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Oil, Fuel, and Electrical System Upgrades
 
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Pelican Technical Article:

Oil, Fuel, and Electrical System Upgrades

Mitchell Sam Rossi

Applicable Models:

Porsche 911 (1965-89)
Porsche 930 Turbo (1976-89)

Oil, Fuel, and Electrical System Upgrades

Figure

This article was originally published in HPBooks' Porsche 911 Performance: Building the Ultimate 911 for High Performance Street or Road Racing, by . Rossi is a contributor to European Car, Road & Track, Sport Compact Car and Los Angeles Times. As part of our selection of vintage 911 must-reads, this book provides a comprehensive look into the high-performance modification of 911's for the street and track. Covering topics ranging from engine building to chassis strengthening, this 144-page guide will certainly take your venerable 911 to the next level of performance. Click here to order this book.

Figure Figure 1: The fender-mounted 911S engine oil cooler.

Figure Figure 2: The 911's modest fender opening.

As we learned in Science 101, liquids flow. So too does electricity. Water, of course, is the dominant fluid on earth, but as the subject of this book is a true 911, there is no need to discuss that particularly molecule. The flow of air as it pertains to aerodynamics is discussed later in the book.

Here, we're looking into the workings of the 911. For the German sports car, and actually every automobile on the road, the most important compound flowing through its veins is oil. It is particularly important with the 911 as this viscous fluid is not simply the lubricating medium of the flat six, but an intrinsic part of regulating the engine temperature. Simply stated, it is the machine's lifeblood.

In 1969, the 911S models were equipped with a secondary, radiator-type oil cooler tucked into the forward section of the right front fender. The small horn grill between the hood and blinker was the only opening for fresh air. For the competition RSR, the Weissach engineers moved a larger oil cooler to the center of the front air dam.

Figure Figure 3: Mounting the B&B oil cooler front and center.

Figure Figure 4: The RSR-style air dam was perfectly designed for the center mounted oil cooler.

Following Porsche's example, I replaced the original front fender oil cooler with a bigger unit from B&B Performance Exhaust and mounted it up front. Designed for the 911, the B&B cooler fills the center opening in both the RS and RSR spoilers. For the S, however, the RS-type front spoiler from Phase I was replaced with a larger, more aggressive RSR unit. This deeper bumper afforded more room to fit the oil lines leading to and from the cooler.

Figure Figure 5: The S's modified trunk box allows air to flow through the center mounted oil cooler.

To further improve the cooler's efficiency, the trunk box was modified by Mark Spraker of Euro-Tek, a fabrication shop in Costa Mesa, California. By reshaping the box, Spraker created a cavity behind the cooler to allow the air flow to pass cleanly through the unit and then emerge under the car, thus eliminating any back pressure that might build up behind the cooler while the car was at speed.

Figure Figure 6: The new external oil lines displace the original, smaller interior lines.

Originally, the oil from the 911S 2.2-liter motor was transported to the fender cooler by lines integrated into the car's chassis. It was evident, however, that the inside diameter of the stock lines was too small to accommodate the increased oil flow required by the new 2.7-liter motor.

Figure Figure 7: Braided steel oil lines connect the cooler with the hard lines.

Along with the new hard lines, the correct thermostat was also acquired. While the S's thermostat was located inside the engine bay, the position for the new thermostat is in the forward area of the rear fender where the lines begin their run to the front of the car. Connecting the thermostat to the engine and oil tank, flexible steel braided oil lines with aircraft quality fittings had to be used since the S's chassis differed from the later models and would not allow the use of standard plumbing.

Figure Figure 8: The S's original oil line thermostat.

Figure Figure 9: Like the 1973 911S, the S's new oil thermostat is mounted in the right rear fender.

Initially, these lines were run horizontally along the chassis but when the 9x18 inch BBS wheels and racing slicks were fitted to the car, clearance became a concern. The oil lines were rerouted into the highest recesses of the fender.

Figure Figure 10: The initial oil line location was found to interfere with the tires.

Figure Figure 11: To clear the wide tires, the oil lines were relocated high inside the fender well.

The next major improvement to the oil system focused on the reservoir tank. When the S was first restored, it was equipped with an oversized oil pressure warning light. As important as oil pressure is to the 911 engine, the red lamp was sized accordingly and, in fact, filled the clock's original dash board location. If any problems arose, the illuminated lamp would signal the driver immediately to shut down the engine.

