Transient Throttle Enhance
The manifold pressure sensor used with the ECU is very fast. It can respond much faster than is required to track any sudden changes in load on your engine. However, the manifold pressure seen at the sensor input may not change as quickly as what is seen by the inlets to the combustion chamber, due partly to the length of the connecting pipe. This delay can be reduced by keeping the length of vacuum hose between the inlet manifold and the pressure sensor as short as possible. Even with very short vacuum hose lengths there may still be a lag between a transient pressure occurring and the pressure reaching the sensor.
Further, when the throttle is cracked open, the sudden change in pressure forces fuel out of atomisation and onto the manifold walls, so it fails to enter the combustion chamber properly atomised, and the engine hesitates. This can be corrected by adjustment of the Transient Throttle Enrichment tables. To overcome any lean out during sudden throttle movement, a Transient Throttle Enrichment function is used to deliver the extra fuel required.
Note that throttle response can also be affected by poor manifold design. This will occur if the fuel injectors are poorly positioned and the fuel is wetting down the walls of the inlet manifold rather than remaining as a mist.
Asynchronous vs. Synchronous Enrichment
The Transient Throttle Enhancement works by adding additional fuel. It can achieve this by adding: Asynchronous Enrichment - Additional injection pulses Synchronous Enrichment - Enriching the current fuelling pulses
The Transient Throttle tables should be set up after the fuel and maps are correctly tuned for steady load running. Attempting to smooth out engine transients before the fuel maps have been optimised for steady state running may become confusing. ...
Transient Throttle is a fuel correction function used to compensate for an opening or closing throttle body. As the throttle is opened and air enters the inlet manifold there is a period of time where the manifold pressure has not reached its final ...
Transient Throttle Enrich
Enrich Rate The Enrich Rate table is used to proportion how much of the Enrich Amount tables are applied. This calculation is based on the rate of sensor movement while opening the throttle (X-axis), and sensor position at the start of the movement ...
Transient Throttle (Throttle Pump) Explained
In this article we are unravelling one of the mysteries of tuning; the often talked about but rarely understood dark art of tuning the Throttle Pump, or as we call it here at Haltech the Transient Throttle Enrichment function. Transient Throttle If ...