Lifting the lid on Diesel Performance Tuning
TECH SHEET
POWERING UP YOUR DIESEL
-LIFTING THE LID ON COMMON RAIL DIESEL PERFORMACE-
We often get asked about the method of generating extra power from common rail diesel engines. This data sheet answers these questions.
In totality, there is only one way to get more power from any motor, in particular a diesel engine, and that is, tune it to use more fuel. More fuel equals more energy and therefore more power.
In a common rail diesel engine, there are three ways to deliver more fuel.
1) Injector Signal Interception
2) Fuel Pressure Control
3) Re-flash the OEM Engine Management System, or EMS for short
1) Injector Signal Interception
In this method, you intercept the ECU controlled injector signal/pulse. In technical terms is signal is called Pulse Width Modulation. This signal controls the injector open duration/time. Intercepting this signal you can extend the opening duration by a fixed value … say 10%
Benefit: This increased duration allows more fuel to be injected. This is an accurate method of controlling fuel flow into the combustion chamber utilising the engine designer’s original Engine Management System (EMS).
By intercepting and manipulating the injector signal you make signal longer thus making the injector close later (increasing the signal strength will also have the effect of lifting the “pintle” higher to make the injection orifice larger)
Issues:
You cannot start injection earlier unless an extremely smart module takes a (inaccurate) “guess” at when the signal is going to occur and tries to anticipate what it should do with the start time of the signal. The estimate may, of course, be wrong because you (the driver) may change throttle position, or the engine initiates another change (ie higher/lower boost) so that injection cycle will not be what the factory (OEM) EMS desires. Therefore, no injector signal interceptors (that I know) manipulate captured opening times.
Problem with delaying the close time is that the combustion process is trailing off and the extra fuel being injected after the fact is bordering on being wasted. Remember, the factory EMS also extends the close time to achieve extra power and this further extension is an extra to this. This would be a doubling of that extension, effectively making the injection duration TOO LONG. It would be like closing the gate after the horse has bolted.
The real benefit is in controlling the injector orifice size with a little extension of injection timing.
On the whole this is a good means of adding more fuel and therefore more power whilst having some limitations on fuel delivery which is that of achieving a maximum of around 20% extra power.
2) Control the Fuel Pressure
With this second option we intercept a signal to the ECU via the Common Rail Sensor. With this intercepted and manipulated signal the OEM EMS then controls the fuel pump spill valve(s) to request more pressure. Incidentally, a common rail injection times are made to vary with more or less fuel pressure and is why common rail fuel systems are extremely accurate in fuel delivery (added to this the new style Piezo injectors now seeing their way onto more and more engines) asks for more pressure and then the OEM EMS controls injector timing to suit the new parameters. This method works very well since the OEM EMS is still in full control of the fuel injection. The signal to the EMS is also undetectable.
No problems exist here except that we are asking the fuel system to hold more pressure and the fuel pressure limiter may open and bring up an engine code (which is not an issue unless if you purchase a Chip It Module as we supply the fix). Note: the fuel pump is NOT asked to work harder as the fuel pump is gear driven and makes max pressure (over 20,000 PSI) just off idle. The extra pressure delivered to the common rail comes from a spill valve(s) sometimes called Suction Control Valves diverting the unused pressure to the common rail rather than diverting it to the tank.
To back up this tuning theory, OEM performance arm Toyota Racing Developments (TRD) which have millions of dollars to throw at any system come out with their own version of a performance module which utilise this common rail sensor style tuning method and provide full factory warranty, thus confirming this performance module validity. These modules are available in UK at UK TRD Dealers at a cost of around $3000.00
Also, as with the injector signal interceptors, as to the fitment of these modules no one will be any wiser as, as they are undetectable to OEM scan tools and thus can be removed without a dealer knowing one was ever installed.
3) The last solution is EMS re-flashing or reprogramming.
Some OEM EMS’ have had their code “cracked” allowing smart software developers, like ECUTEK, to re-flash the OEM EMS settings (or maps).
It’s a VERY GOOD way of making more power however there are some issues that are too problematic for HARD CORE vehicle owners or performance developers to accept. We are one of them.
Here are the issues.
Firstly, the EMS re-flash is a permanent addition to the OEM EMS unless the dealer reflashes a factory update which will overwrite to performance program. It can of course be reversed via propriety software which is only available from the place that first uploaded the re-flashed map. To add or, change or remove the new “tune” will cost you, the consumer, time and money.
As a common run-of-the-mill example: When you need to have your vehicle inspected by the Dealer or the vehicle manufacture, they are able discover the non-standard program placed within their computer and flag your vehicle as having a re-flash and may bring this up if you have any future engine or drive-train warranty claim. This will leave you up the proverbial creek holding the proverbial bag. To save your bacon, you will need to pay for the re-flash to be removed by the original supplier of the performance program and pay for the re-flash to be reinstalled after leaving the Dealer. Also, as mentioned, if the OEM Dealer re-flashes the OEM with a ECU upgrade (which can occur each time you visit your Dealer) you LOSE the re-flash and you need to again visit the re-flash supplier. (ie more $$$)
Remember, this is not the case with the first two options above.
