Twisted Steel Performance
Anything worth doing is worth overdoing.
Might shoot Devils Own a email and see what they say on the subject....
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Water/Meth...again
- Thread starter 6.5L
- Start date
great white
Well-Known Member
Then load 'er up and see whatcha git.
Mine didn't like anything over 25-30% tops. The "displeasure" was audible at that level. We couldn't be sure what was going down below the point where we could hear it, so I just dropped it all together and went straight water. The drop in IAT and EGT is benefit enough for me.
That was also with Snow's Boost juice and cut with distilled water by the way. They had it in the shop the day we dyno'd it so I gave it a try. It didn't like it, although there were gains on the charts. The boys in the shop didn't like the sounds it was making either so it was a unanimous decision to drain it.
I could have run up to 50% I'm sure. It would have taken it. But it was obvious there was going to be long term issues. Cracking a piston crown is an experience I would care not to repeat.
If that kind of stuff doesn't both ya: Give 'er!
great white
Well-Known Member
My other recommendation would be to run a progressive system.
Don't kludge together something from parts with a hobbs switch if you're going to be running large percentages of meth.
A progressive system will come on as the boost rises, keeping the amount proportional to what the engine can swallow.
A hobbs switch will be all on or all off. That's ok if you just want to spike the dyno at the top end with a blast of drugs, but it won't be as effective on the way up nor will it control egt's very well.
My WI will help with EGT's, but it only holds them down. It doesn't bring them down. Once it's hot, it's pretty much there, the effect of the water is greatly reduced. I will see the drop in IAT, but the EGt will drop much less than it would be if I was spraying on the way up to max EGT.
Mine is a progressive controller that is driver "tuneable" and it still didn't like anything over 25-30%. It's a "Devils Own" kit, although they don't actually make the controller. All you have to do is open the case and look a the PCB to know who does. Same people who used to make another retailers unit who doesn't sell WMI anymore...
That's with a 10 GPH nozzle. We tried everything down to a 4 GPH and it still didn't like it. Injection line pressure went up though. To be expected with a greater end line restriction.
I'd also recommend that you take any retailers advice about what works and what doesn't with a grain of salt: it's not like they have a vested interest in what you do with your cash....
Don't kludge together something from parts with a hobbs switch if you're going to be running large percentages of meth.
A progressive system will come on as the boost rises, keeping the amount proportional to what the engine can swallow.
A hobbs switch will be all on or all off. That's ok if you just want to spike the dyno at the top end with a blast of drugs, but it won't be as effective on the way up nor will it control egt's very well.
My WI will help with EGT's, but it only holds them down. It doesn't bring them down. Once it's hot, it's pretty much there, the effect of the water is greatly reduced. I will see the drop in IAT, but the EGt will drop much less than it would be if I was spraying on the way up to max EGT.
Mine is a progressive controller that is driver "tuneable" and it still didn't like anything over 25-30%. It's a "Devils Own" kit, although they don't actually make the controller. All you have to do is open the case and look a the PCB to know who does. Same people who used to make another retailers unit who doesn't sell WMI anymore...
That's with a 10 GPH nozzle. We tried everything down to a 4 GPH and it still didn't like it. Injection line pressure went up though. To be expected with a greater end line restriction.
I'd also recommend that you take any retailers advice about what works and what doesn't with a grain of salt: it's not like they have a vested interest in what you do with your cash....
6.5L
Old Iron Runner
It has a progressive controller that comes with it.
great white
Well-Known Member
So, spurred on by the thought of not knowing why I would get "knock" at higher meth concentrations I spent the day doing some calculations. I didn't put a lot of thought into it when we were knocking on the dyno. I just said "that's knock" when I heard it, the boys agreed, we drained the tank and moved on.
But I hate not knowing the theory behind something once I start looking at it and this topic has forced me into that "mode".
I just got's ta know why.
Now, it's been a while since I've done thermodynamic calculations and I had to make some assumptions as well. There's lots of variances and opportunity for error here and it changes on a multitude of variables. I also assumed adiabatic compression (no temp loss to surroundings).
But depending on the intake temperature (I used turbo discharge temperatures of about 65C-80C, which I can regularly see on my truck at around 4-8 psig) a 20:1 diesel can reach compression temperatures of 500-700C. It can be a bit higher or lower depending on how you work the intake temps. I used compressor discharge temperatures as it made the calculations a little easier (IE: faster) instead of having to also figure out temp delta from ambient through the turbocompressor.
This quote at least seems to indicate my math is in the ballpark:
http://www.extremetech.com/extreme/...d-which-is-best-for-you-and-the-environment/3 - paragraph 3
1000 F is around 530 C. Not irrefutable proof, but it does support my numbers somewhat. Most papers will not give a temperatre for compression due to too many variables.
Now, lets look at the properties of Methanol:
Autoignition temperature of methanol can vary a little bit depending on what source of info you use, but the 470C number is pretty accurate for discussion purposes.
http://www.sciencelab.com/msds.php?msdsId=9927227 - page 2
So you can see that you are playing around with autoignition of methanol in a high compression (IE; 20:1) diesel like a 6.5
I used 20:1 since thats what my 6500 Optimizer runs at. An OEM GM diesel is a touch higher and would have corresponding increases in temperatures.
