A question on water injection.
05-10-2017, 03:38 AM
#1
Honda-Tech Member
Thread Starter
School me on wate injection (a question)
Hallo guys.
I have a quick question on water injection.
Most systems have 2 regulators, one to adust when sparying starts and the other when it goes to full.Like the AME devilsOwn etc
That means that if i set it to start spraying at 3 psi and full spray at 10 psi, the moment i hit 10 psi untill the redline
the same amount of water will be sprayed?If thats the case it would be ok at a b16 with a 60-1 but my turbo hits
full boost on ~3300.From 3300 to 8500 i will probably need like 2 times or more water right?
Whats your opinions on this?
I have a quick question on water injection.
Most systems have 2 regulators, one to adust when sparying starts and the other when it goes to full.Like the AME devilsOwn etc
That means that if i set it to start spraying at 3 psi and full spray at 10 psi, the moment i hit 10 psi untill the redline
the same amount of water will be sprayed?If thats the case it would be ok at a b16 with a 60-1 but my turbo hits
full boost on ~3300.From 3300 to 8500 i will probably need like 2 times or more water right?
Whats your opinions on this?
Last edited by Balor_Gr; 05-10-2017 at 04:14 AM.
05-13-2017, 02:55 AM
#3
Honda-Tech Member
Thread Starter
Re: A question on water injection.
Look i was thinking at 4000 rpm you spray lets say 200cc every minute.
At 8000 you still spray 200cc in one minute.But
at 8000 rpm you have double the combustions at the same 60 seconds so it will be like
spraying 100cc.Because you have the same amount of water for double the combustions.
If i calculate correct at 4000 rpm you have ~ 130 combustions per second x 60 seconds ~ 8000 combustions per minute
so that water injector nozzle sprays 200cc per minute so total water 200cc divided by 8000 piston bangs = every combustion gets 0.025cc water
At 8000 rpm you have 260 combustions per second x60 for minute ~ 16000 combutsions
Now at 8000rpm the same nozzle's 200cc of water go to 16000 piston bangs per minute. So now every combustion gets 200/16000= 0.0125cc of water
ghetto math
If there was a way to take a singnal from an injector or spark for the system to calculate
rpm and spray 100cc at 4000 rpm and 200cc at 8000 rpm this way it would be balanced.
At 8000 you still spray 200cc in one minute.But
at 8000 rpm you have double the combustions at the same 60 seconds so it will be like
spraying 100cc.Because you have the same amount of water for double the combustions.
If i calculate correct at 4000 rpm you have ~ 130 combustions per second x 60 seconds ~ 8000 combustions per minute
so that water injector nozzle sprays 200cc per minute so total water 200cc divided by 8000 piston bangs = every combustion gets 0.025cc water
At 8000 rpm you have 260 combustions per second x60 for minute ~ 16000 combutsions
Now at 8000rpm the same nozzle's 200cc of water go to 16000 piston bangs per minute. So now every combustion gets 200/16000= 0.0125cc of water
ghetto math
If there was a way to take a singnal from an injector or spark for the system to calculate
rpm and spray 100cc at 4000 rpm and 200cc at 8000 rpm this way it would be balanced.
Last edited by Balor_Gr; 05-13-2017 at 03:18 AM.
05-13-2017, 06:30 AM
#4
Re: A question on water injection.
This is why you PWM control the pump with some kind of controller. Unfortunately Im not sure you could easily do this with the Honda ECU since youre probably already out of outputs, but something like a megasquirt could do it. There may be some other kind of controller out there that will allow you to PWM the pump versus RPM or maybe blend RPM and boost.
That being said, it only takes a little bit of water to prevent knock, so if youre praying a little too much down low and the right amount up top, its not a big loss. The water lasts a while.
That being said, it only takes a little bit of water to prevent knock, so if youre praying a little too much down low and the right amount up top, its not a big loss. The water lasts a while.
05-14-2017, 06:29 AM
#5
Re: A question on water injection.
I run the smallest nozzle in the AEM kit, boosting to 14psi, only using low pressure spray. I feel from experimentation and personal tuning that no more is needed and considering a smaller nozzle so I can do even less at lower rpm and less boost, and utilize the 2 stage.
11:1 B16
11:1 B16
05-16-2017, 12:12 AM
#6
Honda-Tech Member
Thread Starter
Re: A question on water injection.
I run the smallest nozzle in the AEM kit, boosting to 14psi, only using low pressure spray. I feel from experimentation and personal tuning that no more is needed and considering a smaller nozzle so I can do even less at lower rpm and less boost, and utilize the 2 stage.
11:1 B16
11:1 B16
This is why you PWM control the pump with some kind of controller. Unfortunately Im not sure you could easily do this with the Honda ECU since youre probably already out of outputs, but something like a megasquirt could do it. There may be some other kind of controller out there that will allow you to PWM the pump versus RPM or maybe blend RPM and boost.
That being said, it only takes a little bit of water to prevent knock, so if youre praying a little too much down low and the right amount up top, its not a big loss. The water lasts a while.
That being said, it only takes a little bit of water to prevent knock, so if youre praying a little too much down low and the right amount up top, its not a big loss. The water lasts a while.
Aparently i found out that AEM's 30-3350, the kit that noone talks about strangely enough ,works with injector duty cycle!!!
Low injector reading (low rpm) = low amount of spray , high injector reading (high rpm) = high amount of spray
Im probably gonna get this kit.
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