tim-spam Posted August 31, 2005 Report Posted August 31, 2005 Does anyone know which way the variable vane turbos work? Is maximum boost achieved with vacuum applied to the diaphragm, or without? Put another way, would loss of vacuum cause low boost or over-boost?Thanks.Tim Quote
Masked Marauder Posted August 31, 2005 Report Posted August 31, 2005 Loss of vacuum would mean low boost. People who have had split vacuum pipes will testify to this! Quote
GSMGuy Posted August 31, 2005 Report Posted August 31, 2005 Quote.... "The turbocharger is an integral component of the exhaust manifold and although it is possible to separate them, they are not supplied separately and should therefore not be disconnected. The turbocharger consists of two elements, a turbine and a compressor. These elements are installed on a single shaft and are contained within a housing. The turbocharger bearings are supplied oil from the engine via the oil supply tube. This is returned to the oil pan via the oil return tube. The turbine uses the pressure of the exhaust gas to drive the compressor. The compressor draws air through the air cleaner and forces it into the intake manifold. The turbocharger vane adjustment vacuum diaphragm unit adjusts the turbocharger vanes according to the vacuum supplied by the turbocharger vane adjustment solenoid valve. The turbocharger vane adjustment solenoid valve is controlled by the powertrain control module (PCM). The actual turbocharger boost pressure is regulated by the adjustment of the turbocharger vanes and so eliminates the need for a wastegate control valve. The turbocharger vane adjustment vacuum diaphragm unit is preset during manufacture and must not be tampered with." And "Principles of Operation - Vehicles with 115 PS Diesel Engine The turbocharger is designed to improve engine induction and engine performance. The list below details the concerns relating to turbocharger performance. l High engine speed produces excessive turbine speed and therefore creates excessive turbocharger boost pressure. l Low engine speed does not produce sufficient turbine speed and therefore not enough turbocharger boost pressure is achieved. The variable turbocharger does not have a wastegate control valve. Instead, it has variable turbocharger vanes which are located in the turbocharger turbine housing. The turbocharger vanes act as the control for the turbocharger boost pressure. The variable turbocharger produces its full turbocharger boost pressure over the entire engine speed range, not just at high engine speed. This is achieved through the adjustment of the vanes and the resulting change in the flow of the exhaust gas. The speed of flow of the stream of exhaust gas is increased independent of engine speed by varying the intake cross section in front of the turbocharger turbine. This drives the turbocharger turbine faster. The higher turbocharger speed produces a high turbocharger boost pressure at all engine speeds. The powertrain control module (PCM) controls the turbocharger vanes. REFER to WDS to diagnose the turbocharger vanes." http://img44.imageshack.us/img44/7017/screenhunter0517pg.jpg http://img44.imageshack.us/img44/5424/screenhunter0520xw.jpg At low engine speeds the PCM actuates the vane adjustment solenoid valve to enable a vacuum to be applied. The vacuum diaphragm unit moves the adjusting ring so that the vanes are set at a shallow angle. The shallow intake cross section this creates for the stream of exhaust gas allows the turbocharger boost pressure to build up rapidly and easily at low engine speeds. http://img78.imageshack.us/img78/9536/screenhunter0562ej.jpg Mike Quote
Guest FlyingDutchMan Posted September 1, 2005 Report Posted September 1, 2005 GSMGuy, that was a very interesting lecture!; roughly knew how the vanes worked but not that there is no waste gate. Keep them coming!FDM Quote
Guest FlyingDutchMan Posted September 2, 2005 Report Posted September 2, 2005 yeah, right.... lolAnyway, do you have something like that on how the PD injection system exactly works?FDM Quote
Guest j_mchattie Posted September 2, 2005 Report Posted September 2, 2005 Good lad GSM - surely the best reply ive seen in a long time Quote
GSMGuy Posted September 3, 2005 Report Posted September 3, 2005 Just so happens... http://img371.imageshack.us/img371/8522/screenhunter0579it.jpg But I can't take all the credit - simply copying and pasteing lol Mike Quote
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