Figure Figure 12: The original oil tank was modified to carry two extra quarts of oil.

Figure Figure 13: The all-important oil pressure light resides in the clock position of the 911's five-gauge dash.

After the S's Phase I reconstruction, when it was run at local, high speed slalom events, this light made itself well known. Under hard braking, the oil moved away from the tank's pick up point which in turned dropped the internal oil pressure to dangerous levels. Now endowed with more horsepower, a more taut suspension and larger brakes, there was little doubt every dive into a corner would further induce oil starvation.

Figure Figure 14: The larger oil tank of a later 911 diminished worries of engine oil starvation.

To alleviate this potential problem, the original tank was replaced by a stainless steel unit from a 1983 911SC. This later tank has a volume increase of nearly two quarts and thus reduces the chance that braking or quick cornering will result in a loss of oil pressure.

Figure Figure 15: The engine bay was changed to fit the later oil tank.

This update, however, is not a simple swap. The 911 oil tank hangs under the right rear fender but the oil filler neck, breather lines and oil filter are located inside the engine compartment via an opening in the bulkhead. Unfortunately, this opening is not standard across the model years. To use the newer tank, the S's engine bay had to be modified.

A 911SC donor chassis was located and the desired section of sheet metal removed by means of a reciprocating saw and about an hour's worth of work. The fabricator then grafted the piece properly onto the project car.

Figure Figure 16: The Fuel Safe fuel tank fits perfectly in the 911 trunk.

For the fuel system, the S was fitted with a 100-liter Fuel Safe fuel cell from Hoerr Racing Products. This particular unit bolts perfectly into the original fuel tank position in the trunk. Its size, however, removes all thoughts of spare tire, tools or luggage space. Fuel Safe offers smaller units that maybe better suited for a multi-purpose car.

Figure Figure 17: A stock 911 fuel pump.

To augment this competition fuel tank, plans were made to replace the S's stock fuel pump with an aftermarket unit repositioned inside the trunk. Because fuel cells are notorious for clogging fuel systems, an auxiliary filter was also going to be placed between the pump and the tank.

Jeff Erickson, the engine's builder, pointed out that the original Bosch fuel pump was both adequate and dependable. He also saw no reason to move the pump from its stock location.

I had to admit, during the years I had owned the car, the fuel pump had been replaced only once. Thus, taking Erickson's advice, I left well enough alone. I did, however, insert a System One fuel filter between the tank and pump. Utilizing a high-flow, 35-micron stainless steel screen, the filter is easily checked and cleaned of any residue that might come through the fuel tank.

Figure Figure 18: An aftermarket fuel filter protects the S's MFI system.

As with the fuel pump, I had grandiose plans for the car's electrical system. To protect the wiring harness from the grit of the sandblaster's nozzle, the torch of the body shop and the painter's over-spray, I had entombed the fuse box, relays and macramé of wire in thick plastic bags and duct tape.

When I finally freed the tangled mass, it was, as I feared, in less than perfect condition. I had carefully labeled each wire so that re-attachment would be a simple affair. Most of these tags, however, had broken loose and collected at the bottom of the bag like flotsam in a seiner's net. Sorting this mess was nearly as tedious at scrapping the undercoating. Nearly, but not quite.

A second idea was to leave the harness complete but change the archaic bullet-like ceramic fuses to the newer bladed type and move the fuse box into the passenger compartment. While the bladed Autofuses look high-tech and orderly in their tightly aligned panels, they do not offer much above the original fuses.

An advantage to keeping the harness in its original form on a part-time street car is that the factory wiring diagrams remain applicable. If an electrical gremlin payed a fiendish visit to the car, any mechanic with an ohmmeter and a Haynes manual could find the problem.

Figure Figure 19: The original fuse boxes were relocated deeper into the trunk.

Changes in the trunk box, however, forced me to move the stock fuse box from the lower left side of the trunk to the flat area beside the gas heater well. The original location was severely limited by the front reinforcement bars that linked the forward A-arm suspension point to the strut tower brace.

Figure Figure 20: The well-designed battery cradle from Rennline.

For electrical power, the battery was set inside the gas heater well. To properly secure the battery, I used the battery relocation kit from Rennline, a Porsche aftermarket supplier in Winooski, Vermont. This fully adjustable aluminum assembly cradles the battery deep within the "smuggler's box" for better crash protection.

Finally, with the oil, electrical and fuel systems up and running, only a few tasks remained before the old S would be ready for the race track.

