MilosB

the effect of runner temp is negligible. even if it was 200C and you have 25C inlet air you maybe get 26C-27C out of it. The velocity and mass of air is very high compared to surface to transfer the heat thus the temp difference is very small. Yes it slowly builds up the temp but its not impactful for the intake charge.

TeamRX8

iTrader: (25)

I edited out that last post, had a brain fart. Regardless of the cutoff seal, the open chamber trapping hot exhaust gas and then releasing it into the intake cycle is the issue.

I know you knocked AI in the past, but it really makes a win/lose difference if setup properly. Even water only is better than nothing; it has zero detonation potential and the added AFR of alcohol in the mix doesn’t require any factoring in. Most water only issues come from poor setup/control and injecting too much. The goal is to only add enough to quench detonation and not power output.

AEM etc are fairly primitive systems. To do it properly an injector-based duty cycle system is needed

direct port is best, but the APV runners would need a solenoid control tied to the opening rpm.

https://usrallyteam.com/index.php?ma...cPath=1_68_347
.
.

3toedSloth

Have you considered a ceramic piston coat on the faces instead?
Mazda has started coating rotor faces. I heard in the late S2 RX-8 but for sure in the current 8C. In part, to reduce carbon build up.
As you can see in a video from the production line, here: (Ignore the added text - some moron didn't know what they were talking about)

Brettus

iTrader: (2)

Unfortunately I've already got a system (snow performance). When I searched - none of the sophisticated systems like the one you posted came up.
But yes I will have a solenoid control on APV runner and it will be rpm adjustable.
Plan is for one nozzle pre throttle and a second staged one on the APV runners.
Have the snow controller also which will ramp up the pump with boost so Ican knock back the flow and not drown the engine as it's spooling. Should allow me to start flow at a lower boost but I appreciate it's not ideal.

Brettus

iTrader: (2)

No .... don't know if that would be practical to do here.

Brettus

iTrader: (2)

Fair enough. Still think it's worth adding some cooling in those runners as they don't have injectors.

MilosB

Intake afr away is for IAT /MAD, but vapour replaces oxygen so it has to be carefull, its non combustible (unless it gets super hot :D )
close to intake ports so the water/meth evaporates just before the ignition, not much of the air volume has been replaced and the water/meth evaporation energy has been used as knock controll. This is what Team was saying and imho the only way it wouldnt rob power. But the amount needed is nuch less than for IAT.

​​i think simmilar way as it is used on bmw m4 (which also uses snow performance as oem if im not mistaken)

People always reference piston airplanes, but there water was used to efectivelly reduce power as it was to much at "sea level". Ie engine was built for 0.7-0.5 MAP and at 1.0Map it would knock.. So they sprayed with water and used up a lot of heat energy converting it in to vapor, preventing knock and reducing engine power.
The latent energy of water is huge so a lot of heat energy that would be usedfor expansion is used for vaporisation.

Ps, this system posted above by Team is a " the ****" something I was looking for / tryingto design formy 2.7bar boosted piston engine

Brettus

iTrader: (2)

No idea what you are saying here ....

MilosB

oh the beauty of my autocorrect on the phone and my terrible English (as its not native besides Norwegian, Hungarian, Croatia, Serbian and a little German)…
lets correct it on a PC:
Injection far away from intake is for IAT / MAD (manifold air density). ie, that will not necessarily help with knock prevention. Vapor replaces oxygen (air in general, buy O2 is what we need) in the intake charge so it has to be carefully added only as much as we need, and that needs to be carefully calculated. water vapor is obviously non combustible (unless it gets super hot like above 1500C :D ).
Injection close to intake ports so the water/meth doesn't evaporate before intake is closed, and evaporates just before the ignition in the combustion chamber, not much of the air volume has been replaced with vapor and the water/meth evaporation energy has been used only as knock control. This is what Team was saying and imho is the only way it wouldn't rob power. But the amount needed is nuch less than for IAT.

