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Location:
Canberra
Registered:
April 2003
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Water Inj. on 4AGZE
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Tue, 02 August 2005 12:46
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I'm putting water injection on my GZE because i've heard mostly positive things about these systems. There are a few grey points i need a few opinions on though.
PLease point out if these are wrong
Before or after charger??
Before
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Compression in a turbo is usually adiabatic. This means that the air is heated as it is compressed, which takes power from the shaft and requires removing through an intercooler. If you inject water before the turbo, then you can move compression to near isothermal, so very little heat is added, and less power is taken from the turbine to compress the air for the same boost level. You can loose the intercooler and therefore suffer less pressure drop between compressor and inlet. All of which gives you the possibility to get more power out the same turbo.
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I'm thinking this will be the same theory for a charger, and take less power from the crank to turn. I've also heard that, if atomised correctly, and with a 45%water/50%methanol/5%softener, it can also help the vanes seal better, and make the charger more efficient. The effect of un-atomised water hitting the vanes worries me though
After
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Here you are adding water to deal with combustion and detonation reduction. Ideally you would inject directly into the chambers to minimise any charge displacement.
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This way can increase timing and not worry about charger damage.
cooler or not to cooler?
With water injection, is it neccesary to run an intercooler? especially with an sc12 struggling to push out >15psi.
Benefits of no intercooler - shorter intake track, les weight, no pressure drop from cooler, better throttle response...
Anyone with experience, your input would be appreciated 
Cheers
Steve
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: Water Inj. on 4AGZE
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Tue, 02 August 2005 13:54
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for a measly $300-500 you can grab an ARC or similar GZE topmount intercooler replacement.
THey are much more efficient than the standard cooler, require stuff all effort to fit, and will probably do more good than water injection....
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Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Tue, 02 August 2005 19:09
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part water/alchohol injection is good for a minimum or about 15% power gains. it increases compression, reduces detonation and makes for a cooler intake.. what more could you want? very similar feeling to a nitrous shot.
problems would be a source of water and injection timing (youd only want it running at WOT and not at the redline)
i don tknow about putting water B4 the turbo though... a short length b4 the throttle body would be good. (your egoing to need some kind of electronics to time this thing)
another thing is to find a injector that can handle water/alchohol. a good one woul dbe a cold start injector, but those you cannot provide a viariable squirt.
dont loose the IC. use it after the charger, no point cooling down teh air then letting it heat up again in te charger.
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Location:
Canberra
Registered:
May 2002
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Re: Water Inj. on 4AGZE
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Tue, 02 August 2005 22:31
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I'm working on it at the moment, mine is a two injector setup, using a surflo pump, an Ebay fuel pressure regulator, standard automotive fuel injectors and Jaycar electronics.
I'm mounting one injector before the supercharger and another after the IC.
I'm planning on either usign soluble oil or radiator corrosion inhibiter to stop the injectors rusting.
I've got most of the hardware together now, hopefully, I can do some prototype system flow testing on the weekend.
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Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Tue, 02 August 2005 22:40
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do NOT inject water before the turbo.
water may not seem it but it IS very hard and will chew your compressor wheel out very fast.ive seen this first hand and its not pretty.
the other flaw that water injection systems when tuned to their limit (lets face it it will be) is if you run out of water,get a blocked injector or have a pump failure you will detonate instantly.
im not saying dont do it,as there is definate gains to be had by using it, but you need to understand it before you fit it up and drive away if you know what i mean.
im considering using it myself,post intercooler with methanol in my rb25/30
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Location:
Canberra
Registered:
May 2002
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Re: Water Inj. on 4AGZE
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Tue, 02 August 2005 23:48
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| rb30 boy wrote on Wed, 03 August 2005 08:40 |
the other flaw that water injection systems when tuned to their limit (lets face it it will be) is if you run out of water,get a blocked injector or have a pump failure you will detonate instantly.
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Exactly the same thing could be said of a fuel injection system, and they seem to work OK...
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Location:
Perth
Registered:
January 2005
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Re: Water Inj. on 4AGZE
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Wed, 03 August 2005 00:25
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Hi,
With regards to pitting/erosion of the turbo compressor wheel, I am sure that the droplet size has a LOT to do with it.
