Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Unleaded 95

Discussion in 'Bling and Appearance' started by TonySV, Jul 21, 2005.

  1. Hi all,

    Was at the Shell servo this morning and notice Unleaded 95. Whats the go with this? Do it have part ethenol?

    Any good for bikes?

  2. Yeah I noticed the new pumps the other day as well. The only thing I can think of is that is being used for the replacement of the LRP they were selling a while ago. For all the people with super loving motors all you need to do is add the valve additive and you use the 95 octane juice rather than the more expensive 98 octane stuff. I do not thing Shell puts ethanol in any of their juice.
  3. The appearance of 95 octane unleaded is partly due to the phase out of LRP but is also due to the fact that standard 91 octane fuel is also set to be phased out in Australia.
  4. Down here I've been using 95 octane for ages...

    Tas doesn't have any servos with 98, 91 is rubbish IMHO, so 95 has been used in the subbie and bike for ages.

    Costs more than 91, but my machines run better and get better mileage.

  5. Gotta be careful with the octane levels or heads might rise.

    95 is ok but some machines like mine say 98 leaded. I can only use 98+

    So if I use 95 I add octane boost at teh same rate as the valve oil.
    1ml per litre. If I am using 95 that should bring it to 98+ as the bottle says it raises the octane 4 points.
    I reckon that the octane boost is more important than the valve oil. I could go a tankful or 2 without the valve oil but to risk heavy ping and lift the head or bend a rod is bad news.

    You opinion fine Sir/s?

  6. really depends on valve seat and valve construction Bwian.

    The "valve oil" is there to lubricate these parts (in the main) instead of the lead in earlier fuels. While all aluminium heads will have some sort of valve seat insert, *most* aluminium heads have valve and valve seat materials that will handle unleaded fuels OK without extra lube for a fair while.
    A good valve lube (like the oz product "flashlube") is a good idea tho, certainly will not hurt anyway.

    I doubt incorrect octane will "lift a head" or damage a pushrod, but will certainly put a hole through your pistons in a very short time. In your case I'd imagine adding Octane booster would be cheaper than buying 98 octane petrol these days.

    Also, Oz 91 octane is reputably not a very high quality at all, any european machine supposedly built for 91 octane struggles on Oz 91, octane boosters or 95 is a safer bet IMHO.


    (edit... I now realise you mean a conrod, not pushrod.. but I still think the piston will burn out first)
  7. The other thing to watch out for is how old the fuel you buy is.

    I have a friend who was Australian Sidecar Champion a few years ago in road racing. He was a member of my Club in Canberra and a close friend. As the series was sponsored by Shell, it was a requirement that all competitors used the Shell hi-octane unleaded.

    Ray had a run of blown engines in the middle of the season and sought some professional help as to why this was happening. He was asked to bring fuel samples which he did and the reults were very illuminating.

    Apparently the higher the octane rating of the fuel, the quicker that octane rating degrades! Ray found that, of the number of drums from which he drew samples for analysis, the difference in octane rating when tested was as much as 5 points and the older the drum of fuel, the further the octane rating had degraded.

    No I'm not suggesting that you camp outside the servo till the tanker pulls in, but, be aware that, since PULP of all kinds is sold much slower than normal ULP, the longer it has been in the servo's tanks, the less the ACTUAL octane rating will be.

    So, buy from big servos that have high turnover and don't leave PULP, particularly, in your tank for long periods, say holidays, storage, etc.

    The end result of this story is that when Ray and his engineer took the results of their tests to the Shell people at the ARRC, they admitted that it was so and agreed that it was probably older PULP supplied to competitors that had been responsible for the spate of engine blow-ups.

    Needless to say, however, they did not agree to compensate, only undertake that they would ensure the drummed fuels supplied to competitors would be as new as they could make it.

    Problems with blown-up engines in the sidecars reduced dramatically after this.
  8. Good advice RC...

    extra bonus, the servo with the highest turnover of fuel is like that for a reason. Cheaper, better service, better reputation for clean fuel.

    sorry to those guys out in the country with no choice tho :?

  9. Exactly what is in the fuel that degrades or goes off? ie: is it some additive that Shell or whoever adds to increase the octane number? I thought that it was just a part of the refining process.
  10. I just looked this up on "How Stuff Works". Here's a link to it.


    If I read it correctly and if I understand it properly, what gives fuel its octane number is the percentage of octane in the fuel. eg: standard ULP has 91% octane, and Optimax has 98% octane.

    So, given this, how would the octane reduce? Does that part of the fuel evaporate or separate or something?
  11. Now this is RIGHT off the top of my head here, but I THINK that the octane additive is aromatic and evaporates away, thus lowering the octane rating over time. I seem to recall that Ray said that, as drums sometimes were opened and not fully used straight away (sidecar outfits don't have very big tanks), when they went back and used them again, the engineers said that the octane additive had evaporated significantly.

    PLEASE don't quote me on that one though. It sounds right, but just because it DOES, doesn't mean it IS.
  12. partly refining, mostly additives.

    Additives to replace the tetra ethyl lead that used to be used in "leaded fuel"

    Tetraethyl-lead was used to increase octane, "stabilise" the combustion process and lubricate valves, the greenies lobbied govt's world wide saying lead was bad, generally they were correct, but in the case of fuel, wrong.

    The lead particles that were emitted by cars (gave the grey colour to exhausts that showed a good even burning) is burnt into a solid indigestible compound that the body discards very quickly, and does not build up in your system.
    Fishing sinkers and curtain weights are far more dangerousto humans than the lead additive in fuel. The carcenogenic additives used in its place are even more deadly to all life.

    TetraEthyl-lead was stable in storage for fairly extended periods, modern additives are far more volatile.

  13. Don't get me started on THAT!!!
  14. I decided to do some more reading of this. Unfortunately, all it did was to make my head hurt....

    It seems that the "How Stuff Works" definition of octane and, well, how it works is rather simplistic.

    The other info that I started reading went into greater detail, and with my chemistry knowledge limited to what happens to water when subjected to 1200c temperature, and what we do to stop it rotting out boilers and turbines, I am having difficulty in understanding the concept.

    http://www.answers.com/topic/petrol has more info on how octane works, etc.

    I've heard of people having problems starting their bikes if left for long periods of time, particularly if they have Optimax or similar high octane fuels in the tanks.

    This might explain why this happens.

    My bike can sit in the shed for up to 2 months at a time (yeah, I know, bad boy, etc..) and aside from low battery issues, it does take a bit to fire up. But once it is, it runs fine.

    The bike, a CBR1000, though, seems to run fine on either standard petrol or Optimax. It doesn't seem to matter what I put in it, as neither performance, fuel economy or engine knocking is affected. The same goes for my car, a 2003 Commodore SS V8.

    In the end, what dictates what fuel you should use is the engine's compression ratio. The Honda is 10.5:1 for example. I tried to find what the Kawasaki ZZR1100's is, but couldn't find it. It would ping and rattle on ULP but was fine on PULP. However, the change in fuels made no difference to performance or economy, just stopping the rattles under heavy load.