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Thierry25 Thierry25 is offline
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Join Date: Feb 2009
Location: FRANCE (Besançon)
Posts: 310
Quote:
Originally Posted by JFairman View Post

The injectors don't seem to be a restriction from my experience.


This is why I think he tapers the metering slits in the control plunger cylinder to a larger diameter towards the top when he CNC enlarges them. I havn't removed it and measured them so I don't know though.
Dear Jim

When I look the very small injector outpout hole and compare it to the size of the metering slits, I really suspect the injectors to be much more restrictive. it doesn't means that the metering slit are not restrictive at all. There is certainly a little margin which can be used in order to increase fuel flow under middle and full metering deviation. I speak about middle deviation, because in your in valuable expérience it is possible that the tuner have increased the slits on the bottom direction which could cause too much fuel at 4000 RPM but which doesn't means you could get tons more fuel at full deviation of the metering arm.

When I see the tons of fuel that the head is able to supply when the injectors are removed ( as Stu did in his matching thread) it makes no doubt to me the injectors are huge part of the equation.

The 3.6T and 3.3T are using exactly the same head distributor. The arm is the same, the metering slits and pins are the same, the valves are the same, the input and output line are the same, same fuel pumps too, but the control pressure is about 0.4 bar higher on 3.6T while the metering cone is a bit larger........ where do you think they get more fuel ?
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Old 01-06-2010, 11:58 AM
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