Figure Figure 21: Military spec couplers.

NEXT UP

When the 911S was stripped to the chassis in preparation for the sandblaster it was the perfect opportunity to yank out the 35 year old wiring and replace it with a new, minimalist harness. At the time, however, I was still clinging to my desire to keep the car street legal and therefore needed to retain the windshield wipers, turn signals, reverse indicator lights, and the license plate lights.

Yet as it developed I realize the day is not far off when the S will only turn a wheel on a racing circuit. Thus, one of the first planned "race only" upgrades is to swap out the bulky stock wiring for a pared down competition loom.

Electricity is a baffling element that often evades common sense. We've all seen the grade school explanation of electron flow using the diagram of a single wire linking a light bulb to a 12v battery and running through a rudimentary gate switch. This pencil drawing is demonic in its simplicity. It falsely gives every home mechanic the belief that the copper web that snakes through an automobile can be reduced to positive and ground. It is not so.

Why do you think Dr. Frankenstein had so much trouble bringing life to his creation? I venture it had nothing to do with the assemblage of human body parts. That was easy. I think the poor doctor was frustrated by the castle's fuse box popping every time he tried to capture a bolt of lightning.

I had the same fear with the S. Sure, it would be easy to cut, chop and yank out the oddly color coded loom, but how to replace it? Where to begin?

To do it right, I contacted Brian Sakata of Sakata Motorsport Electronics. The Southern California-based company specializes in automotive data acquisition, engine management and performance wiring solutions for high performance and competition cars. Sakata has laid his web of plastic wrapped, silver-coated metal into everything from high-dollar desert sand buggies to the current Daytona Prototypes running in the Grand-Am Road Racing series.

Working with such demanding racers, it was not surprising to find that ninety percent of Sakata harnesses utilize components that meet the strict requirements of the U.S. military. These aircraft quality, military spec pieces include wire, heat shrink wrapping, breakers, uplinks and couplers.

Figure Figure 22: Aircraft quality connectors are used to link the electrical systems of professional race cars.

"Everyone knows aircraft quality components that carry a military specification number have been tested under extreme conditions. Everything from the circuit breakers to the couplings are made for harsh environments," Sakata stated.

Addressing the specifics of wiring a race car Sakata explained his technician's approach to the vehicle's unique obstacles. "We divided the car into three segmentsBthe front, the rear and the cabin," Sakata began. "Anyplace the wire has to pass through metal work we'll incorporate some type of panel mounted inner connector. This facilitates quick repair or easy installation of electronic components."

Figure Figure 23: A custom dashboard is arranged with a myriad of switches.

This type of planning is crucial with competition cars. Even minor contact on the track may force the replacement of a quarter panel and light assembly. Connectors offer a race crew an effective way to disconnect a damaged piece and quickly re-attach a new panel without going behind the pit wall.

As ninety to ninety-five percent of each harness is built at the Sakata Motorsport's facility, the technicians rely on a CAD program for layout and wire lengths. Location of the circuit breaker and switch panels, however, is a personal choice. "We can put it anywhere in the car," Sakata said. "It's really what suits the driver and crew."

"We try to put a lot of forethought into the cabin layout," he said. Yet, while the harness is designed with the minimum amount of excess wire, Sakata noted that nothing about a race car is permanent. By utilizing inner connectors between the main harness and a breaker panel, the driver has the latitude to make fine adjustments in cockpit layout without major re-wiring.

Since Sakata's technicians do no fabrication work, the fuse and switch panels must be supplied by the car's owner. Still, Sakata's team tries to help with suggestions. "A lot of fabrication shops forget how tightly a driver is strapped in. You really have to be sure all the switches are within the driver's reach when he is buckled down, and conversely, that none are in his way."

Figure Figure 24: The MXL digital dash from AIM Sports.

Before ordering a harness for a club racer like my 911S, Sakata suggested that I have a good idea of exactly what I had planned for the car. A competition wiring harness would, of course, lose the blinker lights, reverse lights, low fuel indicator and the like.

The critical question Sakata pressed was whether or not I would be competing in enduro races or at night. He also questioned the type of electronics I planned to install beyond the car's basic running needs. Was I going to keep my analog gauges or change to digital? Was I going to combine the two? He wondered if I was going to incorporate a data acquisition computer into the car.

With the 2.7-liter motor being mechanically injected, there was no need for an engine management system, but Sakata asked if I was considering going to a larger motor. Of course. All racers go to a bigger motor....eventually.

