Ok I have already done a search and found some interesting information on this. I have an H22A in my 98 Civic CX, and plan on staying all motor. I am very interested in going either propane or alcohol, or water injection. From what I understand water injection uses up precious combustion chamber volume. It tends to work very well for boosted applications but theoretically it wont work too well for NA. Ok now down to alcohol injection. Now alcohol from what I read corrodes the engine. Quite fast from what I read. Personally I plan on trying to get an engine to last about 50,000 miles or so maybe more (this is just a rough guess or so). So alcohol injection doesnt seem like the way to go for me. Now obviously that leave the propane injection issue. I have heard that it puts your octane about 105 ish. What type of compression on a NA engine will this push? Also how to control the propane injector, how to meter it. Would propane need to be injected if u have say a 13.5 to 1 H22A with a stage 3 Crower cam (or around that duration, maybe larger), after the VTEC crossover point? Obviously the engine would need it at lower RPM's cuz of the lower over lap, and timing. So would the engine need it in the higher RPM's with 93 octane fuel? Obviously I would have to have two set fuel maps for this application. When I am on, and off propane. For short trips when I want to turn off the propane, could 93 octane run a 13.5 to 1 engine with some timing retarding, and proper fuel map? Also lets say I ran propane all the time. How long are we talking b4 I would have to refill on an engine running at 13.5 to 1 (granted I understand the size of the tank matters here but a rough estimate is all I am asking for)? Any advice from the experts here would be great. BTW has anyone successfully done this yet on an all-motor build??

 

come on guys! Anyone? Experts where are u?

 

I have never heard of propane used in high-performance engines, but what do i know . But try this link https://honda-tech.com/zerothread?id=721279, don't know if it will help.I would be intetested if <U>anyone</U> knows what Honda_Tengoku is talking but, so some honda guru please try to respond to this crazy question.

 

I've only heard of propane injection being used in diesel engines, and then only in high-pressure turbo setups. I don't think propane is suited to the kind of cylinder pressues (very light compared to HO turbodiesel cylinder pressures) and temperature ranges that you'll see in an NA application.

It also seems to me that if any kind of injection other than that of an oxidizer like nitrous were beneficial, it would be widely used (or at least we would have heard of it). My roomie runs water injection in his saab, but that motor regularly sees well over a bar of boost, and the water is run more for knock protection than for performance.

Honestly, I doubt you'll find what youre looking for But the only way to find out for sure is to try it yourself, and blow up an engine for posterity