XUD7TE camshaft upgrade

XUD7 turbo motors (XUD7TE, XUD7T) have a camshaft with smaller lift and narrower lobes compared to later XUD7 atmospherics and XUD9 motors. Both camshafts have their pros and cons. Table below summarizes camshaft timing data.

XUD7TE XUD9A
Exhaust opens before BDC
39°
43°
Intake opens before TDC
4°30′
Exhaust closes after TDC
3°45′
Intake closes after BDC
-20°30′
43°
Intake lift height
8.25 mm
8.5 mm
Exhaust lift height
9.2 mm
9.4 mm

 

XUD7TE (1.8TD) and XUD9A (1.9D) camshaft lobes. Lift height and angles are as specified in manual; spline interpolation in between.

Picture above shows XUD7T/TE and XUD7/9 camshaft comparison. Later has higher lift and wider lobes, slightly narrower overlap. Higher lift is always an improvement because it allows greater gas flow. Wider lobes enhance high RPM performance and reduce low RPM. Narrower overlap reduces internal EGR (exhaust gas recirculation): less exhaust gas returns to intake manifold. EGR actually improves low load performance because it reduces combustion temperature and increases efficiency, reduces emissions. But under high load it reduces effective engine displacement (part of the cylinder is filled with inertial exhaust gas, right?). Thus reducing internal EGR might enhance high load performance. Continue reading about valve timing here.

To summarize camshafts: use XUD7TE cam for better fuel efficiency, lower omission, better low RMP and low load torque; use XUD7/9 cam for better high RPM and high load torque.

In the next post I’ll describe replacement procedure in detail.

Camshaft on XU7 turbo engines is longer and has a pulley on the far end to drive either hydraulic pump or vacuum pump. This limits possible camshafts options to two: stock XUD7TE camshaft 0801 C9, XUD7/9 camshaft  0801 C2. Below is a list of car models with one or the other camshaft.

  • stock XUD7TE camshaft 0801 C9 (narrower, lower lift lobes). Application:
    • CITROEN BX TRD Turbo 1769 66 4 Hatchback 1988-1993
    • CITROEN BX Break TRD Turbo 1769 66 4 Estate 1988-1994
    • PEUGEOT 205 Mk II 1.7 TD 1769 57 4 Hatchback 1990-1998
    • PEUGEOT 309 Mk II 1.8 TD 1769 57 4 Hatchback 1989-1993
  • XUD7/9 camshaft  0801 C2 (wider, higher lift lobes). Application:
    • CITROEN C25 1.9 D 1905 51 4 Bus 1987-1994
    • CITROEN C15 1.8 D 1769 44 4 Box 1986-2000
    • CITROEN ZX 1.9 D 1905 47 4 Hatchback 1991-1997
    • CITROEN ZX 1.9 TD 1905 66 4 Hatchback 1992-1997
    • PEUGEOT 205 Mk II 1.7 Diesel 1769 44 4 Hatchback 1987-1998
    • PEUGEOT 205 1.7 Diesel 1769 44 4 Hatchback 1983-1987
    • PEUGEOT 309 1.9 D 1905 47 4 Hatchback 1986-1989
    • PEUGEOT 309 Mk II 1.9 Diesel 1905 47 4 Hatchback 1989-1993
    • PEUGEOT 405 1.9 Diesel 1905 51 4 Saloon 1988-1992
    • PEUGEOT 405 1.9 D 1905 51 4 Estate 1988-1992
    • PEUGEOT 405 Mk II 1.9 D 1905 50 4 Saloon 1994-1995
    • PEUGEOT 405 Mk II 1.9 D 1905 50 4 Estate 1994-1996
    • CITROEN ZX 1.9 D 1905 47 4 Estate 1993-1997
    • CITROEN ZX 1.9 TD 1905 66 4 Estate 1993-1997
    • CITROEN XANTIA 1.9 D 1905 50 4 Hatchback 1994-1998
    • CITROEN ZX 1.9 D 1905 50 4 Hatchback 1994-1997
    • CITROEN ZX 1.9 D 1905 50 4 Estate 1994-1997
    • PEUGEOT 309 Mk II 1.8 Diesel 1769 44 4 Hatchback 1989-1993
    • CITROEN ZX 1.8 D 1769 44 4 Estate 1993-1997
    • CITROEN ZX 1.8 D 1769 44 4 Hatchback 1993-1997
    • PEUGEOT 205 Mk II 1.9 Diesel 1905 51 4 Hatchback 1987-1994
    • PEUGEOT 405 1.8 GLD 1769 44 4 Estate 1990-1992
    • CITROEN C25 1.9 D 1400 1905 51 4 Box 1988-1994
    • CITROEN C25 1.9 D 4×4 1905 51 4 Box 1988-1994
    • CITROEN C25 1.9 1905 51 4 Flatbed / Chassis 1988-1994
    • CITROEN C25 1.9 DT 1929 60 4 Box 1991-1994
    • CITROEN C25 1.9 DT 1929 60 4 Flatbed / Chassis 1991-1994
    • PEUGEOT 405 Mk II 1.9 D 1905 51 4 Estate 1993-1995
    • CITROEN C15 1.8 D 1769 44 4 Estate 1987-2000

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