Sakata grinned. He already knew my answer and countered that I should try to determine which engine management system I would be using. To save money, he would not use the top-of-the-line heat shrink or couplers throughout the car. After all, the S wasn't going to be driven in the week-after-week racing conditions of a professional American Le Mans competitor.

Sakata's harnesses are enveloped in abrasion resistant heat shrink tape and sealed. "The heat shrink is not only for aesthetics," Sakata explained, Abut for weather proofing. The car can basically be dismantled and steam cleaned without worrying about moisture getting into the harness. Most professional race teams, after they've run a long endurance races like Sebring or Daytona, do exactly that. They strip the race car down to the tub, get it steam cleaned and then reassemble it."

So much for just pushing a fist of wires through the firewall. The mere thought of dismantling and reassembling my S for a third time, of course, nearly gave me a panic attack, but what Sakata was saying about the durability of a harness created specifically for the harsh conditions of automobile racing made sense.

Depending on the car's equipment, a slimmed down harness can save four pounds of unnecessary weight. That, along with the fact that the wires now bearing my electrical current are thirty-five years old and certainly in less than optimal condition. Considering the improvements the S has undergone, it is high time for a proper loom. When the license plates come off for the final time, a Sakata wiring harness will be at the top of the "next up" list.

If you would like to see more technical articles like this one, please continue to support Pelican Parts with all your parts needs. If you like what you see here, then please visit our online Porsche catalog and help support the collection and creating of new and informative technical articles like this one. Your continued support directly affects the expansion and existence of this site and technical articles like this one. As always, if you have any questions or comments about this helpful article, please drop us a line.

Figure
Figure 1

The fender-mounted 911S engine oil cooler.

Figure
Figure 2

The 911's modest fender opening.

Figure
Figure 3

Mounting the B&B oil cooler front and center.

Figure
Figure 4

The RSR-style air dam was perfectly designed for the center mounted oil cooler.

Figure
Figure 5

The S's modified trunk box allows air to flow through the center mounted oil cooler.

Figure
Figure 6

The new external oil lines displace the original, smaller interior lines.

Figure
Figure 7

Braided steel oil lines connect the cooler with the hard lines.

Figure
Figure 8

The S's original oil line thermostat.

Figure
Figure 9

Like the 1973 911S, the S's new oil thermostat is mounted in the right rear fender.

Figure
Figure 10

The initial oil line location was found to interfere with the tires.

Figure
Figure 11

To clear the wide tires, the oil lines were relocated high inside the fender well.

Figure
Figure 12

The original oil tank was modified to carry two extra quarts of oil.

Figure
Figure 13

The all-important oil pressure light resides in the clock position of the 911's five-gauge dash.

Figure
Figure 14

The larger oil tank of a later 911 diminished worries of engine oil starvation.

Figure
Figure 15

The engine bay was changed to fit the later oil tank.

Figure
Figure 16

The Fuel Safe fuel tank fits perfectly in the 911 trunk.

Figure
Figure 17

A stock 911 fuel pump.

Figure
Figure 18

An aftermarket fuel filter protects the S's MFI system.

Figure
Figure 19

The original fuse boxes were relocated deeper into the trunk.

Figure
Figure 20

The well-designed battery cradle from Rennline.

Figure
Figure 21

Military spec couplers.

Figure
Figure 22

Aircraft quality connectors are used to link the electrical systems of professional race cars.

Figure
Figure 23

A custom dashboard is arranged with a myriad of switches.

Figure
Figure 24

The MXL digital dash from AIM Sports.

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Comments and Suggestions:
jamesjedi Comments: - Looking for a basic 3.0 EFI article. One that expalins how to do it. Hopefully one that does not cost $$$$.

- I see that some 3.0 engines are using 3.6 plenums, how is this done?
THANKS!
April 24, 2011
  Followup from the Pelican Staff: if we get the chance to perform the repair, we will document it and get it online. - Nick at Pelican Parts  
roster Comments: Does Somebody has an electric diagram for a 964 Porsche Turbo model year 94"
March 24, 2011
  Followup from the Pelican Staff: I think your best bet would be the factory manuals - I don't think they are available anywhere else. - Wayne at Pelican Parts  
wkbergman Comments: Geez,there's a LOT here! And some even useful for ordinary folk. Thanks, fine article, excellent penmanship, too.
WB
August 4, 2010
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 

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