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JimO
1st May 2007, 20:32
i have been using 91 in the raptor but at the first service the mechanic suggested i try 96 which i have , what do use fullas use - for those that dont know the bike has a TL 1000 V twin suzuki motor

TS99
1st May 2007, 20:44
always go with the manufacturer recommendations.

Oakie
1st May 2007, 21:09
The mechanic where I go told me they use 95 on all their bikes, even if the recommendation is 91. This is because '91' on a petrol pump is more of a trade name rather than an accurate indication of the octane. The octane out of a '91' pump may be less than 91. It's a bit like a bike being labelled a '250' when in reality it is only 225cc

James Deuce
1st May 2007, 21:38
The same comments that have been passed for 91 apply to the other octane "ratings". NZ uses the RON (slap happy she'll be right) system of measurement rather than the more robust DIN (German precision) system. Japan uses DIN. Our Octane ratings are already 2 points (approx) behind the reccommended levels.

Contrary to popular opinion higher ratings are ONLY required for engines with relatively high compression ratios (12:1 or more). Higher octane fuel has a slower moving, cooler flame front and a compression ratio under 11.5:1 will result in unburnt fuel and carbon deposits from 98 fuel. 89(DIN) is perfectly acceptable for most modern engines, thanks to modern ECUs and sensors 87 will be fine too. Where did I get this stuff? Kevin Cameron. He knows more about physics, engine design and management and just plain motorcycles than all of KB's database combined and he can regurgitate in a way that an idiot like me can understand.

You're basically chucking money away on dearer fuel. It's called marketing. We all know what kind of people get marketing degrees.

TygerTung
1st May 2007, 22:10
It depends on timing as well.

Even in my 1975 corolla with the 1500 5K innit it pinks on 91 and that only has about 9:1 compression or there abouts, so I have to run it on 95+ because the timing is a little more advanced than the manufacturers specification.

I don't run 91 on anything, even my scooter:scooter: , don't like the stuff, but thats just me.

My 2 stroke has very low compression but that even still melted a piston on 95, although it was getting a bit hot.

Theres more factors to detonation than just compression.

James Deuce
1st May 2007, 22:18
There sure is, and you can cold seize a two-stroke on avgas.

I get the best mileage and the bike seems to run "sweeter" on Caltex 91 than anything else. The CB400 I had was the same.

I had a FIAT with a 9.5:1 compression ratio that demanded 98 octane - more to do with timing than anything else. It would pink like mad on anything lesser.

But we're talking about modern bikes and they're a lot more flexible in fuel requirements.

Steam
1st May 2007, 22:26
Despite reading all the zillions of threads on this over the past few months, I'm still confused.:scratch:

TS99
1st May 2007, 22:40
We all know what kind of people get marketing degrees.

What kind of people are they Jim?? *** says guys with Doctorate in life **

Titanium
2nd May 2007, 00:11
The K1200S runs a compression ratio of 13:1.

Here in OZ I put Shell V-Power Racing (avaliable at the pump) 100 Octane with 5% ethanol.

The handbook states to run a minimum octane of 95, preferably 98 octane or higher.

The 100 Octane is the shizz nizzle and at ONLY $1.30 Oz per ltr.

The 6.0 Ltr SS-V Commodore runs like shit on the stuff.

cheers


peter

90s
2nd May 2007, 07:57
You're basically chucking money away on dearer fuel. It's called marketing. We all know what kind of people get marketing degrees.

I have to say that I run a Eunos 500 (v6) which barely moves and drinks like a fish on 91. On 95 it flies and still drink like a fish, but at least gets 100k more per tank than on 91. On the rare times I see 98 things are even better - worth the extra in better economy.

Both bikes I have had in NZ (2s single & 4s 4) also perform better in terms of power and fuel economy on 95 than on 91. The difference was marked (although our marketing majors might say this was not a double-blind test). I tried only 1 tankfull to be convinced to stick to 95.

Why don't you simply try the different fuels in your bike and see if it pinks, keep a note of economy etc? The price difference between 91 & 95 for a 20l tank bike is currently only a dollar.

peasea
2nd May 2007, 08:56
The same comments that have been passed for 91 apply to the other octane "ratings". NZ uses the RON (slap happy she'll be right) system of measurement rather than the more robust DIN (German precision) system. Japan uses DIN. Our Octane ratings are already 2 points (approx) behind the reccommended levels.

Contrary to popular opinion higher ratings are ONLY required for engines with relatively high compression ratios (12:1 or more). Higher octane fuel has a slower moving, cooler flame front and a compression ratio under 11.5:1 will result in unburnt fuel and carbon deposits from 98 fuel. 89(DIN) is perfectly acceptable for most modern engines, thanks to modern ECUs and sensors 87 will be fine too. Where did I get this stuff? Kevin Cameron. He knows more about physics, engine design and management and just plain motorcycles than all of KB's database combined and he can regurgitate in a way that an idiot like me can understand.

