| Author |
Message |
    
Etennuly
| | Posted on Sunday, January 13, 2008 - 02:11 pm: | 
|
Higher octane fuels do make more power. I was at a school on Champion Spark plugs many years back when an expert explained it. This is from my rusted memory, the same amount of fuel enters the combustion chamber, be it 85 octane or 105 octane. The higher octane burns longer, there by making the explosion last longer as the piston is "pushed" further down the cylinder, thus in actuality making more power.
He showed us how this longer burn works with a flame in a glass tube. The low octane gas burned, in a double open ended glass tube, in an instant flash out both ends. The high octane gas burned slowly and more purposefully further down the tube.
My experience with racing fuels has made a believer of me in the power differences. Perhaps one of you dyno gurus could put a bike on a dyno to do a regular vs. premium shoot out. I'd bet a racing gas would have about 5% more power over a 83-85 octane. |
1324
| | Posted on Sunday, January 13, 2008 - 02:35 pm: |
|
Eeek, I didn't mean to add fuel to the fire (no pun intended), so I'll jump on Saintly's cue and apologize if I also came across as confrontational. I only post based on my experiences, nothing more nothing less.
I've lived in Pennsylvania, Texas, New York, and worked in New Jersey. I've had the same experience in all four states (and countless others I've traveled through). A good example was this gas station near where I lived in Bangor, PA. It was an automated membership only gas station with no attendants. After you activated the pump by inputing your PIN, you could pump gas. The secret for them to ensure no one stole gas was to use the automatic pump feature to shut the valves off. So, when you pumped a full tank and the nozzle stopped, a valve in the pump closed. However, you were able to 'purge' the line by continuing to pump after the nozzle originally stopped. I routinely extracted about 1 gallon from the line by doing this. After the line was empty, the gas stopped flowing. If you then made another transaction to pump more gas, say for my wife's car or a can of gas, the gas would take a second to flow indicating that the gas had to refill the lines.
I did a couple quick calculations a few months ago (based on some rough estimates/assumptions), and I found that regular unleaded gas could only drop my octane vaule by almost a point for my Buell. For my WRX, the difference was negligible at best. So, for the average rider/engine, the drop isn't substantial. YMMV.
As far as my other comment about not using leaded gasolines on VEHICLES (Buells, cars, trucks, boats, ATV's, whatever) with catalytic converters and/or O2 sensors, I stick by it. I'll respectfully ignore Buell's owner manual because I know first hand what leaded fuel does to O2 sensors over time. Leaded fuels were great for engine technology back in the 50s-70s (mainly valvetrain), but they truly aren't needed in most modern engines. For (somewhat) good reading on O2 sensors, read this: http://en.wikipedia.org/wiki/Oxygen_sensor
Nearly all O2 sensor manufacturers will advise against using leaded fuels, so I personally will not use any in my Buell...even though it doesn't have a cat. |
Pwnzor
| | Posted on Sunday, January 13, 2008 - 02:51 pm: |
|
as if to imply that it is the only one in which this has ever occurred.
Didn't intend to sound that way.
you have encountered pumps with fuel in the hose before pump activation on a few occasions.
Indeed, I have had a hose dump gas all over my bike before pulling the trigger. This is why, now, I point the hose at the ground for about 3 seconds before I put it near any vehicle. About 1/3 of the times I do, I am rewarded with a splash of fuel on the ground at my feet.
YOU said:
If you don't get at least 2 quarts of whatever was in that hose last, then you're in an alternate reality.
Let's be realistic here, that's half a gallon. I believe you are exaggerating here, or mistaken. I'm not being confrontational, just as I believe you were not being confrontational previously.
You also said:
I can't tell you how many times me & my co-workers would go there after closing with a 5 gallon can, and "purge" all 12 hoses.
I could practically fill my bikes tank on what we would obtain from that.
If you could really fill your tank from the remnants of fuel in only 12 hoses, I contend that your tank holds less than a gallon, closer to half a gallon. The most I've ever seen come from a hose is maybe 4 ounces. If that. It seems like a lot, because when it's all over your car or your work clothes or shoes, you tend to get a bit pissed off, having just been pissed on by petroleum products.
Either way, there is not supposed to be ANY fuel in the line, there is supposed to be a system in place to clear the line after the pump shuts itself off, and this system is what will suck gas back down the hose into the reservoir after you have paid for it, which is why you are not supposed to top off your tank.
Again, this is non-confrontational banter. Merely shedding some light. |
Ducxl
| | Posted on Sunday, January 13, 2008 - 03:02 pm: |
|
This other thing for which you guys speak of happened noticeably to me once last summer.I forget where but,remember it well.After the pre-paid value expired the pump shut off.I was first attempting to let the last few drops dribble before removing the nozzle but,squeezed it and,i had a very little stream coming out.I held it for almost a minute before i couldn't accept anymore.I was half expecting someone to come out crying foul at my seemingly stealing more fuel than i'd paid for.
