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-   -   Some final questions about WI (https://www.miataturbo.net/methanol-water-injection-22/some-final-questions-about-wi-36236/)

ThePass 06-18-2009 04:17 AM

Some final questions about WI
 
When I installed the turbo I planned to 'some day' go as high as 8 psi... yeah so anyways, I want this motor to last a long time... and I also wanna go fast. 10 psi is fun, but I want more and what seems like the most surefire and foolproof way to do so on this stock motor safely is to add a budget WI kit as a cushion factor or safety margin to eliminate any chance of detonation.

So, I've read around, and have just a few last questions. I am looking at the DO Stage 1 kit, but I am curious how exactly it's operation works - the progressive version I get, but does the basic kit just spray full-on at one given pressure that you set? So if I set it to come on at 8 psi, the pump just goes 100% so it's an on/off sort of deal? If so, how effective is it vs. the progressive? If not, set me straight on this.

My second Q is about the mix - I've heard of guys talking about just running straight water. If I do this, I don't want to find myself with a low tank and trying to hunt down the proper windshield fluid that has the correct meth % in it, I just want to run straight water. I can do this right?

The third and biggest question - does WI decrease performance when simply added to an already tuned without WI setup? My original plan was to tune the car completely without WI at 15 psi, which is kinda pushing it for reliability on the stocker, then turn the WI on for that safety margin... HOWEVER, I know that when properly tuning the car with WI implemented, you would normally lean it out a bit more/add more timing and thereby get more power per psi than without... so my question is, if I just add this on to a tune that is tuned for no WI, will it actually deteriorate performance or will it be ok? I ran across a thread of Magna's where he said slapping WI on nets an immediate slight boost in power due to the simple fact that it is all running cooler... if so, good, but I want to make sure.

I figure I'll use WI for now for that smudge factor to keep this motor safe, and down the road (years I hope) when the motor goes and I build it up, I will then tune the WI in to fully use it's potential, since then the forged bits are the new safety margin ;)

Let me know what you guys think.
Thanks.

magnamx-5 06-18-2009 11:16 AM

ok man Q1 yeah its a simple on/off deal if you size it properly you should have minimal issues.

Q2 You can run h20 alone but you will get all the cooling and none of the octane boost.

Q3 No you should not tune and just throw on WI. That is lazy and prob wont do you any good. Take some seat time and do the shit right. WI is not a safety net :P

ThePass 06-18-2009 12:59 PM

Ok, I had a feeling that just slapping it on with a tune not meant for WI would be a waste... I think I'm going to revise my plan.
I'm thinking I should get an EBC with high/low boost settings, set low for the 10 psi I have now, and high for 15 psi, install the WI and set it to come on at like 9, so it doesn't really affect the low boost tune, and then tune the new 11+ psi cells for spark and fuel with the WI.
This way, I've got a simple safe low boost option that doesn't really use the WI so it conserves the mix, and if I ended up for some reason being out of mix, I can stay on low boost and not need it, but then I also have the high boost setting which not only would be 15 psi, it would also be leaned out around 12.2:1 with more timing and uses the WI to it's full extent.
My only question then is, is it OK for me to set the on point for the WI at like 9 psi for a setup with a 15 psi max? How long does it take for the pump to fill the line - that half second or whatever could it be bad for say, autocross where you are rapidly on/off throttle a lot?

And about just straight h20 - will it offer a significant benefit or do I need that octane boost of the meth to really make WI worth using?

-Ryan

magnamx-5 06-18-2009 01:53 PM

That is a great option. The lag time is pretty much a null effect, and instant for all intensive purposes. Just make sure to get your spray capacity right etc and you will be fine.

Joe Perez 06-18-2009 01:57 PM


Originally Posted by ThePass (Post 420879)
And about just straight h20 - will it offer a significant benefit or do I need that octane boost of the meth to really make WI worth using?

