Water Injection for the Turbo Datsuns

[fo0manchu]

I just did a write up over at NICO about some junk yard washer pumps. Thought I would share it here as well.

http://forums.nicoclub.com/zerothread/471823-budget-water-injection-washer-pump-show-down

 

I'm going water injection in my datsun 510. I figure our datsuns don't have much room in the engine bay, except for you Z boys, so water injection was a perfect alternative if not better. I also didn't want to chop up the front core to mount a FMIC. Especially with my KA in there, there is definitely a lack of room up front.

[ichorid]

dude post here! nico is down right now. Im really curious to see what you did.

[510six]

dude post here! nico is down right now. Im really curious to see what you did.

 

 

For several years a Spearco water injection kit was used in the 3 liter turbo in my 510 which produced 275rwh @12psi.

 

http://oldschool.supracentral.com/htm/h2o.htm#compo

 

The modifications were similar to those shown other than an upgraded pump from McMaster Carr was used with a check valve with a viton seal. It worked just fine at controlling detonation with crappy CA 91 oct., a 'witches brew" of 5% water soluable oil 40% denatured alcohol and 50% distilled water with airless paint sprayer additive for corrosion resistance.

 

Myself, I would mount a small tank in the trunk and use the Shurflo pump with a Hobbs switch to active a solenoid to the mister/jet.

[datzenmike]

I'll finish reading later but I don't think you need much pressure for this. Inject just ahead of the turbo and it will work like a blender. Do you plan on using alcohol mix?

[fo0manchu]

Nico is up now. Yay.

I'll be using a shurflo pump on my setup, however, I just ran some tests with windshield washer pumps to see how much psi they push out. They would work well for a budgeted h20 system. I have all the pieces for mine, and they will be going in shortly. I will get some pictures when done.

[RoadRace]

the washer pump set ups work fine with low-boost (under 15 psi) draw-thru carbed/efi turbo systems. they have (in my research) put out 15 - 30 psi, but the flow rates don't hold up at the higher pressures, which becomes a major problem when you lean on the motor. They don't work as well with efi/intercooled set ups because you have to put the nozzle ~6" in front of the TB after the turbo and the boost pressure cancels the h20 inj pressure, negating the effectivity of the system. which is why the shurflo pump is the way to go. running up to 220psi and with a flow rate that can sustain the power levels that you want, the only thing you will need after that is the varible flow rate controller. running straight methyl hydrate has been flawless in my experience. i know guys that are starting to run nitromethane in small percentages in the tank but i am in no rush to try that.

[datzenmike]

Just run a small hose from the boosted part of the intake to the sealed reservoir with the pump. As boost climbs the reservoir with the mump matches it and the pump pressure remains the same. (well rleative to the manifold pressure)

[RoadRace]

boost-referencing the anti-detonant reservior might not be enough. The actual pressure of the system is generally not as much of an issue as the volume of anti-detonant requred - which has several variables like engine volume, power output, base fuel, and of course boost level and volume of air. There was a few things missing from the authors research, namely the size and length of tubing used and if that spec is applicable to the 'real-world' requirements of what the system is being designed for. 2) the open and restricted flow rates of each of the pumps. if you have a single .020" or .030" orifice then the washer pump will work, but it doesn't matter if you put 100psi through it, its just not gonna flow what you need - relative to the application, of course. 3) it would have been interesting to see what a combination of low-dollar pumps would flow in parallel, possibly into a pressure vessel simulating intake air flow.

[fo0manchu]

Works fine in an efi/intercooler setup. Again, this is a budget setup for low boost. I would never run this setup with anything over 15lbs of boost. This can be setup to run 10lbs of boost and no timing retard. If you read about the pumps, they put out way more than 30psi.

 

Also, nozzles do not have to be 6" away from the throttle body. It can be inches away. Mine is about 2" away from the throttle body and works fine.

 

220psi from a shurflo. Man, thats a lot of psi. I guess that would work fine if you are running a multi-nozzle setup and running like 30lbs of boost. Having one nozzle coming in at 10lbs, then 18lbs, and then 25lbs.(something like that). Keep in mind, using washer pumps is solely for the purpose of cheap, low boost setups.

 

60-100psi shurflo's have been in use for some time now and work excellent.

 

Having them tested in a pressured pipe would be a good test. I might have to do that.

