Bi-Fuel CNG
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Joined: Apr 2006
Posts: 18
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CNG conversions are very straightforward and are very much like propane conversions. Multi-port EFI engines are best converted with injection conversions rather than ancient fumigation systems. In states like OK and UT, CNG makes a lot of sense and can have a very quick payback, especially if you're on the road a lot. If you're not near a public CNG station, you can put in your own VRA but this gets a bit pricey and compressor maintenance can be expensive. See CNG Fueling.
Common injection conversions are the Impco Sequent, Prins VSI, and the Technocarb SVIS. I'm not sure about the price of the VSI and Sequent systems but the 8-cylinder CNG ESIP underhood parts package costs $1,685.41 but newer E85 vehicles are bit more expensive as they require a few more components. You will need a CNG conversion shop to provide the CNG cylinder(s), run the fuel lines, and do the inspection so that the work meets NFPA 52. CNG cylinders are permanently-mounted and are not designed to be removed. If you need the bed-space, you can mount the cylinders underbody in place of the spare tire.
Enbridge here in Ontario uses the ±5% rule of thumb on CNG fuel economy. That is, a CNG conversion will get about 95-105% of a vehicle's gasoline economy in terms of GGE of CNG. As a worst case, you can use 90% of the vehicle's gasoline economy. Also, CNG is often advertised in GGE but sold by the lb (measured with a mass-flow meter) at CNG stations rather than by volume.
Common injection conversions are the Impco Sequent, Prins VSI, and the Technocarb SVIS. I'm not sure about the price of the VSI and Sequent systems but the 8-cylinder CNG ESIP underhood parts package costs $1,685.41 but newer E85 vehicles are bit more expensive as they require a few more components. You will need a CNG conversion shop to provide the CNG cylinder(s), run the fuel lines, and do the inspection so that the work meets NFPA 52. CNG cylinders are permanently-mounted and are not designed to be removed. If you need the bed-space, you can mount the cylinders underbody in place of the spare tire.
Enbridge here in Ontario uses the ±5% rule of thumb on CNG fuel economy. That is, a CNG conversion will get about 95-105% of a vehicle's gasoline economy in terms of GGE of CNG. As a worst case, you can use 90% of the vehicle's gasoline economy. Also, CNG is often advertised in GGE but sold by the lb (measured with a mass-flow meter) at CNG stations rather than by volume.
Last edited by fraso; Dec 22, 2016 at 10:05 PM. Reason: Link Update
It's been a while since the last post but I figured I'd revive this rather than start a new thread.
I have a 2005 F150 5.4L with a VSI-CNG system installed by CNG Interstate here in St. George, Ut. I believe they've left Utah since installing mine, but they have another location in Oklahoma City. Anyway my truck runs like crap on CNG and we've taken it back to them no less than three times trying to get them to fix it. I'm trying to find out if they just don't know what they're doing. They said there is something on the 5.4 I guess forcing them to put the injectors in a different location.
Has anyone else gotten a CNG kit on the 04-10's with the 5.4L, or am I the only one?
I have a 2005 F150 5.4L with a VSI-CNG system installed by CNG Interstate here in St. George, Ut. I believe they've left Utah since installing mine, but they have another location in Oklahoma City. Anyway my truck runs like crap on CNG and we've taken it back to them no less than three times trying to get them to fix it. I'm trying to find out if they just don't know what they're doing. They said there is something on the 5.4 I guess forcing them to put the injectors in a different location.
Has anyone else gotten a CNG kit on the 04-10's with the 5.4L, or am I the only one?