This is likely why people (like myself) report "knock" at methanol concentrations over 10-20%: there's enough at that point they can hear it over the normal "diesel noise" these old clunkers make. Probably why people like Heath Diesel recommended no more than about 10% while they still sold a system. Detonation is likely still there at lower concentrations, just not enough to be heard. Easily masked by the valve train, pre-chamber rattle or popping injectors.
Throw in the heat gain from architecture in the combustion chamber (IE: pre-chamber mouth "lip") creating hot spots and you can easily be in and out of autoignition temperatures even with the WMI rockin' full blast.
This is likely why a modern direct injection engine can sustain higher levels of meth at higher turbo pressures since they typically run lower initial compression, factory intercooling and fewer localized "hot spots" in the chamber itself (DI is pretty much just a open jug compared to IDI).
Not trying to argue, just putting the facts out as I can reason them through. People can make their own minds up whichever way they want to go.
I'm sticking with straight water.
Now, I don't want to look at anything to do with math for at least a week....
But I hate not knowing the theory behind something once I start looking at it and this topic has forced me into that "mode".
I just got's ta know why.
Now, it's been a while since I've done thermodynamic calculations and I had to make some assumptions as well. There's lots of variances and opportunity for error here and it changes on a multitude of variables. I also assumed adiabatic compression (no temp loss to surroundings).
But depending on the intake temperature (I used turbo discharge temperatures of about 65C-80C, which I can regularly see on my truck at around 4-8 psig) a 20:1 diesel can reach compression temperatures of 500-700C. It can be a bit higher or lower depending on how you work the intake temps. I used compressor discharge temperatures as it made the calculations a little easier (IE: faster) instead of having to also figure out temp delta from ambient through the turbocompressor.
This quote at least seems to indicate my math is in the ballpark:
http://www.extremetech.com/extreme/...d-which-is-best-for-you-and-the-environment/3 - paragraph 3
1000 F is around 530 C. Not irrefutable proof, but it does support my numbers somewhat. Most papers will not give a temperatre for compression due to too many variables.
Now, lets look at the properties of Methanol:
Autoignition temperature of methanol can vary a little bit depending on what source of info you use, but the 470C number is pretty accurate for discussion purposes.
http://www.sciencelab.com/msds.php?msdsId=9927227 - page 2
So you can see that you are playing around with autoignition of methanol in a high compression (IE; 20:1) diesel like a 6.5
I used 20:1 since thats what my 6500 Optimizer runs at. An OEM GM diesel is a touch higher and would have corresponding increases in temperatures.
This is likely why people (like myself) report "knock" at methanol concentrations over 10-20%: there's enough at that point they can hear it over the normal "diesel noise" these old clunkers make. Probably why people like Heath Diesel recommended no more than about 10% while they still sold a system. Detonation is likely still there at lower concentrations, just not enough to be heard. Easily masked by the valve train, pre-chamber rattle or popping injectors.
Throw in the heat gain from architecture in the combustion chamber (IE: pre-chamber mouth "lip") creating hot spots and you can easily be in and out of autoignition temperatures even with the WMI rockin' full blast.
This is likely why a modern direct injection engine can sustain higher levels of meth at higher turbo pressures since they typically run lower initial compression, factory intercooling and fewer localized "hot spots" in the chamber itself (DI is pretty much just a open jug compared to IDI).
Not trying to argue, just putting the facts out as I can reason them through. People can make their own minds up whichever way they want to go.
I'm sticking with straight water.
Now, I don't want to look at anything to do with math for at least a week....
6.5L
Old Iron Runner
Granted the temperatures would get hot, but wouldn't the addition of the water lower the actual combustion process since the IAT's would be lower, thus putting off the auto-ignition temperature of methanol and making it more suitable?
great white
Well-Known Member
Pretty much gave my POV in the post above.
If ya wanna do it go ahead and pour in some boost juice.
It may work, it may not.
Cheers
6.5L
Old Iron Runner
Yeah, well, I got a little lost in it, that's why I just asked a simple question
great white
Well-Known Member
6.5L
Old Iron Runner
So it's a maybe?
great white
Well-Known Member
Everything in life is a maybe.
I had detonation when I ran it in my 6500.
If you want to do it, do it. You'll have to decide for yourself if you want to go by the math or experiment with it.
schiker
Well-Known Member
If it does pre-ignite then the diesel injection is going to burn that much faster as the speed of flame front is faster as temperature increases. So again its a snow ball effect and I think made even worse by IDI with the swirl affect to raise cylinder pressure faster than a lower compression DI engine with dispersing combustion shape.
JayTheCPA
Well-Known Member
Dude, Excellent write-up! I actually stayed with the topic and got it.
But, gotta ask, how long did it take to re-learn the slide-rule??? :hihi::hihi::hihi: (Sorry, could not resist)
From my old physics days (post slide-rule, thank you), water will continue to absorb heat until it turns to steam; after that point IIRC it will not absorb as much heat and has unlimited potential in terms of how hot it can get (at least until the atoms want to separate, which is another ball-o-fun).