Jump to content

Welcome to Autoworld Forum !

Sign In or Register to gain full access to our forums. By registering with us, you'll be able to discuss, share and private message with other members of our community.


V-Power is Crap or Not ?

  • Please log in to reply


Posted 19 April 2005 - 05:37 PM


    Fast & Furious

  • Members
  • PipPipPip
  • 1,922 posts
If you put aside all the fancy advertising and Marketing pulp that
advertising agencies like to feed you,then my understanding of Shell V
Power is that it has more than five times the minimum amount of cleaning
agents required by most government standards and that it actively cleans
your engine’s intake valves as you drive. With continued use, Shell V-
Power is supposed to help remove carbon deposits and protect your engine
from future deposites in the long term. Those that have engines that
could benefit from a slightly higher octane rating are likely to benfit
from a very slight increase in peformance output over time with continued
So,reading between all the small print,I dont think anyone will notice
anything different on a few tank fills but maybe will in time with
constant usage.
It begs the question that given the fact that most fuel supliers have
their own additives(secret recipes) in their fuels for different
reasons,what are the consequences if we continuelly mix and match
different brands?


Posted 19 April 2005 - 06:43 PM


    Taxi Driver

  • Members
  • PipPip
  • 372 posts
A quality gasoline additive package would include:

1. Octane-enhancing additives (improve octane ratings)
2. Anti-oxidants (inhibit gum formation, improve stability)
3. Metal deactivators (inhibit gum formation, improve stability)
4. Deposit modifiers (reduce deposits, spark-plug fouling and
5. Surfactants (prevent icing, improve vaporisation, inhibit deposits,
reduce NOx emissions)
6. Freezing point depressants (prevent icing)
7. Corrosion inhibitors (prevent gasoline corroding storage tanks)
8. Dyes (product colour for safety or regulatory purposes).

During the 1980s significant problems with deposits accumulating on
intake valve surfaces occurred as new fuel injection systems were
introduced. These Intake Valve Deposits (IVD), as bro Kaminski mentioned,
were different than the injector deposits, in part because the valve can
reach 300C. Engine design changes that prevent deposits usually consist
of ensuring the valve is flushed with liquid gasoline, and provision of
adequate valve rotation. Gasoline factors that cause deposits are the
presence of alcohols or olefins.

Gasoline manufacturers now routinely use additives that prevent IVD and
also maintain the cleanliness of injectors. These usually include a
surfactant and light oil to maintain the wetting of important surfaces.
Intake valve deposits have also been shown to have significant adverse
effects on emissions, and deposit control additives will be required to
both reduce emissions and provide clean engine operation.

Most suppliers of quality gasolines will formulate similar additives into
their products, and cheaper product lines are less likely to have such
additives added. As different brands of gasoline use different additives
and oxygenates, it is probable that important fuel parameters, such as
octane distribution, are slightly different, even though the pump octane
ratings are the same.

So, if you know your car is well-tuned, and in good condition, but the
driveability is pathetic on the correct octane, try another brand. As
various Clean Air Act changes are introduced over the next few years,
gasoline will continue to change.

When you mix the petrol, it will be difficult to recognize the suitable
petrol for your engine, better change from one brand to another from
empty tank. Once got the suitable one, then stick for that brand.

My experience was to mix the Primax (97) and Projet (92), drivability was
very bad, then mix Primax with Yellow Shell, got the same thing, FC
increased considerably. Will try with full Blue Shell, just to check the


Posted 19 April 2005 - 10:59 PM


    Tokyo Drifter

  • Members
  • PipPipPip
  • 3,274 posts
Good, do let us know the outcome. There's no Projet up north here, so if
you're a constant traveller to the north and wouldn't like to mix petrol,
then better mnot make that your favourite.

BTW, can you explain the results that I got from my experience with these
two petrols (Shell Yellow and Blue) ? The yellow seems more powerful with
the boost going up higher than the blue until the engine is screaming to
very near 6000 revs but the blue just hovers to 5200 and the g/box
upshifts. Does it mean I reach my peak HP/Torque earlier ?


