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water injection/towing/mileage question

G

great white

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Ok.

As some of you already know, I've possibly got a BIG trip ahead of me.

Just a bit shy of 4100 miles, from the west coast to the east coast. Crossing mountain passes and running across the plains in spring/summer.

Loaded down with the fam (me, wife, two big dogs and a bunch of stuff) and hauling my 35 foot travel trailer behind the ol' 98.

I'm considering installing a water injection system to help with the EGT's during the climbs and for a possible increase in MPG's.

But;

Snow's is going to cost me somewhere around 1100 bucks for the EGT referenced system and devils own will be around 700 for a similar (but less fancy) EGT referenced injection.

It will probably just be water as I'll be filling it quite often. I'm not planning to put a huge tank in the truck.

I'm planning on setting the system to start spraying around 800-900 F.

I'm anticipating 8-10 MPG AVG while towing without water injection.

I guess my real question is if I use the water injection, what kind of MPG increase can I expect?

Can I recoup the cost of the system over such a long trip, or even a decent portion of the cost?

:???:
 
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Not certain what he was getting before but 635 got his WMI set up correctly and with his GM-8, standard injectors, and GL4 tune from Heath he was hitting 23 mpg at 100KPH WMI only. Truck is a 3500 dually, 30 Gal Water, 23 Gal Propane, NOx tank, full width tool box, 5th wheel hitch etc weighing in at 8700lbs. Plus, with Semi truck tires on it the rolling resistance is a little high. Running fast and furious with WMI and Propane we ran pretty cool but the mileage...not so much.
 
Heath says mpg goes up running WMI, his is a boost referenced system that regulates progressively more spray with more boost starts spraying at 2psi I have one yet to be installed, I'll be adding a temp controller into mine so it will be a boost over IAT temp before it activates, some theory's out there that 150F IAT is desirable for economy as little pre-heat in pre cups helps with ignition.
 
some quick numbers (this is all pretty rough figurin' numbers):

trip total -4100 miles

Estimate mileage pulling trailer - 8 mpg (might be better, trying to guess low)

Hoped for gain with water injection - 2 Mpg or 10 mpg total

Calculations;

4100mi / 8 mpg = 512.5 gal x $3.00gal = $1537.5

4100mi / 10 mpg = 410 gal x $3.00gal = $1230

Difference between with and without Water injection - $310 savings.

The difference won't quite pay for the water injection system.

But it will pay for about half a Devils own kit and maybe make crossing the mountains a bit easier on the mind by keeping egt's in check.....
 
i would think it would add longetivity to your rig if you buy and if you get another diesel you already got a kit.
 
Woody35 said:
i would think it would add longetivity to your rig if you buy and if you get another diesel you already got a kit.
Click to expand...

And perhaps the TIME it saves you would make it equal the cost of the kit?

Your time + Your Wife's time.

Life is short man, get the WMI!
 
From everything I have seen/read the fuel mileage increase comes from the methanol you are injecting. All the kits recommend their mix of methanol and water which is roughly 50% methanol 50% water. I know from my experience that water does a great job of lowering the IAT and that the 50% methanol mix also lowers the IAT, but changes my AFR from 11.5 to 10.1-10.3 if I don't adjust for it in the tune. This is on a gas burner, damn brother with 6.5 isn't interested in WMI.

I would be game to make a donation to help you buy some extra methanol mix (boost juice) to make a comparison of which one increases fuel mileage if not both and how much. Your long trip should provide some good data.
 
Guess he stops running WMI in the winter?

I use straight water when I am towing because I have 2 x 5 gph plus 1 x .25 gph nozzles and it will use 1.25 gallons in rolling hills in about two hours. I switch to methanol for performance and winter.
 
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I wonder why he doesn't like methanol? Its auto ignition temp is 867 F so it's only going to burn after the diesel hits the cylinder and starts the flame front.

To me using methanol/water blend will cool the IAT and add BTU's to the cylinder when burned. There fore adding power when at WOT or reducing diesel consumption by trading methanol for diesel. What increase in fuel mileage (decrease in diesel fuel used) you see will be offset by increased use of methanol.

Need some data on mpgs increased and how much water/meth used from a dependable source. Then we can see if it really saves us money in the end.

If we are using straight tap water and it increases mpg the kit should pay for itself in time.

If you were getting 15 mpg and WMI increased it to 16 mpg on water alone that would be a 6.67% increase. Buying fuel at $3.00 should save you almost $.20 a gallon. Thats not going to pay off a WMI kit very quickly.

Did you add it for MPG, EGT or HP?
 
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I'll be adding mine for IAT control & Hp, I had an ATA IC for that when I was with my GM-8 and I didn't want to haul a lot of water; but with my ATT that doesn't spend a lot of high boosting IAT I will only spray the WMI when needed so won't be toting a lot of water, so I think WMI will be a better way to control IAT.

I've got tons of data before the WMI, so once I add it, I'll know what the mpg & power benefits are.
 
Your MPG should be 10-11 at 62 MPH flat running. Around 7.5 MPG in the grades flat out on the floor with the orange triangle. The DS4 may give you more fuel, but, it just smokes as you run out of air: Stock fuel and boost vs. turned up fuel and boost at max of 14 PSI: MPG is the same but flat out towing MPH goes up ~ 10 MPH. More power but the same economy on 10% grades, weird.

62 MPH is the sweet spot with 4.10's and the auto.


I include some info on WMI and a different take on it from killerbeeperformance.

(Note link to place does not sell 6.5 stuff and it is in the 6.5 section. For WMI info only.)
http://killerbeeperformance.com/induction/i-f-o-g/
Maybe some interest out there in making the ifog work on a 6.5, but, we would have to make it work with our trucks vs. the canned Duramax kit.
 
just bought a devils own stage 2 injection kit NIB for 230 bucks.

Retails new for 360

Now I can make use of my 3 bar map sensor for more than just reading boost:

DSC03844.jpg


Kinda what I had planned all along....:)

Mods:

You can close this thread if you wish.

:)
 
SCREAMINXL said:
From everything I have seen/read the fuel mileage increase comes from the methanol you are injecting. All the kits recommend their mix of methanol and water which is roughly 50% methanol 50% water. I know from my experience that water does a great job of lowering the IAT and that the 50% methanol mix also lowers the IAT, but changes my AFR from 11.5 to 10.1-10.3 if I don't adjust for it in the tune. This is on a gas burner, damn brother with 6.5 isn't interested in WMI.
Click to expand...

I would highly recommend not using 50% methanol or an alcohol mix in the 6.5 WMI. I would say 20% max, so if you have 5 gallon tank, maybe throw 1 gallon of windshield washer fluid in it, if you have the 99% methyl alcohol kind.

If you knew that our injection at idle was up to 22 degrees before TDC, and inejction timing before TDC was as much as 45 degrees, then bits of diesel could be on fire well before TDC and the methanol combustion doesnt behave the same as diesel. And the air temperatures in the cylinder could be well over 900F way before TDC, because of the high compression. The higher concentration in the air will make it more prone to pre-ignition.
 
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