I'm new to the CNG world and this forum.

I have a 2001 Crown Vic I recently bought that does exceptionally well on fuel mileage [26+ hiway]. The factory says it should only get around 19 hiway. I did 2 things that helped. I replaced the air filter box with a K&N box and cone filter. Then I converted the single exhaust to dual. Very simple since the car already has dual cats. Just add the other side with a crossover and additional muffler. This also adds a slight boost in power.

Now to my question. In order to accurately keep a mileage record, I assume I should fill up at the same station with the same pressure. Even then the pressure isn't always consistant. If the pressure differs by much I won't get as much fuel thereby getting an inaccurate measure of mileage. Does anyone know the ratio of GGE's to pressure? In other words, if I fill up at 3400 lbs one time then 3000 lbs the next, what's the differene in volume? [per 100 lbs or whatever]

Thanks

I have a 2001 Crown Vic I recently bought that does exceptionally well on fuel mileage [26+ hiway]. The factory says it should only get around 19 hiway. I did 2 things that helped. I replaced the air filter box with a K&N box and cone filter. Then I converted the single exhaust to dual. Very simple since the car already has dual cats. Just add the other side with a crossover and additional muffler. This also adds a slight boost in power.

Now to my question. In order to accurately keep a mileage record, I assume I should fill up at the same station with the same pressure. Even then the pressure isn't always consistant. If the pressure differs by much I won't get as much fuel thereby getting an inaccurate measure of mileage. Does anyone know the ratio of GGE's to pressure? In other words, if I fill up at 3400 lbs one time then 3000 lbs the next, what's the differene in volume? [per 100 lbs or whatever]

Thanks

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