Re-flash type companies now “LOCK” the computer so that EVEN THE DEALER CANNOT OVERWRITE IT with a new factory update!!! They say that if you want to unlock the program, just take it back to the flash installer and pay a “small fee”. I bet the “small fee” is not so small.
So after the OEM has overwritten the OEM EMS with an update (ie for the air conditioning or DPF or anti-lock brakes, or surging issue etc etc) you need to take it back to the flash installer and again pay a “small fee” !
If they ever come out with a free re-flash replacement policy, you would still need to get your vehicle to the re-flash installer!
Consider this: You are at the “back of Bourke” your factory computer fails or is playing up or the air-conditioning is not working, or the engine overheats bringing up a fault code and you need the dealer to look at the vehicle …
This is the process if the re-flash is LOCKED:
Remove the OEM computer. Express post it to the flash installer for unlocking and to have the original factory stock tune installed. Have the stock computer mailed back (all at your cost) and reinstall it. After the Dealer has updated or fixed any EMS problem you then drive out WITHOUT the performance re-flash and send the OEM ECU back again to obtain a re-flash all the while having the vehicle off the road because you don’t have a OEM ECU to run the vehicle!
This is the process if the re-flash is UNLOCKED if you don’t want the dealer to know you have a re-flash.
Remove the OEM computer. Express post the computer back to the flash installer to place the original factory tune in the factory computer. Have the computer mailed back (all at your cost) and reinstall it. After the Dealer has updated or fixed the EMS problem you then drive out WITHOUT a flashed EMS. Then park your vehicle somewhere whilst you send the computer to get the re-flash re-flashed!!!
This is the process if the re-flash is UNLOCKED and you forget about the re-flash or just cannot be bothered anymore.
Drive the vehicle to Dealer. Have Dealer berate you about the modification and threaten to void your warranty. Dealer overwrites the re-flash and you drive out with a factory tune.
For these reasons we feel you are much better off with an interceptor style Power Module – Injector or Common Rail (CR) … of any brand.
A little about the Chip It Performance Modules.
All CR Chips that plug into the common rail sensor change the same signal.
HOWEVER, because a Chip plugs into the common rail sensor it does not mean they do the same job.
Some will use the variable resistor method as mentioned below and some brands even vary the resistor effect at idle signal as well. (increase idle RPM)
“SMART” performance module must allow full laptop tune-ability and allow variable increase to be added at any point alone the rev range (or more precisely alone the load points). Low end Chips will only vary values by a fixed amount via an inline variable resistor. We have seen very high price tags on some of these Chip suppliers which try to convince buyers that it MUST be a good Chip because of the price. This is not the case, and for a long time well-known companies have ripped huge profits from consumers for these cheap nasty rip offs.
The Chip It Performance Modules address the fuel maps BASED ON ENGINE LOAD, NOT RPM AND TPS. LOAD POINT ADJUSTMENT is, without a doubt, the best way to tackle this since at 2500 RPM I could be either at a HIGH load point or a LOW load point. Conversely, at 2500 RPMS I could be at 25% throttle or 100% throttle. The load point WILL show the difference and TUNING AT EACH LOAD POINT will mean the engine is receiving a much more accurate tune. Also, our Performance Modules also adjust the turbo boost by a small amount and this helps balance the air fuel ratio. This has a positive effect on performance, efficiency and Exhaust Gas Temps (EGTs). The Chip It Performance Module also allows the factory turbo to this increased boost (+4PSI) without the OEM Computer throwing a wobbly.
Again, top end Chips will be fully programmable via laptop and have individual cells to adjust.
Why put out the info above?
We believe that by telling the truth people will appreciate it and shop wiser.
If you have a good product at a reasonable price people will buy it.
Sooner or later people will need to explain why they are SO expensive for a chip that has basic funtionality.
We believe there is no need to con shoppers about a product and so we tell the story AS IT IS and are on record about the FULL capabilities of our Chips.
We believe you don’t have to BS customers to get business. Some will buy one brand and some will buy the other brand. THAT’S THE FREE MARKET CONCEPT.
Our Chips provide features that others don’t however we are not expensive.
All these features in one module certainly make people take notice let me tell you.
With the above information we will undoubtedly cause some in opposition to be upset with the facts being made public however we trust that the information being in the PUBLIC ARENA will make most happy.
Best Regards
Chip It
Office: 1800 78 48 82
Fax: 02 9807 9000
Address: 50 Buffalo Rd Gladesville NSW 2111
Email: sales@chipit.com.au
Web: www.chipit.com.au