I have a Scoobyecu based eprom board fitted to my MY93 WRX ECU, and what I am wondering is would it be possible to run a toggle switch to the J1 resistor so I could flick between the two Maps ( the base map on the OEM ECU and the Eprom map ), of course I will have to switch the car off to switch between the two but was wondering if this would be possible and would I have to run a earth from the switch or could I run it off a two legged switch


Si

 

you can do it, but why?
If you flick to the standard map, you will be running less power and probably with greater fuel consumption as well (not to mention it will probably be a 100 octane map so more chance of det) whereas your scoobyecu will probably be mapped for uk fuel, offer better driveability and economy and will probably have a smaller chance of det.
If you don't want the car to go as fast, just lose some weight from your right foot!

 

Yes you can switch maps by doing exactly as you suggest, I did it on my old MY95 WRX with Z4 ecu years ago. It enabled me to switch between the OE 12.7 psi boost target and an early 16.5 psi target. The 16.5 wasn't mapped for UK fuel IIRC back then, but I always ran booster (still do now).

You don't have to switch the engine off to change maps, you can do with the engine idling.

Just use a 2 legged switch. The J1 resistor (I think its a 0 ohm link anyway) stands up IIRC, so ther is a long leg running from one end of J1 to the PCB. Cut it half way and solder the switch across the cut. with the switch closed you will be running the OE map, with it open you will be running the ScoobyECU map.

You are aware that irrespective of maps, if you are cruising / off boost (i.e. the ECU is running closed loop) then fuel economy wise it doesn't matter which map is selected. So in some respects for fuel ecomony don't bother with 2 maps, just don't use your right foot!

 

I always run booster to, plus I have a Knocklink fitted so if I see any increase in det I can just sack it off it's only an idea to try it out see how it goes