Hawk 250cc fuel type?

franque · 11-13-2021, 01:16 PM

If it's pinging (US term, pinking is UK + Commonwealth), it's probably running too lean, have you rejetted it?

Also, E3 plugs are a scam, and if you think running premium in a 9:1 air-cooled motor is a good idea, or even makes a whit of difference in mpg, in particular an improvement in consumption, I've got a bridge for sale.

If you look at what octane ratings mean, you've actually got less BTUs per fixed volume with higher octane gas, so unless we're talking about a car with a knock sensor that pulls so much timing that it needs aggressive application of the throttle for normal use, there's virtually no difference, with maybe a slight edge to lower octane fuel, in fuel consumption. In that scenario, you would only see a difference if the engine had enough load on it to be at or near WOT and spending more time there due to the loss of power. Otherwise it's purely psychological, especially in a carbureted TBR7.

11-13-2021, 01:16 PM	#17
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	If it's pinging (US term, pinking is UK + Commonwealth), it's probably running too lean, have you rejetted it? Also, E3 plugs are a scam, and if you think running premium in a 9:1 air-cooled motor is a good idea, or even makes a whit of difference in mpg, in particular an improvement in consumption, I've got a bridge for sale. If you look at what octane ratings mean, you've actually got less BTUs per fixed volume with higher octane gas, so unless we're talking about a car with a knock sensor that pulls so much timing that it needs aggressive application of the throttle for normal use, there's virtually no difference, with maybe a slight edge to lower octane fuel, in fuel consumption. In that scenario, you would only see a difference if the engine had enough load on it to be at or near WOT and spending more time there due to the loss of power. Otherwise it's purely psychological, especially in a carbureted TBR7.
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