| Author | Message | ||
     Dre99gsx |
for the 1125r, which will allow good power w/o knocking to hell? | ||
| Interex2050 |
This depends on many variables including: -ambient temperature -riding style -region of country (Republik of Kalifornia has poo gas) -engine setup (timing, compression, etc.) The safest way to find out is to run low on gas and then put a gallon or so of the lowest octane gasoline and ride... If it pings fill the rest of the tank with highest octane gasoline. If pinging occurs repeat with the middle "grade"... And if that pings too I guess the highest grade is the one to use, unless you want to get really spiffy and mix your own octane mix. My guess would be that since this is a liquid cooled engine (albeit a hot running one) you can run the lowest octane. (Message edited by interex2050 on April 16, 2008) | ||
| P_squared |
Owner's manual says use 91 (95 RON). I get 93 at the pumps here in TX. No pinging, and I won't use less than 91 unless I'm out of gas and have no other choice. YMMV. | ||
| Zac4mac |
Engine: Helicon 4-stroke 72° V-Twin Cylinders 2 Bore 4.055 in. (103.00 mm) Stroke 2.658 in. (67.50 mm) Displacement 68.7 CI (1125 cc) Compression Ratio 12.3:1 I wouldn't put low grade in that, but that's me. Z | ||
| Kravfighter |
Is 95 to high to run in it? | ||
| Interex2050 |
Rant: on I would really like to make it clear... Higher octane is NOT better!!!! The only reason one would want to run a higher octane fuel is to stop auto-ignition (pinging; fuel igniting before the spark) Higher octane gas is not "super", or "high power", or cleaner for that matter One gets the best combustion with the lowest possible octane rating before pinging occurs. So you want to go as low as possible. Not to mention its cheaper too. Rant: off | ||
| P_squared |
Interex2050, not arguing with you. I'm just stating what's in the manual & my personal preferences based upon where I live and what is readily available to me at the pumps. I see no need to run higher than 93, and I see no need to run lower than 91 if I can help it. For the next 2 years, it's a pretty safe bet I'll do exactly as prescribed in the owner's manual, so that if I do have a problem, it's covered under warranty. So, keeping with the owner's manual, 91 is recommended. If an owner chooses to use another rated (higher or lower), that's their decision. | ||
| Interex2050 |
P_squared, My rant was not directed toward you, no worries And your rational is perfectly valid its just frustrating that most people think that using higher octane will add 10000000HP to their engine Or that its cleaner etc... | ||
| P_squared |
You mean to tell me that throwing 107 race gas in the bike at the track doesn't help?!?!?!?!?!  | ||
| Sheridan_bueller |
Maybe, to explain 'octane rating' would be appropriate; Wikipedia: The octane rating is a measure of the autoignition resistance of gasoline and other fuels used in spark-ignition internal combustion engines. It is a measure of anti-detonation of a gasoline or fuel. That being explained, Interex's rant is spot on. The manual, like any manual, is written to the non mechanical persons, (for lack of a more blunt stereotype) to cover all of the variables of understanding available. that's my 2 cents JJ | ||
| Wademan |
Actually running higher octane gas will greatly improve the ability to make power IF ignition timing, compression ratio, cam profiles etc.. are adjusted. But higher octane gas without an adjustment to timing and the others will actually decrease the power output of the engine. So internex is right, and wrong. | ||
| P_squared |
JJ said it best "...The manual, like any manual, is written to the non mechanical persons, (for lack of a more blunt stereotype) to cover all of the variables of understanding available." Depending on a list of variables that we could all contribute to (e.g. Altitude, engine mods, ambient temp., drag vs. road vs. track, etc., etc., etc) would yield multiple results for the "best" octane based upon the scenario. There are different octane ratings and recommendations for reasons. If you don't understand those reasons and choose to deviate from the recommendations, be prepared for anything from "no problem" to "OH $h!t!" responses from your bike. BTW, this thread is making me think of trying to sell race gas to the squids at the track for profit on trackdays, since there's no onsite gas there anyways. "You'll get 10000000HP+ using this 107 on your stock IL4 600. Only $10 for 4 ozs."  | ||
| Odinbueller |
Actually, the octane rating "determines how much the fuel can be compressed before it spontaneously ignites". The higher the octane rating, the higher you can compress it on the squeeze stroke without pre-ignition, which is pretty bad for the motor. Stick with the recommended 91 octane or higher recommendation in the owner's manual, but don't go above 100 octane, as you'll be running a leaded gas that will destroy your O2 sensors. Just in case you're at a track day with a Sunoco pump and a credit card reader  Chris | ||
| Diablo1 |
But higher octane gas without an adjustment to timing and the others will actually decrease the power output of the engine. I have trouble believing this statement without any evidence. I have never seen any "good data" demonstrating a power loss switching from a low octane pump gas to 93 octane pump gas. The refiners go to great lengths to make sure the flame speed and BTU content doesn't change with octane, so you'll have to show me the reasons why }this is possible.} | ||
| Kravfighter |
You guys are obviously smarter than I on this subject, can you tell me what effect octane levels have on gas mileage. It seems like with my XB I got better mileage with 92 octane. | ||
| Interex2050 |
