Whichever way you look at it, the BA – BF Falcon XR6
Turbo is one of the best all-round big used family cars you can buy in Australia. Now
available from around only $18,000, with the turbo Falcon you get plenty of
space, performance, comfort, towing ability – and good ride and handling.
Trouble is, the 4 litre turbocharged engine also drinks a lot...
But
there’s an answer – convert it to electronic gaseous LPG
injection.
The
consumption of fuel won’t decrease – it actually rises a bit – but with the much
cheaper cost of LPG, you can (at the time of writing) literally halve your weekly fuel bill. And
that’s no idle claim – we talked to XR6 Turbo Falcon owner Michael Beltrame
about his car. Michael has owned the car since new and the 6-speed manual now
has about 50,000 kilometres on it. It’s recently been converted to gas injection
by Parnell LP Gas Systems and not only could we ask Michael about his
experience, we were also able to sample the car for ourselves.
But
first, the gas system.
System
The
system uses components primarily developed by Prins Autogassystemen BV of The
Netherlands. Prins supplies the dedicated LPG ECU, the wiring loom,
regulator/converter and filter/sensor assemblies.
However, the most important parts of the system – the
injectors – are manufactured by Keihin, a Japanese company with close links to
Honda. On the Falcon the injectors are mounted in two blocks of three. The same
size gas injectors are used in both naturally aspirated and turbo
Falcons.
The
injectors are connected to the inlet manifold runners by short hoses.
The
gas tank is conventional and contains a level transducer and external electronic
solenoid lock-off valve. It is mounted behind the seat.
The
gas then flows to the converter / pressure regulator that changes the LPG from
liquid to gas and regulates its pressure. In a turbo application the gas
pressure is boost-referenced. From the converter/regulator, the gas flows to the
filter assembly that uses a combined sensor for gas temperature and pressure.
On
turbo cars like the Falcon, a specific MAP sensor is
installed.
The
LPG ECU mounts under the bonnet.
The
system is calibrated for the car by a laptop software package. This also allows
fault diagnosis and graphing of sensor outputs. As seen here, the software has a
specific ‘turbo’ mode.
An OBD
scanner is used to check the LPG tune – if the tune is correct, the short and
long-term fuel trims should not show major and ongoing change
values.
In Use
In
operation, the car always starts on petrol. This is primarily because there is
minimum coolant temp below which the converter cannot function in converting the
liquid LPG to a gas. A short time after the coolant has reached the minimum
operating temperature (both the time and the temperature are programmable), the
LPG control system automatically switches off the petrol injectors and turns on
the gas injectors.
The
driver is provided with a small dash-mounted interface unit. This combines the
function of LPG fuel level gauge, gas/petrol changeover switch, warning beeper
and fault code indicator.
The
internal beeper sounds if gas pressure falls too low and the system switches
back to petrol (eg because the gas is running out). It also warns the driver if
a major fault condition has developed that again causes the car to switch back
to petrol.
The
LPG system can log about 50 faults, including stalling on the switch to LPG, gas
temp too high or too low, gas converter slow to warm up and ‘missing’ at high
revs. A particularly interesting fault that is logged is when the gas system
pressure falls to less than 1.25 bar within 4 hours of the engine being switched
off – indicative of a gas leak.
Cost
As
shown here, the system cost $4,400, that price including fitting and GST.
However, the government will give you back $2,000 so the total out-of-pocket
expense is only $2,400.
So how
does that stack up in terms of payback period? On the basis of current LPG and
premium unleaded prices, Michael’s fuel bill has dropped from $100 a week to
$50. Do the maths and you’ll find that the pay-back period is only 48 weeks!
Yes, in less than a year the conversion cost will be paid for – and after that,
it’s like fuel is at half price. (Of course, those figures are based on current
petrol and LPG prices.)
Driving
But if
the car drives like a pig, or performance is way down, the trade-off for the
conversion will be measured in a lot more than just dollars and cents.
First
we talked to Michael about the car’s driveability on gas. He told us that he
couldn’t detect any difference in power or aspects like idle quality. In fact,
the only difference he could feel on gas was that when the over-rev cut and
traction control action occurred, the effect was softer. That is, the actions of
the rev-cut and traction control system weren’t as harsh.
But
surely power would be down? Well, it might be a fraction – but you’d need a dyno
to find it. On the road the car drove just like any other standard XR6 Turbo –
that is to say, linear in power delivery, refined and comfortable. Throttle
response on petrol and LPG felt the same, and full throttle performance was
undiminished on gas. There wasn’t a hint of stutters, missing or flat spots.
In
fact, cover the in-cabin switch and we wouldn’t have been able to tell if the
car was running on LPG or petrol...
Downsides
We
couldn’t find any downsides in the driving but the installation does have one
negative. With the gas tank installed behind the back seat, two things occur.
Firstly, available boot space decreases. Michael, a family man, told us he could
still fit a large pram in the boot, but there’s no escaping the loss of useable
volume. Secondly, while the rear seat still folds, the opening is blocked by the
tank - long objects can’t be loaded to take advantage of the joined cabin and
boot space.
An
alternative tank position is available – it uses a donut-shaped tank that
replaces the spare wheel. This costs about $800 more than the behind-seat tank
but the main reason that Michael didn’t opt for it is that he was concerned that
with the more rearwards tank location, the weight balance of the car might have
been changed. He likes the car’s standard handling balance, and the current
location of the LPG tank hasn’t altered that.
Conclusion
This
conversion looks like a win/win to us. The end result is a car that retains all
of its factory pluses and yet costs the petrol equivalent of getting about 5.5 –
6 litres/100km fuel economy! If you do high kilometres, the conversion is paid
off very quickly – and even if travelling more modest distances, it will still
be paid for in only a few years.
Michael Beltrame – a qualified engineer and budding
Formula Ford racer – has absolutely no complaints...
Contact: www.parnell.com.au
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