Fuel tank sizes?
 

So both of my cars are imports so I don't really know any of the history behind them. My s4's a savanna gt limited which I think is the model below the ifini as it came with climate control etc. And my s5 I don't really know what model it was. Was filling up the s4 the other day and noticed it's got a 45 or 50L fuel tank in it, while the s4's got a 70 - 75L fuel tank in it.

Were these an option or has my s5 got an aftermarket tank in it?

S4 tanks were around the 16.4 GALLON area and the S5's were aroung 18 gallons. Something to keep in mind when swapping senders, straps... whatever. Dunno what a litre is.... litre cola maybe ;)

Give him a break, he is from Australia.

Seriously, 63L and 70L (S4 and S5)

Screw your gallons, thats really odd the one in the s4 must be smaller. Because theres no way its more then 45L ive had it right on empty and it took 42L or something.

Do the gas stations in Australia use those anti-smog vapor recovery nozzles like they do here in the USA? If so, I've found that in the warmer months these pumps like to shut themselves off prematurely when filling up my '89T2. I assume the anti-smog nozzle function interferes with the tank's ability to properly vent itself, so when it's hot outside, you get a big pocket of air trapped in there that prevents the tank from filling completely. Fix for me is to just remove the nozzle partially, allowing some air to escape, then re-insert and start filling again. You might have to do this several times to completely fill the tank -- on really hot days, I've added another 3~5 gallons after the initial pump shutoff this way.

That thing is a PITA regardless of the car. My truck for example, after it shuts off I can ALWAYS get an extra 1.5-2gals in.

Might be a good idea to add this information to the FAQ/archives, in case it comes up again in the future.

European cars, sizes were not different only by Series, but by model (turbo or NA)

S4 NA = 63L
S4 TII = 70L
S5 TII = 70L
S5 NA = not offered on EUDM

Just to bump this, drove the car till it was close to running out of fuel the other day, as it was the day before pay day and I spent all my cash on other goodies. Think my gauge is out of cal, as I was very unsure if I would make it home. It went down to where I should be out of fuel and the fuel light was still coming on and off not staying on solid. Got it to the servo the next morning and it drank 58L of fuel. When I had filled it up the week before from a fly shit above empty it took 40L.

When my S4 was stock, the gauge would drop to 1/2 in 100 miles, then it would take 200 to 250 miles to get to empty. From what I remember, when the light started coming on I had roughly 3 gallons left.

There is a possibilty that your sender is a little off, the gauge is a little off, corrosion on one of a dozen terminals, etc etc. The fuel gauge is an ohmmeter.... any resistance anywhere is going to affect the readings.

a common issue on the 2nd generation sending units is for the sending unit wires to fray near the bottom of the tank, throwing off their calibration at lower fuel levels.

i've been noticing it alot more lately as the cars are getting older.

I have no idea what you are talking about...

If it was indeed fraying, there would still be electrical contact.
When the wire completely broke, it would obviously lose signal.
Even if you had one wire still intact, the voltage is low enough that one strand of wire would still provide an adequate signal.

I just changed my fuel level sender in my 1987 turbo and saw no evidence of "frayed" wiring.
It was the potentiometer resistance sweep (common problem for any type of (non-sealed?) potentiometer) to degrade this way.


-ted

Do remember they idiot proofed gas tanks. They have a "Reserve" so that people running them to Empty did not run out of gas right at that moment. I know my Taco has a reserve to get another 100+ miles to get some gas.

On my 74 BMW 2002 Empty was Empty I am not sure as to what year they enacted this.

I had the exact same problem on my sender when I was using the stock dash.

When I changed out the dash and built my own using all aftermkt gauges I first tried the autometer generic replacement sender = SHIT
Then I tried the marine Tempo sender = less shit, but still shit.
Then I bought a new Mazda sender and a programable autometer gauge = awesome.
Then I built my own tank and went with a WEMA and the same Autometer programable sender = awesomeness

If you need to replace the sender, which I suspect is highly likely, as Ted said, non sealed units as they are, you can actually see corrosion on the sweep giving inaccurate signals, I have yet to find a better sender than the Mazda units. Aftermkt wise, WEMA is the way to go.

