Dirt and Trail June 2020-2

derives a fuelling map based on
that. Suddenly, tricking the ECU
becomes difficult, hence there are
no piggyback systems that work
on Euro5 machines.
Step forward the Rapid Bike
system that can read the actual
ECU and reprogram it. Again, it
sounds simple, doesn’t it?
Here’s everything that is taken
into consideration when writing
a fuel strategy – air pressure,
air temperature, type of fuel,
quality of fuel, humidity, dust
and impurities. With those
externalities, the tuner uses
ignition timing, fuel mapping,
torque limiters, RPM limiters and
throttle limiters to create the
optimum recipe for performance.
Dean will run the bike on the
dyno, extract the readings from
the ECU onto his special Rabid
Bike device and then downloads
it onto his laptop. He then fettles
all those elements to create the
best combination.
It’s sounding more complicated
now, right? It’s about to get worse.
The R1250GS does not have
one fuel map that it uses for all
scenarios – it has more than 100
maps. There’s a different map
for each gear, for each riding
mode, for each electronic setting,
for starting the motorcycle, for
when the fuel light comes on, for
different engine temperatures –
pretty much every variation of
events and configurations has
its own mapping. And Dean has
to open this all up and figure
out what is what. It gets more
complicated because BMW does
not provide an explanation of
what map controls what function
– Dean has to figure it out.
It’s more than merely making
the fuelling richer or leaner, or
advancing and retarding the timing.
For example, the throttle limiter
controls the butterflies that open
and close to let more air in. In a
previous era, the butterflies were
connected to a cable connected to
the twist grip, and how much the
rider turns the throttle determines
the butterfly opening.
Not any more – with ride-bywire,
an electrical cable leaves
the twist grip and runs to the
The Sprint Filter for the GS is
waterproof, dustproof and offers
significantly better airflow.
It can also be cleaned using
compressed air at a garage.
DynoBike v. 2.1.3.10 DEFAULT user 19-May-20 10:55:26 AM Dimsport DFMTF
ECU. That then Workshop/tuner: reads what you’re
Address: Internet:
doing and interprets Phone: Fax: how E-mail: much
to open the butterflies. On some
bikes, even when you are fullthrottle
on the handlebar, the
butterflies open only 75%. With
Rapid Bike, they can adjust these
openings so that the butterflies
open 100%, although this often
results in a nearly unrideable
bike, so they’ve had to do some
trial and error.
Where Euro5 severely restricts
motors is in the fuel ratio – the
best performance is generally
achieved when the ratio is around
13 parts air to one part fuel.
However, the people in Brussels
have determined that the best
emissions are achieved when
the ratio is 14.7:1, so they have
decreed that all motors shall run
at that ratio in all circumstances.
What this means is that motors
nowadays are hugely starved of
fuel and are running lean. It’s like
making Hussain Bolt run the 100
metres while on a diet of nothing
but lettuce.
Yet, somehow, BMW has
made the GS work, despite these
disabilities. However, it can work
better.
When Dean took delivery of a
1250GS to develop a Rapid Bike
strategy for it, he spent the next
five days tampering with various
maps, loading them on the bike,
running it on the dyno and then
trying again. Eventually, they got
Client name: FIU TEST Vehicle plate: JTP265MP Manufacturer: BMW Model: R1250GS Type: 2019
STOCK
Motor Power 116.3 Hp @ 7673 rpm
Wheel Power 106.7 Hp - Loss Power 12.7 Hp
Engine Wheel Dissipated
Wheel Torque 109.5 Nm @ 6244rpm
Ambient T 20.9°C - P 1026.9mbar - Corr. factor 1.00
Gear 4 - Ratio 3.52
RPM min 2500 - max 9500
Theoretical maximum speed: 188.4 km/h
SPRINT FILTER & FULL AKRAPOVIC SYSTEM ADDED
Motor Power 120.9 Hp @ 7462 rpm
Wheel Power 111.4 Hp - Loss Power 12.9 Hp
Wheel Torque 116.6 Nm @ 6247rpm
Ambient T 14.2°C - P 1035.6mbar - Corr. factor 1.00
Gear 4 - Ratio 3.52
RPM min 2500 - max 9500
Theoretical maximum speed: 188.0 km/h
SPRINT FILTER ADDED
Motor Power 119.0 Hp @ 7821 rpm
Wheel Power 108.3 Hp - Loss Power 23.2 Hp
Wheel Torque 112.5 Nm @ 6096rpm
Ambient T 22.1°C - P 1026.9mbar - Corr. factor 1.00
Gear 4 - Ratio 3.52
RPM min 2500 - max 9500
Theoretical maximum speed: 187.7 km/h
SPRINT FILTER, AKRAPOVIC & ECU TUNE
Motor Power 124.2 Hp @ 7342 rpm
Wheel Power 115.2 Hp - Loss Power 12.3 Hp
Wheel Torque 121.8 Nm @ 6103rpm
Ambient T 13.4°C - P 1035.6mbar - Corr. factor 1.00
Gear 4 - Ratio 3.52
RPM min 2500 - max 9500
Theoretical maximum speed: 187.4 km/h
124
122
120
118
116
114
112
110
108
106
104
102
100
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
68
Hp 66
64
62
60
58
56
54
52
50
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
it right – see the dyno graphs.
2,500
3,000
3,500
4,000
4,500
In fact, they got it so right that
they now export their maps and
strategies to America, Europe
and soon Australia. There are
people in South Africa that
bought a special map from
America only to later discover
that these maps originated in
Kyalami Business Park.
In standard trim, the 1250GS is
a bullet with power throughout
the rev range. After the
5,000
5,500
RPM
6,000
6,500
Performance Technic tuning,
the performance is moved to
another level entirely – it feels
as though its at the coast, with
17% more power. It’s more lively,
there’s more grunt and more
growl, all delivered smoothly and
effortlessly.
That level of performance is not
possible through an exhaust and
filter alone.
performancetechnic.co.za
R1250GS PROJECT BUILD ALL RUNS: Here are the graphs with all the variations of modification – note that
we don’t really look at the actual horsepower numbers because each dyno will give a different reading.
What is important is the difference between the graphs.
– The blue line is a run with the standard bike
– The green line is after the Akrapovic exhaust is added
– The red line with the exhaust and the Sprint Filter
– the pink line is after the exhaust and filter have been added, plus Dean’s five days worth of tuning with
the Rapid Bike system.
7,000
7,500
8,000
8,500
130
125
120
115
110
105
100
95
90
85
80
75
70
65
60
55
50
45
40
35
30
25
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