Camshaft variable timing range, 45 or 48 deg?

[sapote]

This copy is lifted from Cubieman post, showing the intake has 60 deg range, and the exhaust has 48 deg total variable range. The DME will control the vanos within these range to optimize engine perormance.



However, pic below show the S54 exhaust cam only has 45 deg range (128 - 83 = 45) , not 48 as seen in the vanos test software tool. So which is correct, 45 or 48 deg?

[oceansize]

According to this training manual it is 45 degrees. Page 21

MS54B32TrainingModule.pdf

[Obioban]

Perhaps it depends on which tooth you use when inserting the splined shaft, and 45° is the minimum, with the least travel tooth used.
(not that I think it USES more of that travel)

[terra]

My car consistently measures 48, but by default it only uses 45 degrees. Could probably safely tweak the allowable range and the actual vanos MAP to use the full 48 degrees if you need just a little bit more adjustability.

[Cubieman]

Interesting, I did use the "sweet tooth" during re-assembly which did mean a different tooth was used than how I found it.

However, I would think if the test found the cam turned 3° past it's prescribed range the DIS/ISTA test program would show an error, but maybe this is not written into the test program and it simply measures? Also, the DME is aftermarket tuned but I'm not sure this would be a parameter any tuner would even consider changing if it is even possible.

[sapote]

However, I would think if the test found the cam turned 3° past it's prescribed range the DIS/ISTA test program would show an error, but maybe this is not written into the test program and it simply measures?

All the test programs I have seen all commanded the EX cam to move a total 48 deg from advanced to retarded, even though the factory operating range spec says 45 deg. Maybe during the test, they just want to ensure there is enough safety margin of 3 deg free movement out side the normal 45 deg range.