99 RON FUEL

[scooby]

99 RON

[oldman]

Nice to have met you at Nutsford Scooby yer kin lunatic  

[Nick M]

Can't be arsed to read through all that, but was there any discussion about the difference between "Octane" and "RON" ??

I thought the two were slightly different, so Tesco could be selling 99 octane fuel but it might not be much different to normal super unleaded.

[stu999]

Can't be arsed to read through all that, but was there any discussion about the difference between "Octane" and "RON" ??

I thought the two were slightly different, so Tesco could be selling 99 octane fuel but it might not be much different to normal super unleaded.

There was some mention of it Nick....but I lost the will to live after a couple of pages and gave up  

Someone mentioned on the thread that Optimax is about to be replaced with something which I can't remember now too...

[pistonbroke]

They all taste the same to me  

[Karl Woolf]

Whats a knocklink    

[Buzz Billsberry]

Whats a knocklink    

Its like a cufflink but completely different or was that the M621link between the M1/A1 anyway u decide

Hope this helps

Buzz

[neilb]

Google is your friend

Basically it's a visual display for a knock sensor

[Nick M]

Whats a knocklink    

Another toy for you to look at while failing to appreciate that there's a bend approaching at Warp 9....

See also "boost guage" and "air / fuel ratio meter"....

[steve_m]

Whats a knocklink    

It's a device that strengthens the link between two cups of a bra to reduce the giggling effect on track.  It's been around for a while, usually manufactured from alluminium but I gather there's a cf version too.

[stussysoil]

Pretty sure when I went too the WRC in Germany last year some of the Shell garages were selling 100 RON fuel.  These fuel pumps where bright red and had Schumacher's face plastered all over them.

I thought is would have arrived here by now, because it hasn't I am beging to question whether I saw it at all      

Has anybody else seen 100 RON in Europe?

[steve_m]

A high RON isn't a guarantee that this petrol will be any better at resisting detonation, the addatives they add can evaporate very quickly on a hot day leaving you with a 96 or 97 RON fuel after only a couple of hours.

Some interesting reading here:Chevron fuel info

Antiknock Performance

Knock-free engine performance is as important as good driveability. Octane number is a measure of a gasoline's antiknock performance — its ability to resist knocking as it burns in the combustion chamber. There are two laboratory test methods to measure the octane number of a gasoline (see Chapter 3, Gasoline Refining and Testing). One yields the Research octane number (RON); the other, the Motor octane number (MON). RON correlates best with low speed, mild-knocking conditions; MON correlates best with high-speed and high-temperature knocking conditions and with part-throttle operation. For a given gasoline, RON is always greater than MON. The difference between the two is called the sensitivity of the gasoline.

Because RON and MON are measured in a single-cylinder laboratory engine, they do not completely predict antiknock performance in multicylinder engines. There is a procedure to measure the antiknock performance of a gasoline in vehicles (see Chapter 3, Gasoline Refining and Testing). The resulting value is called Road octane number (RdON). Since vehicle testing is more involved than laboratory testing, there have been a number of attempts to predict RdON from RON and MON. The equations take the form:

RdON = a(RON) + b(MON) + c

A good approximation for RdON sets a = b = 0.5 and c = 0, yielding (RON + MON)/2, commonly written (R + M)/2. This is called the Antiknock Index (AKI). The U.S. Federal Trade Commission requires dispensing pumps to be labeled (posted) with the gasoline's AKI.1 Footnotes

1 The gasoline being dispensed must have an antiknock index equal to or greater than the posted value. Rounding the number upward is not permitted. Owner's manuals in the U.S. also must indicate the octane number recommendation for vehicles2 Footnotes

2 Older owner's manuals of some foreign cars specify RON; some more recent ones specify both RON and AKI. by AKI. (R + M)/2 is voluntarily posted in Canada.

Neither the AKI nor the several other single-value indices that have been developed work for all vehicles. The performance of some vehicles correlates better with RON or MON alone than with a combination of the two. And for a given vehicle, the correlation can vary with driving conditions. (See Chapter 1, Figure 1-5 for the variables that affect an engine’s octane requirement.)

As the formula indicates, gasolines with the same AKI can have different RONs and MONs. This may explain why a vehicle knocks with some fill-ups of the same brand but not with others; or why it knocks with one brand of gasoline but not with another. Of course, for a comparison to be valid, the vehicle must be operated under identical conditions, which is not easy for the typical driver.

Generally, three grades of unleaded gasoline with different AKIs are available in the U.S. — regular, midgrade, and premium. At sea level, the posted AKI for regular grade is usually 87 and for midgrade, 89. The AKI of premium grade varies more, ranging from 91 to 94.

The posted AKIs are lower in the Rocky Mountain states. These altitude gasolines historically provided the same antiknock performance as higher-AKI gasolines at sea level. The octane requirement of older-model engines decreases as air pressure (barometric pressure) decreases. Barometric pressure is lower at higher elevations.

Since 1984, vehicles have been equipped with more sophisticated control systems, including sensors to measure, and engine management computers to adjust for changes in air temperature and barometric pressure (see Chapter 5, Gasoline Engines). These vehicles are designed to have the same AKI requirement at all elevations and the owner’s manuals specify the same AKI gasoline at all elevations.

Outside the U.S. and Canada where an octane number is posted, RON is generally used. The owner's manuals also specify the minimum octane grade recommended in terms of RON.

It is difficult for a driver to know whether a gasoline has the antiknock performance the engine requires when the engine is equipped with a knock sensor system. These systems, which temporarily retard spark timing to eliminate knocking, are installed on many late-model engines (see Chapter 5, Gasoline Engines). Retarding the spark reduces power and acceleration. The knock sensor responds so quickly that the driver never notices the knock. Loss of power and acceleration will be the only clues that the antiknock quality of the gasoline does not meet the vehicle's octane requirement.