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Adding 2T oil to your fuel...

Discussion in 'Technical and Troubleshooting Torque' started by Ljiljan, Aug 23, 2010.

  1. Don't know if I like the idea of changing the viscosity of fuel, given that, on what I've been told at least, different RON ratings have varying density and too high a RON in an engine not designed for it causes problems for your spark plugs...injected or needle carbie, I don't feel comfortable until I see someone doing it with the same bike as me. One engine might be able to handle it but another design might not?
  2. 2T oil travells fast? What the hell does that mean?

    The fuel isn't coming all the way from the tank when you open the throttle, anyway... The fuel is constantly pressed hard up against the injector valves, at significant pressure (eg: 32psi), waiting for the valve to open. The fuelpump overpressurises the fuel rail and the excess fuel recirculates through a pressure regulator and return line.

    It's not like you're sending instructions to the fuel pump via steamboat telegraph. It's (virtually) instantaneous. There is no "time leg of fuel" while the fuel has to "travells".

    Frankly, there is an easy way to test it. Go to a dyno with a specific car, do a few runs on 95 octane or 98 octane or whatever the engine likes most, then refill the tank with the blend of fuel and 2T oil and test it again.

    No butt-dyno, no subjective "OMG IT TRAVELLS 10000%!", just one test after the other. :)

    (I sound skeptical, I know... But the butt-dyno is very, very easy to mislead and a dyno run is very, very cheap to do. :p
  3. Couldn't be worse then putting NOS energy drink in the tank.... or could it
  4. I can't see any advantage on a modern engine in Australian conditions, and I can see a few disadvantages.

    I used to occasionally add a dash to my tank in winter in the UK to give pistons, rings and valves a slightly easier time in arctic cold starts, but most of my bikes in those days were horrible old dogs that needed all the help they could get.

    Thing is, oil reduces the octane rating of your fuel, leading, potentially, to detonation or, with engine management, to loss of power as the ECU retards the ignition to compensate, so I can't see it resulting in more power. Advances in 2-stroke technology have generally focussed on reducing the quantity of oil, or keeping it away from combustion entirely, because it's detrimental to performance, even in engines that need to use it.

    The only possible plus that I can see is that it might give some protection against the corrosive effects of water in ethanol blended fuels.

    Edit: I've just looked at the links and see that they seem to be talking about diesel engines. The first one, even allowing for English not being the poster's first language, contains enough rubbish (as pointed out by Spots) that I couldn't take it seriously.

    Without dyno results, it sounds like bullshit to me.
  5. From my research into it (10,000km road use in my RS125 and racing in an aircooled 1970's Kawasaki 100) heres my pointers on using it:

    For general road use, not necessary at all. It will provide some level of additional engine protection, especially in vehicles that are not used daily. The detergency of higher-spec 2T oils will help keep the cylinder and valves clean, but generally this isn't needed in 4T's because they aren't burning oil as 2T's are designed to do. The 2T oil inevitably leaves some residue behind as it burns, and the better oils leave less... but still need the high level of detergency to keep the engine reasonably clean.

    The flash point of the oil is critical in providing performance gains in competition 2T's, but I doubt that it would have any benefit whatsoever in a modern 4T engine. The ratios at which you would be using the stuff would be 0.5% minimum to 2% absolute maximum, so not enough to provide a real, worthwhile gain in any case... even if it was hot-shot stuff like methanol. Also, the good stuff costs in excess of $25 per litre.

    Cheapest very good oil (JASO FD rated) is Castrol TSS ($25/L), cheapest every-day oil (JASO FC rated) is Valvoline 2T 'Racing' ($10/L). Both can be had at SuperCheap, as well as 'racing use only' Castrol R30 and A747. I have used both Castrol 2T 'Racing' & TSS in my strokers and found a difference in performance, but not one warranting the cost for road use. I have used JASO FC rated stuff in my Valiant at a ratio of 1 in 120 and found no real difference. May have run somewhat smoother, but this may have been the placebo effect. Regardless, it runs best on straight 95 octane Shell fuel - and this is an engine designed in the 1960's.

    Modern 2T oils are rated using the JASO F'X' series. FA was the original designation, no longer applied. FB is used to denote oils suitable for basic 2T hardware such as chainsaws, lawnmowers and whipper-snippers. FC has superior shear strength, lower flash point, and higher detergency. This means it protects better against wear, burns more easily, and keep the engine cleaner than FB rated oils. JASO FD rated oils have superior detergency and marginally better shear stength than FC rated, and are also likely to have a much lower flash point (~75'C). Usually only found on racing 2T oils costing in excess of $25 per litre.

    The summary? Unless you're running an Aprilia RS125/250 or similar, I would leave the 2T oil alone. Perhaps if you have a bike that you only ride once a week or less, then it'd be beneficial to use around 0.5~1% 2T oil in your fuel. Otherwise, there is very little point.

    Regards - boingk
  6. That's what I was thinking too...wouldn't reducing the octane rating by a substantial degree cause detonation before the spark? Precisely what you want to avoid for maximum efficiency?
  7. When we were racing the 125gp bike, we always used to dump the leftover race fuel into the car...

    smelled good,

    I'm guessing that the drop in octane rating caused by the 2T oil was more than compensated for by the fact that the fuel the oil was mixed with, being Elf 124 leaded....

    The only benefit I can think of was the additional "upper cylinder lubrication"
  8. Oh yeah, forgot to add that it'll destroy your catalytic converter and make a mess of your mufflers packing and baffling. The former one is illegal, the latter one will rob you of power.

