water meth set up

[BHPerformance]

Hi currently have a mini R53 want to set up the water meth its already been wired up but I'm sure its incorrect looking at it they've pwm the pump and the solenoid is just going to switch on / off, 

wouldn't it be better to switch the pump on and pwm the solenoid ?

[Adamw]

No, PWM on the pump with the solenoid open is generally the preferred option.  The reason is if you PWM the solenoid you dont have a continuous flow, you have a relatively low frequency pulsed flow.  At different RPM's etc those pulses will bias certain cylinders - some cylinders will get all the wmi and others will get none.

There are some high frequency solenoids to allow the solenoid to be PWM'd, but most arent.

[BHPerformance]

oh ok perfect thank you, there doesn't seem to be any fail safe there's a level sensor in the tank but it hasn't been wired up

guess my best advice is to play it safe until it has a fail safe and don't use a 4d fuel and ignition table  

 

[plox]

When I was looking for fail safes it seemed the flow sensors weren't reliable so I ended putting a pressure sensor post solenoid, it measured pressure and the ecu had a switch for boost/fuel/Ign tables based on the pressure being within the correct region. Seemed to drop back often when fluid was low (& without any surge protection) so was worth while.

I found prometh had a fast acting solenoid with low draw, majority of the rest were not suitable for pwm as per the above.