Converting: Dedicated to Bi-Fuel

[Black Mariah]

What would it take to convert a dedicated CNG vehicle to Bi-fuel (CNG and Gasoline)?

(Please do not respond with: Just buy the bi-fuel version in the first place. I get that option, BUT that is not what my question is...)

Specific model / year I'm concerned with is a 2001 F150, dedicated CNG. Obviously, you would need a gasoline tank, fuel pump, and plumbing -- but what about the injectors, computer, etc?

I would imagine the computer and injectors could be swapped from an F150 bifuel truck, but is the engine optimized in the dedicated CNG version in any way for CNG (e.g. different compression ratio), such that it would not convert well to also running gasoline?

Are the engine sensors and emissions control equipment (other than the computer program) identical between the dedicated CNG and the Bifuel models?

Has anyone ever done this?

(Please do not respond with: Just buy the bi-fuel version in the first place. I get that option, BUT that is not what my question is...)

[Surfdancer]

Re: Converting: Dedicated to Bi-Fuel

The dedicated 5.4L does have a higher compression ratio. I'm sure you could tune it to run some very high octane stuff (Sunoco race gas, etc), but it may be marginal on 93 octane premium.

The CNG fuel injectors are too big for gasoline. You would have to add a second set, along with a gasoline fuel rail (including the backpressure regulator and tank return line).

Of course, there is the programming in the EEC. It's mapped for CNG, and you would probably have to have a second gasoline EEC override it with a program suitable for a high compression gasoline engine.

It may be less costly to swap the engine and EEC if / when you add the gasoline tank, then use a bi-fuel kit.

In the end, it may not be a cost effective changeover.

[CNG MOTORS]

Re: Converting: Dedicated to Bi-Fuel

It is more costly to go this route than to start with a gasoline engine. You will pay more for a converion this way than you would starting with a gas vehicle. More components are needed this way