Anybody use water injection?
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Originally posted by downshift
shiv knows what he is talkin bout. dont argue just listen.
shiv knows what he is talkin bout. dont argue just listen.
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Since Shiv is not doing much R&D on the Subaru side of things (unless STi stage II development has begun), he doesn't post here much anymore because he has nothing new to say. I imagine, however, that the Water Injection debate has begun anew at www.evolutionm.net and that you can find some new posting by him there.
downshift, I agree that Shiv knows what he's talking about. However, his powers of persuasion can be a bit lacking at times. He certainly does a LOT of research and knows as much about the theories of operation of the internal combustion engine as most OEM engineers, and his opinions are based on extensive knowledge and first hand experience. However, when his opinions on technical issues are questioned or doubted, he often gives brief defenses of them and leaves us to either agree with him or not. He's also incredibly busy, and simply doesn't have time to expound in detail why he does things a certain way. I think it's fair to say that most people educated in this field will agree with his positions, although not all. (Those of you who don't, please don't take offense to that remark.) My position on these matters is that Shiv's opinions and ideas almost always jive with what little I've learned in the past few years about how engines work and how to maximize their efficiency. I think that intelligent people who educate themselves in the manner Shiv has will almost always agree with him as well. Those who don't probably have a different perspective.
My, I digress. Back on topic, I haven't forgotten my promise to expound on my opinions regarding Water Injection. My apologies for gettign busy (and lazy
) the past couple weeks.
downshift, I agree that Shiv knows what he's talking about. However, his powers of persuasion can be a bit lacking at times. He certainly does a LOT of research and knows as much about the theories of operation of the internal combustion engine as most OEM engineers, and his opinions are based on extensive knowledge and first hand experience. However, when his opinions on technical issues are questioned or doubted, he often gives brief defenses of them and leaves us to either agree with him or not. He's also incredibly busy, and simply doesn't have time to expound in detail why he does things a certain way. I think it's fair to say that most people educated in this field will agree with his positions, although not all. (Those of you who don't, please don't take offense to that remark.) My position on these matters is that Shiv's opinions and ideas almost always jive with what little I've learned in the past few years about how engines work and how to maximize their efficiency. I think that intelligent people who educate themselves in the manner Shiv has will almost always agree with him as well. Those who don't probably have a different perspective.
My, I digress. Back on topic, I haven't forgotten my promise to expound on my opinions regarding Water Injection. My apologies for gettign busy (and lazy
) the past couple weeks.
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wow... first time looking at this thread in a long time. If I knew that my input was requested, I would have jumped in sooner. I haven't read every post in this thread. I'm afraid I just don't have the time right now. As for my stance on WI, I am neither pro or against it since I'm sure there are applications where it may prove to be beneficial once the tuning clouds have subsided. However, I have yet to see a Subaru application which results in clear power gains through water injection. I won't argue that a water injected car may be more thermally stable, all things equal, under sustained road racing conditions. But then again, under those conditions, I recommend the use of race gas as a knock surpressant, not water. It's more expensive, but it can result in both substantially greater power out as well as improved engine efficiency (if remapped accordingly).
As for WI on WRXs, I have yet to find an application which shows substantial power gains, even through appropriate re-tuning. Interestingly enough, another tuner over in the UK, who's opinion I trust also came to similiar conclusions in EJ20 applications, despite his indirect affiliation with a leading WI company. I have my theories as to why the EJ20 is reasonably WI-unfriendly but that's all they are... theories. Again, I am sure that there are applications where WI is useful. Especially on engines which struggle on the knock threshold to run any reasonable advance numbers at max load (such as an stock EVO, for instance, which runs a measely 4-10 deg of spark advance at WOT from 3000-6200rpm.) Here, an incremental 2-3 degree bump in spark advance yeilds huge relative efficiency gains assuming the absense of knock. More than enough to overcome the power robbing attributes of displacing air and fuel with H20.
Please understand that I approach this whole WI debate from the end results on the Dyno and work backwards from there. If I can or can't make extra power with WI, I try to figure out why that is, or isn't, the case. Likewise, I don't make up my mind as to its merits of WI unless I see evidence of it on the Dyno where, as one could say, is where the rubber meets the road.
Hope that better explains my stance on WI. Please feel free to use it and experiment with it. No harm in that. I'd just encourage everyone to confirm that they are seeing the gains that they expect on the dyno. Not by noting how much more boost, or additional ignition advance they can run.