On the subject of water injection on the 4AGZE. I have tried it with success using a positive displacement windscreen pump that generated 60psi and would you believe a $1 garden spray nozzle before the supercharger (actually just after the air filter). The droplet size was fairly coarse _BUT_ Seat of the pants difference was surprising, a bit more torque everywhere. Right up to 7000rpm the cars acceleration was improved, and no torque drop off up steep hills, mind you, this was with the standard intercooler.
This with no injection or ignition changes.
I now have an 18psi SC14 setup and have an improved home-made mist injection system that I will hopefully set up this weekend.
details at :-
http://www.e-wire.net.au/~nrparker/MR2/MR2.htm
(links at top of page)
If any setup could benefit from WI my one will. 18psi is generating a shitload of heat in the SC, but a LOT more torque!
Might have to get the SC rotors coated in a higher temp coating!
I'll let you know how it goes.
Nick.
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Location:
Canberra
Registered:
May 2002
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Re: Water Inj. on 4AGZE
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Wed, 03 August 2005 00:41
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Did you notice an actual increase in boost?
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On Probation
Location:
Sydney
Registered:
April 2005
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Location:
Canberra
Registered:
April 2003
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Re: Water Inj. on 4AGZE
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Wed, 03 August 2005 10:29
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| Ben Wilson wrote on Wed, 03 August 2005 08:31 |
I'm mounting one injector before the supercharger and another after the IC.
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Just do both, I like it 
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On Probation
Location:
Sydney
Registered:
April 2005
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Re: Water Inj. on 4AGZE
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Wed, 03 August 2005 12:51
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Running two injectors is common.
A sequential system is even more common. A smaller (primary) injector is used at low boost, positioned after the IC and a larger (secondary) injector is used at full boost/Throttle before the SC or intercooler, to completly cool down the charged air.
It is ok to inject water before a super charger, however not such a good idea before a turbo charger.
I hope this helps.
Thanks Jordan,
fross@bigpond.net.au
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I supported Toymods
Location:
Sydney
Registered:
May 2002
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Re: Water Inj. on 4AGZE
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Wed, 03 August 2005 14:12
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| THE WITZL wrote on Tue, 02 August 2005 23:54 |
for a measly $300-500 you can grab an ARC or similar GZE topmount intercooler replacement.
THey are much more efficient than the standard cooler, require stuff all effort to fit, and will probably do more good than water injection....
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Not a bad option the ARC top mount. They do work better less heatsoak due to bigger core end tanks and do not require any real maintance like water injection.
I had running an ARC (AE101GZE) and re-routed my window washers to positon aiming towards the cooler. So Whenever I wanted more throttle response i'd just press the Water for the wipers.
If you can try go a W2A setup. But yeah try out the water injection setup for your self and let us know how it goes 
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Location:
Brisbane
Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 00:52
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| nick.parker wrote on Wed, 03 August 2005 10:25 |
I now have an 18psi SC14 setup and have an improved home-made mist injection system that I will hopefully set up this weekend.
details at :-
http://www.e-wire.net.au/~nrparker/MR2/MR2.htm
(links at top of page)
If any setup could benefit from WI my one will. 18psi is generating a shitload of heat in the SC, but a LOT more torque!
Might have to get the SC rotors coated in a higher temp coating!
I'll let you know how it goes.
Nick.
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Has anyone else actually got this amount of boost out of an SC14??? Are they a roots style or eaton? Either way I thought they would be over-spinning to generate more than about 15 psi???
I am thinkin of doing a WI system on a 1G-GZE that injects just after the throttle body. The idea is to set up a pressure tank, which is pressurised by a boost line. When boost comes on, the tank increases in pressure, injecting water into the intake at a rate prescribed by the size of the nozzle.
My biggest concern is the water/ethanol mix siphoning out of the tank. I was planning to use a small inline pressure valve in the 1/8" injection line, set to open at say 8-10 psi. However i am not sure about how much force there is in the venturi effect the intake will create on the nozzle.
Not alot on a tiny little mister i would think???
Any experience i ppl have that i can draw on would be greatly appreciated.
