SaabCentral Forums banner
1 - 2 of 2 Posts

·
Registered
Joined
·
5,975 Posts
Discussion Starter · #1 ·
I'm in the process of building water injector from various spare parts, i'm going to use a spare pressure sensor(overboost maybe.. fixed under the NS dashboard and connected to the APC) and a mate is in the process of designing the controller for me.

As the pressure sensor gives different resistance depending upon pressure the controllers going to use a couple of transistors which wil detect when the voltage drops to a certain level and then switch on the water injectors, in theory I should be able to use 2 transistors so that I can run 2 separate water pumps, each set to come in at a different pressure.

Has anyone else put together anything like this? I know that there's a few versions out there that are switch operated, anyone built their own controller?

I'll post the wiring diagram once it's put together and working just incase anyone wants to do the same.

I may also invest in some spare components and knock a few control units together to sell for a small fee, but they would be sold as paper weights though to remove any liability of me knackering someones car!!!!!!

Anyway I should have the first version working by early June (awaiting May pay to help percure the bits I need!) so i'll post the results then.

I'm also thinking of running 2 mixes, at the mo I'm going to try 75/25 water/ethanol mix on the first injector and a 95/5 water/ethanol mix on the second one.
 

·
Registered
Joined
·
167 Posts
Voltage drop?

The APC has a constant current output of 5 mA which in combination with the resistance of the pressure transducer gives a voltage of roughly 60 - 950 mV corresponding to the applied boost of 1 - 2,5 bar (absolute) respectively.

I have used the ERL (Aquamist) Fi2A amplifier for water injection control so far.

Cheers,

Tadek
 
1 - 2 of 2 Posts
Top