Defective/poorly maintained pumps? |
Ironken
| | Posted on Sunday, January 13, 2008 - 03:30 pm: |
|
Higher octane fuels do make more power. I was at a school on Champion Spark plugs many years back when an expert explained it. This is from my rusted memory, the same amount of fuel enters the combustion chamber, be it 85 octane or 105 octane. The higher octane burns longer, there by making the explosion last longer as the piston is "pushed" further down the cylinder, thus in actuality making more power.
He showed us how this longer burn works with a flame in a glass tube. The low octane gas burned, in a double open ended glass tube, in an instant flash out both ends. The high octane gas burned slowly and more purposefully further down the tube.
My experience with racing fuels has made a believer of me in the power differences. Perhaps one of you dyno gurus could put a bike on a dyno to do a regular vs. premium shoot out. I'd bet a racing gas would have about 5% more power over a 83-85 octane.
I've always thought that to fully realize the benefit of race gas (high oct.) you must have the compression to utilize this, you raise a good point though and are making me think a little.....what kinda backs up your rationalle are diesels.....part of the advantage of diesels are that instead of one quick combustion event around TDC is the characteristic of diesel that allows it to have a long combustion event through the power stroke.....hmmmmm |
Etennuly
| | Posted on Sunday, January 13, 2008 - 07:20 pm: |
|
To be sure the power gain is noticeable with no tuning, but if you tune an engine to run on 105 octane(timing/jetting) it can realize quite a bit more power. And if you build an engine to run on it even more so. |
Neurorider
| | Posted on Sunday, January 13, 2008 - 08:29 pm: |
|
Hi Guys-just thought I would chime in with a thought and a question about octane: In an EFI bike with electronic ignition, doesn't the bike retard it's ignition if pre-ignition or pinging start? Doesn't the O2 sensor cause a change in the ignition or injection if the engine is not finished burning the fuel? My point is, if either of these are true, then higher octane fuel would allow the motor to max-out its settings and produce a bit more power (to a point, not sure how much) and lousy octane fuel would cause it to run a bit more conservatively, compromising some power. However, I'm not sure if that assumption is accurate on Buells because I'm not sure which of the engine control parameters are set by the fuel mapping and which are variable based on combustion. Anyone here know enough about FI to answer that? I'm stayin' out of the whole gas pump thing  except to say that a couple of times very late at night that extra splash out of a hose, after a station is closed, is enough to get home on! But, that was probably 25 years ago too, before I learned to plan better...
doc in Arkansas |
1324
| | Posted on Sunday, January 13, 2008 - 09:32 pm: |
|
Hi Guys-just thought I would chime in with a thought and a question about octane: In an EFI bike with electronic ignition, doesn't the bike retard it's ignition if pre-ignition or pinging start? Doesn't the O2 sensor cause a change in the ignition or injection if the engine is not finished burning the fuel?
The only way to truly monitor detonation is to employ a knock sensor. Someone correct me if I'm wrong, but to the best of my knowledge, Buell doesn't use knock sensors on any of its bikes (maybe the new 1125r?). Automobile engines use knock sensors, but they are only possible because extensive time and engineering effort goes into balancing NVH. In other words, the engine's block, head(s), cranktrain, valvetrain, etc. need to be optimized in such a way that no resonances occur around the detonation resonance frequency (4000-6000 Hz for many engines I know of, but I'm sure they vary even more). The basic design of all air cooled Buell/HD engines is so old, that NVH was hardly a concern and thus, no knock sensor is employed.
The O2 sensor on the other hand, is essentially how the ECU knows if combustion is rich or lean; our Buells use a narrowband O2 sensor to do this. |
Old_man
| | Posted on Sunday, January 13, 2008 - 10:28 pm: |
|
I would have to see dyno results.
A bike that runs on regular tested with regular gas.
The same bike on premium.
I doubt that there would be much difference. |
Clutchless
| | Posted on Sunday, January 13, 2008 - 11:24 pm: |
|
The only advatange I have noticed with premium is better gas milage. |
Acejay
| | Posted on Thursday, January 17, 2008 - 10:02 am: |
|
hey i'm not any kind of expert, but i didn't think that higher octane fuel on its own will make more horsepower. what is does allow you to do is run more timing and higher compression without detonation, and therefore make more power.
thats why leaded fuel cars made plenty of power as they were higher octane, and when unleaded came in power dropped like crazy.
i always run my bike on 98 octane (you call this 95 in the US i think), because it pings like crazy on the lower octane petrol.
the v8 in my car is does not have a knock sensor and was built to run on 91, and if it makes any more power on 98 over 91, i'm buggered if i can tell the difference. Certainly it can be tuned to run on 98 and this will squeeze some more out, but not that much really on its standard comp ratio. |
|
