water/methanol injection and 6.2

[3ace]

I'm looking for comments on using water/methanol injection on my 1991 Chevy 6.2. My diesel mechanic told me that the system is good to use but not on my 6.2 becuase I'm also using SVO as a fuel. I wouldn't think that using SVO would have any bearing on using WMI. Any comments? :)

[DmaxMaverick]

A couple things come to mind. Good and bad.... (assuming the 6.2 is N/A).

There's nothing wrong with WMI, if used moderately, and not with the intention/expectation of getting more power. It's great for cooling the EGT a bit, which has other benefits. Too much is a step backwards (for the same reason explained below).

Methanol, or any other additional fuel, used in a N/A Diesel is counterproductive. Unless your intent is merely to substitute one fuel for another, it won't gain anything, and in most cases, is a net loss. A N/A engine relies on atmospheric pressure to fill the combustion chamber with air/O2. This is a finite value, with many limiting factors. A properly tuned and maintained, healthy, good running N/A diesel will have a shortage of air/O2. Adding more fuel won't burn that additional fuel (or may burn it, at the expense of not burning the #2). Space in that tiny combustion chamber is very limited. There's only so much room available, and it can easily be used up by stock fueling (indicated by black smoke). More fuel would just be more black smoke.

If you had a turbo (or another method of stuffing more air/O2 into that cylinder), well.....That's a game changer. More air means you have the ability to burn more fuel (of any sort).

[3ace]

A couple things come to mind. Good and bad.... (assuming the 6.2 is N/A).

There's nothing wrong with WMI, if used moderately, and not with the intention/expectation of getting more power. It's great for cooling the EGT a bit, which has other benefits. Too much is a step backwards (for the same reason explained below).

Methanol, or any other additional fuel, used in a N/A Diesel is counterproductive. Unless your intent is merely to substitute one fuel for another, it won't gain anything, and in most cases, is a net loss. A N/A engine relies on atmospheric pressure to fill the combustion chamber with air/O2. This is a finite value, with many limiting factors. A properly tuned and maintained, healthy, good running N/A diesel will have a shortage of air/O2. Adding more fuel won't burn that additional fuel (or may burn it, at the expense of not burning the #2). Space in that tiny combustion chamber is very limited. There's only so much room available, and it can easily be used up by stock fueling (indicated by black smoke). More fuel would just be more black smoke.

If you had a turbo (or another method of stuffing more air/O2 into that cylinder), well.....That's a game changer. More air means you have the ability to burn more fuel (of any sort).

My engine does have a banks sidewinder turbo. Am I understanding you correctly that I now would be able to use WMI at moderate levels? If so how does one go about setting up the correct amount of WMI?
Thanks.

[DmaxMaverick]

WMI is good, at any level. Trial and error is the best guide. Start low, and work your way up until performance plateaus, then back off a little. You may be surprised at what you get out of it. Skip the methanol (windshield washer fluid). Your pump is already capable of providing all the fuel you can burn, and alcohol has a much lower BTU (meaning: power) than #2, with the O2 available. If you aren't blowing some black smoke at WOT under load, turn up the pump. Keep an eye on your EGT gage, all the time. WMI will give you a significant advantage in this area.

[3ace]

Thanks, dMaxMaverick for the insight. #4 (http://www.thedieselpageforums.com/tdpforum/showpost.php?p=272790&postcount=4) http://www.thedieselpageforums.com/tdpforum/images/buttons/report.gif (http://www.thedieselpageforums.com/tdpforum/report.php?p=272790)
http://www.thedieselpageforums.com/tdpforum/images/statusicon/post_new.gif Today, 12:59 AM
DmaxMaverick (http://www.thedieselpageforums.com/tdpforum/member.php?u=3239)

Have a good day.

[Edahall]

DmaxMaverick,

I'm looking for your insight on whether or not water injection improves fuel economy for solo freeway driving. I've asked this question before and the response I always get is we sell this to improve power / lower EGT's, not increase fuel economy. The reason I ask is because my goal is to get my 1990 Suburban that we put in a Cummins to get as good or exceed the fuel economy of my 1982 Suburban. So far, I'm up to 26 mpg but would like to get 30 mpg or more.

