NoPistons -Mazda Rx7 & Rx8 Rotary Forum

NoPistons -Mazda Rx7 & Rx8 Rotary Forum (https://www.nopistons.com/)
-   Single Turbo Discussion (https://www.nopistons.com/single-turbo-discussion-13/)
-   -   -water Injection- (https://www.nopistons.com/single-turbo-discussion-13/water-injection-23576/)

jspecracer7 08-29-2003 08:07 PM


Originally Posted by epion2985' date='Aug 30 2003, 09:58 AM
11 air to 2 octaine right

lol...no. 11.2 : 1

FrestyleFC3S 08-29-2003 10:06 PM

why did you have a 4 post conversation with urself ....when u were just copy and pasting?

epion2985 08-30-2003 04:54 PM

well I posted the main part but then I found more stuff, and then some more, and then I wanted to comment on something ^^

FrestyleFC3S 08-31-2003 12:43 AM

theres a button called EDIT

1Revvin7 08-31-2003 12:54 AM


Originally Posted by FrestyleFC3S' date='Aug 31 2003, 12:43 AM
theres a button called EDIT

Chill out, you could have just pm'd him. He is here to learn like everyone else.

jspecracer7 08-31-2003 07:46 AM


Originally Posted by 1Revvin7' date='Aug 31 2003, 02:54 PM
Chill out, you could have just pm'd him. He is here to learn like everyone else.

lmfao...Freestyle's bitching about someone who's contributing useful information to the forum. https://www.nopistons.com/forums/pub...1047683561.gif

Dragon 08-31-2003 01:11 PM

I haven't read the first page, but here is some information that should be helpful to some of you...



11-11.2:1 is a relatively safe a/f ratio, peak power is somewhere around 11.7-12:1 or so, but you GREATLY increase the chance of blowing your **** up for a measly 10-20hp if you run toward the lean side. The reason a rotary needs to run rich is actually for two reasons.



# 1. Poor atomization of fuel due to the design of the rotary engine and the fact that the combustion chamber where the air and fuel needs to be when it ignites is moving. The atomized fuel is burnt, but their is some left over that isn't atomized that gets kick out with the exhaust causing a rich reading on the O2 sensor.



# 2. The extra fuel is also needed to cool the rotor. This helps eliminate hot spots that can cause predetonation.



if you run too lean you will get very hot ex temp, however if you run too rich you will also get very hot ex temps due to the left over fuel burning in the ex manifold. The way we used to tune prior to getting our kick ass wide bands was to tune rich to start and watch the ex temps drop as we took away fuel until the ex temp wouldn't go any lower. If you continued to take away fuel it would start to rise again and you knew you were getting too lean.



Here is what air/fuel ration is. I.e. Stoic. Say you have 1 gram of fuel, in order to burn all that fuel efficiently you will need a mass of 14.7 grams of air for it to oxidize with during the combustion process. This gives you the 14.7:1 ratio. When you run a richer a/f ratio you are basically giving the engine more fuel than the air to be had can burn. This extra fuel evaporates in the engine and removes heat. Another benefit from this and also from the water injection is that when a fluid evaporates taking away heat it also expands and will create more tork and can also aid the spooling a turbo faster since the exhaust pressure will be increased and be more dense.

ZeroBanger 08-31-2003 01:17 PM

Solution:



Run water injection and go home happy https://www.nopistons.com/forums/pub...IR#>/smile.png

Dragon 08-31-2003 01:22 PM

Just found this.. https://www.nopistons.com/forums/pub...#>/biggrin.png http://www.zaxjax.com/Air%20Fuel%20Ratio%2...cal%20Paper.pdf This will help you understand what a/f ratio is

little rotor 08-31-2003 07:20 PM

Does anyone have any experience on what happens to EGTs in the presence of water injection? Dragon's post implies that they are considerably lower which is what you'd expect.



But I'm not sure that this is good for spooling a turbo. I've heard many times how the drive for the turbine comes from both the difference in pressure and temperature accross it, not the pressure difference only. On piston engines running antilag the pre-turbo EGT's are huge.



I have no personal experience with this, but I'm just trying to consider any downsides to water injection.


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