Recently I decided to get 310s but I heard that the car will run rich under these injectors. I was thinking of buying either unit to control it and make it more stoich. What unit should I buy?, is there a difference between them?

 

S-AFC = Fuel Controller
V-AFC = Fuel and VTEC Controller

 

I ran ran 310s with no electronic compensation and there were no problems; when the car is running closed-loop it automatically adjusts. You may want to drop your baseline/static fuel pressure a bit, but mine had NO problems being too rich. Too lean, on the other hand...

As for the Apex stuff, the diff between the two is that the V-AFC has VTEC control built in and gives you the ability to build a fuel adjustment map for low throttle/high throttle and low cam/high cam (four maps) instead of just low throttle/high throttle (two maps) on the S-AFC.

At least that's how I understand it.

 

I have 310's in my car right now with no piggy back controllers, it runs fine. I just lowered the rise rate in my FMU to 8:1.