99 Octane
 

Yes please just found it on sale at the local Tesco. Noticed a big difference especially as the previous fuel in the tank had been bog standard unleaded. I also got an extra miles out of a tank full, 120 miles up to 130 That’s the stuff for the DD bike then. Does anyone know of a higher rated fuel on the high street?

Mike

:mad:well thats our cat out of the bag then:P

If only life was that simple....:

http://217.199.188.40/xmb/viewthread...6486#pid256983

well, the experiment that AK did on the bikes was quite informative on the dyno, so we are sticking with the 99 octane:)

If your bike is set up to take advantage of high octane fuel it's worth it :)

Only today was discussing this with an off-road racer. He heard of octanes upto 150!!! Some help, some do damage. As cc above says, your bike has to be setup for it.

Andy

I always used to use shell's optimax, but if there's more power out there to be had I want it. I believe Avgas - aviation fuel is 100 octane

The hand book just gives a min of 95 says nothing about max.

Mike

Yeh, used avgas on a KX250, but mainly to help the pistons, as it has loads of lead in it.

I do use Optimax on the 900ss as much as possible, but it doesnt make any difference to the R1.

Andy

http://www.aaoil.co.uk/

£14 a gallon tho !

And illegal in DD

[Edited on 3-2-2006 by couchcommando]

you cant use avgas for racing - rule book states commercially available for retail (or words to that effect) and i dont think the octane is over 100 for road race (but i could be wrong)

Avgas & similar are not good for your road bike either - we've used it on the drag cars (better to be a top fueller eh?)
but that is when AK (& gang) can strip & rebuild after most runs.

C:)

im going to try something revolutionary im going to " twist the throttle " more.....maybe even brake later or EVEN carry more cornerspeed.....

guess u race gods that have ridden to the edge of your abilty are looking now at the weakness in your bike for that extra advantage...........:devil::roll:,.....

My mate in california nearly fell over when I said I was now using 97 octane not 95, he can struggle to find the minimum required to run his merc. 93.
In texas he says it can go down in to the mid 80's in octane, that why they all run big engines to get power, because the fuel is crap.

1.5 Fuel

All engines must function on normal unleaded fuel available from normal filling stations open to the general public. The use of any octane boosting or other additives, is strictly forbidden.

Tesco's is normal enough:)

Why do you have a dynojet kit and race exhausts, it would have been cheaper to twist the throttle " more.....maybe even brake later or EVEN carry more cornerspeed.....
;)

here we go....fight fight fight.

slightly different....but then again i did not expect a moderate reply from a race god............

one day i will attain the dizzy heights of being able to worry about spark plugs and fuel types..till then i will concentrate on my riding.............. :P

In your defence you do need every advantage you can get in this cheap race series.........;)...

Not slightly different at all, you are asking why carry out mods when you can ride harder ?
By this logic no mods should be allowed until you can ride a standard bike at 100%......there is no one in this series that can ride a bike at 100% so no mods would get done !

For those who either a/ can't be bothered or b/ don't understand Shazzam's posting let me make it very simple.
The higher the octain rating the SLOWER the fuel burns-high octain fuel is a waste of time unless you have the compression to make use of it-in fact it will give you lower performance since it won't burn quickly enough. AK's top fueller would be using horrendous compression ratio's hence the need for high octain fuel. My TZ runs on Avgas-but it uses a 16:1 compression ratio............enough said?
Also as has been pointed out Avgas/race fuel/additives etc are specifically excluded from the rules-as long as you can buy it in a standard petrol station-and it's unleaded-that's fine. I put the last bit about being unleaded in since you are not able to buy leaded fuel, or even lead replacement petrol any more apart from a a very few select stations which keep it for 'historic vehicles'.
So avgas will give you no advantage unless you are running really high compression-but then if you were doing that you'd be outside of the rules anyway-catch 22!

John

I wasn't gonna share this but I've got some race air, I carry it in a cardboard box in the back of my van. If you want some just bring your airbox and £10 and I'll fill it up for ya, one airbox full should last one days racing and add 15hp, now don't say I never do anything for ya and form an orderly queue :)

Ya, Ive heared of this, its called HOT AIR most newbie racers swear by it , its likend to Bull **** you may find that usefull later on in the season :lol: 4D

Put me down for £60 Worth of that there super air will yu :smug:

Save your money and just breathe into your airbox for 30 seconds :o

:lol:

let me in here im the chemist

first of all as long as you can buy in in a normal filling station (the rules)

the more bhp you have the better the advantage of using high octane

the chemistry bit : higher the octane the more the fuel will compress before explosion hence use more of the cylinder hence higher bhp.

