[Vwdiesel] Hydraulics and heat: was,

[Lee Hillsgrove]

  Something else I thought about concerning pumps and heat generation: The
1.5/1.6 uses a 9 mm piston in the injection pump. The manual transmission
TDIs use a 10 mm, and the autos use an 11 mm. I'm not sure what the
injection pressures are offhand, I'd have to look it up, but the autos use
the 11 mm pump with smaller injectors compared to the manuals because they
just barely missed the emissions goal and by running a higher injection
pressure with smaller injector holes, the same amount of fuel would be
injected but in a finer spray so that it would burn cleaner, allowing them
to squeak by. An interesting tidbit that relates to the current discussion
is that *only the autos*, with their bigger pump and higher injection
pressure, come equipped with a fuel cooler in the return line back to the
tank. No, not scientific, but notable, wouldn't you think? Why didn't VW use
a cooler on the manuals, since they both have the same governor mechanism?

 A popular swap to increase power, btw, is to use an auto pump on a manual
or install manual injectors in an auto.

 I'm headed out for a few days starting tomorrow morning and I don't know if
I'll have internet access, but I will probably have a few more points to
make when I get back. I'm quite sure of my position on this matter, perhaps
James can explain it better as I think he shares my view.


  Lee
  Oo-v-oO
  PP-ASEL
  KB1GNI