Water Injection
10-31-2003, 05:11 PM
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Water Injection
A new forum sponsored by Auqamist has started on Water Injection. Anyone using FI might want to check it out here:http://www.turboice.net/forum/
10-31-2003, 08:13 PM
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Been there. I know it works in theory. But I just don't like the idea... thanks for pointing this out, though, FP. Post your own experience, however, as I'd love to hear how it's working for you.
CB
CB
11-01-2003, 10:53 PM
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I looked into installing one on mine and did not like how the windshield wiper water reservoir was buried into the right fender.
That discouraged me from installing one.
Secondly I heard that it would be better to install it after the throttle body was the second thing that discouraged me.
I would like to hear about others that have installed theirs.
I was going to go with aquamist S1 kit with a 1.0mm nozzle.
That discouraged me from installing one.
Secondly I heard that it would be better to install it after the throttle body was the second thing that discouraged me.
I would like to hear about others that have installed theirs.
I was going to go with aquamist S1 kit with a 1.0mm nozzle.
11-02-2003, 04:19 AM
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Originally posted by Honda-S2000VTec
I looked into installing one on mine and did not like how the windshield wiper water reservoir was buried into the right fender.
That discouraged me from installing one.
Secondly I heard that it would be better to install it after the throttle body was the second thing that discouraged me.
I would like to hear about others that have installed theirs.
I was going to go with aquamist S1 kit with a 1.0mm nozzle.
I looked into installing one on mine and did not like how the windshield wiper water reservoir was buried into the right fender.
That discouraged me from installing one.
Secondly I heard that it would be better to install it after the throttle body was the second thing that discouraged me.
I would like to hear about others that have installed theirs.
I was going to go with aquamist S1 kit with a 1.0mm nozzle.
11-02-2003, 09:16 AM
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My interest in this was generated by concerns I had about engine longevity back before I had the AEM EMS and had no idea if the stock ECU was seeing detonation and pulling timing. Thus, anything to cool the charge seemed prudent and worth considering. I wasn't interested in it as a means of getting more power out of the car (cooler charge = more aggressive timing = more power). Since the EMS install, I've been able to see from my datalogging that I've no need to be concerned about detonation (admittedly, I'm not running a huge amount of boost and my timing is conservative), despite the fact that I'm producing more than enough power to satisfy my needs/interests. I've also been able to tell that the huge intercooler is doing its job well -- my AIT's are very close to ambient temperature except under very slow driving (where I'm not in boost anyway). But I suppose if you're looking for more power, this is a good means of getting it.
CB
CB
11-02-2003, 09:47 AM
#6
I dropped Aquamist some email awhile back and published thier response but I can't find it...fperra i think you were on that thread too. I still think it's interesting but I agree with cbender if you can manage it accurately it's not needed...
My neighbor has spent the last few months supercharging an 88 325i. He's using a homemade water injection system with alcohol mixed in. The system was easy to make the money's in the nozzles..$60 bucks each I think. He has it built so he can turn it off or on and then it comes on with rpms and throttle control. His intake is almost cold to the touch with it. He's running a 1 liter eaton with a mass air and a chip..no intercooler.
there is some good information in the usgov archives too, I think I published that link as well but cant find it...
fltsfshr
My neighbor has spent the last few months supercharging an 88 325i. He's using a homemade water injection system with alcohol mixed in. The system was easy to make the money's in the nozzles..$60 bucks each I think. He has it built so he can turn it off or on and then it comes on with rpms and throttle control. His intake is almost cold to the touch with it. He's running a 1 liter eaton with a mass air and a chip..no intercooler.
there is some good information in the usgov archives too, I think I published that link as well but cant find it...
fltsfshr
11-02-2003, 03:39 PM
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I ran water injection (Aquamist 1s system) on my CRX for quite a while. In principle it works very well, but in reality it is not very effective for supercharged cars, especially positive displacement supercharged cars. For turbo cars it can be useful if you're limited on intercooler size or flow. Here's why.
On any FI car, you need to inject the H2O _after_ the compressor section. If you inject it before the compressor section you're not putting the water where it needs to be in terms of temps/evaporation, etc. Yes, the Aquamist atomizes water very well from the nozzle, but it needs to fully evaporate for maximum benefit. In a PD SC car, this means injecting after the blower rotors. Usually, this leaves very little space for injection because the blower is likely to be very close to the intake ports of the cylinder head. The result is that it is very,very difficult to get proper distribution of H20 to each cylinder (water vapor does not flow the same as air). Thus, you end up injecting too much (or not enough water) and there is little time for the water to absorb heat. On my CRX, even with aftermarket engine management, power gains were zero, and we had to advance the timing just to get power back to where it was _before_ the water injection was installed. Any more and it began to detonate again.
