Thoughts on nozzles

[sdminus]

I'm about to alter my WI system from a boost related switch set up with 2 stages to one with a controller with an adjustable fuel curve.

I currently have 2 jets in the system rated to about 4.9 GPH. I need to have a tad more water avalable for when i tune with more boost. Would i be better off ditching these jets and getting one large jet or by a few more and stager them over the inlet tract. I was thinking this way might help atomise the water better.

Scott :?:

[sdminus]

Anybody!!!!!

[Richard L]

Originally Posted by sdminus

Anybody!!!!!

I probably need a bit more information of your water injection system and how you plan to control the flow with fuel curve.
I will do my best to help.

Richard

[sdminus]

Cheers I will be running the cooling mist systyem with there controller which i has an adjustable contoller.
( can alter the curve) I will have 1.0 GPH 3.9GPH and 2 x 0.5 GPH jets. I will be running at max 40 GPH i will have a fuel curve later on when i start tuning but so far the car is in bits. I have some info forom the datalog on the old 550cc and 850 cc injectors but will have more form the new 850cc 850cc injectors when running again.

Scott

Richard have you seen my other post of mixtures.. do you have any thoughts on my post . You can mail me @ sdminus@yahoo.co.uk

[Richard L]

Originally Posted by sdminus

Cheers I will be running the cooling mist systyem with there controller which i has an adjustable contoller.
( can alter the curve) I will have 1.0 GPH 3.9GPH and 2 x 0.5 GPH jets. I will be running at max 40 GPH i will have a fuel curve later on when i start tuning but so far the car is in bits. I have some info forom the datalog on the old 550cc and 850 cc injectors but will have more form the new 850cc 850cc injectors when running again.

Scott

Richard have you seen my other post of mixtures.. do you have any thoughts on my post . You can mail me @ sdminus@yahoo.co.uk

I think I know how your system work but changing the PWM curve to change the pump speed will not give you a wide range of flow. 4x pressure will only yeild 2x flwo change. Does your controller is capable alter the system pressure between 60psi to 240 psi?

I think the best thing you do first is by logging the flow against the PWM signal, once you know how much liquid is injected - one can start in a better footing.
Starting at 10-15% water to fuel. If you want to inject 100% methanol, there is more reason to know the actual flow against the PWM curve.

Richard

[sdminus]

Cool cheers richard.

One thing i keep milling over is this ratio. i have been told by many to tune for 12 afr with 10-15 %water. but my base map will be about 11.1:1 so say 0.76 lambda.
i would say 10 % of this would be 0.076 lambda
so if i subtract this i get 12.2:1 or 0.83 lambda
So if i tune for 12.2:1 and add the 10% water would i not be tuning for an equivelant of 30 % more fuel or 0.228 lambda
if so then the new mixture would be the equivelant of 0.60 lambda or 8.82 on petrol. I am told water is 1/3 more efficent than fuel. COuld it be that we are over watering our cars. These figures seem a little extreme but i am no maths expert.

Scott

[Richard L]

Originally Posted by sdminus

Cool cheers richard.

One thing i keep milling over is this ratio. i have been told by many to tune for 12 afr with 10-15 %water. but my base map will be about 11.1:1 so say 0.76 lambda.
i would say 10 % of this would be 0.076 lambda
so if i subtract this i get 12.2:1 or 0.83 lambda
So if i tune for 12.2:1 and add the 10% water would i not be tuning for an equivelant of 30 % more fuel or 0.228 lambda
if so then the new mixture would be the equivelant of 0.60 lambda or 8.82 on petrol. I am told water is 1/3 more efficent than fuel. COuld it be that we are over watering our cars. These figures seem a little extreme but i am no maths expert.

Scott

I am not sure if you are interpret the 12afr and 10-15% water as a means of replacing "fuel for burning" or "fuel for cooling". I got the impression that you are trying to relate to the former (buring) rather for the latter (cooling).

The main purpose of adding water is for cooling. Adding water will not alter the afr but it will alter the in-cylinder temperature. An engine will have the highest combustion temperature as it approachs lambda 1. Combustion temperature on either side of lambda1 will be lower. I am not saying you achieve maximum power or manximum torque at lambda=1.

I am not sure if that is what you are trying to discuss, but please tell me I am off track.

Richard

[sdminus]

I was thinking of the cooling effects of the water. I was just working on the 3-1 ratio of water. It seems to me that adding 10 % water for cooling would be the equivilant to adding 30% of fuel for cooling.

I know i may be wrong here but replacing like for like seems to straight froward...

Scott

[Richard L]

The following charts are calculated based on:

10Kg of air, Gasoline's latent heat capacityof 350KJ/Kg
Water's latent heat capacity of 2256KJ/Kg
Methanol's latent heat capacity of 1109KJ/Kg

Injection water at different ratio to fuel at 100% water and 75% Water/25% Methanol. You can see the at 100% water injection, only 3% of w/f fuel ratio is enough to replace 2.5 point of a/f ratio (dotted line). As soon as 25% of Methanol is added, the a/f ratio is dropprd to 12.0 - loosing some cooling capacity




Each of the following chart show a 25% percent increase in Methanol concentration of the mix.



lastly, just methanol is added and no water. The chart on the right is 100% water




The two charts show (first and last) that you will require to inject twice the amount of methanol to equal the latent heat of water alone. Methanol is relatively low cost and very effective as a coolant so what is the problem?

When higher concertration of methanol is injected, you need to lean your engines a/f ratio to accomendate the extra fuel or your engine will bog down and loose power. Consequentially - one runs the risk of putting the engine into heat stress if the supply of methanol is suddenly interrupted. Injecting water does not affect the a/f ratio. It appears that 50/50 mix has the best of both worlds.

[sdminus]

Thanks richard.

Scott