Thread: 044 fuel pump
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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
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Originally Posted by 911st View Post
Did the 4 pumps come from a catch tank fed by two pumps?

Some times multiple pumps are run to get fuel from each side of the fuel cell so there is less chance of starvation. One to each corner of the cell would be interesting.

Was the 962 CIS, MFI, or EFI?

I would think, pumps in parallel for quantity at moderate pressure (EFI).

Pumps in series for pressure which is what Porsche did with the 930's CIS.

Would the order of the pumps make any difference.

I was wondering if someone added a higher spec pump it might best be the last pump in series. Especially if they have built in pressure regulators. The one with the highest regulation spec might be best to have last.
962 had an early version of race Motronic EFI.
The race motronic ECU box was red in color and most teams had 2 of them mounted on the bulkhead to the left of the driver seat so the driver could unplug the harness from one and plug the other in if it failed during a 24 hour endurance race. This motronic ECU had a fuel mixture trim knob on it so the driver could adjust the fuel mixture while driving.
They could richen it up for more power if they had plenty of fuel or lean it out and shortshift to get better milage if running low on fuel in a race.

I was doing mostly fiberglass and bodywork on the car back in the mid eightees so I don't know all the details and I don't remember if there were more fuel pumps then the 4 I mentioned. Alot of what I learned was during lunch conversations with the rest of the guys on the team.

Also, every teams crew chief set the car up a little different and they were always trying new things for more speed and reliablility so like alot of other systems on the car there is no concrete answer to the fuel pump set up, they could all be a little different after time and team modifications.
The fuel cell was filled with chunks of yelow colored gasoline friendly large-open cell foam rubber that kept the fuel from sloshing around during cornering and braking. I don't know if there were seperate fuel pickups on the bottom of the cell or if there was another fuel pump inside the tank.
The fuel cell has 2 fill openings at the top, one on each side of the car. Only one was used during a race while the other was closed off.
The direction the cars were pointed in through the pits in relation to the pit wall and the teams fuel rig decided which one was used.

The 935 had a seperate surge fuel tank between the main fuel tank and the injection pump each with it's own dual or triple fuel pump array running.
I remember the 935 used the same fuel pumps that the Mercedes 6.3 liter engine used from the 280 SEL 6.3
Both of the 935 and Mercedes 6.3 used mechanical fuel injection.
Old 01-27-2010, 11:13 AM
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