Brettus

iTrader: (2)

Ah , got ya now. This is exactly what I've been trying to understand via internet searches and not really getting anywhere with. Thankyou.
I have IAT relatively well controlled and ethanol was taking care of detonation up to what I call the 'zone of death' (past 7500rpm and 400g/s).
My strategy heron out is to just avoid that zone (by dumping boost) and take care of knock up to that point while preventing carbon buildup with w/m.
So maybe I should just use a small nozzle pre throttle and put a larger one as close as I can to the ports?

MilosB

if your IAT is managed than I would put them only near ports ( i see no benefit at throttle body, you are just making the intake charge moist) . Remember, the less you have added, the less variable is in the system and less failure points.
while you are on a MAF base map, you are ok and you will immediately see the impact on air mas flow, but on a speed density maps, it can get very confusing very quickly

Brettus

iTrader: (2)

I think a small one pre throttle could still be worth it for those occasions when IAT can climb ... IE heat soaking at idle etc. So you get some IAT cooling at low rpm for initial takeoff etc. I think it's also not good to dead head the solenoid at high pressure (300psi in this case) so having one at throttle allows use of a check valve with a lower cracking pressure (40psi).
So for the other nozzle(s) how close is close enough for the effect you describe ?

MilosB

What are your average IAT's ? I need to do some math

TeamRX8

iTrader: (25)

probably didn’t understand my post fully

.

MilosB

the guy probably forgot more than I know :D he's a genius

Brettus

iTrader: (2)

Interesting talk ...........not much on the 'how to' side of things though.
Listening to that makes me wonder why NONE of the literature from the mainstream supply companies even attempts to explain how to achieve what he was talking about.
It's all "Shove a heap of water in before the throttle body and call it a day" !

Brettus

iTrader: (2)

Which would explain why my early attempts failed and why no-one else seems to have made big power with this method. Everyone has treated it as "insurance" and not really attempted to get the moist ....or the most, out of it!

3toedSloth

Do you mean in NZ? Surely there's some shops doing it. I have the stuff to do cerakote at home. But they're here in the US.
I'll be trying it out with my next rebuilds. Hoping it helps keep the carbon buildup from getting too bad.

MilosB

I would be careful with Ceracote.

TeamRX8

iTrader: (25)

it’s what Rice Racing has been doing in AUS for a long time, he doesn’t get enough credit for it
.

TeamRX8

iTrader: (25)

If you can afford destroying engines finding out the hard way, then more power to you.
.

3toedSloth

Well, that's counter the advice from some who have race development experience (and Mazda, above). Note, I'm talking about the TBC (thermal barrier coatings) not the lubricating side skirt coatings. The side skirt coatings don't help since the rotors float.

TeamRX8

iTrader: (25)

on a short lived, unlimited $$$ professional motorsport race engine maybe

think about what happens if even one small flake chips off, might as well not run an air filter in the Sahara desert.

you mean well, but people who don’t truly understand the real world magnitude of certain concepts tend to misperceive an ant hill as being Mt. Everest, when it’s not.

it’s not like you should focus first and foremost on learning how to build a respectable, long lasting Renesis engine first, let’s throw a bunch of variables you read, heard, and convinced yourself of in the imagination of a of a glory seeking heart about, but have no actual experience with, into the mix as well. It’s only money and it grows on the tree in your backyard, right? Just go out and pick some more whenever you want, no problem.

I guarantee you wouldn’t be the first person on here to invest in it and not only never see a true benefit, but feel the loss of financial investment as well. Put together an engine with less than optimum used parts and put your money in that instead. Yeah, that makes sense.

As it was said, “the heart deceptive above all and exceedingly misleading; who can know it …?”
.

3toedSloth

Mazda is definitely not interested in coatings that only last short term. Anyway, I have good info from better places so just trying to share.

MilosB

Doing something in a factory aplication is not near what you can do afternarket..
The substrate for a good coating is not any material, it is a material chosen particularly to be able to have a very good adhesions with the coating.
It is done on VIRGIN material, that has than been chemically further cleaned and activated. Not something that is cast iron that wil absorb oil like a spunge

​​​​​