(Download a copy of this report in PDF format here)
After 7 months of intensive testing Thorney Motorsport (TMS) can now
categorically confirm what the entire car tuning World already knew -
the quality of fuel you use in your car has a direct effect on the
level of power your car provides.
TMS specialize in honest, no bullsh*t tuning of BMW’s and
Vauxhalls. Our knowledge, skill and attention to detail have given us a
reputation of testing without compromise and product development
without compare so when we develop any new product we know it’s the
best that can be achieved.
We spend countless hours seeking new ways to eke out extra
power from road and race cars and always knew that the quality of fuel
used in the car does make a huge difference in power level and delivery
but we surprised to find out that no-one had actually conducted any
reported data on the actual effects fuel quality made on cars, both
tuned and standard.
Our move to our new £750,000 custom workshop in Milton Keynes,
Bucks gave us the opportunity to try the (then) new 99 Octane fuel
available from Tescos (there are three local stores, all of which
supply the 99 fuel) so we conducted some early testing and were amazed
at the results the fuel gave - the cars drove faster, power delivery
picked up quicker and they held the power for longer.
However, anecdotal evidence based on ‘feel’ is not enough for
us to rely on so we set about conducting the most in-depth fuel test
ever done in the UK.
The Equipment
To
accurately measure a car’s performance you need an accurate vehicle
dynometer. A chassis dynometer (also called a rolling road) is a
sophisticated piece of equipment that allows you to drive a car as you
would on the open road (the wheels turning on rollers) whilst it is
strapped down in a fixed position. The vehicle’s static position allows
us to connect up an extensive list of measuring equipment to monitor
and measure what the car is doing, including power and torque. Think of
it like a patient hooked up to a heart monitor.
At TMS we’re fortunate to own one of the World’s most advanced
chassis dynometers - the Dyno Dymanics Low Boy 450 Chassis Dyno. Dyno
Dynamics are world renowned for creating one of the most accurate dynos
available and are used accross the globe from everyone from car tuners
to fuel suppliers. Their accuracy has earned them the nickname the 'Ego
Buster' for the equipment’s ability to measure data and not manipulate
it.
The Dyno Dynamics dyno has a feature called 'Shootout Mode'
where the operators ability to manipulate or amend readings is locked
down, and all the measuring features are locked off so all the system
can do is measure. Such is their faith in the accuracy of their product
all the Dyno Dynamics dynos are linked globally and their measurements
monitored to ensure accuracy. Failure to comply with their stringent
methods of operation gets you removed from their global list of
recognised operators. In short, it’s accurate and has a unique system
to ensure that that accuracy is maintained.
The Thorney Motorsport dyno cell, showing the Dyno Dynamics chassis dyno
To give an accurate reading of what the car is doing on a dyno
you need to generate a large airflow to replicate as near as possible
the conditions on the open road. To this end we have installed the
highest airflow dyno cell in the UK. Four one metre radial fans
generate a combined airflow of over 120,000cfm (cubic feet per minute).
Two fans are situated behind the vehicle to suck out the hot
air generated by the vehicle engine and exhaust and two further fans
blow air over the vehicle. With all four fans in operation we exchange
the entire air contents of the cell every 5 seconds. Basically it’s a
wind tunnel with a dyno in it.
The Thorney Motorsport dyno cell, showing the 1m radial fans
We mount the dyno on the surface of the floor to allow airflow
to run under the vehicle, this allows us to run low race cars but also
to allow proper airflow to rear engined cars which need under floor
airflow to keep cool. It also allows direct chassis strapping of the
vehicle to ensure they are secure and give consistent measurements.
The Vehicles Tested
Thorney
Motorsport specializes in tuning and enhancing BMW and Vauxhall cars.
Our specialist cars are the BMW M3, the Vauxhall VX220 and the Vauxhall
VXR range. We are accredited with full Vauxhall Motors warranty
approval for servicing and repairs, the only UK tuning firm to have
such recognition from any manufacturer.
As a consequence of our area of expertise it made sense to
test cars we knew well so we chose a 2003 BMW E46 M3 CSL, and as a
control car a standard Toyota MR2. We are also testing with a 2006
Vauxhall Astra VXR and will release this data when it is finalized.
BMW E46 M3 CSL
The BMW was chosen primarily due to our view that it represents the
finest engineered 6 cylinder engine ever developed. The S54 engine in
CSL form generates 350-360bhp at the flywheel which in itself is an
enhancement over the standard M3’s 340bhp. We have modified this
further with our ‘Stage 2’ tuning package where we add a Milltek Sport
performance exhaust and race catalytic converter and remap the car’s
ECU with advanced engine code to give a flywheel power figure of
380bhp.
Toyota MR2
The Toyota was chosen specifically because the car represents an
older vehicle but with a recognized advanced design of engine. Run in
purely standard form the vehicle should generate 175 bhp at the
flywheel.