[datzenmike]

Hang on. Pressure means very little. There are pumps that can produce thousands of PSI but only a trickle of volume. You won't need to spray fine droplets of water, I think a 200,000 RPM turbo blender would do this just fine. The squirt from a windshield washer would be plenty. You want a pump that can supply the correct volume (or more, but not less) of water at your maximum RPMs and Boost. A single nozzle would supply a set volume. If just enough for say 3K RPMs then it won't be enough at 6K, the equivalent of running lean. If good for 6K it would be rich at half the RPMs. Too much water will over cool the combustion process and kill power. Some way would need to be found to increase the water delivery as the RPMs increased.

 

 

Some thoughts... the majority of the time nothing is needed. Only under severe boost would there be detonation that needed taming. Different humidity and temp. would change the level at which detonation occurs. A knock sensor would be perfect for detecting detonation and triggering water injection. (just like ignition retard) But it would only turn it on, it couldn't vary the amount.

[fo0manchu]

dual setup with 2 pressure switches, using smaller misting nozzles. If running 12lbs/boost, one can set it up so one pump comes on like at 5 and the other at 9 or 10lbs boost.

 

However, Datzenmike, the finer the droplets the better. It will do a better job at lower temps and absorbing the heat. The turbo really doesn't do a good job of breaking droplets into smaller ones. After all, if you are running 10 lbs of boost, those droplets are only seeing that 10 lbs. Ever shoot an air blower from a air compressor at water drops on a car. It just moves them and doesn't really break them up any, even at 60psi of air pressure.

[datzenmike]

I'm assuming that the water is injected before the turbo... 30,000 to what 200,000 RPM? turbine blades aren't going to chop it up?

[fo0manchu]

if you are spraying pre-turbo, you want it misted as fine as possible. You want the most water pressure with the smallest nozzle size possible. The reason for this, is so you don't pit your blades, or worse break pieces of it off. Water droplets hitting your compressor wheel going that fast can be detrimental to your turbo. The goal of spraying pre-turbo would be that the mist is so fine that once its between the blades it evaporates and cools down the heat given off by the turbo, bringing the temp of the air very close to the ambient temp.

 

I know I don't do the best job explaining this, but before I did water injection I spent a great deal reading. I just searched for "pre turbo water injection".

 

However, I plan on doing pre turbo water injection later on. The benefits are pretty fricken awesome. One of them being, making your turbo run a lot more efficient as if it were a bigger turbo and totally changing up the compressor maps... Sweet!

[510six]

if you are spraying pre-turbo, you want it misted as fine as possible. You want the most water pressure with the smallest nozzle size possible. The reason for this, is so you don't pit your blades, or worse break pieces of it off. Water droplets hitting your compressor wheel going that fast can be detrimental to your turbo. The goal of spraying pre-turbo would be that the mist is so fine that once its between the blades it evaporates and cools down the heat given off by the turbo, bringing the temp of the air very close to the ambient temp.

 

I know I don't do the best job explaining this, but before I did water injection I spent a great deal reading. I just searched for "pre turbo water injection".

 

However, I plan on doing pre turbo water injection later on. The benefits are pretty fricken awesome. One of them being, making your turbo run a lot more efficient as if it were a bigger turbo and totally changing up the compressor maps... Sweet!

 

 

 

An example of a typical water injection mister/jet.

 

I agree that the shurflo pump would be the best choice. Are you going to use a Hobb switch to activate the pump, do you plan on using a controller to vary the voltage to the pump?

 

IMO running 12 psi with a "smallish" turbo I wouldn't see a problem with using a basic water injection system.

 

My only complaint with systems that add methanol as fuel/chemical IC is the ability to really fine tune the amount of methanol/alcohol delivered. The solution initially was found to be running two very large injectors in the intake tract aimed at the turbo about 12" away, this provided maximum cooling effects from the methanol.

 

 

This shows an over 80* drop in temps using 35% methanol as the total fuel.

 

[RoadRace]

if you are spraying pre-turbo, you want it misted as fine as possible. You want the most water pressure with the smallest nozzle size possible. The reason for this, is so you don't pit your blades, or worse break pieces of it off. Water droplets hitting your compressor wheel going that fast can be detrimental to your turbo. The goal of spraying pre-turbo would be that the mist is so fine that once its between the blades it evaporates and cools down the heat given off by the turbo, bringing the temp of the air very close to the ambient temp.