What Monty said.

I've been running my race engine on Elf 4T (Superbike fuel) generally available to the public.....well maybe, as long as you shop at the pumps at Silverstone!... but the engine was developed and mapped to utilise its properties. Oh, and like CK said, it was only £70 for 20 litres!!!

Rgds, Rob

US fuel is rated on MON scale, we use RON scale, 95MON has a higher octane rating than 95RON

Higher octane fuel is less prone to detonation. On a modern car the knock sensor would kick in and retard your ignition, to protect the engine from det. With the appropriate hardware and software its possible to remap ignition and not just fuelling as a standard power commander does. So using a higher octane fuel with less risk of detonation means that the ignition can be advanced, and that on its own brings power gains.

No. Using a slower-burning octane fuel and then raising the ignition advance to compensate - doesn't increase power.

There are two basic ways to increase the power of an engine. One way is to increase the amount of fuel and air being burned and another is to increase the efficiency of the burn itself. Raising the compression ratio of an engine primarily increases combustion efficiency. An engine will run most efficiently when the fuel/air mixture can be compressed as much as possible. More heat, more compression and the fuel/oxygen reaction will happen more quickly and more efficiently.

The main reason that high compression engines aren't manufactured anymore for street bikes is higher exhaust emissions. The extra heat produces more oxides of nitrogen (NOx). From a design point-of-view it also decreases reliability as the engine is under greater strain. So to increase the compression ratio of an engine designed for lower internal forces may require changes beyond high compression pistons.

The additional compression also produces higher cranking loads and additional blow-by. The higher cylinder pressures bypasses the rings easier so more combustion gases get by the rings into the crankcase. So consider using the Corsa breather canister and plumbing instead of the stock setup. You need to assure that the intake properly scavenges the crankcase of the increased blow-by without sucking any oil into the intake tract.

Further, you'll need to run higher octane gas to assure reliable high compression without detonation. Gas octane availability above 98 RON (92 R+M/2 in the US) is limited to aviation and race fuels, so most modern engine designs designed for high octane gas use knock sensors and computers that adjust the ignition timing on a real-time basis, so that they can be run nearer the detonation point without being damaged.

However, chances are that you'll be able to run a 13:1 compression ratio before exceeding the octane requirement of readily available pump gas.

Simply stated, when you raise the compression ratio you risk damaging your engine from pre-ignition. The resulting shock wave can shatter a four-stroke piston. So, you first need to make sure that the ignition timing is set properly to prevent engine knock under a variety of load, fuel, and environmental conditions that affect engine knock.

There are two primary factors which govern engine ignition advance. First, the constant time to burn results in a need for a linear increase in advance as a function of RPM. Second, higher RPM and loads lead to higher turbulence and faster burn times. So, the ignition advance should initially increase with RPM and then taper off and even decrease as the engine speed increases further. As a function of load (manifold pressure for example) the timing should decrease, ultimately being limited by engine knock and exhaust temperature. Before computers and solid state ignitions came into general use, manifold vacuum hoses and centrifugal advance mechanisms on distributors were used to advance engine timing.

On Ducati superbikes the ignition system is integrated with the fuel injection system to form a combined integrated engine management system which is operated by the electronic control unit (ECU). The ECU uses inputs from various sensors to calculate the required ignition advance setting and ignition high-tension coil charging time. There is no factory provision for adjusting the ignition timing on these models, although as you point out, there is a method using an aftermarket programmable EPROM or Power Commander to modify the ECU ignition map.

Consequently, to make the best power (safely) from a stock compression bike, you should use the lowest octane fuel recommended by Ducati - as a result of extensive testing. If it knocks under real-world high temperature and load conditions, use the next higher octane grade or try a different brand fuel.

[Edited on 2-5-2006 by Shazaam!]

So why do they only state a minimum of 95 in the book but no max? if the fuel available at the pump can do damage to the engine??

Higher octane can't damage it, lower than reccomended can, hence it states the minimum.