The Testing Process
Thorney
Motorsport specializes in accurate data collection and vehicle
enhancement. Honesty, integrity and transparency are all bywords of our
company ethos. We planned the testing (which we imagined could
potentially generate politically upsetting results) meticulously so
that our data would stand up to scrutiny and expert breakdown.
Each car was initially run for 3 full fuel tanks on Total 95
Octane fuel, different fuel stations were chosen and the cars filled at
different times of the day. After three full tanks were consumed by the
vehicle we tested the car on the dyno and recorded the data. Specific
data as to weather, barometric reading, humidity, air temperature and
engine intake temperature were all recorded.
Next, each car was then run for three full tanks of BP
Ultimate 97 Octane fuel and the process repeated. Again all external
readings were taken and logged. We then repeated the process again with
Shell Optimax and finally Tesco 99 Octane fuel, again we used three
full tanks of each fuel between testing and logged all the external and
vehicle data on each test.
We repeated this process for approximately 8 months. In total
the cars were measured between 18-34 times in weathers as varied as 6
to 35 degrees ambient temperature. The Dyno dynamics dyno has an
inbuilt compensator to address variance in ambient temperatures but we
still ensured that each car was measured in comparable weather
conditions (one of the reasons it all took 8 months).
The Results
The different colour lines represent the different fuels used in the car.
Click the thumbnail for the full-sized chart
The red line at the bottom shows the car running on 95 octane fuel,
the jump in power and torque when changing to either Shell Optimax or
BP Ultimate is quite significant. However what we also found was there
was another jump when changing to the Tesco 99 Octane fuel (the pink
line).
So switching from 95 octane fuel to Tesco 99 Octane gave an
extra 8.1bhp (almost 5%). As well as these peak gains the charts show a
clear improvement throughout the rev range.
For the E46 M3 CSL the difference was even more pronounced:
Click the thumbnail for the full-sized chart
The difference between running 95 Octane fuel and a higher octane
fuel from BP or Shell was very noticeable on the open road and the dyno
confirmed this, the car did indeed very sluggish on the lower octane
fuel. Interestingly the BP Ultimate and Shell Optimax performed almost
identically, a fact quite evident on the chart; the lines are difficult
to separate.
But what was nice was the extra gains that Tesco 99 Octane
fuel gave over and above the BP and Shell fuels. There was a clear
improvement in both torque and power that was both evident on the road
and the dyno.
This apparent gain in power is due to the ECU of the car’s
ability to advance the ignition timing to take advantage of the extra
power the higher octane offers. Looking at the air/fuel ratio on the
charts does show that the higher octane fuel allows a more efficient
burn creating more power.
Click the thumbnail for the full-sized chart
The chart shows the car’s ECU when running on 95 Octane fuel
enriches the fuel mixture (adds fuel) to compensate for the less
efficient burn and to avoid early detonation. This extra fuel robs
power as the air/fuel mix is less efficient. By changing this fuel to a
higher octane the car is able to advance the ignition (essentially
using less fuel at higher rpm’s) to create more power.
The Conclusion
Our
role in the motor trade is to enhance motor vehicles beyond the process
of compromise that manufacturers have to follow. We use our skills to
adapt and extend the operating levels of cars by enhancing their power,
their handling and their braking by fulfilling a need from our
customers who demand more from their cars. For us and we expect for all
the tuning industry any method which facilitates this process of
vehicle enhancement (ie it makes it easier for us to do our jobs)
should be seen positively.
It is clear from the testing that whilst older engines show a
clear benefit of running higher octane fuel, more modern, sophisticated
engines have the ability to advance their fuel timing to take full
advantage of this enhancement to a far greater degree. For the BMW M3
CSL the difference between running 95 octane fuel and Tesco 99 Octane
fuel was over 40bhp, that’s over 10%.
It is our fundamental belief and now our clear recommendation
to our customers that if they want to maximize the power of their cars,
before they even consider using our services to enhance the power of
their car further, they should use the best fuel they can buy. The
simple fact borne out of our extensive test is that using Tesco 99
Octane fuel will make your car more powerful. It will feel faster,
accelerate faster and perform better. If you’re going to tune your car
at least give it the best fuel it can run on and in our opinion, based
on extensive testing that fuel is Tesco 99 Octane.
As a postscript to the testing we also measured the relative
fuel consumption of the cars during the testing with the conclusion
that the higher quality fuel did offer a greater mpg than 95 octane
fuel. However fuel consumption testing is conducted under different
conditions which we (even with our facilities) would be unable to
recreate to an extent we could stand by.
John Thorne, MD Thorney Motorsport
john@thorneymotorsport.co.uk
Tel. 01908 238 798
(Download a copy of this report in PDF format here)