Posted 20 April 2005 - 10:49 AM



  • Members
  • Pip
  • 59 posts
I switched to V-Power a month ago. The difference was immediately
noticeable. Engine runs smoother and quieter and slightly better pick up.
I switch back to Petronas during one refueling and noticed that ther is
no noticeable drop in engine performance. I'm abit confused. Maybe V-
power already clean up the engine after one month's use.


Posted 20 April 2005 - 02:21 PM


    Taxi Driver

  • Members
  • PipPip
  • 372 posts

Please correct me if there is wrong statement and or formulation.

I start with the widespread misconception (in my humble opinion) coming
from :

“If ignition retardation causes power to drop, then ignition advance must
cause power to rise. So, an engine with a sophisticated engine management
system can produce more power on high octane petrol”.

As I mentioned before that on modern engines with sophisticated engine
management systems, the engine can operate efficiently on fuels of a
wider range of octane rating, but there remains an optimum octane for the
engine under specific
driving conditions.

Engine management systems have a map for maximum advance and maximum
retard for a given octane petrol and driving conditions.

Note that :

1.At a given RPM, there is optimum ignition timing for a given octane
petrol. Any sooner or later, and the engine will not be performing

2.Higher octane fuel is harder to burn, means lower combustion speed, so
need more time (though in ms) to burn the given quantity of fuel. To do
this the timing shall be advanced.

3.Engine Management System can only improve performance with higher
octane fuel if the engine is knocking when running on the recommended

When you filled in your fuel tank with Shell Yellow, your engine will run
at the OPTIMUM ignition timing. This might correspond to the maximum
advance timing of your engine. You got Optimum Power.
But when you filled with Shell Blue (higher octane), this will need more
advance in timing to complete the combustion, but no further advance
timing on your engine. It means that the fuel will not be completely burn
(not enough time), less engine power as a result.

Look at the following formula :
Engine Power (BHP) = VE x CID x RPM/5252
VE = Volumetric Efficiency
CID = Cubic Inches Displacement
Or Engine Power (BHP) = Torque x RPM/5252

As I said, at a given RPM, there is optimum ignition timing for a given
octane petrol. For your case, this optimum ignition timing might
correspond to the maximum advance. So at a given RPM you got a maximum
power with Shell Yellow, but less power with Shell Power.

When you reach at 5252 RPM, you will see that the Power = Torque. At this
RPM your brick got more power with Shell Yellow, hence more torque. But
when used Shell Blue, you got less power, hence less torque. Any
additional RPM will not help you to increase the power.

Look at the simple expression : RF = P/V – r D V/2
RF = Resultant Force
P = Power, V = speed, P/V = driving force
r = air density, D = Drag Coefficient of Your Brick

At constant speed RF is equal to Zero, hence P = ˝ r D V V. So, any
additional RPM with no additional power will not move the car any further
speed. Unless you go downhill, there is additional potential energy due
to gravity and RF becomes positive, you gain the speed as a result.

FYI, when you run Dyno Test, the intersection point between power and
torque curves shall be at 5252 RPM, other than that the dyno test is not
right (the case when the unit used is in English unit, means Power in BHP
or HP and Torque in lb.ft). If using SI (metric) Unit, Power in kW and
Torque in Nm, the figure 5252 will certainly change.

As for laxamana case, his brick still has room to advance the timing to
achieve the optimum timing condition, thus got more power when using
higher octane petrol. Again that depends on engine management system
mapping and driving conditions. Any additional 0.1 g/kg water in
humidity, this will reduce the apparent octane petrol number by 0.25 (RON
octane rating number is tested under sea level and zero humidity).

Glock19, Hope that this explain your finding experience with your brick
(more or less laah). Other brick with different engine management system
will respond differently when using higher octane petrol. It is wise that
you stick on Shell Yellow for your optimum performance.


Posted 20 April 2005 - 06:00 PM


    Taxi Driver

  • Members
  • PipPip
  • 372 posts

I add a bit, just to give better sight.

Just look at back the formulations :

1. Power = Torque x RPM/5252
2. Power = ˝ r x D x V x V

Starting from you press the gas pedal, more fuel added into combustion
chamber, more heat produced and hence more power, thus RPM will increase
and gives certain Vehicle Speed. With your EMS installed in your brick,
this stuff will search and calculate the optimum operating octane petrol
to produce Optimum Power. This will give certain conditions in Throttle,
Engine Speed (RPM), Vehicle Speed (V), and Engine Load. These parameters
will be used to determine the gear shifting rules, called Fuzzy
Interference Logic Unit Control.

