Fuel Capacity

The total capacity is 18.5 US gallons (of which 4 US gallons are considered the reserve).

 

Does each tank has exactly 9.25 gal or one is larger than the other?

 

How do you know you have 1/2 a tank - if you are measuring that off the guage that would be fairly innacurate I think.

The reserve is not a seperate tank. There are two tanks linked together with a pipe under the car. The "reserve" just means the light comes on when it gets down to the last gallon or two!

When you run the engine fuel is pumped to the injection system from the left side tank. In fact the way the CIS system works is that a lot of fuel is pumped to the metering head, some is drawn off to run the engine & the remainder is sent back to the tank - and it goes back into the right hand tank.

Therefore if you put stuff in the left side tank via the fuel filler & then run the engine for 5 minutes, that will mix it all up - it flows at a heck of a rate!. You can achieve this without running the engine by unplugging the blue plug on top of the metering head and switching the ignition on - that will start the fuel pump and circulate the fuel. I have used this (plus disconnecting/diverting the return fuel line) to empty the fuel tanks on my 328.

Aside from all that, best way to stop fuel going stale over the winter is to brim the tank I think.

 

9.25 gallons -- if you can trust your gas gauge . There is no separate physical "reserve" tank. The total capacity is 18.5 gallons -- they are just telling you (in a poor translation IMO) that, of those 18.5 total gallons, you should consider the last 4 gallons as the "reserve" and start seriously thinking about refueling when the level gets down that low (i.e., after burning 14.5 gallons).

It's usually better to store it with a full tank as Iain suggested -- that way there is a lower volume of air inside the tank where condensation can form -- just a suggestion...

 

Add the StaBil just before you fill the tank, at the gas pump.

Your ratios are not that critical, about 1 oz per 2 gallon for a years protection, 1 oz per gallon for two years.

I use the stuff for my longer term storage gas that is used in generators and ATVs, it does keep varnish from forming.

Doug

 

Good comments. Fuel stabilizer is important when storing a vehicle
for three to six months or more. I also store my classic cars with
full fuel tanks to avoid excessive condensation during the colder months.
I'm not so sure it is as important with the Ferrari fuel tanks as it is
with metal fuel tanks. If you are running carbs, it is essential to run
the engine after you use stabilizer fluid to assure that the carbs are
well run through with stabilizer to avoid varnish build up in the many
critical areas.

 

Is the gas gauge unreliable because the indicated level varies between tankful to tankful even when the car is sitting stationary and level? Or is it just that each car indicates a different fuel level when they have the same amount of fuel in them?

Certainly, I get the huge variations in indicated fuel level between right and left turns, slope etc., but I am wondering about how much I can trust the "low fuel" light. Mine seems to come on at 14.5 gallons remaining (thus 4 gallons of remaining fuel) when the car is stationary and level, but I wonder how much beyond the light coming on I can drive. It is the first time I have ever run the tank that low. (I don't need advice about not driving to such a low level but, you know, sometimes coming home late 20 miles from home it would be nice to know I can confidently make it back.)

 

IME, gas gauges are fairly repeatable (so no tank to tank variation on the same car), but not so accurate -- so the total miles that you can drive once the light turns on could be somewhat different from car to car, or how much gas is really in the tank when the gauge needle shows 1/2 full could be somewhat different from car to car. I very rarely, like maybe once in 20+ years, have allowed the fuel level to get down to where the warning light comes "on" so I have no idea what would be a distance that could "confidently make it back" even on my own car.

 

Perfect response. Thank you.

I will use the gauge with a little more confidence but with caution.

In defense of driving until the light comes on, there is no in-tank pump that needs gasoline as a coolant, so the only peril is the consequences of running out of gas. (I am not going to test.)

In the name of science I have intentionally run the tank dry on my E30 BMW. It has a range estimator “computer”. I have determined empirically that I can go an additional 12 miles after the computer says I have zero range. Fun with cars.

 

There is much experience here suggesting a rule of thumb that when driving the light begins to flicker with about a hundred miles remaining and goes solid with about 50

 

I average 19mpg on ‘82 308GTSi. Resetting my tripmeter each fill up and go up-to 260 miles between fill ups. Agreed the tank light is indicating the need for fuel at that point. Could go further if absolutely needed. So around 14 usable gallons.....

 

The “take away” for me is that I no longer need to be nervous about fuel level as the light flickers on and off. I can drive until it is solidly lit and know, at least in my car, that I still have approximately 4 gallons left.

 

But why let it get that low to start with?! Mostly joking... my wife kills me, every single time I get in her car it's practically empty. I just don't understand. I fill up at half a tank, 3/4 at the most.

 

+1 -- I can't count the times that my wife has said to me when leaving: "answer the phone just in case I run out of gas before I get to the gas station"

 

The problem is with the design of that fuel system even with a few gallons left parking it on a slope to the right the fuel runs into the right tank and the fuel pump cannot get it there. Also fast seeping left turns it can starve for fuel. I run cars to the low fuel light regularly but will not do it in the 328 because of too many experiences like that.

 

Steve,

Two '89 328s here, a GTB and a GTS. On both cars, the fuel warning light comes on exactly at the same mileage usually (considering that I drove them about the same way, on about the same roads, etc...) i.e at 445 kms indicated on the daily trip counter (odometer) if I had filled the tank(s) to "full" and put the trip counter to "0" just after.
The light is first intermittent for about 30-40 kms, going "on" only in the right turns (if my memory, etc, but it might also be the left turns...) then stays permanently "on" at 490/500 kms, at which number I can put 59 to 60 litres in the tanks, meaning the reserve is...mor or less exactly the 14 litres specified in the owner's manual. 14 litres also means "about 120 kms before the car is bone dry and stops".
It has been so for the last thirteen years; meaning I actually don't look very often at the fuel gauge, only at the daily trip counter. When it is nearing 450kms, warning light or no warning light, then it is time to look for gas.

Rgds

 

Fuel mileage? You bother to check?

 

Having drained many and refilled them to the top, they do hold exactly what Ferrari says they hold. .

 

Don't disbelieve your comments at all, but that is the most ideal situation -- same model, same year, so probably has fuel level senders and gauges from the same vendor batch. My comment was more related, to say, comparing the behavior of a late 70's carb 308 to a 328. You can certainly "learn" your own cars exact behavior, but, IMO, just like the oil pressure gauge, you shouldn't try to read the gauge down to 1/2 a needle width, and think that that's the exact accurate value. The fuel level gauge face should be marked:

3/4 to full = yeah, you have plenty of fuel
1/2 = still have a fair amount so no worries yet
1/4 = get some fuel

 

On my several cross-USA drives in my '89 328. My primary indicator that I needed fuel was "I'm tired of sitting here, I want to stop for a few minutes...might as well fill the tank!"

 

Same here. And we live out in the sticks, far from gas stations. I don't know why she'll pass all those gas stations on the way home with low fuel, and not stop. Her car burns about a gallon for a round trip to the nearest station! I never like to drive around with less than 1/4 tank.