Wademan, Good point that I failed to mention. Diablo, I believe the reason has to do with, reaction activation energy... A lower octane fuel is "super" energized from the compression stroke and so the instant there is a spark the combustion begins. On the other hand, a higher octane fuel is less energized (with respect to the activation energy of combustion), so in turn combustion is delayed. Gas mileage eh... I will have to sleep on that one, hope to provide an answer shortly | ||
| Cutty72 |
From a very good source, thanks Chris. Generic vs Branded gas. Like the old saying "don't buy gas from a gas station that doesn't hold the name of the refinery". The gas it self is the same UNTIL it is put into the semi truck to be hauled to the gas station. What happens is that the actual gas gets a additive injected into while it fills the semi. This is where the differences start. Generic is gas such as Speedway, KMart, Wal Mart, Sams, Admiral, Clark, Rich, Meijer, and many others that aren't list in the next list. The generic gas comes from Mobil, and Marathon gas tank terminals but again changes with the additives. BRANDED is Mobil, Marathon, BP (use to be Amoco), Sunoco, Shell. Side note, there use to be BP & Amoco. BP (British Petrl) bought Amoco (American Oil Company). The govt says that all these oil companies have to add "additives". The additives have different chemicals but mostly the same. The additives contain fuel milage enhancers, cleaners, evironmental crap and other good shit that your motor likes. The cleaners are good for your motor, duh! However, if the govt says you must inject "1" (I don't mean 1 additive I mean just 1 as a unit)that's all the generic gas' gets. However, the Branded gas inject 3 times that amount. This is to ensure that their gas performs better than the generic gas. HERE'S WHERE THE GAS STARTS GETTING MORE DIFFERENT. Branded GAS + 3 additive (sometimes ehtynol and becoming more normal) = Good GAS Then you have GAS + 1 additive(generic) + ethynol = generic gas. Which brings us to ethynol. This is something that the govt is pushing onto the oil companies. It is acholhol. The oil company such as Marathon gets a BIG tax break for using it in their generic gas. They get a tax break at the tank terminal, and the gas station. Here's the incentive for using it. It helps the gas burn MORE therefor cleaner. Cleaner means better for the tree huggers. Now they don't inj. ethynol into the branded gas. Now cleaner burn also means cleaner gas tank. Just think about it, you can clean stuff with acholhol. When the semi's are hauling all branded gas they get a type of "non-luster" to the inside of their trailers. Then they haul some ethynol inj. gas and from driving down the road (splish splash) gets the inside of the trailer all clean. Now we have all heard of these guys saying, I put that ethynol injected crap gas into my "car/truck/bike" and it •••••• it up. The problem is that the ethynol has cleaned out the gas tank and all that crud and crap has crapped up their gas filter and maybe injectors. You also may hear about it drying out o-rings and such. I try to use it everyonce and a while to keep everything clean and shinny but not all time. Bottom line.... Generic gas gives you less good stuff plus ethynol. Branded gas gives you 3 times good stuff and no ethynol (harder to find with no ethynol) Now to understand what happens with octane now. NOW that the ehtynol has become almost completely involved... So now there isn't even really standard 87, or 93. There was never 89. 89 is blended at the pump (where you fill up) with 87 & 93 to make the 87. But with the ethynol being in almost every gallon now a days. The ethynol is 103 octane... so that will raise the octane of the product. So now your gas is blended at the tank farm as it goes into the semi trailer tanker. For example... our 93 octane Ethynol 10% of 103 octane = 11.3 93 octane product is 74% of the liquid = 68.82 85 octane product is 16% of the liquid = 13.6 ============================== 93.72 octane or what you get at the pump | ||
| Zac4mac |
Nice story, but all gas here in Colorado has Ethanol in it. Not a bad thing, I can't remember the last time I had a fuel line freeze up in the winter. Gas is good. Ethanol is good. You can drink it too. Methanol is bad. You can drink it, but you'll go blind. MTBE is BAAAAAD. Zack | ||
| Diablo1 |
Wademan, Good point that I failed to mention. Diablo, I believe the reason has to do with, reaction activation energy... A lower octane fuel is "super" energized from the compression stroke and so the instant there is a spark the combustion begins. On the other hand, a higher octane fuel is less energized (with respect to the activation energy of combustion), so in turn combustion is delayed. I never heard of that one before, so I'm a doubting Thomas. I have actually compared the effect of changing octane from 87 to 105 on the same engine in back to back runs. The only change was the fuel. Guess what? Absolutely zero effect on power. No increase and no decrease. 87 octane was enough to prevent detonation, so the higher octane did nothing (good or bad). The test wasn't with a Buell motor, but that doesn't make the data bad.} | ||
| Slypiranna |
Manual...ah, manual...read the manual. ...this IS NOT rocket science. ...this engine does have 12+:1 CR & operates at temps up to 229' F! ...I think high test pump minimums would seem safe in a daily driver with a LITTLE alky in ok...as written in your owners manual? Do you all think that the engine design team overlooked your all's locals in the world and the available fuels therein? AND DO NOT base this thread on the DRAG race thread that used lower octane fuel for a 1/4 mile all out pass(es)...that is a completely different scenario compared to the wide range of operation governing a daily driver. So who's flyin' to the moon tomorrow?...can I go? |