For example :
1. IF Throttle is Low and Vehicle_Speed is Low and Engine_Speed is Low
and Engine_Load is High THEN Shift is Gear No_1.

2. IF Throttle is High and Vehicle_Speed is Moderate and Engine_Speed is
High and Engine_Load is Low THEN Shift is Gear No_2.

Etc ….. etc …… etc ……

So using different of Octane Petrol, gives different conditions in
Throttle, Vehicle Speed, Engine Speed and Engine Load, depending upon the
EMS mapping logic for a given octane petrol.

It seems that your EMS mapping logic get an optimum power when using
Shell Yellow, giving certain conditions on Throttle, Vehicle Speed
(Engine Power from equation 2), Engine Speed (RPM) and Engine Load
allowing you to shift the gear at closed to 6000 RPM (with respect to
Fuzzy Interference Logic Unit Control installed in your brick).

But when used Shell Blue, your EMS mapping logic can not give you optimum
power (see my previous explanation), thus different conditions on
Throttle, Vehicle Speed, Engine Speed and Engine Load as a result,
allowing you to shift-up the gear only up to 5200 RPM.

This Fuzzy Interference Logic Unit Control can be combined with Driving
Mode parameters which are Vehicle Speed, Variation of Vehicle Speed,
Slope Resistance and Accelerator, giving other Rules in Gear Shifting,
such as steep uphill mode or gentle downhill mode. For S70 the driving
modes are E/S/W – Economic, Sport or Winter).

Just example for Driving Mode :

1. If Vehicle_Speed is Low and Variation_of_Vehicle_Speed is Small and
Slope_Resistance is Positive_Large and Accelerator is Medium Then Mode is

2. If Vehicle_Speed is Medium and Variation_of_Vehicle_Speed is Small and
Slope_Resistance is Negative_Large and Accelerator is Small Then Mode is

The driving mode output can then be further used to affect the gear
shifting procedure. For example, if mode is Steep_Uphill_Mode, a
downshift is necessary in order to obtain greater engine power. If mode
is Gentle_Downhill_Mode, we also need a lower gear than would be the case
for a flat smooth road. The lower gear provides engine braking power.

Typical gear selection rules could look as follows:
1. If Mode is Steep_Uphill_Mode then Shift is Gear No_2.
2. If Mode is Gentle_Downhill_Mode then Shift is Gear No_3.

Don’t be surprised when you change the octane petrol, gear shifting will
also change. Or when you drive in a very humid ambient, gear shifting
will also change, because higher air humidity will reduce the apparent
octane petrol.

Hope, this help you to get better sight (understanding).


Posted 20 April 2005 - 06:14 PM


    Tokyo Drifter

  • Members
  • PipPipPip
  • 3,274 posts
Vol940, Yes I get the drift .... Thanks & ''Salute''

Blue Power is out for me for sure....Wink


Posted 20 April 2005 - 11:12 PM



  • Members
  • PipPip
  • 246 posts
Wow! Excellent explanation from vol940 ThumbUp

Had a similar experience to laxamana. I tried v-power when it first came
out. Immediately felt an increase in power and smoothness. Stuck to it
for a few tankfuls. But after a while, power started to taper off.
Switched back to shell sylkron and found no difference with v-power after
that. Am guessing that v-power is claimed to have detergent properties,
it must have cleaned up the valves.

From my observations, shell sylkron has slightly better power but makes
the engine a little rougher and louder. Petronas primax on the other
hand, makes the engine very smooth and quiet but seems to lack abit of
power. Now loyally using shell sylkron. I think the differences in the
fuel composition for me are more profound since my carb engine doesnt
have an EMS to compensate for the fuels properties.

For those who are mixing fuels, try 2 parts primax and 1 part v-power. I
did this for a while and had power and smoothness at the same time. Gave
that up cos visiting 2 different stations to fuel up was getting annoying.

Question to the sifu's:
Apparently BMW claims that their cars (especially the higher end models)
must use v-power or the engine could be damaged. Does this make sense?


