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NA Water Injection
Ok after extensive forum/Internet searches I've decided to setup my own water injection system. Let me preface:
This is water injection only no meth. This is not for HP gains. Although hopefully it will allow me some extra tweaking room. This is to maintain engine cleanliness and to allow me to run cheap pump gas. I'm planning on using a Devils Own progressive system based of MAF voltage. What I really need to know though is what is the max flow rate I'll need in WOT. I can guess for cruising conditions by assuming 25% water to fuel (which may be lowered to 10% based on results.) but I have no idea what WOT fuel consumption is. Any suggestions? |
Why are you doing this? Cleanliness? Do you think it is going to prevent carbon build up?
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I do believe it will prevent carbon buildup as well as reduce combustion temperature which should be good for the seals. It should also increase the effective octane of the gas. If it only allows me to run regular instead of premium with no knock then it will pay for itself in a couple year. In short I want to give it a shot.
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Originally Posted by Harlan
(Post 4024914)
I do believe it will prevent carbon buildup as well as reduce combustion temperature which should be good for the seals. It should also increase the effective octane of the gas. If it only allows me to run regular instead of premium with no knock then it will pay for itself in a couple year. In short I want to give it a shot.
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Found what I needed in a roundabout way. Stock fuel pump delivers 30GPH nominal. I'll set up a 3GPH max proportional system and things should be peachy.
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I was actually wondering abut trying water/meth injection on rx8 as well. My other car is twin turbo Audi S4 and I have been running water meth kit on it for over 2 years now..love it
you will be fine just running regular windshield washer fluid which is 70/30 mix of water and methanol. I know that rx8 is NA and that generally NA cars will see much smaller benefit by running the water/meth injection. Lowering IAT and increasing octane (both get you better timing) will net some benefit especially on the hot weather days where your IAT will be over 100F..with meth kit you can get your IAT lower than ambient temperatures by as much as 50F..so on 100F day your rx8 will produce the power like it is 50F day..not to mention that it would steam clean the engine in the process. Harlan please let me know how it turns out, I might follow the suit. Regarding the nozzle size: my guess is to get the smallest 2 sizes they sell and then you will have to do some tuning to optimize you controller settings. Kit I have on my Audi is devils own, give them a call and they can help you with nozzle sizing. One more thing injecting only water will not raise your octane, you need to add methanol for that purpose. |
Originally Posted by Harlan
(Post 4025075)
Found what I needed in a roundabout way. Stock fuel pump delivers 30GPH nominal. I'll set up a 3GPH max proportional system and things should be peachy.
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He is talking about injecting only water. Here is food for thought though.
Originally Posted by Richard Paul
(Post 877493)
I was hoping not to have to be the one to reply here but..so no one else eh??
Zeuschel used water/meth on the Merlin race engines at Reno. This was 50/50 mix. BUT these were very highly supercharged race engines and also had 120+ fuel. I can't recall exactly how much boost they ran and if I did I'd have to kill you if I told. 40-50 psi might be in the ballpark. The tune on these engines was so far beyond what Rolls Royce designed that they sent a telex saying GOOD LUCK. According to Rolls calculations Dave was running 3500 + HP. The H2O/Meth injection was used to control detonation and a complex anolog system of metering it was built custom. Realize that we are talking a lot of liquid to carry around on a plane for the entire race. Therefore it was regulated to use during critical times. as pointed out by the turbo user above it was only effective when used in a system that would otherwise not be viable. Ricardo has a section on water injection and I havn't read it in 20 years I think he basicly calls out that it makes more power then if it were detonating but iif you could not detonate you'd make more power without it. Don't forget while methonol has a much higher resistance to detonation it has half the BTU's. When in the presence of water it will obsorb same and really being used as a coolant. Put the fire out and it is cooler. But why did you start the fire in the first place? To get the heat and thus expansion to move the rotor. Ha, you thought I was about to say piston. It is not an explosion it is a controlled burn you want. So not to ramble on