I've been doing a lot of reading on this subject, and I'm coming to the conclusion that water alone is highly effective knock-reducer. There may be some small palliative effect from methanol, however I don't believe that it justifies the expense and complexity.

hustler 06-18-2009 02:27 PM

so is it dumb or a waste of cash to just get a 2gph nozzle and spray at like 10psi+ when I'm on the track or running 91octane instead of 93, and to keep EGT down on the track? Is there an FAQ which answers these questions in plain engrish?

gospeed81 06-18-2009 02:40 PM

I've been wanting to ask a lot of these questions too. It's almost like WI is the elephant in the room here, we all know we should be doing it, and most of us want to, but we're afraid to admit how little we know.

Searching brings up some good stuff, but I thought about making a wiki article for beginner setups once I get mine sorted out.

I also planned on doing a simple switched (8psi+) setup with straight water (not hustler water). I want three things out of it: advanced timing, cooler charge, and detonation protection. I plan to tune it just for full throttle and set and forget, no failsafe.

I think all I lack is a pressure switch, a tank and some lines.

My issue is I can't bump my boost up over 11psi without producing obscene amounts of heat that my nearly MSM sized intercooler can't handle. I don't want to get rid of the very nice, perfect fit BEGi coldside piping, so I don't plan on upgrading the IC. I hope that with WI I can bump it up a little over 10psi, and advance the timing enough that I can run like a 14psi car.

magnamx-5 06-19-2009 01:26 AM


Originally Posted by gospeed81 (Post 420916)
I've been wanting to ask a lot of these questions too. It's almost like WI is the elephant in the room here, we all know we should be doing it, and most of us want to, but we're afraid to admit how little we know.

Searching brings up some good stuff, but I thought about making a wiki article for beginner setups once I get mine sorted out.

I also planned on doing a simple switched (8psi+) setup with straight water (not hustler water). I want three things out of it: advanced timing, cooler charge, and detonation protection. I plan to tune it just for full throttle and set and forget, no failsafe.

I think all I lack is a pressure switch, a tank and some lines.

My issue is I can't bump my boost up over 11psi without producing obscene amounts of heat that my nearly MSM sized intercooler can't handle. I don't want to get rid of the very nice, perfect fit BEGi coldside piping, so I don't plan on upgrading the IC. I hope that with WI I can bump it up a little over 10psi, and advance the timing enough that I can run like a 14psi car.

Yes it can.

Hustler your newb ass cant handle WI, and at your power lvl i would run atleast 5gph past 9 psi with timming in the high 20's. You limp dick pussy.

ThePass 06-19-2009 03:14 AM


Originally Posted by magnamx-5 (Post 420895)
Just make sure to get your spray capacity right etc and you will be fine.

I assume you mean the amount of flow, not the capacity of the tank?

That brings up the next noobtastic question...
Nozzle sizes: The DO kit comes with a 3 and a 7 gph nozzle... everyone throws around nozzle size numbers with little info on why a given size is right for a given car/setup/power level... Is there a proper way to figure out what to use?

-Ryan

Joe Perez 06-19-2009 12:06 PM

One method would be to use the nozzle size calculator provided by DevilsOwn: Alcohol Nozzle size Calculator - Devilsown Methanol Alcohol Water Injection

ZX-Tex 06-19-2009 12:10 PM


Originally Posted by ThePass (Post 421194)
Nozzle sizes: The DO kit comes with a 3 and a 7 gph nozzle...

Actually you can order it with whatever two nozzles you want.

magnamx-5 06-19-2009 12:21 PM

yeah I usualy calculate in ratio to fuel I run 1/4 of my fuelling capacity in WI You should aim for alil less than that. With some wiggle room for if or when you up the injectors or turbo and wanna run more boost.

Joe Perez 06-19-2009 12:42 PM

With a simple on/off switch, or even a PWM progressive controller, it's pretty much a crap-shoot anyway. A nozzle that gives you the "perfect" amount of water at X kPa & x RPM will be off by huge amount at other load conditions. Just use a 3 or 4 GPH nozzle and be happy.


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