In the world of Ford XR6 Turbo modification
there’s a fairly limited number of options when it comes to tweaking the engine
management system. You can either go for an add-on interceptor/piggyback
computer or you can reprogram the factory ECU using a Flash Tuner module.
But there is another approach – one that, until
now, we had no idea existed. You see, there’s one man in the whole of Australia
who can reprogram the Ford ECU directly via laptop. This man is David Alexander
of Silverwater Automotive Services (SAS).
Reprogramming the Factory ECU
David Alexander (who has expensive experience
reprogramming Delco, Kefico, Siemens and various other management systems) got
stuck into ‘cracking’ the latest Ford ECU after purchasing an XR6T ute
exclusively for R&D purposes.
Using a custom programming platform, David says he
can access every part of the factory program. Of course, not all parameters need
adjustment in a typical power-up application but it’s handy to have the
flexibility – nothing remains that you wish could be adjusted.
We must point out that reprogramming the factory
ECU has substantial advantages over an interceptor or piggyback system - the
Ford ECU has a lot of internal logic that simply cannot be imitated by modifying
inputs and outputs. The nearest rival is the Flash Tuner module (which is
currently being sold under various names). Flash Tuner reprograms the ECU via
the car’s OBDII port while David Alexander’s approach requires putting a hole in
the ECU case for direct laptop access.
With his laptop plugged into the Ford ECU, David
can alter the onboard volumetric efficiency calculations, set the target
air-fuel ratio, alter MAP sensor and injector calibration (which makes injector
swaps relatively easy), change open-loop switchover and alter the complex torque
control strategy (which is largely intended for protection against
modification).
Ignition timing maps can be altered on the basis
of load v rpm and there are plenty of other related parameters. Knock sensor
sensitivity, the amount of knock retard and ‘tip in’ throttle ignition timing
are all adjustable and there’s control over intake air temperature and coolant
temperature compensation. Rev and speed limiters can also be raised.
In addition, David can alter turbo boost pressure,
idle speed, cooling fan control, camshaft timing, diff ratio calibration and
electronic throttle calibration (the relationship between the position of the
accelerator pedal and the opening of the throttle valve). David says the factory
throttle calibration is a good compromise but in a custom tune he typically
increases the throttle valve angle at light pedal positions. This gives a
livelier feel.
In the case of vehicles with an automatic
transmission, David can also change the shift rpm, eliminate the inbuilt torque
reduction on gearshifts and increase transmission solenoid pressure (to reduce
slip during gearshifts and potentially improve transmission life).
In essence, there is total control of the factory
ECU. The only downsides are the lack of auxiliary outputs (a Unichip, for
example, has spare output channels to control shift lights, intercooler water
sprays and more) and tuning cannot be performed in real-time. This means you
can’t hold the engine at a certain rpm and load combination and make tuning
adjustments to optimise output – it’s a case of repeatedly making changes and
following up with a dyno run.
Associated Mechanical Mods
With total control over engine management
parameters it’s no surprise SAS is now offering tailored upgrades for XR6 Turbo
owners. There are no off-the-shelf kits but SAS is more than willing to
recommend the combination of parts for satisfy your needs.
We tested SAS’s development ute which is fitted
with the in-house developed air intake upgrade, bigger injectors, firmer valve
springs, reprogrammed ECU and a shortened diff ratio.
SAS improves airflow through the air intake by
adding an extra snorkel into the airbox. The secondary intake snorkel draws air
from behind the left headlight and supplements the factory over-the-radiator
snorkel. A washable K&N panel filter is also installed. You may notice in
this photo that David’s ute (which was purchased second-hand) is equipped with a
Tickford snorkel.
The standard XR6T fuel system reaches its limit
somewhere around 280 – 310kW depending on the air-fuel ratio you’re happy to
settle on. SAS gets around this by installing a high-flow set of twin spray
injectors which are a straight swap. The rest of the fuel system remains
standard.
Interestingly, David has shortened the diff ratio
in his ute to give improved real-world performance without needing to increase
engine output. He says no matter how much you tweak ignition timing and boost
response, the relatively low compression ratio turbo engine feels a bit flat at
low revs. But by swapping the standard 3.46:1 diff for a 4.1:1 unit, the engine is
much quicker to build revs and come onto boost. SAS doesn’t get involved in
gearbox and diff modifications so this job is farmed out to a nearby specialist.
Oh, and be aware that a diff swap is relatively easy in the case of the XR6
Turbo ute (which runs a live axle rear) – it’s a much bigger job in sedans.
The valve springs in David’s ute have also been
upgraded early in the development process. We’re told that valve spring tension
varies from car to car and, unfortunately, the SAS ute was one of the examples
with very soft springs. This was identified as valve bounce under increased
boost pressure. SAS’s solution is to fit a set of Ford V8 valve springs (which
were chosen after considerable bench testing). They probably aren’t suitable for
all-out power applications but they are well suited for mild power-ups.
Of course, the SAS XR6T ute also has a custom
engine management reprogram. David has changed the injector calibration, tweaked
parts of the volumetric efficiency calculations, lightly altered cam and
ignition timing, changed the target air-fuel ratio and tailored boost pressure,
idle speed and diff ratio calibration. Electronic throttle calibration has also
been modified. David has increased throttle opening in the section of the map
that corresponds to cruising at 110 km/h. This change serves to reduce the
required accelerator pedal angle and improve comfort.
On-Road and Dyno Testing
On the road, the SAS XR6 Turbo ute offers
electrifying performance with absolutely no glitches, no stutters and
near-standard induction noise – no strange whooshing and gobbling noises. The
engine starts first time, idles like a stocker (though at s-l-i-g-h-t-y higher
rpm than standard) and there’s excellent throttle response. This is likely due
to the shorter diff ratio as much as the altered tune. Mid-range torque is fat
(enough to keep the rear tyres on the edge of adhesion) and top-end pull is
strong given the standard exhaust system is retained
On the SAS Dyno Dynamics chassis dyno, David’s
standard XR6 Turbo ute – with its automatic transmission – developed a very
healthy 193kW at the wheels. Now, with the mods outlined, power has elevated 32
percent to 255kW (though note that diff ratio has also been changed). Boost
pressure has increased from the original peak of 6 psi to 11 psi.
Interestingly, David expects the ute would make
similar power on slightly less boost because of the limitations of the standard
intercooler. An upgrade ‘cooler and a high-flow exhaust are certainly next on
the list.
It’s worth noting that, even with 255kW at the
wheels and with plenty of hard driving, David’s XR6T ute has had no related
transmission problems. It’s possible this can be attributed to the custom ECU
program which reduces transmission slip during changes.
So how much will a direct reprogram and these
mechanical upgrades set you back?
Well, an ECU reprogram on its own costs
substantial AUD$1300. Add to this AUD$230 for the air intake modification,
AUD$1650 for fitment of the bigger injectors and, if you’re unlucky, you might
need to upgrade the valve springs (with pricing yet to be established).
The final price stacks up pretty well
with other comparable aftermarket kits so, if you can get your car to SAS in
Sydney, it’s certainly worth taking a close look.
Contact:
SAS
Silverwater Automotive Services
02 9748 1300
info@silverwaterauto.com.au
www.dynotuning.com.au
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