here the answer to your question is no it is not going to help the NA engine except in some odd cases. I don't see those cases being with the rotary. Don't put out the fire, use it. On another note Z tried nitros for a couple of years but in the end said "I can blow up engines without it, why add to the scrap." When he did run it they had a bottle of nitrogyn that pressurized the nitros bottle so the flow stayed the same for the whole race. In the street systems that are used today the only pressure is from the agent itself. since the added fuel is constant you will get richer as the bottle emptys. Carrying bottles in the wing of a plane the size of your Oxy/Act welding set has it's own drawbacks. Fact: this is the first application of nitros, WWll. Both the Germans and the British did their own studies and came upp with about the same answer. ~5 lbs per min burned will ~= 100 Hp. Doesn't matter if it's in a fighter plane or a lawnmower. Want to know how much of a "shot" you really have??? Put it on a scale and run it for 60 sec. If it looses 2.5lbs then you have a 50hp shot. Remember the flow will not be constant over the whole 60 sec. So use the "math" Luke and only run it for a few seconds. Or enough so you get a good time. You will have gotten the whole 50 hp but it will be uneven, more power at the start of the burn. Compounded by the fact that it will be richer as you go also. If you always use a full bottle there will be little difference though. Bigger bottle=more consistant runs. All you get today, I'm going back to bed. https://www.rx8club.com/showthread.p...+kit+installed |
hehe did you notice who posted last in that thread
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water injection on NA?
not necessary and probably not a great idea. Listen to Richard Paul, when it comes to cars he knows his stuff. |
Injecting water does not raise octane, it raises the effective octane. Since the water does not burn it contributes nothing to true octane; however it does remove a lot of heat reducing the potential for destination. From Wikipedia:
http://en.wikipedia.org/wiki/Water_injection_(engines) In internal combustion engines, water injection, also known as anti-detonant injection, is spraying water into the cylinder or incoming fuel-air mixture to cool the combustion chambers of the engine, allowing for greater compression ratios and largely eliminating the problem of engine knocking (detonation). This effectively increases the octane rating of the fuel, meaning that performance gains can be obtained when used in conjunction with a supercharger, turbocharger, altered spark ignition timing, and other modifications. Increasing the octane rating allows for a higher compression ratio which increases the power output and efficiency of the engine. Depending on the engine, improvements in power and fuel efficiency can also be obtained solely by injecting water.[1] Water injection may also be used to reduce NOx or carbon monoxide emissions.[1] I can't find the reference offhand, but the best way it was explained to me was: Water alone is used to prevent detonation, a water meth mix is used to get as much power out of an engine as possible before detonation. Since this mod is not meant to create any insane boost in power, nor do I wish to alter the Fuel air ratio with injection, it makes sense to use plain water. All this will do is allow the use of cheap pump gas while maintaining good burn characteristics and keeping the engine cool. If properly tuned it could give a slight power boost or a slight fuel economy boost, but that is an eventual goal. |
If your not having any detonation then why bother? Many people run 87 octane without issues.
As far as cleaning, well that has never been tested or proven, it's just one of those things rotary guys have done but it never really been tested on the Renny in an scientific fashion. It's kind of like premixing, it seems like a good idea and the theory is good but no one has ever done any real scientific testing of it to know if it really makes a difference on the Renny. |
This thread is making me nostalgic for the 50s, when I'd read Popular Science, Mechanix Illustrated, etc, and the back pages would have ads for water injection. "Ever notice how your car runs smoother in the rain? Install our system and get that all the time."
Ken |
Yes those were the days ......I was young ....felt invinsable....beleaved any thing was possible....yadayadayada...now I pick my battles.
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Looking into water injection for my track car, NA street ported motor. The inherent problem with the renesis apears to be the side seals loosing strength due to high EGT's and the flow of exhaust gases out of the housing. After loosing a few motors and each supposed fix has not solved the problem, a respected RX8 engine builder on this forum suggested I use water injection to cool the EGT's. Even a small amount of water will make a big difference and should lengthen the life of my motor.