Also, I am not an expert on WI. Tuning a few cars with and without it does not tell me everything there is about it's merits. Feel free to question my notions and experiment yourselves. However, my limited experience tuning with it does provide some conclusions which need to be explained in some reasonable manner.
Best Regards,
Shiv
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As for WI on WRXs, I have yet to find an application which shows substantial power gains, even through appropriate re-tuning. Interestingly enough, another tuner over in the UK, who's opinion I trust also came to similiar conclusions in EJ20 applications, despite his indirect affiliation with a leading WI company. I have my theories as to why the EJ20 is reasonably WI-unfriendly but that's all they are... theories. Again, I am sure that there are applications where WI is useful. Especially on engines which struggle on the knock threshold to run any reasonable advance numbers at max load (such as an stock EVO, for instance, which runs a measely 4-10 deg of spark advance at WOT from 3000-6200rpm.) Here, an incremental 2-3 degree bump in spark advance yeilds huge relative efficiency gains assuming the absense of knock. More than enough to overcome the power robbing attributes of displacing air and fuel with H20.
Please understand that I approach this whole WI debate from the end results on the Dyno and work backwards from there. If I can or can't make extra power with WI, I try to figure out why that is, or isn't, the case. Likewise, I don't make up my mind as to its merits of WI unless I see evidence of it on the Dyno where, as one could say, is where the rubber meets the road.
Hope that better explains my stance on WI. Please feel free to use it and experiment with it. No harm in that. I'd just encourage everyone to confirm that they are seeing the gains that they expect on the dyno. Not by noting how much more boost, or additional ignition advance they can run.
Also, I am not an expert on WI. Tuning a few cars with and without it does not tell me everything there is about it's merits. Feel free to question my notions and experiment yourselves. However, my limited experience tuning with it does provide some conclusions which need to be explained in some reasonable manner.
Best Regards,
Shiv
________
IOS GAMES
Last edited by Vishnu; Mar 7, 2011 at 04:14 AM.
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Shiv wrote
wow... first time looking at this thread in a long time. If I knew that my input was requested, I would have jumped in sooner. I haven't read every post in this thread. I'm afraid I just don't have the time right now.
wow... first time looking at this thread in a long time. If I knew that my input was requested, I would have jumped in sooner. I haven't read every post in this thread. I'm afraid I just don't have the time right now.
I suggest you read all the posts first before making your contribution to this thread - Please stop making sweeping statements that were not related to this thread.
Peter Head
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I am not sure I would take it that way. We each have our work and life priorities, based on the time he spends on it - his work is his life. And within that there are priorities and there is only limited time, I know this community wishes he was present as much as in the past rather than the Evo and other models, but that is what it is.
I guess I am pleased that he did take the time to give the most thorough and balanced response that I have seen from him on this topic. Though it appears that we will never agree with each other on things such as water doesn't displace air (when you consider density benefits and fuel reduction in the charge) or consumable fuel.
Until last summer when I decided for myself to take the time to research all the information out there on water injection my conclusions were based on the same basis as his is. It has worked for me every time when putting the rubber to the road or the rudder to the water (and helped others with prop to air) - but I could never explain why. If I had posted about it based on those observations my posts would be equally sweeping - as a matter of fact some of my posts on NASIOC early last summer before I really got into researching it probably were.
Keep in mind that Corky said it was a band-aid in two paragraphs and walked away from the topic - Shiv put more into his reasons for his conclusions than Corky did.
I would like to see a more considered response - but his time is his own to contemplate the many aspects of performance, there is no reason to expect his priorities to be ours. He has contributed too much not to repect the things he decides to work on even if they are not what others wish for.
Ed.
I guess I am pleased that he did take the time to give the most thorough and balanced response that I have seen from him on this topic. Though it appears that we will never agree with each other on things such as water doesn't displace air (when you consider density benefits and fuel reduction in the charge) or consumable fuel.
Until last summer when I decided for myself to take the time to research all the information out there on water injection my conclusions were based on the same basis as his is. It has worked for me every time when putting the rubber to the road or the rudder to the water (and helped others with prop to air) - but I could never explain why. If I had posted about it based on those observations my posts would be equally sweeping - as a matter of fact some of my posts on NASIOC early last summer before I really got into researching it probably were.
Keep in mind that Corky said it was a band-aid in two paragraphs and walked away from the topic - Shiv put more into his reasons for his conclusions than Corky did.