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Location:
Perth
Registered:
January 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 01:53
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Hi,
Yep, a few people. Log onto www.mr2oc.com (US owners club site) theres a couple of guys there getting 18-20psi (SC14 conversions of course) One guy is doing 13.5 sec quarters. I hope to do this time and better with a few more mods. Gotta love the stock 4AGZE!
I've got my ECU controlling a mist nozzle now, just got to drill and tap to put the Aquamist nozzle in. Will post my results.
I am using a tyre compressor to generate 100psi to compress air above some water and force the water through my auamist nozzle.
Tyre compressor = $6, Aquamist pump = $700......!!! Of course you need an air pressure reg and some fittings which brings the price up...
Do some calcs mate. The SC14 is not 'overspinning' to generate 18psi on an engine the size of a 4AGZE (<10K speed at 7500rpm). Also the Eaton SC is a Rootes SC, but has three lobe rotors which are twisted. The lobes are twisted to reduce pressure pulsations - you know, the whining sound...??
Don't get confused with 'twin screw' superchargers which have often have different diameter 'male and female' rotors which run at different rotational speeds, and actually compress the air as it moves axially along the enclosed volume between the rotors. Examples of twin screw superchargers are Sprintex, AutoRotor...
Cheers Nick
[Updated on: Wed, 28 September 2005 02:06]
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Location:
Brisbane
Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 02:42
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My understanding is that Eaton superchargers are twin screw, ie nmale female rotors.
Also i have a 1G-GZE not a 4A which probably makes all the difference in terms of achieving that sort of boost out of an SC14...
Back to the WI tho;
I am thinkin i will not need to worry too much about atomisation if im injecting before the S/C as it will atomise the water very well itself. Thus i am lookin at a smaller (read lower psi) nozzle which can run from boost pressurising a radiator pressure tank.
????
I have heard of it being done but cannot find any examples...
The idea is that injection volume increases relative to boost, rather than the "all or none" pump setup. (not to mention no pump cost, wiring, etc)
However when boost = X, rpm's can vary and that is what determines air volume so i think this idea is flawed.
All water injection expertise needed please!!!! 
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Location:
Perth
Registered:
July 2002
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 03:04
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| terra wrote on Wed, 03 August 2005 03:09 |
part water/alchohol injection is good for a minimum or about 15% power gains. it increases compression, reduces detonation and makes for a cooler intake.. what more could you want? very similar feeling to a nitrous shot.
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How does water injection increase compression???
Mimimum 15% power gains???
Similar to nitrous???
Does it increase erection size as well???
Do you read Zoom, hot fours or something like drifting AE86 masturbation weekly??? 
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Location:
Perth
Registered:
January 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 03:51
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Hi,
In general, water mist prevents detonation (greatly raises the threshold) and enables the use of more ignition advance.
In high boost engines it will mean no fuel dumping is required to keep combustion temps down. As the extra fuel can be replaced with water. This means you can run a better (leaner) AFR to make more power (more cylinder pressure!).
I have used a crude water injection system before that worked well, using a garden sprayer nozzle and windscreen washer pump...it turned on at about 2psi and only had one setting - full flow. It was just after my air filter (for mounting convenience). See my website for details (link in sig)
With my new system I can use an angle based trigger of my injection solenoid, turn it on for a variable time (time from 3D map). So it is not flawed like you suggested at all. Infact if you want to get picky your system is restricted as you cant use an arbitrary function of water flow vs boost pressure!
Twin screw / twisted rotor...I don't care what you call it, but to those in the know, a twin screw implies internal compression which the Rootes (EATON) does not have. What makes Eaton interesting is that the air inlet is axial..unlike a lot of Rootes blowers, and like most (all?) twin screws.
Regards, Nick
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Location:
Brisbane
Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 03:51
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| Blown86 wrote on Wed, 28 September 2005 13:04 |
| terra wrote on Wed, 03 August 2005 03:09 |
part water/alchohol injection is good for a minimum or about 15% power gains. it increases compression, reduces detonation and makes for a cooler intake.. what more could you want? very similar feeling to a nitrous shot.
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How does water injection increase compression???
