Propane Injection + Water Injection Applications 2

[MCubed]

Please excuse my ignorance, but here it goes:

Currently I am modifying a NA EFI gasoline (non-diesel) engine to a turbo application. I have succeeded the first time, but now I am going into uncharted territory (larger turbo). I have been using an Aquamist Water injection system to help deter knock. Now I have seen the use of of Propane in some applications to be successful, but most of the applications have been diesel engines. So here is the questions I have for you automotive experts:

1. Can a combination of water and propane injection be used?

2. Where would be the best place to inject propane (from my experience would the in the intake runners for better dispersion into each cylinder)?

3. From my reading on other applications, once you use the propane injection you are able to run more boost (to a certain extent) on the same fuel system (i.e., same amount of fuel being used)? Propane's A/F is 15.7-15.8, so does that mean I would need to inject more gasoline to make up for the lean A/F of propane?

4. What are the pros and cons of running propane? What are the pros and cons of running water+propane (if it is possible)?

Any other information will be greatly appreciated.

Thanks,

Carlos

 

[robear99]

I'm a newbie here and still trying to digest this long and complex string. From what I have gathered here and elsewhere, it seems that propane injection can be used primarily as a power booster (lots of propane) or primarily as a catalyst or combustion enhancer (a little bit of propane). As a booster, it seems that a turbo system with or without a nitrous bottle will provide enough air to burn the additional fuel. As a catalyst, I believe the idea is to get a more complete burn of the primary fuel (gasoline or diesel) which results in reduced emissions, better fuel economy and some performance gains. I am still gathering info on this subject and considering a potential mod to my 1971 4X4 Jimmy (which runs a 91 TPI borrowed from a Vette). Take a look at

http://www.welshtec.com

for some interesting info.
Okay, sorry to bother... that was my two cents worth.

 

[franzh]

Read any claim by any vendor carefully. I checked the website you state and found a couple of things interesting. I recently had a little more insight into that product but still challenge the true results.

By changing the injector pulse-width you obviously change the AF ratio, which is what happens here, but the true reason is that when metering in a small amount of alternate fuel (LPG vapor) the O2 sensor detects the richer mixture, then reduces the injector pulse. The resulting AF ratio is not too far off. Just monitor the O2 sensor or exhaust and watch and see.

Adding LPG to either diesel or gasoline will NOT result in a “catalyzed” reaction as claimed by many vendors! On a diesel engine, you are simply dumping more fuel into the engine, period. On a gasoline engine, today’s stoich controls are pretty good and the exhaust catalysts require a very tight AF ratio to remain active (and alive too!) Dumping in more fuel changes the entire profile.
Franz

 

[masthead]

Hi M4
I also am interested in this water + propane injection and have found this thread most interesting. My own quest is to do it for a vintage diesel (1983 Mercedes 300 D turbo) which does not have an intercooler. The quest is to mimic the intercooler by selective cooling via water and or propane. Propane under pressure and injected aft of the turbo (in limited amounts) was the 1st thing to come to mind to let if flash and do its thermal exhange thing there by dropping boost temperature at least close (hopefully) to the intercooler's contribution...and even consider high pressure water injection added to the turbo's housing just ahead of the outport expansion chamber so that it would hit near the tips of the turbo impeller vanes for max thermal exchange...while also adding demineralized water cut with alcohol (which alone may be the best approach).
I am hoping you guys may have something to say about this concept as I can see some critical and important counter points around here...remember the idea is to "cool" more than to enrich the fuel but a cleaner burning fuel on that old Benz would be a added welcome...I have seen those old Benz diesels really perform when tweaked out of stock and clean themselves up quite a bit...I was even thinking of what a MAP, vacuum, throttle family of sensors would do added to a processor for proper meetering of this new mix to the fuel/air system...
thanks
Jeff

 

[turbocohen]

If you want to clean up try

http://www.stanadyne.com/new/ppt/ppt_dfa.asp

Then order their performance formula. There is no better diesel additive out there imo.

As for water or alky injection, the side effects are often corrosion of ring lands and sludge formation in oil.