Your bike made faster

Your bike
made faster
project k1
Used K5/6 header, along with
PC3/K&N/dyno set-up, added
5bhp and 4ft-lbs of torque
from 5000 to 8000rpm
Breathe
right
words mark white Pics rory game
Don’t bust the budget in your quest for increased and usable
power. As little as 70 quid can deliver seriously good results…
112
Most of us know that the best bet
for faster lap times is a well set up
chassis. And most of us also know
that we ride bikes because of our
carnal appreciation of power and
the pursuit of the chequered flag,
real or imaginary.
No surprise then that a couple of
months ago we restored the power
lost to defective secondary throttle
butterflies and a seized exhaust
valve. The successful result was a
healthy starting point to build on
and a slight midrange advantage
over a GSXR1000 K9 we already
had. However, what we needed now
was start/finish straight and dual
carriageway slaughtering top end…
Few people know more about this kind
of performance than Tim Radley of Race
Developments, Gloucester. He’s been
building and tuning engines for twenty
years and when he points the way
forward the wise choose to follow…
Step one: making the most of
restricted, and often compromised,
breathing is key to improving
performance. Refreshingly Tim
immediately steered us away from
spending mega bucks on a full
aftermarket exhaust system, preferring
instead to investigate cheaper exhaust
alternatives: if successful this would
mean cash left to splash on areas of the
engine that would, later, serve up bigger
and chunkier power gains than we could
reasonably expect here.
As far as factory spec equipment goes
the standard K1 headers are quality kit,
but Tim assured us there are small but
healthy gains to be had by fitting
standard headers from a K5 or K6 Thou.
So, we bought a cheap used set from a
breakers which, on inspection, proved to
have a small balance pipe between the
centre tubes and much better fabricated
collector sections; gas flow
improvements were clearly there for the
taking. To help matters along, while still
not busting the budget, we decided to
also fit a K&N filter and experiment with
different intake trumpets, or velocity
stacks to give them their proper name.
Fuelling duties were turned over to a
Power Commander III and we also had
the luxury of the Scorpion race can that
the bike came with from a previous
owner.
costs
secondhand
K5 header
£80
power
commander
III
£298.33
K&N Air
Filter
£34.16
Dyno time/
set-up
£176.25
Total
£588.74
113
I arrived early at Tim’s shop with a can full of fuel and a pair of gloves for
changing very hot things. Our first job was a base run which gave us a
peak figure of 147bhp and 78ft-lbs. This was slightly better than the
results from its last spin on the roller, but that was down to using a
different dyno, atmospheric conditions, tyre etc. Time to change the
headers and install the K&N and PCIII. Seven corroded and one snapped
header bolt, multiple energy drinks and blunted drill bits later the new
set-up was on. A ‘zero map’ was loaded into the PCIII to effectively null its
interference and a 1bhp peak increase measured. More encouraging the
engine now carried its gained power much further on towards the limiter
instead of dropping off as before. In fact 4bhp and 2ft-lbs more just before
the sparks were cut. Tim, being the expert that he is, constantly evaluated
each and every dyno run for clues about which way to take future engine
work - cam timing changes seemed favourite.
Next Tim programmed the PCIII so the fuelling was perfect for the setup. He did this at many throttle opening and rev combinations. The
result was a healthy 149bhp and 79ft-lbs.
Time to try the velocity stacks. Put simply velocity stacks are ‘horns’
that are placed in the air entry way of the throttle bodies. Their job is to
smooth air flow into the engine, but different lengths act differently
depending on the rpm range. Tim has a collection of stacks in various
lengths and diameters which he uses for testing and development
purposes and these are what we used. Hayabusa versions fit the GSX-R’s
airbox and are longer than the K1’s originals. We tried two longer centre
stacks and all four long, but even after altering the fuelling we ended up
with small losses with all combinations other than the four short
standard ones, so we left these in. Tim did comment that after some more
serious engine work it would be worth re-trying various combinations.
Next we replaced the standard end can with the Scorpion race version.