Posted 21 April 2005 - 05:56 AM


    Taxi Driver

  • Members
  • PipPip
  • 372 posts

It does make sense, if the engine has high compression ratio or low
compression ratio equipped with turbo. High end models are for the rich
guys and V-power is nothing for them (in term of cost).


Compression Ratio - 5:1 Octane Requirement 72
Compression Ratio - 6:1 Octane Requirement 81
Compression Ratio - 7:1 Octane Requirement 87
Compression Ratio - 8:1 Octane Requirement 92
Compression Ratio - 9:1 Octane Requirement 96
Compression Ratio - 10:1 Octane Requirement 100
Compression Ratio - 11:1 Octane Requirement 104
Compression Ratio - 12:1 Octane Requirement 108

Most brand of petrol in the country sell 97 octane petrol, and some
provide also 92 octane petrol (projet and also petronas). Formula 1 only
allow 102 octane rating, piston engine aircraft use 115 octane rating.
I do not know exactly the octane rating of V-power but surely greater
than 97, might be 100 or 102 octane rating.

The octane rating of gasoline tells you how far the fuel can be
compressed before it spontaneously ignites. When gas ignites by
compression rather than because of the spark from the spark plug, it
causes knocking in the engine. Knocking can damage an engine, so it is
not something you want to have happening. Lower-octane gas
(like "regular" 87-octane gasoline) can handle the least amount of
compression before igniting.

The compression ratio of your engine determines the octane rating of the
gas you must use in the car. One way to increase the horsepower of an
engine of a given displacement is to increase its compression ratio. So
a "high-performance engine" has a higher compression ratio and requires
higher-octane fuel. The advantage of a high compression ratio is that it
gives your engine a higher horsepower rating for a given engine weight --
that is what makes the engine "high performance." The disadvantage is
that the gasoline for your engine costs more.

The name "octane" comes from the following fact: When you take crude oil
and "crack" it in a refinery, you end up getting hydrocarbon chains of
different lengths. These different chain lengths can then be separated
from each other and blended to form different fuels. For example, you may
have heard of methane, propane and butane. All three of them are
hydrocarbons. Methane has just a single carbon atom. Propane has three
carbon atoms chained together. Butane has four carbon atoms chained
together. Pentane has five, hexane has six, heptane has seven and octane
has eight carbons chained together.

It turns out that heptane handles compression very poorly. Compress it
just a little and it ignites spontaneously. Octane handles compression
very well -- you can compress it a lot and nothing happens. Eighty-seven-
octane gasoline is gasoline that contains 87-percent octane and 13-
percent heptane (or some other combination of fuels that has the same
performance of the 87/13 combination of octane/heptane). It spontaneously
ignites at a given compression level, and can only be used in engines
that do not exceed that compression ratio.

During WWI, it was discovered that you can add a chemical called
tetraethyl lead to gasoline and significantly improve its octane rating.
Cheaper grades of gasoline could be made usable by adding this chemical.
This led to the widespread use of "ethyl" or "leaded" gasoline.
Unfortunately, the side effects of adding lead to gasoline are:

1. Lead clogs a catalytic converter and renders it inoperable within

2. The Earth became covered in a thin layer of lead, and lead is toxic to
many living things (including humans).

When lead was banned, unleaded gasoline got more expensive because
refineries could not boost the octane ratings of cheaper grades any more.

Airplanes are still allowed to use leaded gasoline, and octane ratings of
115 are commonly used in super-high-performance piston airplane engines
(jet engines burn kerosene, by the way, though with different types such
as JP-A1 for cy tint x č[č[XS3s (pid, edit_time, author_id, author_name, ip_address, post_date, topic_id, post_title,


Posted 22 April 2005 - 02:32 AM



  • Members
  • PipPip
  • 101 posts

According to the brochure, the new S40 2.4i compression ratio is 10.3:1
and I've been using CALTEX wih RON 97 since day one. Based on your
compression ratios, it looks like i need higher octane rating for optimum
engine performance. Is that right?
What is octane rating for V-power anyway?

BTW, I've tried V-power in my previous car, 1.8 Altis, with compression
ratio of 10.0:1, but I didnt feel the "power" and decided to switch back
to CALTEX with noticeable "power" feeling. I've stick to CALTEX since

Volvo S40 2.4i Geatronic Safari GreenCool