What's the secret to better gas mileage? By jster (Read 3,045 times)

[go4it]

Higher octane serves one purpose and one purpose only.......To reduce preignition commonly known as ping. The higher the compression ratio the hotter the burn. The hotter the burn the easier (faster) the ignition. This causes the preignition in higher compression engine. By increasing the octain it increases the ignition temp of the fuel avoiding the preignition or ping.

There is no question the Chinese use a different method for calculating the octane level of a fuel. As I remember their 90 octane is equal to the US 87 octane. In a car you ca neasily test for the lowest octane your car can safely use. Listen for the ping. No ping under heavy load no problem. But with scoots and cycles it's not quite that easy because you may not hear the ping. But when I had my 54B it loved running on 87 octane and gave me a true 60 to 65 MPG. Which as I indicated MPG has nothing to do with the octane rating. And with only 625 miles on it when I crashed it it wasn't even broken in yet. So I would assume it would have improved. I just bought a CF Moto V5 that most people claim to get 70 to 75mpg. I'm hopping for the best. Bob

[go4it]

Aug 31, 2011 23:08:17 GMT -6 neallyb said:

For instance - my friend filled up his SUV in Austin with ethanol flavored gas and drove to Oklahoma CIty. It took 1 1/2 tank of gas. Because real gas was available in OK - he filled up with real gas in OK and drove home -- it only took 1 tank to get back with the real gas.

I'm sure yet, but that sounds like a substantial increase in efficiency.

Botton line if you can't get it what's the difference?

The proper way to adjust the carb is to set the idle at the rated speed say 1800rpm when the engine is fully warmed. Now turn off the motor and turn in the HS screw to full colsed (CCW). Then reopen it to 2 full turns from the seat (CW). Now restart the motor and slowly continue to turn the HS screw 1/8 turn at a time until the motor reaches it's max speed. If needed during this process re-ajust the idle as needed (will likely require a few idle adjustments). When you reach the max speed while adjusting the HS screw you have the correct HS adjustment. Now readjust the idle to spec. and your good to go. And never mind those burns they will heal...LOL

Increased octane is to reduce pre-ignition only. It does not improve fuel eff or power. Higher compression motors require it because the higher the compression the higher the burn. This causes lower octane to ingite to quickly causing per-ignition (PING). In a car or truck you can hear the ping under load. This is a good sign to use a higher octane fuel. With a scooter or motorcycle you may not be able to hear the ping. Personally I always ran 87 octane in my Roketa 250 54B and it was very happy and I got 60 to 65mpg.

Bob