I would like to see a more considered response - but his time is his own to contemplate the many aspects of performance, there is no reason to expect his priorities to be ours. He has contributed too much not to repect the things he decides to work on even if they are not what others wish for.
Ed.
Last edited by jehcpa; Jan 12, 2004 at 04:50 PM.
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Jehcpa,
Personal views and discussions are not the same thing.
We have here on this thread with two very different results with water injection implementation on the WRX: Shiv and Annointed
(http://forums.nasioc.com/forums/show...n&pagenumber=1)
Rather having a fragmented discussion with people posting their views without specific relationship to previous post is similar to reading a book with pages missing or pages from another book inserted.
Can we spent a bit more time discussing how the two results can be so different?
Peter head
Personal views and discussions are not the same thing.
We have here on this thread with two very different results with water injection implementation on the WRX: Shiv and Annointed
(http://forums.nasioc.com/forums/show...n&pagenumber=1)
Rather having a fragmented discussion with people posting their views without specific relationship to previous post is similar to reading a book with pages missing or pages from another book inserted.
Can we spent a bit more time discussing how the two results can be so different?
Peter head
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Originally posted by peter head
Shiv,
I suggest you read all the posts first before making your contribution to this thread - Please stop making sweeping statements that were not related to this thread.
Shiv,
I suggest you read all the posts first before making your contribution to this thread - Please stop making sweeping statements that were not related to this thread.
Best Regards,
shiv
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Last edited by Vishnu; Mar 7, 2011 at 04:14 AM.
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Originally posted by peter head
Can we spent a bit more time discussing how the two results can be so different?
Can we spent a bit more time discussing how the two results can be so different?
Also as I previously mentioned has anyone asked the poster on clubwrx to follow up on his results? That may well provide some of the insight you are seeking. Annointed's thread is still active and answers there would be easy to get - try to revive the clubwrx thread - the answers may yet be gleened from between the two.
While I agree that the flow of a thread can sometimes be disjointed and have gaps and jumps - I also think we should try to work within the framework that other than for disruption really is an unmoderated discussion area. Also my assumption is that everyone is being sincere in their posts so I give everyone that benefit of the doubt when I can and hope other do as well.
Ed.
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Big turbo/high boost application (like the WRX running the 18G), when operating on pump gas, will often operate on the steep portion of the MBT curve. That is, every additional degree of advance you put into it, will result is substantial torque gains, all other things equal. Similarly, they can often be run at leaner AFRs due to a reduced exhaust backpressure and exhaust gas reversion/charge dillution. They also tend to run less advance (like the EVO) due to the higher mean cyclinder pressures associated with running big turbos at high boost.
Smaller turbo (stock, VF23, VF30, etc,.) applications, due to their airflow/boost limitations (which results in lower engine VE which results in lower peak cylinder pressures- all other things equal again) will operate further up on the MBT curve where things start to flatten out (that is, additional advance does not yield big torque gains). They typically seem to be happier operating at richer AFRs with substantial spark advance.
Please note that I really hate making these gross generalizations.
These two situations will result in widely different results when WI is integrated into the system. The first application will benefit more than the second. This is because the power loss associated by the air/fuel displacement and slower charge expansion rate is easily offset (or more than offset) by the additional advance one can run and the allowable fuel enleanments made possible by the in-cylinder charge cooling courtesy of H20 vaporization. That's one of the fun things about being on the steep side of the MBT curve. Anything you can do to run more advance and get a more potent charge expansion rate will result in more power.
Being on the flat portion of the curve is boring since adding more advance and leaning things out doesn't yeild substantial enough gains to compensate for the air/fuel displacement.
Just my yet-to-be-proofread 2c.
shiv
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Smaller turbo (stock, VF23, VF30, etc,.) applications, due to their airflow/boost limitations (which results in lower engine VE which results in lower peak cylinder pressures- all other things equal again) will operate further up on the MBT curve where things start to flatten out (that is, additional advance does not yield big torque gains). They typically seem to be happier operating at richer AFRs with substantial spark advance.
Please note that I really hate making these gross generalizations.
These two situations will result in widely different results when WI is integrated into the system. The first application will benefit more than the second. This is because the power loss associated by the air/fuel displacement and slower charge expansion rate is easily offset (or more than offset) by the additional advance one can run and the allowable fuel enleanments made possible by the in-cylinder charge cooling courtesy of H20 vaporization. That's one of the fun things about being on the steep side of the MBT curve. Anything you can do to run more advance and get a more potent charge expansion rate will result in more power.