Now I am not going to just slap a kit on there and say I solved the problem. I am starting by installing a dual EGT guage and a NTK standalone wideband (to make sure my stock unit is accurate). I am going to monitor my peak EGT's and based on what i find I will use water injection to bring the peak temps down a few hundred degrees. From what I hear, a properly tuned renesis will still see EGT's in the 1600-1800 range at high load/RPM's. I think getting it down to the 1500 peak range should make a big difference. The tune will remain the same and back to back WOT runs will be done to see if there is any power gain or loss. Water wont make power by itself and because I am not lowering IAT (as you would in a FI application) I should not see a power gain. If I only use enough water and not too much, I should not see any power loss. For a controller I want a progressive controller capable of being operated by MAF voltage. I think the devilsown controller should do the trick but if anyone has any other recommendations I am open to suggestions. |
/\ interesting idea - look forward to seeing what you find .
It has been reported here that WI actually increases EGTs but that was on an FI engine. Also : NA track car ? Thought yours was procharged ? |
Originally Posted by Brettus
(Post 4193591)
/\ interesting idea - look forward to seeing what you find .
It has been reported here that WI actually increases EGTs but that was on an FI engine. Also : NA track car ? Thought yours was procharged ? |
Originally Posted by Highway8
(Post 4193587)
Looking into water injection for my track car, NA street ported motor. The inherent problem with the renesis apears to be the side seals loosing strength due to high EGT's and the flow of exhaust gases out of the housing. After loosing a few motors and each supposed fix has not solved the problem, a respected RX8 engine builder on this forum suggested I use water injection to cool the EGT's. Even a small amount of water will make a big difference and should lengthen the life of my motor.
Now I am not going to just slap a kit on there and say I solved the problem. I am starting by installing a dual EGT guage and a NTK standalone wideband (to make sure my stock unit is accurate). I am going to monitor my peak EGT's and based on what i find I will use water injection to bring the peak temps down a few hundred degrees. From what I hear, a properly tuned renesis will still see EGT's in the 1600-1800 range at high load/RPM's. I think getting it down to the 1500 peak range should make a big difference. The tune will remain the same and back to back WOT runs will be done to see if there is any power gain or loss. Water wont make power by itself and because I am not lowering IAT (as you would in a FI application) I should not see a power gain. If I only use enough water and not too much, I should not see any power loss. For a controller I want a progressive controller capable of being operated by MAF voltage. I think the devilsown controller should do the trick but if anyone has any other recommendations I am open to suggestions. https://www.rx8club.com/series-i-tech-garage-22/research-experimental-8-a-226850/ |
Originally Posted by xexok
(Post 4193645)
Check his other thread, much bigger than this one and also newer.
https://www.rx8club.com/showthread.php?t=226850 |
I just assumed since both were by the same guy it was the same thing. He just didn't know what he wanted then I guess.
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Mmm, ok. You may wish to read this post and look at the attached pdf. https://www.rx8club.com/showpost.php...&postcount=209
Steam (water vapor) and water/meth will not have the same effect. Water alone will increase the effective octane, ie. delay the onset of detonation. Water/meth does it moreso. As far as EGT reduction is concerned, I'm doubful, assuming one doesn't also wish to reduce power output. I'll defer to either real measurements or the math, but memories of max power (water/meth injection) takeoffs of C-119s over my childhood home at night, streaming 20 feet of flame from the exhaust stacks, may color my thoughts on the subject. To get any advantage from an na engine, one would have to tune ignition and a/f closer to the edge of detonation. However, that edge is not so easily related to maf as it is with "stationary" engines which acft engines effectively are. In a car, full throttle at 7k rpm in second gear is less critical than, 1/2 throttle up a hill at 3k rpm in 6th. Water/meth triggered by maf might protect in the former, but not even come on in the latter case, unless it was on pretty much all the time. 1940-1960 water/meth injected aircraft engines only used it for takeoff. They could sustain full power for short periods of time, but reduction was required within a few minutes. Exceptions were allowed for "war emergencies", but after use of WEP, an engine replacement or rebuild was mandatory. Max allowable manifold pressures were roughly 60" Hg or twice atmospheric or in (poor) automotive terms 14" Hg of "boost". "Insane" levels of boost for these engines is racing only, with a 50/50 chance of destroying the engine in a 15 minute race. YMMV. |
As far as flow requirements, this may be of interest:
http://www.rotorsportsracing.com/per...njection1s.htm Their options look to have enough program robustness to do what's needed. ~$1k though. |
Originally Posted by Highway8
(Post 4193587)
The tune will remain the same and back to back WOT runs will be done to see if there is any power gain or loss. Water wont make power by itself and because I am not lowering IAT (as you would in a FI application) I should not see a power gain. If I only use enough water and not too much, I should not see any power loss.
