Unlocking Your Cars Potential.. Remaps
In our series of posts so far, we have largely talked about mechanical performance upgrades such as brakes, tyres, suspension, and bushes. Apart from exhausts we haven’t really touched on anything that has any effect on engine performance. This month we are going to look at arguably the biggest modification you are likely to make to engine performance, which is known as ECU or engine mapping, remapping or historically, Chipping.
Our modern cars have a ‘brain’ known as an Engine Control Unit (ECU). ECU’s first started appearing on cars as far back as the mid-seventies and have over time, like most computers become increasingly sophisticated. The ‘ECU’ is an Electronic Control Unit, that controls multiple functions including, fuel and ignition, but they also control, idle speed, and valve timing. The ECU performs many calculations per second based on various sensors including CPS (Crank Position Sensor), MAP (Manifold Absolute Pressure), MAF (Mass Air Flow), and the drivers demand, or throttle position.
Jaguar spent lots of time and money mapping the ECU in our cars so why would we want to fiddle with it? Well, that’s a good question. Most people assume that when we talk about mapping or remapping, we are only talking about wanting to make the car go faster, producing torque, and in turn BHP. Both of those things are often desirable and are sometimes exactly what we are trying to achieve, however something that is often not talked about is optimising, getting the best out the fuel available and making the engine run more efficiently. Not all the fuel available across the world is the same but manufactures tend to write maps for ‘average’ fuel. Fuel in the UK tends to be of a higher grade so we can optimise the engine for that fuel. Manufacturers also always build in huge safety margins for their powertrains, but in time you will often see them offering tuned limited editions as they know the engine is more than capable handling more power and torque. An example would be the XKR. When launched in 2009 the Gen III 5.0 XKR engine offered 503 bhp, two years on Jaguar offered the XKR-S with the same engine producing 542 bhp. They did this by tuning, in the full knowledge that the engine could easily handle it.
We have spent many years developing our maps with tuning expert and partner Stephen Dowell at PVE. We have extensively tested these not only running on the Chassis Dynamometer (Dyno) at PVE but in real time on the road and on track. Between us we’ve amassed hundreds of hours developing calibrations for JLR range. This allows us to then be able to remap your ECU by either writing through the diagnostic port on most cars or by removing the ECU and installing the map on bench, here at Swallows. This varies according to the Jaguar model.
One of the most common remaps we do is the 3.0d as found in the earlier Jaguar XF’s. These diesel engines respond really well to remapping. These vehicles are fitted with the Bosch EDC17CP11 ECU’s (2009 – 2016), Jaguar installed both the 240PS calibrations, and the 275PS calibrations to the same hardware level. The 275PS models were badged ‘S’. This immediately means that we can apply the calibration differences into the 240PS ECU, and be up to 275PS right out of the box. We change the calibration to mimic the JLR calibration. We can manipulate the ECU calibration further still to release more torque and power. Generally, we can see a safe healthy 320bhp from an otherwise standard 3.0 V6D.
During development of our calibrations datalogging is the absolute key to being able to finish up with a professional calibration. Being able to modify various tables within the ECU structures while still being able to leave all of the safety parameters in place. We see a good many torque limiters ‘Maxxed Out’, along with the relevant DTC (Diagnostic Trouble Code) removed from the ECU software. This can mean that essentially the ECU has picked up an error and would normally put the vehicle into ‘LOS’ (Limited Operation Strategy), or Limp mode as its commonly known as. However, as the ECU calibration has been modified to remove this DTC, the ECU will carry on as per normal. From the driver’s point of view this often isn’t a problem. It will feel and drive as it should. It is however, unsafe for the engine in question, and not good practice.
We believe that remapping, done correctly is perfectly safe. Since we started Chip-Tuning, and remapping back in 1998, we’ve seen and heard various horror stories though, which would be enough to put anyone off! Mostly these can be put down to some of the reasons I’ve mentioned above within the calibrations. IE, banks of DTC’s removed. Some of the very generic tuning from the cheaper end of the market purchased from what we like to call – ‘file farms’, often use tuning methods that frankly are downright unscrupulous. Including, ‘Tuning’ the ‘LOS’ tables!
It’s very difficult these days to know exactly what you’re paying for. Historically, a ‘Custom’ tune exactly that. A dyno session that would ascertain the torque and power of the vehicle in question along with some in depth datalogging. The calibration would be modified, flashed onto the ECU then the process repeated. Nowadays, a ‘Custom Tune’ can apparently be achieved on your driveway without even driving the vehicle. That’s not to say that the calibration wouldn’t be of good quality but advertising it as ‘Custom’ is a bit of a stretch!
Datalogging is a subject that’s well worth touching on. When developing a calibration, or performing a ‘Custom’, or ‘Bespoke’ calibration we datalog lots of data. OBD II data is usually not much use for tuning. A lot of the PID’s we want to see are not transmitted over the OBD II protocol anyway. We use various datalogging systems for the JLR range, including HP tuners and dataloggers of our own design. These run on the main Powertrain CAN lines, and we’re able to see lots of data, and at speeds that make it useful. This data would normally include the basics, like ‘Lambda’, ‘Boost’, ‘RPM’ and so on, but also some more in-depth tables. ‘Torque’, ‘Table Weight’, ‘Knock Count’, and so on. Information is key. It’s important that you use a reputable tuning company, that understands the models.