[DmaxMaverick]

DmaxMaverick,

I'm looking for your insight on whether or not water injection improves fuel economy for solo freeway driving. I've asked this question before and the response I always get is we sell this to improve power / lower EGT's, not increase fuel economy. The reason I ask is because my goal is to get my 1990 Suburban that we put in a Cummins to get as good or exceed the fuel economy of my 1982 Suburban. So far, I'm up to 26 mpg but would like to get 30 mpg or more.

You won't ever see a measurable amount of fuel economy increase with WMI alone. Asking for a 15% increase is a tall order, for any economy mod. WMI will NOT add power. It will NOT increase fuel mileage. It is not a fuel, and when used, takes up some valuable space in the combustion chamber, previously available to fuel and O2. It can allow other methods of increasing power or economy to work more efficiently, such as lower EGT's or reduce piston crown and valve temps (which may help reduce internal physical and molecular friction). A cooler intake air temp also allows for a more dense air charge. If any gain can be attained, it is very likely the conditions will be so specific, the window of gain would be so narrow, it would be irrelevant to any result. With this in mind, the ROI (Return On Investment), if any gain can be realized, will never pay for itself (which is the goal of economy, correct?).

Fuel economy increases can be seen with WMI on gassers, under certain conditions. They are different animals. The combustion chambers are filled under a deliberate vacuum, so they have some room to spare. A Diesel engine is allowed all the air it can ingest, and engine speed/power is determined by the amount, timing and duration of fuel injected, and doesn't require a O2:fuel ratio (ideally about 15:1, by weight, for gasoline) to be maintained.

Asking for 30 MPG in any Suburban, with any powerplant (with appreciable power and drivability characteristics), will probably never be seen. Not saying it can't be done. The Suburban is a heavy vehicle with a heavy drivetrain (adds parasitic loss), and just doesn't have the aerodynamics to support an MPG goal vehicle. This is very evident when we see the same powerplants in other vehicles, such as a caprice wagon, Corvette, Camero, etc. (each can easily exceed 30 MPG), and they are not lightweight cars. However, they have a drag coefficient that's a night and day difference, compared to a Suburban or pickup. If you were able to stuff this engine into a Nissan Sentra, 40-50 MPG (or even more) wouldn't be an unrealistic goal. It's all relative to where you stand, and what you have to work with. Criminals break man-made laws on a regular basis. Physical laws, not so easy.

[More Power]

Back in 1995 when I first started browsing the internet, I found a series of articles written by a boat owner who ran a Yanmar marine diesel. This is a small engine. He experimented using a variety of alternative fuels that were fed directly into the engine using very simple and crude methods.

He experimented with propane, by simply screwing a fitting into the intake and controlling flow with a valve. Since a boat engine is run at a more or less constant speed, once he had the propane valve set, he could leave it for as long as he wanted to cruise. He also experimented with alcohol - as a fuel source. For the alcohol, he used a gravity feed and a small valve to control flow.

As I recall, he indicated that whatever alternative fuel is used, the engine must produce its power on least 25% diesel fuel, otherwise predetonation became a problem. So, at least in his case, alcohol was used as a fuel extender.

Nowadays, people are experimenting with hydrogen generators, like that offered by Diamond Eye (www.diamondeyeperformance.com (http://www.diamondeyeperformance.com)) to use as an alternative fuel source to improve overall mpg.

This is one of the beauties of an older mechanically fuel injected diesels.

Jim

[Edahall]

DmaxMaverick,

Thanks for your insight on this. I'm glad that I ran it through you before spending any resources on this. I'm probably pretty maxed out on engine efficiency for this rig. Aerodynamics is probably not as much of a factor for me as other drivers since I rarely drive this vehicle over 60 mph but the boxy front end does not help.

Now any insight on hydrogen generators? It uses power from the alternator to create hydrogen so I have my doubts on this for increasing fuel economy.

[DmaxMaverick]

"Economy" is relative. For example: Right now, Diesel is about $3/gal (more in my area). If you get 20 MPG, you drive 20 miles for $3. Simple. If you had a fuel alternative, but your mileage dropped to 10 MPG, but that fuel only costs $1/gal, it will cost you $2 to drive 20 miles. (or any combination of fuels to average the cost/miles). A hydrogen generator sounds cool, and the fuel is relatively "free". The cost of install and service is the price. Do some math and figure out how much it will cost to drive 20 miles, over the next 200K miles (or whatever distance seems realistic). That will give you an idea of the real economic gain/loss.