Quote:
Originally Posted by Crazyrabbit
Sam,
Now I understand.
If the pressure control valve and bleed orifice let the case pressure get too high,
the lift pump will take too much power to drive, making the IP inefficient.
If they let the case pressure go too low, the pressure pump may not be able to fill completely,
which could limit maximum power, and
could cause cavitation damage within the pressure pump.
(1) There is no connection to injection timing.
That is set by the cam position (I like mine at 0.038"), and the cold start device, which can advance the injection timing by 2.5 degrees.
So, measuring and adjusting the case pressure to the low limit could improve MPGs.
(2) Does your document address adjusting case pressure, and give limits?
This reminds me that I was thinking of installing an exhaust gas temperature gauge and while driving at a constant speed on level ground, see if an optimum advance over the 0.038" setting could be seen within the range of the cold start device.
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CrazyRabbit,
Response to (1) above - I'm pretty certain that case pressure increases with RPMs and thus this is the physical parameter that this originally mechanical only IP uses to vary timing well beyond the 2.5 deg. advance used in the mechanical Cold-Start device.
Response to (2) above - No I do not remember reading anywhere about specific pressure ranges that are normal... but I think I might be able to get this from the IP shop in Portland, OR that I have used twice now!
I too am inclined to think in such R&D terms... but right now I'm still busy trying to get my '81 Rabbit p/u to a reliable Daily-Driver condition and will very soon be swapping the rebuil
T 5-speed tranny! I just received my custom fabricated shifter linkages and boshings/bearing for the shifter system! Next I want to do my first timing allignment fine tuing using the Dial-Indicator tool I have purchased for just over $100!
Let me send you this 1.65mb (60+ pages) PDF instruction booklet from Bosch!
Q - Can you tell me if this PDF file is something this FORUM would want to make available to it's Members?Regards,
Sam Ross