I replaced my honda civic d15z4 engine with a d16A.
Apparently, VTEC engages at 5500rpm on these engines.
My car is still practically standard, I'm not sure if it does switch over, if it does, the sound is very subtle, but I'm not sure that the place I bought the engine from gave my mechanic a matching ECU (I'm not sure whether I would need the same ECU to run this engine in my car)
So my question is, will the VTEC switch over happen without the PBB-J61 ECU that the d16A was released with?
VTEC requires the ability to understand the state of the environment and motor in order to change the valve timing.
Various sensors from oxygen, engine rpm, barometric pressure, engine temperature, air temperature, oil pressure, throttle position effect the the various timing events of a VTEC engine.
All of these inputs effect how and when the ECU will control oil pressure to effect cam profiles at various rpm's.
The ECU for the correct motor is necessary in order for the VTEC system to function properly.
There are model years and series that have overlap in which an engine may perform reasonably with a different model year engine but it is highly recomended that ECU match the year and model for which it is designed. The ECU will require the matching harness as well as there are additional input sensors on VTEC engines.
Yes you will need a compatible ECU for your new engine. The ECU reads multiple signals from your engine and will change your camshafts timing accordingly. When your engine gets high rpm, your valve timings should be adapted to get the VTEC boost.
Any VTEC ECU should work as long as the VTEC solenoid is connected and wired to the ECU. I have a 94 integra with a B18C1 (DOHC VTEC). When I bought the car it had an ECU for a SOHC VTEC engine. VTEC would still engage. You might be able to test it with a test light on the pigtail for the VTEC Solenoid.