On a turbo car, things are a little better, because you can inject the water between the compressor section and the intercooler. The intercooler is critical here because it gives plenty of time and volume for the water to evaporate and can even improve heat transfer. I have seen some turbo cars pick up 10-20 hp from H2O injection, but they have typically utilized smaller than ideal intercoolers and the water acted to improve the efficiency of the heat exchanger.
Even in the case of a turbo car, you'll need engine management to take advantage of the water injection properly, and then you'll find that the relative benefits, as cbender pointed out, tend to be pretty minimal unless your intercooler is undersized.
UL
On any FI car, you need to inject the H2O _after_ the compressor section. If you inject it before the compressor section you're not putting the water where it needs to be in terms of temps/evaporation, etc. Yes, the Aquamist atomizes water very well from the nozzle, but it needs to fully evaporate for maximum benefit. In a PD SC car, this means injecting after the blower rotors. Usually, this leaves very little space for injection because the blower is likely to be very close to the intake ports of the cylinder head. The result is that it is very,very difficult to get proper distribution of H20 to each cylinder (water vapor does not flow the same as air). Thus, you end up injecting too much (or not enough water) and there is little time for the water to absorb heat. On my CRX, even with aftermarket engine management, power gains were zero, and we had to advance the timing just to get power back to where it was _before_ the water injection was installed. Any more and it began to detonate again.
On a turbo car, things are a little better, because you can inject the water between the compressor section and the intercooler. The intercooler is critical here because it gives plenty of time and volume for the water to evaporate and can even improve heat transfer. I have seen some turbo cars pick up 10-20 hp from H2O injection, but they have typically utilized smaller than ideal intercoolers and the water acted to improve the efficiency of the heat exchanger.
Even in the case of a turbo car, you'll need engine management to take advantage of the water injection properly, and then you'll find that the relative benefits, as cbender pointed out, tend to be pretty minimal unless your intercooler is undersized.
UL
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11-02-2003, 06:34 PM
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fperra - Thank you for spreading the word about our water injection information forum. Just to clarify though the site has no affiliation with Aquamist or ERL, other than that Richard from ERL is a member of the site and he was kind enough to post a link to it on his site. The forum is actually sponsored by an Aquamist dealer (Charged Performance), though as much as can be acheived it seeks to remain noncommercial without advertising or vendor sales pitches in order to not dilute its intended informational content.
Throttle body posters - Yes the recommendation of many is to jet before the throttle body if it can be done. However there is no requirement for this. Many applications out of necessity or for purpose do jet after the throttle body, a check valve just needs to be employed to prevent siphoning during vacuum states. The recommendation before the throttle body has its sources generally in the desire to have as much time as possible to mix with the induction charge evenly before the cylinders. However with cars that have longer intake tracts (like horizontally opposed engines) jetting after the TB is fine.
With regards to jetting pre or post compression - either can be done in theory and both will provide the same intercooling described. It doesn't matter when the water is introduced - the water will absorb heat when it encounters it. The issue with posting pre-compression relates to chargers that are centrifugal and use lightweight materials - this can unbalance or pit the material. This has not been seen on heavier duty deisel turbos or on any roots blowers that I am aware of. Many GTPs are using WI with success pre-blower both before and after the throttle body. The nice thing about injecting before a roots type of blower is that it does ensure even distribution on what would otherwise be a short intake tract. Injecting after a roots blower is problematic unless multiple jets are used because of the short intake tract post blower. Generally on centrifugal chargers there is plenty of intake for even mixing post compression so there is no need to risk damaging the compressor by injecting before hand unless one is sure the materials can handle it.
Use of water injection solely for intercooling is limiting the understanding that water plays in combustion and engine efficiency (whether discussing power efficiency or economy efficiency) - I worked up a paper that goes through everything water injection affects and why it is the pinnacle of tuning tools. The immense amount of feedback from that paper was the reason I started the forum.
Here is the paper: Water Injection Paper
While it was written with turbo-charging in mind, it is equally applicable to all forms of forced induction as well as high compression N/A applications. My original use of water injection as a kid in the 80's was for high compression small and big block V-8s.
To take full advantage of water injection control over fuel and timing is required - with tuning control water injection adds more than you might expect. Without tuning control water injection is little more than an additional buffer to knock and with too much water and continuing overly rich fuel settings is likely to hurt power.
Lastly - some users have successfully eliminated intercoolers using water injection. This provides a lot of opportunity when you can eliminate excess pipe length and also the associated pressure drop of intercoolers.
