What petrol to use?

[TS99]

The fuel we have in NZ is basically cheap crap by comparison to overseas. Gull is made outside NZ, it is made to meet higher specifications so their base fuel at 91 will exceed our 91, I promise you. Their Super is great and so is BP's Ultimate 98.

I've heard that too about the Gull product. Something to do with Marsden having antiquated refining equipment, and less than ideal flushing procedures between, say, a petroleum refining dump, and a diesel refining dump. (so i've heard)
Has anyone done a proper distillation of these products to get the indicated octane levels?

I tend to agree that most modern bikes should be pretty happy on 91 (with some exceptions as previously mentioned). So I was surprised to discover that the Sprint HATES 91. I have been forced to use it once or twice (e.g. refuelling at Te Araroa) and she really rattles when asked for anything more than a tootle when on 91

I concur. Maybe the ECUs on the 99-04 models weren't up to the job, but then the manufacturer's recommendation is 95RON. Also there are two different ECUs in the Sprints; MC2000ECM up to VIN89736 then MC1000ECM from VIN89737 upwards.

[98tls]

FWIW my TLS runs decidely better on the good stuff.........ive fitted a TRE and mucked about with a yosh box but even when bone stock it ran better with the good stuff................

[98tls]

Have a look at TLZONE.NET theres a sub forum in there dedicated to raptors etc and a better more knowledgable bunch of blokes you wont find.............

[Sanx]

I know this might not be particularly relevant to this particular case or NZ in general, but the UK's Fifth Gear TV show did a fuel comparison a while back. Three cars: some horrible cheap Nissan Micra-esque hatchback, a Mondeo-sized midsize saloon and an Impreza STi. They compared stock 95 Octane (the lowest available in the UK) from a supermarket with BP's 97 and Shell's 98. On the hatchback, it made stuff all difference. On the saloon, there was a 1% or so increase in HP between the 95 and the 98.

The Impreza though was a little different. There was something like a 8% increase in power and torque between 95 and 98 octane fuel. It was about 20hp more.

Consider most high performance bike engines are exactly that; high performance. Use the best stuff you can find ... it's unlikely to do it any harm and more likely to do it some good.

[disturbed]

hmmm. ive got a 88vfr400. what fuel should i be running? ive been running on 95 premium since i got it (3 weeks) should i be running on 91?

[Conquiztador]

Not wanting to repeat what I have said before, but as this thread is clearly new:

Higher octane petrol has additives to stop it from igniting before the spark is igniting it. When using a low compression engine or a engine that does not get overheated use 91. It will ignite when it is supposed to: When the spark comes.

In a high compression engine or an engine that gets very hot you will get the mentioned ping as a result of the fuel igniting BEFORE the spark comes. This then makes the ping noise as a result of the explosion working against the movement of the piston instead of exploding at the right time and pushing the piston down and accelerating the engines movement.

Petrol is made to burn. It will burn when you add a spark. BUT it will also burn as a result of high compression and a hot environment that has no spark added.

So the higher the octane rating, the more additives are in the petrol to stop it from exploding too early.

Yes, the timing will have a bearing. Also the valve opening times. And the shape of the chamber etc. But in the end it is simple: You want the petrol to burn when the spark ignites it. Not before. If your engine is burning the petrol before the spark ignites it then you need to increase the octane rating until the petrol explodes when you want it to.

This is why a bike that gets hot/has early timing/high compression will give you more hp and more mileage from higher octane fuel as the lower octane fuel will explode too early reducing the performance of the engine.

End of rant. Soap box back in the corner.

[disturbed]

yeah.... that didnt really answer my question ive just been reading mixed reviews on here about 91 and 98. people saying 91 is best and others saying to run a higher octane. my bikes from 1988 so im guessing it would be tuned to 91 because im sure they didnt have higher octane then. or am i just talking a heap of bs :slap:

[Conquiztador]

yeah.... that didnt really answer my question ive just been reading mixed reviews on here about 91 and 98. people saying 91 is best and others saying to run a higher octane. my bikes from 1988 so im guessing it would be tuned to 91 because im sure they didnt have higher octane then. or am i just talking a heap of bs :slap:

If your motor is standard then go by the manufacturers recommendation.

If your motor is tuned/hotted then you will need to do the research re what is best for your engine.

One more thing to what I did write above yesterday:
If you are using high octane petrol in a low compression/low hp engine (remember that high octane petrol is made to better withstand higher compression and higher temperatures) there is a chance that the high octane petrol will not be properly burned before the stroke is over. This can cause petrol left in chamber, petrol in to header pipes. If this happens you are getting new problems. Like the petrol still burning when it is blown out in to the header pipes.

[Usarka]

I've actually done that very test and published the results on here. I got a massive variation in mileage and performance between manufacturer and octane rating. The difference between Shell 91 and Caltex 91 was 50 kms per tank on average. None of the higher octane fuels matched the mileage of the 91 fuels.

did you try gull aswell and if so how did that stack up?

[disturbed]

yeah the bikes standard, due for a fill soon so i think ill try some 91

[limbimtimwim]

My RVF (Very similar engine) was always a little happier on higher octane fuel. Only a teeny tiny bit happier though. I noticed that the dead spot around 6000rpm was worse on 91.

[Chocky]

I dont know shit about compresion but what I do know is my 95 RF900 will not lift the front ( 1st, no clutch,sitting upright) with a tank full of 91 and it will with a tank full of 98. I've never heard it pink/rattle on any type of gas and the 98 is only few dollars more per tank soooo.....

[kitsune]

Cheers for this thread guys very usefull , i am running 91 in my ninja, the manual states use nothing lower then 90 octane , im thinking of trying some 95 next fill - the engine is still new however , not even 200k's on the clock yet, whats the best way to go ? , anyone else with similar bikes whats your thoughts?
Compression Ratio 12.7:1 FYI

[Pancakes]

Cheers for this thread guys very usefull , i am running 91 in my ninja, the manual states use nothing lower then 90 octane , im thinking of trying some 95 next fill - the engine is still new however , not even 200k's on the clock yet, whats the best way to go ? , anyone else with similar bikes whats your thoughts?
Compression Ratio 12.7:1 FYI

95 is 91 with additives, 98 is 98 so it's kinda not what people think. If I owned a ZX10R... it'd be 98 unless there were no alternatives.

[Static]

heres another question to chuck into all of this which petrol stations should i/we make an effort to go to and which ones (if any) should be avoided