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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
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Hmm...it would be optimal to have a dizzy where vaccum advances the timing. In that case you can take the hose off the bell, adjust on-boost timing to whatever you feel comfortable with (depending on ambient temp, fuel quality, boost etc.)

My other (non-P) car has that solution. Vaccum advances the dizzy and vaccum line is taken off the tap that sits directly over the throttle butterfly. The trick part is that there is little advance at idle (as butterfly masks the tap so it sucks from both parts of the butterfly). As soon as you prod the gas, butterfly moves from the tap and hose is submited to vacuum, advancing the timing. When boost comes online advance is canceled and distributor bottoms out on whatever you adjusted it to.

It's also a safe should hose that controls dizzy rupture. Only thing that happends if vacuum disappears is that dizzy runs on max preset full-boost advance (which is typically less than low-load advance). The tap-on-butterfly trick is also neat as it allows engine to idle at low advance (giving stable idle and good emissions) but starts advancing as soon as you start driving.
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Thank you for your time,
Old 06-23-2008, 03:04 PM
  Pelican Parts Technical Article Directory    Reply With Quote #62 (permalink)