reserve margin is used to compensate for high altitude conditions. The driver won’t notice performance loss at high altitude because the reserve margin is used for that.
• The manufacturer has the normal operating line in an area with best efficiency for the normal output it delivers. It doesn’t mean that when going over that normal operating line performance gains can’t be made. They can, but it most cases (not all!) less efficient than the normal operating line would do.
• The manufacturer has lowered the desired air consumption to fit the desired torque curve or power output to its demands. There can be 2 power outputs available for one engine. Example is the VAG CNBD 2.0 TFSI engine that can be delivered as 180bhp – 320Nm& 211bhp – 350Nm.

 

Below an example is given of a 4 cylinder diesel engines stock (Blue) operating line and an optimized one for higher torque/power output (red line).

If you look at the graph you see we will not go near the maximum permissible speed point (highest line). The efficiency of the compressor map starts to decrease over there and causes high temperature conditions which eventually could lead to less air than would be provided with less boost pressure. More boost is not always more air! It is also important to look at the left side of the graph. The dotted line is called the surge line. Once the operating line is over the dotted line, a typical surge sound will be heard. Operating in this area will lead into problems. Next is to observe for the right line which is called the choke margin. When operating close to this line the compressor efficiency will be low (high boost pressure temperature).

Once the re-calibration is finished it will be loaded into the ECU. With the new calibration new logs are made to observe if the changes that were made are also reached. In most cases a fine adjustment needs to be made to perfect ionize the end result. The purchaser of the re-calibration can view the logs at our workshop to see which changes are made and we can tell the purchaser why we have done that.