Ford Mustang Tuning

Our foray into the world of Ford Mustang ECU Mapping came about when we were asked by members of a Mustang owners club to perform some performance validation tests on our Rototest hub dyno, which is well known for being accurate and consistent, and of course not being subject to the many issues that high-torque cars suffer with when using conventional rolling roads.

It was a great day with like-minded fellow Petrol Heads, and as you can imagine – the sound that these Mustangs made was absolutely glorious!

We were fortunate enough to have several different models of Mustang present, with a range of tuning modifications from simple bolt-on superchargers through to highly strung water/meth dependent beasts!

Apparently none of the cars had the befit of having properly optimised ECU calibrations, rather they had either an ECU flash-file supplied with the supercharger kit or had a custom tune done remotely by a firm in the US. Unfortunately some of the ECU calibrations were in quite a bad way causing engine detonation, lack of full throttle, torque-limiter issues etc which was a real disappointment on the day. However, looking on the bright side at least the owners were now aware of the issues which would in the worse case scenario have caused catastrophic engine failures!

Coincidentally, prior to this event we were approached by the US company HP Tuners who produce ECU tuning solutions for many American and European cars, and wanted us to become one of their distributors but we hadn’t at that time had the opportunity of working with them yet.

The owner of the gorgeous yellow GT500 Mustang asked us to try to and fix the engine detonation problem by way of tuning the ECU properly, so this was an ideal opportunity to work with the HP Tuners platform and learn more about these cars, which of course we relished!

The symptoms we identified were; engine detonation, low power, and poor drivability. The driver was previously unaware of these issues, probably thinking them to be normal.

The first thing we learned was that there was no secondary air temperature sensor correction within the ECU calibration, a function which is absolutely essential for engines having forced induction (turbocharger/supercharger). The ECU needs to know what the temperature of the air is in the intake manifold/plenum in order to make appropriate map compensations. The Mustang, like many standard cars has it’s intake temperature sensor in the mass airflow (MAF) sensor, which being in front of the supercharger is measuring only the ambient/under-bonnet temperature – a big problem!

Over a couple of weeks working with the Engineers at HP Tuners we (relatively) quickly solved this problem and now had full secondary air temperature compensation functionality, so that the main ECU map tables can alter properly according to the temperature in the intake manifold.

For anyone who’s interested, there’s a good explanation of engine management systems and sensors etc here.

The second thing we learned was that the ECU functionality was very complex, having as many as 50 look-up tables for each parameter, which is probably the most over-complicated ECU that we’d seen up to that time.

The third thing we learned was that the ECU calibration was atrocious having unusually large jumps in ignition timing, spurious torque-limiter activations, and incorrect AFR curve. At that time we didn’t know whether any or all of these issues were due to the OEM Ford ECU base calibration or the flash-file supplied by the supercharger kit manufacturer.

Optimising the ECU calibration is a relatively simple flow-process once we understood the Mustang and HP Tuners platform properly.

Once completed the engine boasted an additional 75hp at the hubs (approximately 100 flywheel horse power) which improves acceleration and top speed, much better drivability (no more slow speed hesitations/jerkiness), and of course it was no longer detonating/trying to kill itself, so a win-win-win!

Here’s the before/after performance analysis which you can see is pretty impressive: