Fuel

[froudy]

I meant to post this a few weeks ago, but things here have been a bit hectic to say the least recently..

I always use Texaco Premium Unleaded 95 Octane. Texaco in my home town is always a penny or two cheaper than the three supermarkets and it's the closest as well.

My commute to work and back is 70 miles a day, three times a week. I do two days and then fill up at 140 miles and then fill up again on my last journey home so that the tank is full and ready for the next weeks commutes. This particular day I had done 70 miles and decided to top up with Texaco Supreme Unleaded 97 Octane. I wasn't really expecting it to make any noticable difference as I'd only put 7 litres in to top up...How wrong could I have been!! It totally transformed the performance. Smoother throttle opening..Better accelleration and all round a far "crisper" ride.

I'm sure others have used 97 octane...Was your experience the same?
I don't plan on using it all the time though due to the extra cost. 95 octane is £1.22/litre and 97 octane costs considerably more.

[grog]

Quick answer Froudy. 91,95 or 98 in mine makes no difference.

[T 24]

I use 98 or 99.

[seth]

I use 95 but do notice the bike is betrer/smoother with 97 .
I did put on some 102 in it in Germany and wow it was a fantastic difference the bike seamed to come alive big time .

[Mick_J]

Cant say I've noticed any difference but I have to run Esso super 97 in the MZ and Speedtriple (as they have plastic tanks) and did not notice any difference there either.

[Andre]

I use 95 but do notice the bike is betrer/smoother with 97 .
I did put on some 102 in it in Germany and wow it was a fantastic difference the bike seamed to come alive big time .

I never tried Aral Ultimate 102. It is unique in that it is produced exclusively in an Aral owned refinery and has its own logistics to keep it separate from other fuel. It is ethanol free. I assume you put it in your bike that has the 4° ignition advancer and Yoshi cam?

[seth]

@Andre
It was Aral Ultimate 102 fuel but it was in the standard bike .

I can't wait to try it in the other  tuned one sometime soon.

[Andre]

I guess I will give it a try someday.

[gsxbarmy]

When I had my 14 I ran it exclusively on 97 octane after about 8k miles - ran so much smoother and crisper.

[Horse]

Technically the higher Octane fuel in an engine that has no way of advancing the ignition to make use of the resistance to detonation will have no impact at all in fact the addition of an octane booster will decrease the calorific value of the fuel, in other words high octane fuel has less energy. In the old days tetraethyl lead was added which while it stabilised the fuel it did not add any energy value, not sure what they use now some degree of BTX possibly, Toluene maybe. All that being said I believe what everyone perceives as a better/crisper running engine while a lot is the placebo effect a percentage could be that the higher grade fuel is of a more consistent quality so there will be some benefit. I am sure someone cleverer than me will have different/better info but that is what I believe and have seen it backed up in the old days on a dyno whilst playing around with fuel and advance curves. Newish engines with lots of electrickery and the ability to run just inside the detonation curve definitely make more power with higher octane fuel but I am sure the 14 does not have that capability, pretty sure it doesn't even have a knock sensor to retard the timing it will just ping until the fuel/ ignition timing is altered. Just my 02 cents worth, have had many piss up discussions around this and whilst never convinced fellow bogans that they were wasting $ in most cases, it was always entertaining to discover that their seat of the pants dyno was infallible.

Cathchya,

[Andre]

The 14 is set up for 91 RON. There is nothing in its fuel injection system to adjust for different octane ratings. Ethanol does boost octane and has lower energy content. No idea what else they use.

Better quality (base) fuel may be used in premium. Aral claims that for their Ultimate. It's the only company that claims that for their premium fuel as far as I noticed. All the others claim superior additives for their premium.

[Batkwaka]

As I understand it, Octane is only a fuel stabiliser used to stop pre-ignition in high compression engines. It adds nothing to the flame front itself.

[Speedy1959]

I use the 97 every other fill up..
Saves me putting injector cleaner in every so often.

S

[T 24]

@horse
You are correct, but nothing is so simple.
We here up north have 95E10 and 98E5 petrols, containing 10 or 5 % of ethanol, Shell V-power even more alcohols.
I didn't notice any differences between them in my stock 14 or in my wifes XJR 1300.
But we can have also slightly modified engines with higher compression ratio, or charged engines, what will need higher octanes.
I use 98 or 99 oct. + water/meth injection against detonation and keeping engine clean  in my turbo 14.

[Horse]

T24 as you say once you start changing any of the engine variables then the higher octane fuel is needed but it must be able to facilitate the longer burn period or increased combustion pressure to achieve any gains, So while the higher octane fuel generally has lower calorific value, over the longer period of pressure on top of the piston it will give more power, as all higher octane fuels have greater resistance to detonation you can advance the timing, up the compression pressures ETC to get the extra energy ( burn time) out of the fuel. As I try to explain to my pissed petrol head friends unless you compliment the fuel with altered engine variables( like newer high tech engines do) you are wasting $s ( not withstanding better/more additives). Although personally when I see some injector cleaners on sale I prefer to put them in at my discretion ( never notice any difference to be honest) I believe I get more value out of a capful of metho every couple of months to much else ,

Catchya