Being on the flat portion of the curve is boring since adding more advance and leaning things out doesn't yeild substantial enough gains to compensate for the air/fuel displacement.
Just my yet-to-be-proofread 2c.
shiv
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Last edited by Vishnu; Mar 7, 2011 at 04:14 AM.
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Shiv,
Your answers are greatly welcomed and I thank you for delving deeper into the myth of WRX tuning.
Without looking into the specifics of the two set-ups, I agree that it is difficult to compared.
Perfect MBT timing is a goal where all tuners should strive to reach, but often met with machanical constraints such as small turbos and back-pressure of the exhaust system.
Ideal air/fuel ratio equally important to good tuning, it is "generally" accepted that a/f approaching 12:5 to 1 is an ideal ratio where maximium power is achieved at knock-free environments.
Tuning techiques differ between companies, in this case, Vishnu and Turbo XS. Method employed is largely being influenced by the operator's personal preference, for example Shiv prefers to dump fuel and XS prefers to use water injection - both achieved 'similar' results.
I accept that dyno readings differ greatly between companies, but the (comparative/successive) gain/loss plots on the same dyno on the same day can be regarded as a pretty reliable indictor of how each method achieved their results. Because of this, we can reasonably safe to assume that the power plots be used represent the merits of each tuning method used.
My observation so far lead me to believe that the remaining item to be discussed is the method used by the two tuners, dumping fuel and water injection. Both works but which is a (slightly) more viable?
My guess is, since the latent heat of water is six times that of fuel, lesser chance of displacing the air/fuel mixture in the cylinders is the main contribution of making better comparative power gain as shown on the XS method - I could be totally wrong and will welcome any comments.
Peter head
Peter Head
Your answers are greatly welcomed and I thank you for delving deeper into the myth of WRX tuning.
Without looking into the specifics of the two set-ups, I agree that it is difficult to compared.
Perfect MBT timing is a goal where all tuners should strive to reach, but often met with machanical constraints such as small turbos and back-pressure of the exhaust system.
Ideal air/fuel ratio equally important to good tuning, it is "generally" accepted that a/f approaching 12:5 to 1 is an ideal ratio where maximium power is achieved at knock-free environments.
Tuning techiques differ between companies, in this case, Vishnu and Turbo XS. Method employed is largely being influenced by the operator's personal preference, for example Shiv prefers to dump fuel and XS prefers to use water injection - both achieved 'similar' results.
I accept that dyno readings differ greatly between companies, but the (comparative/successive) gain/loss plots on the same dyno on the same day can be regarded as a pretty reliable indictor of how each method achieved their results. Because of this, we can reasonably safe to assume that the power plots be used represent the merits of each tuning method used.
My observation so far lead me to believe that the remaining item to be discussed is the method used by the two tuners, dumping fuel and water injection. Both works but which is a (slightly) more viable?
My guess is, since the latent heat of water is six times that of fuel, lesser chance of displacing the air/fuel mixture in the cylinders is the main contribution of making better comparative power gain as shown on the XS method - I could be totally wrong and will welcome any comments.
Peter head
Peter Head
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Judging by your response, you misinterpreted, or failed to completely undestand, my post. Also peter, are you affiliated with any WI company? Every post you've made on this site has been in defense of WI as tuning tool.
shiv
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Last edited by Vishnu; Mar 7, 2011 at 04:14 AM.
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I am not here to misinterpret, undestand or dis-credit anyone, I am here to learn the truth - or close to it.
As this thread is titled "anyone use water injection", I tried to keep the topical discussion on water injection related matters.
MBT timing, I repeat, is governed by mechanical constraints. Shiv more or less explained this earlier - power difference is mostly attributed by the engine components. I have no problem with that. (yet to be disputed by Shiv soon)
I am, however, question the use of fuel as a coolant - in fact Shiv is leaning towards using fuel as a coolant, again I have no problem with that either. When fuel is used as a coolant - I cannot agree that it will make more power than using water as an in-cylinder coolant.
We will all agreed that when oxygen is fully consummed by the fuel after complete combustion, the end product is CO2 and H2O. Excess fuel produces Carbon Monoxide (CO) - Each carbon molecule exits the exhaust pipe will carry an oxygen molecule along side. The rate of depletion of oxygen is directly proportion to the production of CO or a/f ratio. which means to me that the richer you run your engine, the more oxygen is being absorbed and power is robbed.
