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spuggy spuggy is offline
Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 3,523
Originally Posted by parasailsam View Post
So my 911 should have the 2 fuel pumps if it has one in the engine bay right?
The second fuel pump - the rear one - would be mounted on a bracket underneath the car, by the transmission. On a stock 930.

I'm calling the can below the deck lid hinge in the last pic the rear fuel pump.
Am I right?
The outermost one (next to the CDI) looks like a stock fuel filter to me, and the one slightly closer to the firewall looks like a stock fuel accumulator.

And Spuggy,
What readings should I be looking for when I get the sensor to read the AFR's?
Thanks guys
That's the subject of much controversy. The factory apparently said (at the time) "for a 930, anything that doesn't have unburnt fuel running out of the exhaust pipe isn't too rich". That's a quote from a factory-trained 930 guy - in fact, 930 tech secretary for the UK POC.

Times have changed. That's no longer how you set up 930's. Costs 30-40 HP in the midrange, apart from anything else (like contaminating the oil with the excess gas).

For best power, and good engine safety, most people would be very happy to maintain low twelves - say 12.2 or so - under boost all the way to redline.

In practice, most unmodified CIS fuel systems on 930's dump far too much fuel into the system (10's or lower) as soon as boost comes on, and then cannot maintain AFR's to safe levels as RPM's rise.

A Brian Leaske adjustable WUR can help dramatically here - as it lets you tune the onset PSI and amount of boost enrichment to a certain extent.

Sam, you say you have a '79 3.0 SC motor in there, but you don't mention any changes to the pistons.

What compression ratio are you running that motor at? What ignition timing?
'77 S with '78 930 power and a few other things.
Old 01-24-2009, 05:28 PM
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