 

I know I don't do the best job explaining this, but before I did water injection I spent a great deal reading. I just searched for "pre turbo water injection".

 

However, I plan on doing pre turbo water injection later on. The benefits are pretty fricken awesome. One of them being, making your turbo run a lot more efficient as if it were a bigger turbo and totally changing up the compressor maps... Sweet!

 

you don't spray before the turbo unless you have to - like in a draw-thru system. as mentioned, there are some factors to consider, the big one is compressing anti-detonant, you can atomize it all you can, but its going to be compressed again when it leaves the turbo, you can't compress a liquid and you will NEVER vaporize 100% of it - if you have an intercooler, this is rule #1 on what not to do, anything introduced can puddle in the intercooler and 'go boom' at some point beyond your control. when spraying anything into an engine with a T/Body, you have to assume thats its going to be after the turbo, if so equipped. 6" in front of (before) the TB is the optimum location for maximizing atomization and intergration of the injected substance with the intake air. This has been proven, if you have good resuts with the nozzle anywhere else, then cool - keep it up. but if you have a problem in the future, consider moving the nozzle.

 

there has been disussion about flow rate vs pressure: this is a reference document from Alkycontrol. the nozzle size is there proprietary numbering, but the orifice (and flow) gets bigger as the numbers do. i run 2 M15's. Ok - apparently i can't post a picture - interesting, well, its a nice chart...

 

Foo - please elaborate on this statement:"One of them being, making your turbo run a lot more efficient as if it were a bigger turbo and totally changing up the compressor maps... "

 

from my experience - and please understand i am not a turbo expert - the compressor map is finite, based on the physical fixed properties of the compressor entry 'mass flow' (diameter, radius, blade design. etc) using corrected air numbers. obviously this can change slightly due to atmospheric conditions, which is why its made using corrected numbers - is this what you meant? using the early atomization and cooling properties of methyl hydrate to increase turbo performance?

 

and yes, i did see that the washer pumps had more than 30 psi - but these numbers - although useful - had little significance because they were 'labratory' numbers. you need to have more pressure than you need to compensate for real world factors, like hose length, hose diameter, 90 degree bends in the hose, nozzle diameter and voltage drop - basically the installation is very important to the performance of the system. a 60 psi pump will generally not give you 60 psi when installed, and if you need 60psi, well, you don't want to run anything at 100% all the time.

 

i'd still like to see the flow rate of the washer pumps, i'd even like to see the pump from the mercedes headlight washers, its got to be a high tech unit. Just run them for one minute into a can and measure what you have, then do it with a T fitting and 2 hoses into the can. then put nozzles in there and see what happens.

[fo0manchu]

I still don't 100% agree with the 6" before TB. I guess it would depend on ones setup and what engine they are running. In my case, its on a ka24de which has long runners so it has plenty of time to cool the air charge. But it would make sense mounting it 6" or further away, say if using it on an sr20det with an after market plenum as those are really short. As far as maximum atomization, the only thing that will atomize water is the nozzle and the pump. So once the water droplets are in the intake track, the air in the intake will have a negligible effect on further atomizing the water droplets.

 

Here's a link about nozzle placement: http://www.alcohol-injection.com/articles/where-to-locate-your-alcohol-water-injection-nozzle-2/

 

Here's a discussion about pre-turbo injection: http://www.aquamist.co.uk/phpBB2/viewtopic.php?t=267&postdays=0&postorder=asc&start=0&sid=17871242657337781b7db7b268de2a41

 

Theres more articles/discussions if you google it as well.

 

510Six: Yep, I got a pressure switch activating the pump. My setup is really basic right now. I always like to start real simple, get all the kinks out of it, and then start to upgrade the system little by little. My system so far is a single nozzle, check valve, shurflo pump activated by a pressure switch at 4psi. No innercooler = no psi drop going through the innercooler + faster spool time.

 

BTW: I like this discussion, all this is making me more knowledgeable about water injection and how to tweak my setup more for the best outcome later on. Thanks for discussing! :cool:

[510six]

I think the "basic" system you have will work just fine for your application. A friend with a 522 CI Ford stroker motor is going to be using a very similar water injection setup to cool the intake charge with a Borg Warner S480 turbo @10psi. I don't see a problem with either systems.