How do I wire in an RPM switch with a progressive kit?

2bfi · 09-19-2008

I have a 1.8L Civic with a Jackson Racing supercharger and a D.O. Progressive Kit.

The supercharger makes substantial boost at low rpms. Activating the injection at this low speed would pump in too much water/methanol. Going to a smaller injector would not inject enough mixture at full rpm & boost. Where in the circuit can I add an rpm controlled switch?

I want injection to start above 4000 rpms and 2psi.

If it is wired in the ignition +12 wire, it would be going on-off-on-off each time the speed goes above or below 4000 rpm. That might destroy the controller.

I definitely cannot place it between the controller and pump.

If wired in the ground side of the pump, it might cause an pump fault condition or burn the controller. I read somwehre here that a guy burned his controller coz of a weak pump ground.

Any help would be appreciated. Thanks.

2bfi · 09-23-2008

I just thought of an idea. What if I wired the rpm switch to a relay that goes between the green wire and the MAP sensor signal wire. Below a 4000 rpm, the DO Progressive Controller doesn't get any voltage from the MAP, and won't switch on. Above 4000 rpm, it received map voltage and would switch on if the boost is right.

Is that feasible with no bad effects?

09-19-2008	#1 (permalink)
2bfi Water Injection Newb Year: 1999 Make: Honda Model: Civic Join Date: Jul 2008 Posts: 3	How do I wire in an RPM switch with a progressive kit? I have a 1.8L Civic with a Jackson Racing supercharger and a D.O. Progressive Kit. The supercharger makes substantial boost at low rpms. Activating the injection at this low speed would pump in too much water/methanol. Going to a smaller injector would not inject enough mixture at full rpm & boost. Where in the circuit can I add an rpm controlled switch? I want injection to start above 4000 rpms and 2psi. If it is wired in the ignition +12 wire, it would be going on-off-on-off each time the speed goes above or below 4000 rpm. That might destroy the controller. I definitely cannot place it between the controller and pump. If wired in the ground side of the pump, it might cause an pump fault condition or burn the controller. I read somwehre here that a guy burned his controller coz of a weak pump ground. Any help would be appreciated. Thanks. Last edited by 2bfi; 09-19-2008 at 07:01 PM.

09-23-2008	#2 (permalink)
2bfi Water Injection Newb Year: 1999 Make: Honda Model: Civic Join Date: Jul 2008 Posts: 3	Re: How do I wire in an RPM switch with a progressive kit? I just thought of an idea. What if I wired the rpm switch to a relay that goes between the green wire and the MAP sensor signal wire. Below a 4000 rpm, the DO Progressive Controller doesn't get any voltage from the MAP, and won't switch on. Above 4000 rpm, it received map voltage and would switch on if the boost is right. Is that feasible with no bad effects? Last edited by 2bfi; 09-23-2008 at 10:26 AM.