Difference between revisions of "Chip Tuning - The Reality, The Myths and Everything Inbetween"

From PrecisionCodeWorks
Jump to navigation Jump to search
Line 27: Line 27:
 
====Map====
 
====Map====
  
[[File:injector-1.jpg ]]
+
[[File:injector-1.jpg|200px ]]
  
  

Revision as of 14:25, 12 October 2015

In this section we hope to dispel the myth/ignorance that have been instilled into many chip tuners. The resulting information is plain engineering fact and direct experience of the combined 50 years trade and formal education in our trade.

Custom Tuning Files

Fact - In chip tuning there is no such thing or ever was..

For any formally qualified automotive/calibration engineer the custom remap debate is amusing to say the least for a number of reasons;

Firstly – . After 2004 most engine management systems became a closed looped torque based model simply put, the engine management is adapting (optimizing) the tune of the engine in almost real time based on the hard code or what is known as the statistical dynamics element of the memory. A quality remapping engineer understands and respects this and simply enters the correct desired targets in the correct places to the code and the system references the sensors accordant (closed loop or PID) thus using these settings to achieve the desired result. The one and only time a 'custom' strategy is required is when a vehicle is modified to a point where the dynamics employed by the factory ECU are no longer valid for example - a larger turbo is fitted requiring new PID loops to be employed.

"Even under these circumstances, only a small modification is required to a base calculation within the ECU to correct the internal equation."

Think of an ECU in its simplest form, it's a calculator programmed to receive values in terms of voltages and frequencies at a rate of 1 to 200 HZ or in layman's terms 1 to 200 times a second dependent on the type of value it needs to sample. For example - sensor values such as coolant temperature, are a slow changing value, so a sample of 1-5 HZ is fine. Where fast changing variable's such as manifold pressure, It requires a faster sample rate of say 50 HZ or 50 times a second. The processor then first of all references (for the sake of this explanation) three memory models within the ECU, one known as 'statistical elements' and the others as we know them as 'maps' and 'curves'

Statistical elements

Ideal gas.png

This is the core structure of the ECU function - It can be made up by a number of control algorithms such as 'Motronic' and elemental rules such as ideal gas law, this also includes configuration switches and curve/map address library for the controller to switch between based on the strategy or mode required.

Curve

MAF-EXP.png

The curve structures in the ECU are a vital and are often mistaken as torque limiters by 'CUSTOM MAPPERS' or re-scaled in a effort to bypass a mechanical limit resulting in a loss of resolution and refinement. An ECU can only interpret what a engine is doing by its input signals via the relevant sensors. This is usually done by voltage or frequency - so the 'curve' is the real world signal conversion to a digital value the ECU can use in a calculation to out put to its PWM's

Map

Injector-1.jpg


Basically a data matrix, a table of data values arbitrated to a output of the ecu drivers or PWM's referencing values such as requested torque, boost, lambda and air flow. These are desired targets based on the data and control logic influenced by the 'curve' and 'statistical elements'. ALL employing PID control - understanding this will expose the ignorance of most chip tuners.

Advanced ECU Engineering Principles

Diesel Tuning / DPF Removal and Smoke Emissions

No Smoke No Poke

Basic engineering fact - Smoke is WASTED energy. This is the product of a badly written calibration, by normally adding fuel because its the easy and quick map to find with absolutely no recognition to thermodynamic principles,stoichiometry or Volumetric efficiency. A correctly written calibration will provide the cylinder with the correct amount of air to completely com-bust the given fuel. PLEASE understand that fuel is fixed sum (energy) for the ECU and air is variable, an engine is driven by the heating of air to gain the most power you must heat as much volume of air as possible from a relative due point (exothermic reaction), the fuel already in cylinder must be burnt completely to extract the most energy (allowing for the boundary layer), a complete burn of fixed fuel = more heat, more heat = more power, basic physics.

Diescyc.gif

Manufactures go to huge lengths to achieve the perfect/maximum thermal efficiency in engine design striking the perfect balance from a induction temperature and the heating point of the fuel vs permissible exhaust temperature (EGT) whist targeting the idea push/pumping(expansion) cycle or adiabatic process. The problem in tuning a diesel engine for a manufacture is purely down to controlling EGT relative to particle matter and Nox (nitrogen oxide) emissions the very reason forcing the use of DPF systems.

So how is the damage done? - By modifying the lambda (fuel relative to air) the first issue is the over loading of the DPF management cycle as the filter is designed to handle a certain amount of matter vs measured flow vs a oil quality / engine ageing strategy, think of it like this - tuning a engine it is a given performance air filters provide more airflow by using better more expensive materials. Currently there is no material solution for DPF to achieve performance increase other than (at best) an increase regeneration cycles to keep flow optimized resulting in increased fuel use for such a regeneration leading to the inevitable shorted life cycle. So adding fuel = Dead DPF.

Turbochargers suffer greatly from tuning ignorance, and are a fundamental component in managing the efficiency of a engine. The compressor map of a turbo dictates the dynamics of the air heating process with the cylinder temperatures vs EGT calibrated precisely known as the 'flame wall' as diesel fuel ignition timing is dictated by the mass vs relative fuel temperature respecting thermodynamic variables / eg - the fuel pressure (endothermic reaction), fuel mass (duration), start of injection (timing). We see issues with calibrations where the mass (duration) is modified the SOI (timing) is modified along with increased rail pressure resulting in the movement in flame wall causing a cascade rise in EGT thus damaging the turbocharger due to the pardox of increased boost pressure only compounding the issue. Another issue born out of over fueling and flame de-tuning is the sooting of the exhaust wheel of the turbo causing a imbalance of the turbine and jamming of a variable geometry where applicable thus greatly reducing the life of the turbocharger.

