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spuggy spuggy is offline
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Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 2,825

I'm still trying to get a handle on most of this vacuum stuff too, so I had a few questions - the first being anyone got good vacuum diagrams for a 930? Does one even exist, and why isn't it in the factory manual?

I thought the wastegate had a vent line on the top, which just goes to atmosphere, and the control line on the side, which actually only needs boost, rather than boost/vacuum?

From memory, a post by beepbeep a while ago (regarding boost gauge plumbing) said:

Intake after butterfly: shows vacuum, no boost spikes.

Intake before butterfly: no vacuum, boost spikes.

I guess that if there's vacuum, it wouldn't hurt the wastegate(? this is a question, not a statement) to take off the control line post-TB because the wastegate doesn't need to be doing anything whilst there's vacuum, and if there's boost, there's positive pressure in both the throttle body and the intercooler?

Only thing is, you might get better boost control if the wastegate can "see" boost spikes and respond, and isn't the factory setup pre-TB?

Nice looking motor there, 125shifter....
'77 S with '78 930 power and a few other things.
Old 06-01-2007, 04:09 AM
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