Forum americano de TDI's:
Post sobre limite de rotação ...
"A TDI can safely rev in excess of 8,000 rpm without throwing a rod, pump or anything else based on physical limits of piston speed etc etc.
The TDI is RPM limited not by a "Governor" but the smoke map. To prevent smoke due to the very small injection window required to meet emissions fueling is restricted and limited so as not to allow rpm's in excess of 5100.
At or around 4200 rpm fueling begins to be reduced. At 4600 there is a rapid reduction in permissable Injection Quantity that limits any further increase in RPM at 5100. This can be interpretted as a "Governor" but in fact its the emissions controls kicking in to prevent excess smoke.
Due to the high rpm range of the TDI motor injection and combustion must occur in some instances within 3 miliseconds, in comparison an F1 race engine running at 17,500 rpm has up to 5 miliseconds to accomplish the same thing! The TDI in order to meet emissions must reduce the maximum fuel injected per stroke since there is no longer sufficient time to inject fuel nor is there enough advance range remaining within the Injection pumps range of adjustment.
The PD motors since they are not mechanicaly limited like the VE pumps can offer more range of adjustment but you find yourself limited by peak cylinder pressure to to the extreme range of advance needed to make the motor work at much more than 5100 rpm.
When you look at a modified TDI's performance chart you can see that there are ways to trick the ECU into allowing higher fueling longer in the rpm range. I have personally gotten 5300 rpm from a TDI with reasonable smoke output and power bands continuing into the 4600 rpm range (11mm & .216 injector combinations which trick the ECU into thinking there is lower IQ values than actual).
Bottom line, RPM's are limited by the Smoke map rather than actual rpm inputs."
Post sobre limite de rotação ...
"A TDI can safely rev in excess of 8,000 rpm without throwing a rod, pump or anything else based on physical limits of piston speed etc etc.
The TDI is RPM limited not by a "Governor" but the smoke map. To prevent smoke due to the very small injection window required to meet emissions fueling is restricted and limited so as not to allow rpm's in excess of 5100.
At or around 4200 rpm fueling begins to be reduced. At 4600 there is a rapid reduction in permissable Injection Quantity that limits any further increase in RPM at 5100. This can be interpretted as a "Governor" but in fact its the emissions controls kicking in to prevent excess smoke.
Due to the high rpm range of the TDI motor injection and combustion must occur in some instances within 3 miliseconds, in comparison an F1 race engine running at 17,500 rpm has up to 5 miliseconds to accomplish the same thing! The TDI in order to meet emissions must reduce the maximum fuel injected per stroke since there is no longer sufficient time to inject fuel nor is there enough advance range remaining within the Injection pumps range of adjustment.
The PD motors since they are not mechanicaly limited like the VE pumps can offer more range of adjustment but you find yourself limited by peak cylinder pressure to to the extreme range of advance needed to make the motor work at much more than 5100 rpm.
When you look at a modified TDI's performance chart you can see that there are ways to trick the ECU into allowing higher fueling longer in the rpm range. I have personally gotten 5300 rpm from a TDI with reasonable smoke output and power bands continuing into the 4600 rpm range (11mm & .216 injector combinations which trick the ECU into thinking there is lower IQ values than actual).
Bottom line, RPM's are limited by the Smoke map rather than actual rpm inputs."
