Hello from northern Canada

[cRiPpLe_rOoStEr]

Propane switches from liquid to vapour way faster than gasoline, but it's not the same as CNG which is mostly methane. Going leaner on propane is also not that easy as with CNG, due to different anti-knock indexes. I don't remember exact figures but, while propane has a lower AKI than regular gasoline, CNG fares better than ethanol regarding that.

[BlackGold6.4]

Originally Posted by cRiPpLe_rOoStEr

Propane switches from liquid to vapour way faster than gasoline, but it's not the same as CNG which is mostly methane. Going leaner on propane is also not that easy as with CNG, due to different anti-knock indexes. I don't remember exact figures but, while propane has a lower AKI than regular gasoline, CNG fares better than ethanol regarding that.

I remember them installing a vaporizer with different spark plugs and bunch of work but mostly saving huge on fuel because I was a courier driver back then. I wouldn't mind if you explained the difference between CNG and the others so it can clear the mud in my mind.

Thanks

[cRiPpLe_rOoStEr]

Originally Posted by BlackGold6.4

I remember them installing a vaporizer with different spark plugs and bunch of work but mostly saving huge on fuel because I was a courier driver back then.

There is no vaporizer for CNG, as it's already stored at vapor phase, yet often there is a pressure reducer because it's stored around 3000-3600 PSI, while propane is stored at a much lower pressure (which I don't remember right now but it's noticeably lower). However, while pressurized, propane is at liquid phase, so when it's either left to de-pressurize or heated (through a heat exchanger connected to the coolant circuit, after the vehicle having been started on gasoline) it switches to vapour phase.

I wouldn't mind if you explained the difference between CNG and the others so it can clear the mud in my mind.

CNG main component is methane.

[BlackGold6.4]

Originally Posted by cRiPpLe_rOoStEr

There is no vaporizer for CNG, as it's already stored at vapor phase, yet often there is a pressure reducer because it's stored around 3000-3600 PSI, while propane is stored at a much lower pressure (which I don't remember right now but it's noticeably lower). However, while pressurized, propane is at liquid phase, so when it's either left to de-pressurize or heated (through a heat exchanger connected to the coolant circuit, after the vehicle having been started on gasoline) it switches to vapour phase.




CNG main component is methane.

Ok .. I see, right on and thank you.

[cRiPpLe_rOoStEr]

Illegal LPG conversions actually used to be fairly common in my country, mostly relying on home LPG bottles and no vaporizer, yet the intake manifold would often freeze. The only car converted to use CNG (yet still capable of using gasoline) on which I saw the intake manifold freezing was a mid-'90s "baby Camry" Corolla which an uncle of mine used to own, with the 7A-FE engine. Such uncle used to claim cars older than '97 were better suited for a CNG conversion because they're not legally required to be fitted with an electronically-controlled (always more expensive) conversion kit, yet a multi-port CNG injection would've been better suited to the 4A-FE anyways...