Porsche Repair: Sudden Loss of Power, tubing size, mint condition

Question
Hi Dave! I'm a Brit living in the home of Porsche, Germany and I've recently purchased a near mint condition 1986 911 (930) Turbo with an original works upgrade to 330bhp. The car has 115Tkm on it which is not too bad for a near 20 year old! I've only taken it out 3 times, each time allowing plenty of warm up time to ensure the second oil loop is back up to temperature before really opening it up. However, yesterday after about 40km of steady driving, the engine lost all power all of a sudden, I pulled over as I couldn't find any power through any of the lower gears, switched off, got out to look for sudden loss of oil, saw nothing, got back in and it started up again without any problem, and got me home fine. Could this be a petrol pump problem? Or lack of oil? Any thoughts? Thanks very much. Rich

Answer
Yikes!  What a great car.  You're a lucky guy.  

If I understand correctly the car lost power but was still idling fine (I assume) until you shut it down.  So the car didn't die.  If this is true then it's unlikely you have an electrical problem, especially if it started up again right away.  I'm sure you checked the oil level more than once so I don't believe oil's an issue...unless the car died.  I suspect there was a fuel delivery issue at speed.  

I assume that's where you were...at speed.  Let's suppose the engine was upgraded and the fuel pump was not.  It's likely it delivers the correct pressure, but at speed, when the engine is sucking in fuel quite rapidly, if the volume isn't suffcient the car will act as if it is starved for fuel.  When it idled fine by the side of the road, the fuel pump had plenty of push.

There are likely other possible causes, but the age and specs on the pump are something you might want to check.  Here's the issue:  the pump delivers fuel at its pressure, let's say 45 psi.  The size of the tubing limits the volume to xxx liters per minute.  If the engine wants more volume at speed the only way to do this is increase the tubing size...or replace the pump with a higher pressure pump.  Then you'll need a pressure regulator at the engine to bring the pressure back down to where the engine wants it.  With the extra pressure from the pump, even at speed, the engine should be happy because the volume will still be there where it's not now.

Dave