Mimimum 15% power gains???
Similar to nitrous???
Does it increase erection size as well???
Do you read Zoom, hot fours or something like drifting AE86 masturbation weekly???
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I tend to agree...
minimum 15% gain
It would feel more like umm, an intercooler. Prpobably since they are both cooling the intake charge.
The compression thing tho, well... No again. I think. The water will replace some of the intake charge volume. Ecept that water cannot be compressed so it is essetially taking up the space of fuel???
Ethanol is added to the injection mix so that some of this volume is a fuel & will compensate for power loss of less fuel, and running to lean???
WHERE ARE ALL THE GOD DAMN EXPERTS???
SHOW THYSLEVES AND SPEAKETH TO ME...
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Location:
Brisbane
Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 03:59
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| nick.parker wrote on Wed, 28 September 2005 13:51 |
With my new system I can use an angle based trigger of my injection solenoid, turn it on for a variable time (time from 3D map). So it is not flawed like you suggested at all. Infact if you want to get picky your system is restricted as you cant use an arbitrary function of water flow vs boost pressure!
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Please elaborate on this para. I am not suggesting your idea is flawed, rather mine.
How does your system vary volume of water injected at hypothetically 3000rpm @ 15psi compared to 6000rpm @ 15psi???
I cant see how mine can and that is my concern.
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Location:
Toronto, Downtown
Registered:
September 2004
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Location:
Perth
Registered:
January 2005
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Location:
Brisbane
Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 06:44
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Thanx heaps nick. Sounds like a pretty comprehensive system you have. Tell me how you calculated water volume???
Also on the S/C thing i tried to find out about the rootes / twin screw thing:
There are three commonly used types used in today's automotive world: Roots type supercharger, and Eaton or twin-screw type supercharger, and Centrifugal type supercharger.
taken from - http://www.answers.com/topic/supercharger
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Location:
Parramatta
Registered:
July 2002
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 07:00
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i have looked into this for a very long time now and i will one day get around to it, i think water injection is a great thing there is very little downsides, and major upsides to it. I belive with a combination of both an air to air cooler and the water injection you can not go wrong this is what i will be doing i have the air to air, and having an mr2 there is not much for cooling without getting a water to air. (wishing i did this at the time) however i am going to throw on the water injection and this will fix those extra hot days, and prevent detination.
all that you have to make sure is that you do have an extra pump and water always in the tank other wise tune it so that you could get away with the use of no water. Or better yet use water injection as a saftymeasure, ie have the cooler air to air and then put water injection to cool the intake charge just that little bit more. so this way its not reliant on the water.
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Location:
Perth
Registered:
January 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 07:01
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Ok.
Don't believe everything you read. Or atleast read it in a few different places first - same goes for everything on this planet!
The Eaton has helical (twisted) rotors, this is not the same thing as a screw compressor. The main point is the Eaton does not have 'internal compression'. Real twin screws have more complex rotor designs and cost more than Eatons! Sometimes twin screw has different size male and female rotors to reduce inertia....I can understand why people might call the Eaton a twin screw though. BUT :- the Eaton is a 'fancier' Rootes design _Nothing_ more.
To calculate water volume...go to Google or find an expert or do it empirically (play). Crudely, water (by volume) is usually a percentage of fuel like say 5% - 30%.
Cheers, Nick
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Location:
Toronto, Downtown
Registered:
September 2004
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 07:03
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you could allways just buy an ecu with enough outputs/imputs to controll the water injection with corrections for inlet air temps etc
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Location:
Brisbane
Registered:
July 2005
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 07:14
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Yeah well i was planning to calculate it roughly (for the purpose of sizing the nozzle) as follows;
(engine capacity X max rpm X (1 + max boost psi/14.7))
to get air volume per minute
ANS X air/fuel ratio X 10%
to get max water volume per minute
Then calculate the same for lower revs and work out how the fuck to get the water volume to vary in between... as discussed
Sound ok at a glance???
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Location:
Rockhampton QLD
Registered:
July 2004
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Re: Water Inj. on 4AGZE
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Wed, 28 September 2005 07:52
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Anyone know who sells arc intercoolers?
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