Ed.
www.turboice.net
Throttle body posters - Yes the recommendation of many is to jet before the throttle body if it can be done. However there is no requirement for this. Many applications out of necessity or for purpose do jet after the throttle body, a check valve just needs to be employed to prevent siphoning during vacuum states. The recommendation before the throttle body has its sources generally in the desire to have as much time as possible to mix with the induction charge evenly before the cylinders. However with cars that have longer intake tracts (like horizontally opposed engines) jetting after the TB is fine.
With regards to jetting pre or post compression - either can be done in theory and both will provide the same intercooling described. It doesn't matter when the water is introduced - the water will absorb heat when it encounters it. The issue with posting pre-compression relates to chargers that are centrifugal and use lightweight materials - this can unbalance or pit the material. This has not been seen on heavier duty deisel turbos or on any roots blowers that I am aware of. Many GTPs are using WI with success pre-blower both before and after the throttle body. The nice thing about injecting before a roots type of blower is that it does ensure even distribution on what would otherwise be a short intake tract. Injecting after a roots blower is problematic unless multiple jets are used because of the short intake tract post blower. Generally on centrifugal chargers there is plenty of intake for even mixing post compression so there is no need to risk damaging the compressor by injecting before hand unless one is sure the materials can handle it.
Use of water injection solely for intercooling is limiting the understanding that water plays in combustion and engine efficiency (whether discussing power efficiency or economy efficiency) - I worked up a paper that goes through everything water injection affects and why it is the pinnacle of tuning tools. The immense amount of feedback from that paper was the reason I started the forum.
Here is the paper: Water Injection Paper
While it was written with turbo-charging in mind, it is equally applicable to all forms of forced induction as well as high compression N/A applications. My original use of water injection as a kid in the 80's was for high compression small and big block V-8s.
To take full advantage of water injection control over fuel and timing is required - with tuning control water injection adds more than you might expect. Without tuning control water injection is little more than an additional buffer to knock and with too much water and continuing overly rich fuel settings is likely to hurt power.
Lastly - some users have successfully eliminated intercoolers using water injection. This provides a lot of opportunity when you can eliminate excess pipe length and also the associated pressure drop of intercoolers.
Ed.
www.turboice.net
11-02-2003, 08:13 PM
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No, no pitting, just fragging the unsealed bearings on the rotors of Eaton blowers. Been there, done that. Do not inject before the blower unless you want a nice rebuild invoice from Magnussun. Furthermore, injecting before the compressor ends up wetting out the compressor section which reduces the effectiveness of the water you _have_ injected.
Water injection has its uses, but if you've got a good intercooler its not particularly cost effective (since a properly sized intercooler should see charge drops of no more than 1-2 psi and keep temps within 30F of ambient - worst case. The only exception is if you want to inject a little methanol without going through the pains of a dedicated methanol fuel system.
UL
Water injection has its uses, but if you've got a good intercooler its not particularly cost effective (since a properly sized intercooler should see charge drops of no more than 1-2 psi and keep temps within 30F of ambient - worst case. The only exception is if you want to inject a little methanol without going through the pains of a dedicated methanol fuel system.
UL
11-02-2003, 08:54 PM
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Ouch - I can mark that one up as the worse experience I have heard of before the compressor. The GTP crowd must have sealed bearings as I have not heard this from their experiences. I have always avoided before the compressor because there really is no compelling reason to unless you have a roots type right on top of the plenum with short runners - but now that has to be conditioned on having sealed bearings.
BTW even completely negating the intercooler benefits of water injection - the role it plays in the cylinder during compression and combustion is much more significant. For instance it is a very difficult proposition on top mounted intercoolers to inject before the intercooler anyway - yet WRX tuners are experiencing great gains injecting after the intercooler in front of the throttle body. Most of them are already using aftermarket intercoolers so they are not seeking intercooler effects.
Though it is incredible how much efficiency you can gain by eliminating a pound or two pressure drop if you can eliminate the piping and core associated with an intercooler completely. The turbo doesn't work as hard, the charge isn't as heated, yada, yada...
Ed.
www.turboice.net
BTW even completely negating the intercooler benefits of water injection - the role it plays in the cylinder during compression and combustion is much more significant. For instance it is a very difficult proposition on top mounted intercoolers to inject before the intercooler anyway - yet WRX tuners are experiencing great gains injecting after the intercooler in front of the throttle body. Most of them are already using aftermarket intercoolers so they are not seeking intercooler effects.
Though it is incredible how much efficiency you can gain by eliminating a pound or two pressure drop if you can eliminate the piping and core associated with an intercooler completely. The turbo doesn't work as hard, the charge isn't as heated, yada, yada...
Ed.
www.turboice.net