Wideband and water injection question

[crazyboost]

I just got my water injection kit and am in the process of installing it, but im also looking into getting a wideband, because i hate hooking up a laptop to log timing, knock ect. My question is wouldn't the methanol/water mixture mess with the AFR outputed by the wideband (AEM most likely)? Anyone have any experience with tuning water injection and wideband. thanks

 

[crazyboost]

Also I was wondering if my 02 dump would affect the widebands output readings? thank you

 

[dsm-onster]

It barely affected my WBO2 readings.

If you're running a water/alky mix, you'll need to run a bigger nozzle than what most run for pure H2O. With a 50/50 mix usually a nozzle that will flow 25% of your total fuel flow (or equal to one injector) is plenty. I realized this later in the game and that's when my WBO2 readings started to show a little richer. But nothing more than 0.2-0.3 difference in my case. If you're going to run straight alky (isopropenol, meth, ethenol), you will nead to research. I know you'll need a much larger flowing nozzle. And running straight meth (w/out gas) it likes to run rich. But I don't know how this carries over to meth injection w/ gasoline.

 

[crazyboost]

thanks alot dsm-onster! anyone else know about the 02 dump affecting it? I have heard that exhaust leaks will screw it up? does an 02 dump count as one?! I would think that since a ton of gas is exiting the dump and nothing entering into the flow (because its only open during WOT) that the exhaust gas would be the same and the 02 readings would be the same if it was recirculated, but hell i dont know, anyone have any experience with wideband and 02 dump or external wastegates?

 

[Kmiller86]

As long as your exaust housing on your turbo still has the divider between the wasgate and where the exhaust usaully goes, you will be fine. I have a PLX M-300 and there was no difference between when I had the stock o2 housing and the one with the dump. I also asked this question about a year ago and that was the answer that I got from many people.

 

[1990EclipseGSX]

Actually, when running methanol the AFR your wideband registers is richer than your AFR in actuality.

Here is a geekoid post from another forum...

Stoich Values:
Gasoline = 14.7
Methanol = 6.40

Weight:
Water = 8.33lbs/gal
Methanol = 6.59lbs/gal

Specific Gravity:
Gasoline = .737
Methanol = .791

Specific Gravity Differences:
Gasoline = 1.07 more dense than methanol
methanol = .93 less dense than gasoline

Equation to get Percent Methanol to Water Injection by Mass:
(Methanol Weight per Gallon)(Volume of Methanol in Mixture) = Methanol Total Mass
(Water Weight per Gallon)(Volume of Water in Mixture) = Water Total Mass

(Methanol Total Mass)(100)
(Meth Total Mass) + (Water Total Mass) = Methanol Percent by Mass

Equation to get Actual Percent of Methanol Injected:
(Methanol Percent by Mass)(Total Percent of Water Injection Mixture) = Methanol Percent Injected

Equation to get Mixture Stoich Value:
(Meth % by Mass)(Meth S.G. Difference)(Meth Stoich) + (gas %)(gas S.G. Difference)(gas Stoich) = Mixture Stoich Value

Equation to get REAL AFR:
(Mixture Stoich Value/WBO2 reading) x 14.7 = REAL AFR


Example:
75% meth injection to 25% water by volume at 20% of fuel delivery and a WBO2 reading of 11.2:1AFR.

Percent Methanol in Water Injection Mixture by Mass:
(6.59lbs/gal)(.75) = 4.9425

(4.9425)(100)
4.9425 + 2.0825 = 70% Methanol by Mass of 20% Water/Methanol Injected

Equation to get Actual Percent of Methanol Injected:
(70%)(20%) = 14% Methanol injected to Fuel

Mixture Stoich Value: (.14)(.93)(6.4) + (.86)(1.07)(14.7) = 14.36

Real AFR: (11.2/14.36) x 14.7 = 11.47 REAL AFR

Also check out this link http://www.techedge.com.au/vehicle/wbo2/wblambda.htm and read through the Lambda and AFR's for different fuels. Lambda is independant of fuel used, but AFR is dependant on the fuel used.

 

[crazyboost]

thanks again 1990 and kmiller, looks like it will work with my 02 dump and h20/alky injection. I'll just have to use that formula and remember some numbers so i can get close to that when tuning. Ideally I would want close to 11:1 on pump gas at WOT and close to stoich (14.7:1) at idle and low throttle cruising, correct?

 

[GVR4592]

It depends on how much methanol you are using. Methanol's stoich a/f ratio is 6.4:1, so if you are injecting a lot of methanol and running 11:1 a/f you could potentially be running lean and burn up your engine. Since you are partially substituting methanol for gasoline, your fuel tuning needs to reflect that.