For a controller I want a progressive controller capable of being operated by MAF voltage. I think the devilsown controller should do the trick but if anyone has any other recommendations I am open to suggestions. http://naca.central.cranfield.ac.uk/...a-wr-e-264.pdf FI use of water injection is not about lowering intake temperatures, although that happens too, it's about preventing knock. The water acts as internal coolant and cools off the hot parts that would otherwise cause det. The devils own controler has a couple problems. First it does effect MAF voltage, so you will see your fuel trims change and other screwball indications like abnormal MPG. For that a resister before the controller could work well. The second problem is the controller is using PWM to control the pump, on low volumes this does not change pressure as the pump already cycles off on high pressure. I got by this by using a recirc line. This also allowed my hose to depresurize when the pump stopped running. (20 feet of hose at 100# takes a minute to come down with a 1gph nozzle.) As for what really works. Try using a water free coolant like Evans NPG. I use Prestone non mixed because I'm cheap. It should remove some of the engine hot spots by not letting the cooling passages go into DNB/Dryout. http://en.wikipedia.org/wiki/Nucleat...cleate_boiling
Originally Posted by HiFlite999
(Post 4193711)
To get any advantage from an na engine, one would have to tune ignition and a/f closer to the edge of detonation. However, that edge is not so easily related to maf as it is with "stationary" engines which acft engines effectively are. In a car, full throttle at 7k rpm in second gear is less critical than, 1/2 throttle up a hill at 3k rpm in 6th. Water/meth triggered by maf might protect in the former, but not even come on in the latter case, unless it was on pretty much all the time.
Luckily our ECU can distinguish between high load at low RPM and high load at High RPM. Tuning only for the region where you inject water isn't rocket science. Here is what I would do. Convert to water free coolant. Set up a multi-stage injection or proportional injection based off MAF. Then tune for it. You can easily see when water injection fails as your coolant temp will increase, doubly so if you are pushing advanced timing. This will give you a few seconds to lay off the throttle before you are into trouble. |
i have been running w/m injection for a number of years. I do not run it at all times.
Here are some interesting findings from my experience. 1- it does work in helping with detonation control 2- you will loose a little power --i lost 10 hp in the upper rpm ranges with one 175cc nozzle injecting progressively from the maf voltage. Its interesting that my A/F's DID NOT CHANGE when the w/m was on. We guess it was not a large enough volume. So unless you inject enough to alter the a/f's then this will not affect the maf readings/tune 3- it will help to keep the internals cleaner--i have torn down two engines after using part time w/m and they were cleaner than the engines that didnt use it. Even Paul and Mr E (Mazmart) were interested in this finding. You do have to keep in mind that w/m in large enough quantities can interfer with lubrication. It is a question of balance. you are not injecting before the maf are you? if you use wwf use only the -20F blue colored type. you can use bottles of HEET ( yellow bottle only) and distilled water to mix your own. You can use water alone. Mechanics have steam cleaned engines for decades--no different here. Theoretically our engine could actually make more power with a lower octane gas lol. You could run this injection set up with a trigger to only inject during whatever load level you actually need it. This way a gallon will last a while. never tune for w/m in this engine using the type of controller and pump you are running. Its not quick enough. |
olddragger, several questions regarding your power loss with W/M injection.
Are you FI or NA? how did you measure your power loss? was it several dyno runs with w/m off followed by the runs with w/m injection on. what were the conditions, hot or cold day? did you log your timing and EGTs? |
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