In the dyno room the noise didn’t seem to be that much louder, but the
Scorpion is straight-through which means it certainly did alter flow. We
saw improvement across the entire rev range and Tim set to work
mapping the PCIII for ideal fuelling, paying careful attention to all
160
Full power dyno run
150 ■ After mods (152.43bhp)
■ Before mods (147.37bhp)
mods (80.64ft-lbs)
140 ●● After
Before mods (78.19ft-lbs)
130
120
110
Simulate roll-on
■ After mods (169.51mph)
■ Before mods (168.74)
110
100
90
80
70
60
50
40
-1
0
1
2
3
4
5
time (s)
6
7
8
9
This pair of acceleration runs are the dyno equivalent of a
before and after mods roll-on test on the road but actually
provide a much more controlled environment for doing it.
60% throttle
■
■
●
●
After mods (126.08bhp)
Before mods (123.63bhp)
After mods (74.05ft-lbs)
Before mods (70.84ft-lbs)
power bph
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
2
3
4
speed (rpm x1000)
5 6
7 8 9 10
11 12 13
The facts never lie
2
3
4
5
6
7 8 9 10 11 12 13
speed (rpm x1000)
Here’s the before and after 60% throttle runs and the huge
gains in torque and power are very obvious. This extra
4ft-lbs in the midrange will be felt where it’s needed.
114
100
90
80
70
60
50
40
30
bph
Making the most of
breathing is key to
improving performance
180
170
160
150
140
130
120
speed mph
Tim (sitting on bike) logged 97 dyno runs not including those he needed to warm the engine/tyre/dyno and analyse clutch/tyre slip. This means the results
were as true a reflection of the modifications as possible. Velocity stacks were stock test units Tim had in stock. Unfortunately, in this state tune, they had
little or no beneficial effect. However, when we get into the more involved internal engine work they should come into their own and provide a power uplift
throttle positions and loadings. The
result was a peak of 152bhp and
80ft-lbs with a midrange gain of 4bhp
from 4k to nearly 10k before the top
end really took off compared with the
relative wheeze of standard.
While Tim was mapping the bike he
kept stressing the importance of partthrottle set-up. It is worth noting that at 60% throttle, in its final
configuration, we had gained a very useful 5bhp and 4ft-lbs from just
over 5000rpm to 8000rpm. That kind of improvement will show up very
well on the road, especially on exiting bends as that is when most people
hit 60% throttle.
While the bike was on the dyno and for each new modification Tim ran
acceleration tests alongside the usual power/torque runs. Race
Developments uses a Dynojet 250i model dyno which features lots of
trick upgrades for various specialised tests. Among these is a static torque
module which allows the dyno to perform controlled rate sweep tests
which provides information conventional dynos cannot. The standard
250i comes with an electronic eddy brake unit which can hold the engine
at a set rpm and throttle opening so a consistent start point is repeated for
these kinds of tests and as long as a suitable gear is chosen and tyre slip is
monitored carefully the data can be very rich. After the mods the bike
was reaching its peak speed nearly 0.3 seconds faster on an 8-second
acceleration run from 4000 to 12,000 rpm, which translates into real
world acceleration improvements.
So has it all been worth it? Well, for a fraction of the cost of a new full
race system we’ve gained substantial power and torque everywhere and
increased the top end, right to the limiter. These are the kinds of
improvements that will make the GSX-R1000 K1’s engine live up to its
grunty reputation. Tim also teased me about the possibility of more to
come and having seen him in action it’s time to start spending some of
that money we have saved here and delve inside the engine.
At wide open throttle it’s easy to see the huge gain in top end power compared with
standard, there’s no denying that. But look closer at the 5-6k rpm region and before,
there was a pronounced dip in the power/torque curves. All engines prefer a certain rev
range to run at optimum efficiency and conversely they have a region where factors in
the physical design of the engine don’t work as well. It’s here on most bikes. After Tim
had altered the fuelling to compensate the dip was less noticeable, but this should be
improved further with more in-depth engine work to come.
THANKS & contacts
w w w . r a c e d e v e l o p m e n t s . c o . u k 0 14 5 2 3 0 5 3 4 3 .
w w w. d y n o j e t . c o . u k 0 19 9 5 6 0 0 5 0 0
115