    I don't think the oil reduces the octane rating, if anything it'd actually increase it as the oil is less volatile than fuel.

    - boingk
  9. I
    Trust me, it does. That's why a diesel will run very nicely on its own sump oil when the rings and valve guides get too worn. Potentially spectacular.

    Cat converters aren't a legal requirement on bikes in Oz btw (or weren't when I looked at the ADRs a few months ago). We only get them because other markets require them.

    But, as I edited my last post to mention, the links given seem to be talking about diesel engines, so any effect of oil on petrol motors is moot.
  10. They do seem to be talking about diesel engines, so here goes...

    No, thats because they're a compression-discharge ignition based engine. Yeah, those little CDi badges do mean something haha. The enormous compression ratios (15~20:1) heat the diesel to such a point that it will readily ignite and burn well enough to be used as a fuel. These very high compression ratios are also partly responsible for diesel engines relatively high torque and potentially very good fuel economy. Its also why you can run a diesel engine on vegetable oil (once warmed up).

    CAT converters may not be a legal requirement, but emissions standards are. If you are unfortunate enough to have to deal with the automotive emissions agency (or whatever its called) then you will find that out for yourself. A friend in town had to strip his pride and joy (WRX STi) to go and get the emissions testing done after getting defected. Even back to stock form it was mariginally over and caused him all sorts of grief.

    On octane ratings, they generally measure how hard a fuel is to ignite. The higher the number the more energy that particular fuel will withstand (in the form of heat and compression) before it ignites - ideally after being triggered by the spark from a spark plug. Its why low octane fuels will detonate or 'ping' in a high performance engine - they prematurely ignite due to heat & compression. Thus, a substance with a relatively low flammability will increase octane ratings when added to fuel.

    Cheers - boingk
  11. I repeat, the ADRs do not contain emissions standards applicable to bikes. All your mate had to do was unscrew two wheels and fit a bloody great gyroscope :wink:.

    As to octane ratings with an oil admixture, Rotax (among others) agree with me.
  12. Interesting stuff, cheers PatB. As for the mates car... I think he was doing stupid things with it. Never got the full story, but why else would he have been emissions checked?

    - boingk
  13. Well, maybe he was. Here in WA, it would be pretty much standard procedure, when pulling over a modded fast Jap, for the copper to have a look under the bonnet and write up a defect notice for anything that looked non-standard. Not necessarily fair or reasonable, but it's the way it is and it doesn't look like changing anytime soon.

    The ADRs applicable to bikes are interesting. When you look in detail, they're actually pretty sketchy. The only one that would really be a pain to meet for almost anything that could be regarded as safe to ride would be the noise regs. Everything else (brakes and lights basically) are really just common sense.
  14. Nice. So the emissions-strangled burden-beasts we get here are almmost purely because thats what the rest of the world (ie America) gets? Hmm... no wonder we can go nuts on the aftermarket scene then...

    As for our noise limit, its still only at 50% of the revolutions that maximum power is made at AFAIK. I don't know about you, but 94dB is a bloody loud noise to me, and to do that at not even half of redline seems a bit nuts... I mean, hell, how loud d'you wanna make a bike?

    On lights, if its pre-August '72, they only aneed a rear taillight that illuminates the plate, marks position in red at night, and illuminates further with application of rear brake. Throw in a headlight and you're ready to roll.

    - boingk
  15. Agree, but I suggest Red Bull.....
    After all, they are winning GP's.................. hehe
  16. Purrdy much. Most bikes sold globally aim to comply with the EURO3 and now EURO4 standard for emissions and noise.

    Most, anyway. I've got a great example, very close to my heart: Triumph Tiger 1050 comes with a catalytic converter and complies with EURO4 everywhere...

    .... everywhere except Australia and South Africa that is, where instead of a cat they've welded (welded!) an ordinary piece of stainless pipe where the cat is meant to be!

    Woe betide anyone caught behind the Tiger when its rider opens up the throttle. :p Mmmm, benzene, excess hydrocarbons and other nasty chemicals...
  17. ^ NICE! I now have a favourite motorcycle manufacturer. That is seriously awesome, sketchy and admirable. Go Triumph!

    Meanwhile, I'm still polluting the hell out of the place. What with my '80 Chrysler Valiant cage, and the GSX-1100 in my sig, I reckon the Pruis brigade would be right pissed with me. Still, apparently thats better than me buying a new car and bike, both of which would have to be newly manufactured & thus contributing an enormous amount of pollutants to the atmosphere before they even drive a solitary kilometer.

    Makes you think - boingk
  18. It's a while since I looked at the noise test specs, but ISTR that the 94dB is measured quite close to the exhaust outlet (0.5m rings a Bel but I could be wrong). As noise levels (or, more correctly, sound pressure level) reduce by 6dB for every doubling of distance, that might not translate to very much at all when you get up to ear level. It's not that I particularly want a loud bike, it's more that it might be hard to produce a compliant bike without hanging a muffler the size of a dustbin off the side of it, as many manufacturers appear to need to. But I don't know for sure 'cos I've never had to do it.

    I'm no organic chemist, but ISTR reading, round about the time unleaded petrol was coming into widespread use in the UK, that benzene goes straight through a catalytic converter anyway. Or am I suffering the effects of breathing good old leaded super?
  19. Standardised static test is at 45 degrees from exit of muffler at a distance of not more than 0.5m, pretty sure. There is a more complicated version for moving vehicles, can't remember exactly what it is. And yes, some of the mufflers out there don't look too crash hot... although some of them really do... Hmmm.

    - boingk