while i am sold on AI for turbo'd rotaries i suggest you find a proper intercooler before doing AI...



an intercooler removes a huge amount of heat from the engine ALL the time. the rotary need all the thermal help it can get.



further, i am not sold on injecting water and alcohol at the compressor wheel. there are highly mixed opinions and i personally don't want to speculate since a number of things work on a piston engine that don't work on a rotary. (optimum egt rotary 1640 degrees, piston engine 1320)



get a decent intercooler. it's cheaper than another engine.



howard coleman

I for one wouldnt use the staged system ( more oftern refered to as a dumb system ) its just to imprecise.

I am also moving away from sureflo pumps and pure alch injection now all for various reasons. Like howard said differant set ups work out better on differant configs. From my experiance pre turbo does work. I will be doing it on my new turbo for sure. I am also gonna run 50:50 or 70:30. rotaries make more power with a mixture rather than straight alch.



Scott

I have heard that shooting at the turbo can cause errosion. I have aluminum IC pipes so I and just going to shoot post IC.



I agree with Howracer more failsafes the better...

hi scott,



thanks for your contributions to this section which i hope will become an important rotary resource.



i agree with you that staged AI (w no electronic controller) is latter day tech and has been deservedly superceded by progressive controllers.



since you have more miles on your AI than i, i wonder about the reasons for some of your comments....



"moving away from the sureflo pump"

one of the reasons i decided on Alkycontrol as my AI vendor was the fact that they spend over 2 hours re-doing the pump so it is 100% methanol happy. there are other electronic/electric mods also. the last thing we need w AI is any system failure. since Alkycontrol has over 1000 of these pumps out and they are almost all 100% alcohol and racing i consider my pump plug n play.



you are refixturing your setup to inject partially pre turbo. what was it you didn't feel you got injecting in the elbow? was it poor distribution? after looking at your throttle body pix it does appear the alcohol was favoring the rear. i decided to inject pre elbow and biased towards the front rotor. we will see how that works.



my concerns w injecting pre turbo are: water is a very heavy substance 8.5 pounds per gallon. (alcohol 6.4). i think that increased density at the compressor will decrease output. it may also coat the blades which may cause an increased cavitation tendency as well as clog the intercooler. additonally, if you should ever get a blowback spark into the pre throttle plate area your entire system will go kaboom.



the alcohol part of your injectant will attack your aluminum compressor, housing, intercooler and piping.



i know preturbo has been done before but i wouldn't want to take the risks. i do not see a major upside to trade against.



as to making more power w water and alcohol.... there are numerous reasons to run water as AI. there is nothing wrong w water, as there is nothing wrong w alcohol or a mix. they each accomplish different things, however making more power from a water alcohol mix on the rotary v alcohol only isn't one of them.



we'd all be interested in what you have learned running AI. i am just now trimming gasoline from my map and adding alcohol and will keep interested parties updated. i run 2 M10 nozzles and have my alcohol coming on at 5 psi.



howard coleman

hi howard.



I have been conceared with the surflo pump and the quality of the atomisation. The majority of pump from water injection systems only give 60 psi max. The current nozzels need at least 60 psi min to atomise. As the flow rate of the pump goes up the head of pressure goes down. So if the pump is only giving out 60 psi to start with on a small jet by the time it ramps up to a larger jet the atomistaion is very poor. I am told ( and i believe ) that the only way a vari speed control system can work correctly is with a 250 psi rated pump.



I am currently working on a inj duty based system with good safty features. https://www.nopistons.com/forums/pub...1047683358.gif



When i get back on the road again. ( still with the mark 3 system ) i am going to change the injection point to the bottom of the intake elbow. Ie in the bottom of the V. I am going to use aquamist jets due to there fantastic atomisation. I have a video some place that i made to compare the 2 jets. I am going to try this for a while but i want to sort this other set up asap. ( i am not using the same vendor for this next kit https://www.nopistons.com/forums/pub...DIR )



We ran preturbo methanol on a 12A turbo. ( elford turbo ) it had no intercooler and blew almost straight in to the ports. The 12a was a high compression engine which we turbo charged and added a turbo dizzy to. The carb sprayed fuel on to the compressor wheel full time wether on boost on not. ( the tubo had sheilded bearings ) as well as this methanol was injected at 1 gph in to the velocity stack. The car with out meth could just about cope with 7 psi of boost. ( knock was quite high and the carb struggled to fuel it ) with pre turbo meth it made 16.5 psi at lower knock. The methanol made up the extra fuel that the carb could not. The dizzy retarded 1 deg per 1 lb of boost and stoped retarding at 10 lb. This car was repeatively drag raced all day long and survives to this day.



here is a section from a friends post on ausrotary.



Pre-turbo WI: 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.



Water has a very high latent heat of vapourisation, but once you have reached the saturation pressure in air, then you gain no more cooling at that point. However Dalton's law comes to the rescue at this point and if you bung in some other miscible fluids, say methanol and acetone, then each has its own saturation pressure, and you get an accumulative cooling effect. A little petrol would do the job if you added a second injector for it.



And here we hit the first problem. You need fine atomisation to avoid potential blade damage. For this you need an airshrouded injector, such as VW used in some of their CIS systems (hunting applications list for those). RX7s have an airpump that can be turned to this application. Other option is to weld a bung into the scroll as most of the compression happens here.



I need to run some numbers on exactly the effect of various fluids here, but imagine if you had cut the power needed to get the PSI wanted by a 1/3. You would get spool up at 2/3 of the gas flow before and could run at higher boost once you had spooled.....................................end of post



I found that my rotary made more power with a 50:50 mix right from the base tune. When im back up and running i am going to re tune it to 50:50 and then post the graphs and logs



Scott

so you do not know the effects of of the 5050 mix water/meth if sprayed at the wheel? and also i am so close to getting the car done but i am so indecisive on getting the coolingmist kit or just going with a front mount intercooler. what are your thoughts and thanx again you explained so much

I only know the effects of 50:50 pre turbo on a skyline. But that also ran an intercooler. I have milled this idea over so many times and i still dont know. you are supposed to get good coooling from the 3 part mix. ie meth,water,acetone. I am trying to get a better spray distribution over the runners but so far my new idea is untried. If i was you i would get a aquamist dds3. search for it online and read the pdf doc. This will give you the safty and is quite cheap. The dual stage kit will be ok but i dont think they are good.

maybe you should concider a intercooler unless you wanna get a very involved WI system. Im quite a way from trying this out so i cant say for sure.



http://not2fast.wryday.com/turbo/glo...rbo_calc.shtml



Try this calculator it may help.



Scott

well scott i made up my mind and im going with the dual stage coolingmist kit with no intercooler. any advice on where to put the injectors exactly? i was thinking one at the elbow going against airflow and one closer to the turbo also againt airflow.

I know this thread is old, but i thought this might be useful info.

The cooling mist pump that comes in there kit only has a service life of 100 hours! https://www.nopistons.com/forums/pub...1047683358.gif

That does seem like a while Howeva that info is not public knowledge.



I suppose it depends how many hours a day you spend on boost !



Scott