Drive line and chassis harmonics - Manufactures again go to huge length to control engine running frequency and this 'noise' causes long term damage to components a simple example is the presence of a dual mass flywheel which is tasked in part to countering this issue in conjunction with tuned engine mounts and phased injection strategies. By not respecting these components in a calibration all will lead to early failure.

The work is already done in the ECU to increase the performance to a sensible point without compromising the powertrain the key is understanding the physics on which the calibration was designed, so the next time you see a youtube video of a vehicle pumping a dyno cell full of black smoke think about what you have read here and the ignorance of some tuners.

EGR Removal the Plain facts

Its a well documented obsession of enthusiast diesel owners to remove a EGR or an owner with a faulty EGR to wants to remove it.

EGR removal in engineering terms will break down into a number of issues.

We are currently seeing tuners offering EGR deletes on vehicles equipped with LIVE DPF systems. We DO NOT offer this service for a number reasons. First of all, as part of the integral emissions system that was embedded into the software, the EGR and DPF systems work together in the regeneration process, as such we only remove EGR functions with DPF deactivation.

If the EGR system is deleted by means of duty cycle and airflow modification, this will have a negative impact on the DPF regeneration cycle. The DPF system was designed to work along side the EGR using different strategies in the passive and active regeneration process.

Gasoline / Petrol Stage 1234+ Tuning

FACT - Its a load of BS, its ether tuned correctly or not.

Usually started from vehicle owner forums run/owned/funded by tuning companies thus pushing 'sponsors' -- pushing the myth that every time an extra piece of hardware is installed on the engine, then a calibration adjustment is required.To a certain degree this is true when you get to high levels of modification. In the eyes of the general public, this poses a grey area between the stage 1 and 2 ++ tune calibration. On a modern torque based petrol ECU, the fitting of the following requires NO further modification;

  • Full exhaust system with decat
  • Cold air intake system or air filter replacement
  • Inter-cooler upgrade
  • Basically anything that improves airflow into and from the engine.

The truth of the matter is, a correctly calibrated ECU will be able to deal with the extra air or air at a higher relative density (cooler) thus adjusting fuel and advance trims accordingly (adaption). This is where people assume, that having all of this hardware fitted they require further adjustments.

It has should be noted that some companies offer stage 1 and 2 tunes to completely stock vehicles. After 20 years we are still waiting for some one to explain what the difference is.

The requirement for a further calibration would be hardware such as;

  • Upgraded much larger turbocharger
  • Upgraded injectors / fuel system
  • Larger MAF or modification to run on MAP alone (Alpha N)
  • Basically anything that requires re-calibrating or re-scaling from standard production sensor curve (input)

Even then how this falls in the the mythical stage scale is yet to be seen. ITS ETHER TUNED CORRECTLY OR NOT.

ECO Tuning and Driving Style Changes

Fact - A client has owned a vehicle for (X) amount of time, over that period time regardless of how the vehicle is driven the client will have a very good idea on how economical their vehicle is. They have an ECO tune as they would like to gain extra economy, driving exactly the same journeys as before the remap. Soon after they realize that the return is the same or worse and only to be told that they need to drive the vehicle in a different manor. At this stage alarm bells should be ringing as this exposes several problems.

  • cover up of a poor product
  • incorrectly calibrated data
  • the engine is running inefficiently

An engine running more efficiently will not require different load conditions. To summarize, vehicles used daily on similar routes with a PCW ECO calibration will return extra MPG under the same operating conditions.

Clone / Copied Tools

FACT - with most things in life, there will always be copies, clones, rip offs. For example DVD movies and CD Albums. When it comes to chip tuning, Yes many tools have been copied/cloned etc. A quick google search will reveal the extent of how many clone tools are a wash over the internet. As an example, try and search FGtech for the legitimate FGtechnology website, lets put it this way, its not in the top 10 results. The fact that china has gone all out on manufacture and marketing of these tools, and even to the point of starting websites with very similar names means that people very little experience in chip tuning may be duped into thinking they are buying a legitimate tool a fraction of the cost of the genuine article.

DO clones Works?

This question is very difficult to answer, as clones are clones and it will be up to the user to test. The quality of the components and construction varies. The tools cannot be used while connected to the internet, so they cannot be updated to the very latest software/firmware, some protocols may or may not work due to old or corrupt software/hardware. The best source of information on these tools is the internet, like a chip tuning forum etc, although most major chip tuning sites actually ban the talk of clone tools, as you can imagine this is quite a taboo subject.

For someone looking to start up a professional chip tuning business, then there in no compromise for a genuine tool. Genuine tools are built as the manufacturer intended, All of the protocols listed 99% of the time work, so there is no real chance of error.

WE DO NOT USE OR SELL CLONE TOOLS - We are a file Calibration service

The economy of the clone tool market for a professional tuner is a false one. If you take into account possible lost time/earnings and replacement of damaged ecu's, it doesn't take many bad jobs to be at the same expenditure that a genuine tool would cost in the first place. Where possible, always use a genuine tool.

If you require advise or would like to order a particular GENUINE tool then we will be more than happy to help.