Re: My OHC VTEC - Lowered, Stiffened, FFE'd and Now with ITBs!! The MAP value is measured by teeing vac lines from all 4 throttles. However, this is not through the accumulator but directly connected to the MAP sensor. The MAP reading is stable, if you can call it that. With ITBs, you will damn never get any vac readings above 15-17% throttle. It usually reads ambient pressure (around 960-870mbar) at 20% throttle lol. However, I see MAP readings of around 300 mbar at idling, which is pretty close to what people with plenum will see.
The fuelling/ignition maps are Alpha-N, so MAP readings are not taken into consideration when calculating the fuelling. It's a hell of a lot more responsive than a plenum with a single TB, mainly due to the short intake tract. There is no hurdle to speak of. The car's been running perfectly fine as a daily-driver, while having the responsiveness and punch beyond 3k RPM. |