I don't think it is taxed - yet. I read somewhere the equiv $/gallon is about 2.15 at the moment.
30% less volumetric efficiency does not translate directly into its volume in the tank, its the volumetric efficiency of the engine for the fuels. Its hard to explain, but you do need more CNG to get the same power you get from gasoline, but the method of getting the CNG in the engine and how long that takes is pretty important. Remember, horsepower is calculated (not measured) by integrating the torque curve with regards to time. There is an approximate formula to go from torque to HP, but i am wandering here.
The octane value of CNG is about 130. You can get back a lot of the lost power by forced breathing. You sure won't detonate at 130 octane.
Also, to the other poster mentioning having a dual fuel setup, there are issues there. The main one is having to have 2 fuel tanks. Say goodbye to your trunk. If you have a CNG only vehicle, you can replace the gasoline tank with the CNG tank under the car.
The other big issue is you need to tune the engine for the fuel you are running to get the maximum efficiency. To run dual fuels you have to compromise on the engine settings, so neither fuel will run optimally. I am guessing you would need to reprogram for the CNG, not sure how that is done or if every car can be easily modified.
I am contemplating a CNG conversion on a 108 car. The car is < $2000 so I don't care what the CNG kit costs. My holdup has been trying to find a fuel station. The home compressors are expensive (around $3k).
Fred
Quote:
Originally Posted by Botnst
The empty tank heavier, the fuel lighter but requiring 30% greater volume to get the same miles/tank? So the tank must be larger to accommodate the the reduced efficiency adding more weight?
Does natural gas cost 30% less? Is it subject to the automobile fuel taxes?
I dunno.
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