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Post by prodigit on Jul 22, 2012 13:29:42 GMT -5
Should I get premium or regular?
Specs:
Single Cylinder, 4-Stroke, SOHC / 257cc
Cooling System Water Cooled
Bore X Stroke 70.00 X 66.80mm
Compression Ratio 10.00 : 1
Horse Power 14.75HP
Top Speed 85.00mph
Max Torque 13.00
Ignition Type C.D.I.
Starter System Electronic Ignition
Engine Oil SAE10W-40
Lubrication Wet Sump
Transmission Fully Automatic CVT / Chain Drive
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Post by derbi on Jul 22, 2012 13:36:35 GMT -5
Use the octane that allows the scooter to run with out detonation or knocking, for higher compression engines use the higher octanes.
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Post by prodigit on Jul 22, 2012 15:16:37 GMT -5
It has an EFI, so I suppose it won't knock with regular gas?
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Post by derbi on Jul 22, 2012 17:53:07 GMT -5
It has an EFI, so I suppose it won't knock with regular gas? Not true, My2011 PCX has EFI and a 11.0:1 compression ratio anything under 93 and my scooter knocks. i never use the lower octane fuels. |
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Post by greg on Jul 22, 2012 19:50:10 GMT -5
use gas with no ethanol if you have that option in your area. octane lvl is probably less important.
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Post by prodigit on Jul 22, 2012 21:27:37 GMT -5
I've done some reading on the topic, and think the compression ratio plays an important role in choosing the right gasoline! My compression ratio is 10:1. Combined with altitude (the higher you are,the lower the grade of fuel),and engine temperature. My engine is water-cooled instead of air-cooled, so it should also handle lower grade gasoline. Also, I've noted that the HP rating for my bike is considerably lower than other bikes (14,xHP (260cc) vs 18+HP on other bikes (250cc), which make me believe it could have something to do with a different type of gasoline). In US, usually 93 = high grade 89-91 = mid grade 87 = low grade I found this on wikipedia: "Recently, with the addition of variable valve timing and knock sensors to delay ignition timing, it is possible to manufacture gasoline engines with compression ratios of over 11:1 that can use 87 (MON + RON)/2 (octane rating) fuel." also: Motorcycle racing engines can use compression ratios as high as 14:1, and it is not uncommon to find motorcycles with compression ratios above 12.0:1 designed for 86 or 87 octane fuel Another quotethey ALL recommended staying below 11:1 on pump gas. one even said below 10:1 lol! Most websites I've seen, all say that 12:1 compression ratio is pretty high, and most of the time require premium grade gasoline (93). Also the higher you're up in the air, the lower the octane rating can be. Unfortunately I live at near to sea levels. So 12:1 is normal to have high grade fuel. another quote from this site said: Generally, engines with compression ratios of 9.3 : 1 or less will safely operate with unleaded 87 octane fuel. This website describes what pinging is, and the pinging sound. It seems to happen when accelerating or going uphill (in other words when the motor is taxed). I generally don't expect to tax the motor very hard, so another one in favor of lower grade fuel... Regular fuel might be borderline, but high grade might be too much (perhaps ok for run in). I think I'll go with mid-grade fuel. |
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Post by wile on Jul 22, 2012 21:33:52 GMT -5
Good choice, 89 is fine, 93 burns at a slower rate needed with high compression motors. The scoots are NOT high compression motors unless of course you had it built for raceing.
Wile
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Post by prodigit on Aug 4, 2012 2:12:38 GMT -5
ok, manual states 90 or higher for the 2012 EFI model, mid grade is only 89. I will go with premium (91 to 93). It seems fuel can give the edge when racing at 80+ MPH. So far with ~91 I can get 82MPH. I have the impression this bike will be able to go 85MPH with some minor tuning and best fuel.
I was thinking,
any idea how I could harvest the wind (when driving) to increase pressure on the air intake? Would be nice if my performance could be increased by having an air intake that scoops up the air, and causes a high pressure field in the air filter. If there was some way to do that, the performance could increase a bit...
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