two fuel tanks

I never understood the twin fuel pumps, a tradition Maserati continued with cars that only had a single fuel tank like the Bora. In that example there had a single filter ahead of both pumps. Nice, a single impacted filter takes down a car with two pumps!

Maybe it was a balance issue with the two tanks as well as being a practical placement as dictated by the rest of the car's design. Look at how oddly shaped fuel tanks are in today's cars. My jag has two pumps in a blow formed plastic tank and you can never utilize the last 2.5 gallons of capacity because it's needed to make certain the pump doesn't overheat. The fuel gauge is an approximation as a result.

My Espada has the silly dual tanks that require you to fill from both sides. It has a 5/16" crossover hose so you'd be waiting a long time to fill it just from one side. That car has a single filter and pump with no pressure regulator (originally). The fuel filter and pump sit directly over one of the rear mufflers ... I changed that!

Go figure ...

 

Lots of cars with 2 tanks: Many Jaguars, Ferrari's, Masers and as Bob states also the Espada.

In most cases, especially with high performance cars, you want the tank(s) to sit low. If you don't have space for a single big one, mount 2 smaller ones. On some cars double fillers llok sexy (Jaguar XJ) and on others it is downright impractical. With 2 tanks you also need a filler high up if you don't have switch-over gear, otherwise you could not park the car slanted side-ways with full tanks.

It's fun at the pump to park inbetween 2 rows of pumps and fill both tanks simultaneously. Did that with a De Tomaso Deauville during the second oil-crisis. People got aggressive!

Best,

Jack.

 

Are the dual pumps used to increase fuel circulation and reduce fuel temperature, as in other makes?

 

I am very pleased with dual tanks on my Indy.

2x 50 liters and 1 can go on highway cruising (60-80mph) for 6 hours without visiting gas station. That is basically modern driving... Indy could not have had such feature with only 1 tank (without altering car design in major way). As it was designed, fuel tanks fit very nicely behind each rear wheel. Nicely balanced, not interferring with Vignales sleek body design.

Granted, a modern sportscar only needs a 50-60 litre tank for same distance covering achievement, but still. And many cars settle for small fueltanks regardless. Saves percieved kerb/laden weight? And many cars also settle for less grand/sleek designs.

It is also fun, I agree, to fill her up using both sides hoses although I don't do that often.

Martin

 

No. The fuel pumps are independent. The dual pumps do provide some level of redundancy ... or one more thing that can break, depending on how you look at it.

What I do not understand is why on the some models, such as the Sebring and Mistral, the dual tanks were interconnected and have a single filler while on the Ghibli the tanks are independent. It would have been much more convenient to interconnect the tanks and provide the ability to fill up from either side of the car.

Ivan

 

One possibility is when you park on an incline, one side to the other, the gas can transfer from one tank to the other and run out a vent it it's not high enough. I would never park that way but ...

Having a single fill cap and vent that's high enough would solve all of that though.

 

Not sure I follow what you are saying. The image below are the two tanks on a Mistral which are interconnected via hose #15. The vents on of both tanks are also interconnected and then to the single filler. How would having two fillers and having each tank vent to that filler be any different?

I think there is a reason as to why it was not done ... I just can't figure it out. Could it have been a change in safety regulations by the time the Ghibli was made? Let's face it, having a big hose in the back of the car connecting the two gas tanks is not the safest thing in the world. Oh ... did I mention that the two Ghibli fuel pumps have points (points = sparks)

Ivan
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The situation in the Khamsin is very similar. A large hose connects the smaller side tank and the main fuel tank. Items #48 fuel transfer, #45 common vent, #40 who knows just some Italian thing?
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I think Maserati just likes the word Dual

early ghibli


Dual carbs
Dual brake boosters
Dual gas tanks
Dual pumps
Dual water thermostats
Dual brake calipers on the front
Dual clutch
duel exhaust

It's like the redundancy of a moon shot

 

The Merak has two tanks and a 1" balance tube which is where the system gets its supply, what is interesting is they run a Copper tube the full length of the Right hand sill probably to stop vapor lock.

I am running two independant tanks in a car wich only had one for capacty reasons with switchable sides so on track days I can balance the car better by filling the passenger side only. Yes it has twin fillers ,
Jack thanks for the tip that sounds like fun!!

Graeme

 

The diagram is instructive but incomplete as it doesn't tell me where everything is located with respect to all the parts. Having never owned either of those cars I will defer to you. But what I was talking about is the situation where one side of the car is at a much higher elevation than the other such as parking on an elevated bank of a road. If both tanks are relatively full then this could allow the fuel from one side to overflow out the venting system of the other. I don't know that this is possible in the cars being discussed. It was just a suggested possibility. I've seen it happen on other cars.

The car in you diagram has a single filler not duals and the vents are interconnected with a single exit point on the filler side?

 

Single filter. OOOPS

 

A cooper fuel on the full length of sill? Where's that going?

 

It's quite simply its fuel cooling system

 

Is it under the rocker panel or ?

Think it helps?

Some guys have put fins on the coolant pipe, some were even copper, that run to front. I have no idea it that really helps. Boras are a lot more desperate when it comes to cooling issues.

 

Yes, Bob, under the rocker panel. I don't have a qualified opinion about the effectiveness of the system; don't know how the Merak would have behaved without it....

 

Yep! The Merak has two fuel tanks interconnected by one pipe at the bottom portion of the tanks. The Merak also has two fuel filters running off of one line. One fuel fillup makes things conventional. The fuel line runs behind the rocker panel for cooling purposes. The SS does not use copper tubing, but uses a petrol friendly clear tubing of some sort.

With the fuel tanks properly insulated and couple that with the gas tank enclosure being insulated, as I have done, one does not need to worry about the fuel ever over heating.

Ciao,
George

 

The Ghibli fuel lines also run in the rocker panels. During restoration they are frequently moved.