RICESP Water Injected RX7

[RICE RACING]

Full credit for my system ideas goes to Eldred Norman and Hugh McInnes.

Eldred gave me the idea for the air water atomizing nozzel and Hugh the pneumatic nature of operation.

basics first:

A pressure vessel is linked to manifold pressure (open link, no one way valves etc) this pressure being tied to intake manifold pressure determines the fluid line pressure and thus the delivery rate is in proportion to the vessel pressure, it works in an acceptable fashion on most high performance single turbo cars in regards to metering. What happens in this basic form is that at peak boost there is a higher water to fuel ratio or percentage (lets say maybe 35%) and as revs rise past peak torque/boost onwards to peak power point the ratio can come back to a more correct target say of 20%. It naturally delivers more fluid where its needed mostly at peak cylinder pressures (and over doses a bit at lower revs if the boost builds up quickly) but if the AFR is kept anywhere north of 11.11:1 then the power losses of this brief over water rate is below 5% in my experience.

ahhhhh now from this pressure vessel it goes to a filter stage, then a solenoid (which is ok enough to be used with 50/50 water meth) and is controllable enough to be used off a PWM circuit on an ECU that has this function if you want to fine tune the delivery rate at lower rpm's etc. then to the water side of the nozzel.

The other side of the nozzel is plumbed to the same pressure source and it blows a small volume of air out two small orifices which explode the stream of water into finer droplets, which generally are fine enough to allow it to be used on the lower pressure side of a turbo inlet system (between air cleaner and compressor wheel). From my research of war time WI tests this injection location will give a maximum air flow increase of around 4%... so will make your compressor flow 4% more for the same given rotational speed, after this amount the effect gets saturated from the info I have been able to find on the topic.

In its simplest form the WI system is turned on by boost pressure, via an adjustable pressure switch, but in my case I control it off the ECU though I do not trim the delivery rate its set to 100% values so its on or off and flow is determined by boost pressure. Good thing about this is its relative to boost so the more boost you run the more water flow and its basic and seems to work ok for me. The water nozzle has a precision flow control valve so the rate can be adjusted from 100cc to 850cc/minute, according to my calcs at 20% WtoF that should cover a 2.6lt motor to 1000bhp in turbo form.

This is it in action: http://www.youtube.com/watch?v=8Lizxy3XIY8 (on lap top you can see VBOX telemetry of pressure transducers mounted in the water line and air line, doing calibration)

That's roughly everything about it. Once again I cant pay enough respect to the old boys who I got this idea from back when I was doing my engineering diploma and dreaming of one day having a turbo rotary that I could make fast I progressed through weber jets just squirting solid streams of water doh! to running mixes of meth to water cause I could never get it to work with stock ignition, and then not really knowing much about the flow rates to effects or any real progress, I wanted to give up on WI as I thought it was "shit" but when I had one engine fail I decided to look into it properly found the right nozzels, pulled my finger out and tested the flow rates, upgraded the ignition system and the rest as they say is history........ I would never ever run a car without water injection, the more I research it over these years and through my own experiences the more I love the stuff. Sadly its only a topic of interest for engineering types I have foudn over the years its because I honestly believe you need to have some formal thermodynamics and engineering exposure or qualifications to understand all of the old reports you can find these days thanks to the internet. Most enthusiast have no hope let alone performance shops and lord help us the current age of internet only businesses and forum guru's who seem to pop up at a seemingly exponential rate these days.

I love this forum and all of the smart people on it who have contributed and know just how great WI is, it feels a bit stupid talking about this as it was all done and realized to a very high level of understanding during the war in the 1940's, but we can only hope the good word gets spread and many others can benefit from what we are lucky to know

My fingers hurt :lol:

[downpipe12]

Thank you SO much for taking the time to explain your system! By far the cleanest and highest quality custom pre-turbo setup I have ever seen.

Have you done any experiments testing out pre and post turbo setups? What I am wondering specifically...is would adding a small nozzle pre-turbo benefit a properly tuned post turbo setup?

[RICE RACING]

Some may find this little update interesting:

This afternoon (ambient 28deg C at time of test) could not control myself and needed to go for a drive during the week I simply adjusted the plug gap, changed the spacing of the leading plugs distance from the rotor face, took 2% out of my main ECU fuel table and turned my W/M back to 3 turns setting.

Drive it and its an animal :shock: pulled the best yet and I was game enough to look at the mixture meter before hitting 7800rpm in 3rd gear (100mph or so) and it was 10.5 to 10.6:1 AFR the power on the on board logger showed 415rwhp (est 498bhp). I was expecting the AFR to go leaner as last time I tested it in that spec on the water injection setting it was about 10.9:1 AFR (but I changed the plug gap *narrower*) and took a tiny bit of fuel out of the ECU map? and it went the other way?).