I hope someone could post some evidence to support my claim. Water on the other hand does not have that problem - I fully suspect the two tunes- Vishnu (fuel dump) and TurboXS (water injection) may carry more substance than what Shiv has led me to believe.
Shiv, I am no more affiliated with water injection than you are affiliated with fuel-oil companies.
Peter Head
As this thread is titled "anyone use water injection", I tried to keep the topical discussion on water injection related matters.
MBT timing, I repeat, is governed by mechanical constraints. Shiv more or less explained this earlier - power difference is mostly attributed by the engine components. I have no problem with that. (yet to be disputed by Shiv soon)
I am, however, question the use of fuel as a coolant - in fact Shiv is leaning towards using fuel as a coolant, again I have no problem with that either. When fuel is used as a coolant - I cannot agree that it will make more power than using water as an in-cylinder coolant.
We will all agreed that when oxygen is fully consummed by the fuel after complete combustion, the end product is CO2 and H2O. Excess fuel produces Carbon Monoxide (CO) - Each carbon molecule exits the exhaust pipe will carry an oxygen molecule along side. The rate of depletion of oxygen is directly proportion to the production of CO or a/f ratio. which means to me that the richer you run your engine, the more oxygen is being absorbed and power is robbed.
I hope someone could post some evidence to support my claim. Water on the other hand does not have that problem - I fully suspect the two tunes- Vishnu (fuel dump) and TurboXS (water injection) may carry more substance than what Shiv has led me to believe.
Shiv, I am no more affiliated with water injection than you are affiliated with fuel-oil companies.
Peter Head
Last edited by peter head; Jan 16, 2004 at 05:13 PM.
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The full support is many pages of worth of technical language on the chemical process of combustion - i.e. each of the steps to CO2 and H2O (it is not a direct process but rather many steps).
An introduction and synopsis of it is here:
http://not2fast.wryday.com/thermo/wa..._chemistry.txt
Imporant quote from above:
Going to the source of that note, I would add this:
* Source: Combustion, Third Edition, Glassman, p. 76
I focus on a couple things - many aspects benefit from additional present water during the intake and compression stroke - but during combustion is really where WI shines. For instance the additional water during certain steps provides additional radicals, peroxide and oxygen to those individual processes. Since it is net water in and net water out the net is not additional oxidation but it helps the process of oxidizing the hydrocarbons we seek to release the energy from. In effect - the proper amount of water assists and enhances combustion in a closed combustion chamber.
Ricardo's results prove it here:
I know it may be repetitive of earlier posts but any further support is not really feasible in a forum format.
An introduction and synopsis of it is here:
http://not2fast.wryday.com/thermo/wa..._chemistry.txt
Imporant quote from above:
This simple reaction accounts for 99% + of the conversion of CO to CO2. It is important in that fully two thirds of the energy of carbon combustion is released in the CO ==> CO2 process and that this process occurs slow and late in the combustion of the fuel. Excess water can and does speed this conversion - by actively entering into the conversion process thru the above mechanism.
...thus one can conclude - correctly - that hydrocarbons inhibit the oxidation of CO.
It is apparent that in any hydrocarbon oxidation process CO is the primary product and forms in substantial amounts. However, substantial experimental evidence indicates the oxidation of CO to CO2 comes late in the reaction scheme. The conversion to CO2 is retarded until all the original fuel and intermediate hydrocarbon fragments have been consumed.
It is apparent that in any hydrocarbon oxidation process CO is the primary product and forms in substantial amounts. However, substantial experimental evidence indicates the oxidation of CO to CO2 comes late in the reaction scheme. The conversion to CO2 is retarded until all the original fuel and intermediate hydrocarbon fragments have been consumed.
I focus on a couple things - many aspects benefit from additional present water during the intake and compression stroke - but during combustion is really where WI shines. For instance the additional water during certain steps provides additional radicals, peroxide and oxygen to those individual processes. Since it is net water in and net water out the net is not additional oxidation but it helps the process of oxidizing the hydrocarbons we seek to release the energy from. In effect - the proper amount of water assists and enhances combustion in a closed combustion chamber.
Ricardo's results prove it here:
I know it may be repetitive of earlier posts but any further support is not really feasible in a forum format.
Last edited by jehcpa; Jan 15, 2004 at 02:06 PM.
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A short brief update on the EcuTek tune...
http://www.clubwrx.net/forums/showth...579#post486579
Ed.
http://www.clubwrx.net/forums/showth...579#post486579
Ed.