You're basically chucking money away on dearer fuel. It's called marketing. We all know what kind of people get marketing degrees.

A lot of what you say is true and you obviously have some reliable sources. I built racing engines for nigh on thirty years and detonation/pre-ignition and flame fronts were things I studied in some depth. A high compression ratio (I'm sorry to disagree with you) is NOT the only factor to consider when looking at octane ratings etc. For example; comparing two different styles of combustion chamber will possibly clear the air.

A large cylinder with a relatively inefficient port/chamber configuration, two valves per cylinder, a compression ratio of (say) 10:1 and a given ignition curve will require a higher octane fuel than an efficient port/chamber configuration (read pent roof, for example) with multi-valve layout and the same compression ratio and ignition curve. Forget the compression ratio, forget the timing, call them the same. The more efficient port/multi-valve, pent roof chambered engine will run ok on lower octane fuel, the other won't, I can assure you.

Theorizing is one thing, doing is another and the dyno is a very useful tool. I've built Chevy's with conservative compression ratios that required careful distributor tuning to run on 'super' pump gas but the same size engines with more efficient cylinder heads (port,valve/chamber configurations) could go much higher in the compression ratios, use more intial ignition timing and run way more total ignition timing while making more power and not detonating.

There are so many variables, like squish and swirl to consider, then technical terms such as adiabatic expansion and chemical dis-association creep in but until shit like that is explained it's difficult to grasp the importance of octane. 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.

Simply put; if your engine is tuned correctly (ie, the ignition timing is right and your plugs are correct) then try 91. If it 'pinks' go up a grade. That noise you hear is damaging to your engine, particularly rings, pistons, bearings and head gaskets. If you modify your engine and different camshafts enter the frame, or a higher compression ratio, then use the best fuel you can find. What's a few cents to preserve your efforts and your engine?

If in doubt; use the best.

Hitcher
2nd May 2007, 10:26
Cheap is good!

The sticker on the tank of my (former) ST1300 said to use 98. I used 91 with no ill effects performance-wise. The inexpected termination of the ST was in no way related to the fuel in the tank.

James Deuce
2nd May 2007, 10:28
Why don't you simply try the different fuels in your bike and see if it pinks, keep a note of economy etc? The price difference between 91 & 95 for a 20l tank bike is currently only a dollar.

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.

For my bike, running it on anything other than 91 is costing me money, and even saying that running it on Shell 91 is a hiding in terms of cost.

peasea, you're not disagreeing you're fleshing it out.

Simple rule of thumb for bikes:

Race Rep: 95, or higher if you feel like chucking money away

Italian Race rep: 98 Octane

Modern BMW: 98

Everything else: Go by the Manufacturers recommendation. 91 should be fine if your engine is healthy. But stick to Caltex is you can manage it.

Caveat: if it pinks go a grade higher as peasea says.

vifferman
2nd May 2007, 10:35
The VifFerraRi runs better on 98 (go figger - it should give less power, as it doesn't have a knock sensor) mainly to stop pinking when the engine's hot, but in the winter I swap to either 91 or a mix of 91 and 98 (alternate fills) as it doesn't start as well on 98 when the weather gets cold.
I avoid 95 as I've had very bad results in the past with my previous VFR. The plugs are teeny-tiny ones, and get fouled with all the extra xylene/toluene the Big Four bung in to raise the octane rating.

Bass
2nd May 2007, 12:23
I too have played with racing engines a bit and so done some study on the causes of pre-ignition.
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

TS99
2nd May 2007, 19:28
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
2nd May 2007, 19:36
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
2nd May 2007, 19:38
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
3rd May 2007, 01:26
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
18th October 2007, 17:45
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
18th October 2007, 19:09
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
18th October 2007, 19:56
yeah.... that didnt really answer my question :confused: 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
19th October 2007, 09:51
yeah.... that didnt really answer my question :confused: 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
19th October 2007, 09:54
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
19th October 2007, 17:05
yeah the bikes standard, due for a fill soon so i think ill try some 91

limbimtimwim
19th October 2007, 18:02
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
20th October 2007, 14:10
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
22nd October 2007, 14:02
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
29th October 2007, 00:36
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
29th October 2007, 22:43
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

kitsune
30th October 2007, 00:21
I just switched to shell over the BP stations, and am still on 91, but the difference has been massive, trying 95 next fill from same place, then seeing what the stuff from BP is like . Cant get 98 where i am tho suckz i know