It was allot of fun and I hope also to get back one input box from Race Logic (sent for repair!) then I can hook up all the proper instruments and do some more tests, relative to the first one. My intention was to reduce the fuel mixture to somewhere around 11.8:1, but it feels very great as it is now + set like this is less stress full on the engine and turbo especially when pushing high gears and speeds for extended power use............. thoughts anyone?

Oh here is a pic of the WI testing (not sure if I posted this in other pages, I'd reload to check but I have the gayest internet speed in human existence)

[downpipe12]

odd that it went the other way. did you change the mixture at all? i don't know if changing plug gap could affect AFR readings...never heard of that...but thinking about it a little, anything that changes the burn could possibly affect the readings? pure speculation...

either way, more power is always good. i would suspect even more if you do manage to lean it out a bit more...

[RICE RACING]

Yeah :? oh well my #1 priority is durability under hard stresses rather than output in one test, its a constant battle within. You settle on one target then you get that and you always want to move on to another... I find it best if I don't drive it all the time then when you get back in it your still surprised with how well it goes (prob a good general tip for life).

In another thread on here a few years back I posted my findings when using my works engine dyno for a Formula SAE engine we were calibrating and also tests I have with a Toyota Supra on a rolling dyno and noticed zero effects on power readings from these types of mixtures all the way to the *ideal* mixture settings, the one constant there was (I found) sufficient ignition energy/capacity. This could be what I am seeing with the reduced plug gap? Obviously BSFC is wildly effected but that is the least of my concern or should I say a low priority over durability then power output.

[RICE RACING]

Originally Posted by downpipe12

odd that it went the other way. did you change the mixture at all? i don't know if changing plug gap could affect AFR readings...never heard of that...but thinking about it a little, anything that changes the burn could possibly affect the readings? pure speculation...

either way, more power is always good. i would suspect even more if you do manage to lean it out a bit more...

You were right

I took it out again today, but with computer hooked up and did 2 full 3rd gear pulls to 100mph and 8000rpm and what I saw the other day just glancing at the mixture meter was a rich spot that showed up after 7400rpm or so to 8000rpm, in the two tests today with 3 turns on the WI and 50/50 with 2% reduced fuel map was 11.0 to 10.8:1 AFR and in the rich zone down to 10.1:1. Moral is you can't trust yourself and must data log all of this stuff.

car is consistently more powerful, showing ~280rwkw (or 370rwhp) on small up hill accent with 1.2kg/cm boost pressure.

I did my final fuel trimming to set the base tuned AFR to 11.0:1 with the W/M activated, from here on in I can simply change the target AFR number and it will automatically adjust the fueling to whatever AFR I want to experiment with.

Ambient air temperature today was 18 deg C during the test and at the end of 3rd gear the AIT was 45deg C, the second test was a long probably 20 degree incline hill and the start AIT was 30 deg C and again at the end of 3rd gear it was 45 to 46 deg C, this is measured after the throttle body and maybe a foot from the inlet port, with high speed sensor. Goes really well for low level of boost (220kpa absolute) and heavy AF mixture.

[downpipe12]

sweet!

that is a cool feature being able to auto-adjust to a target AFR. I would start leaning it out maybe just .1 at a time and see what happens.

[RICE RACING]

Originally Posted by downpipe12

sweet!

that is a cool feature being able to auto-adjust to a target AFR. I would start leaning it out maybe just .1 at a time and see what happens.

I forgot to add the reference time for 90kph to 140kph pull in third gear was 2.84 seconds (last was 3.11 seconds) so its a fair bit quicker this was not in my ideal test location (had uphill gradient, makes it even more impressive.) and last test was in 10 deg C v's today closer to 20 deg C. You can see on my site how this 90-140 time compares to lots of other cars I test http://www.riceracing.com.au/vbox-ii...ing-tuning.htm

This was before I did the final trimming of the AFR curve too when I get the same conditions and the other VBOX module back I will post up the full data log back to back to the first reference test. The car is a rocket today is the first time I have had a massive smile and laughed out loud after passing a truck and a few cars banked up in front of me. I doubt I will waste time optimizing it any further, but you never know :lol:

[downpipe12]

something tells me you will...just a hunch, lol...

cool man, i look forward to future updates.

have you played around with post-turbo injection setups as well? or just the pre-turbo stuff?

[RICE RACING]

Originally Posted by downpipe12

something tells me you will...just a hunch, lol...

cool man, i look forward to future updates.

have you played around with post-turbo injection setups as well? or just the pre-turbo stuff?

only pre turbo, Richard made me up some custom kits many years ago now and they were the ultimate, featured pre and post turbo situations for injection.... I personally did not get around to using them sadly and decided to refine my own basic set up.

All of the data I have found to date has showed pre turbo is more advantageous for a power increase comparing running with and without, where as post while reducing knock does not give the performance gains. Though I have never tested that myself personally I must mention.