:rofl: I've noticed that with alot of newer cars as well, take my Jeep. When the light goes on there's about 100 miles left if you're on the highway at a reasonable speed. Cold winter mornings letting the truck warm up and siting in traffic, 50 miles. I know this becuase I put 5 gal in my mounted jerry and drove the thing empty, twice :rofl: Then I drove a few miles to the gas station and put 15.3 gal into a 22 gallon tank. Stupid vapor reserve things

take a pill...

when the wires are worn the resistance gets thrown off giving a less accurate signal at the lower fuel level range where the most wear generally is. eventually the wires break and the gauge reads zero before the tank is actually empty, i figured you could gather what i was getting at. i have seen a number of 2nd gens with frayed wires below 1/4 tank which worked fine up until that point then dropped to 0 on the gauge as soon as they hit the bad spot.

Can I use an S5 tank in my S4 if I swap the straps also?

Technically, yes, but there's alot of wiring to do. Plugs are different, senders are different, fuel pump pickups etc etc.

:banghead:

i really don't imagine it is that difficult to swap them. the S5 sender plugs right into the S4 harness at the LR strut tower 4 pin rectangular plug. you just won't have the junction on the top of the tank anymore as the S4 is a solid connection to the strut tower.

i have swapped a few S4 pump housings into S5 tanks as the bulkhead connector style of the S4 pump housing is much more durable than the S5/S6 for high horsepower applications without the need to modify the housing for passthrough connections. you do need to cut and add ring terminals to the S5 fuel level sender and low level sensor and modify the S4 pump housing to lower the pump to the appropriate level though. but that is an afterthought and doesn't apply if you are swapping everything from the S5.

Resistance values that the gauge will see could also be different so there would be alot of trial and error with the S4 sender in an S5 tank. Then again, the values could be the same.... would need a journey into two different FSM's to make sure

Somewhat related to this thread - 1970 MG Midget tank holds 25 Litres (Approx 6 gallons). With the 13B Extend Port under normal driving my range from full is 100km (60 miles).
Yes, I plan on installing a larger tank in the near future. On the upside, I always use fresh fuel.
Downside is no warning light or reserve - empty means empty!

How the heck is it so inneficient? When I drove my car down south I was getting around 13L/100km

Real cars come factory standard with 120lt carbon fiber fuel tank :lol:

Good to hear from other Aussies...
I believe the inefficiency is partly due to the lack of a fuel regulator - or at least I hope so. I believe the fuel pump is over supplying to the Weber. I have fitted a Mallory 4207 last night and am yet to set at 4 PSI. Fingers crossed.

Rice Racing, 120 litres is a lot of weight to be lugging around... I cant think of any car that comes standard with a carbon 120L - enlighten me.

The SP rx7 did (which he owns) and u can only put 60L of fuel or so in if u desire

Thanks Mazdabater, I had no idea they were factory produced at 120L and of carbon construction.

Australia had a special high performance version of the RX-7 in 1995, dubbed the RX-7 SP. This model was developed as a homologated road-going version of the factory race cars used in the 12hr endurance races held at Bathurst, New South Wales, beginning in 1991 for the 1995 event held at Eastern Creek, Sydney, New South Wales. An initial run of 25 were made, and later an extra 10 were built by Mazda due to demand. The RX-7 SP produced 204 kW (274 hp) and 357 N·m (263 ft·lbf) of torque, compared to the 176 kW (236 hp) and 294 N·m (217 ft·lbf) of the standard version. Other changes included a race developed carbon fibre nose cone and rear spoiler, a carbon fibre 120 L fuel tank (as opposed to the 76 L tank in the standard car), a 4.3:1-ratio rear differential, 17 in diameter wheels, larger brake rotors and calipers. An improved intercooler, exhaust, and modified ECU were also included. Weight was reduced significantly with the aid of further carbon fibre usage including lightweight vented bonnet and Recaro seats to reduce weight to just 1218 kg (from 1310 kg). It was a serious road going race car that matched their rival Porsche 911 RS CS for the final year Mazda officially entered. The formula paid off when the RX-7 SP won the title, giving Mazda the winning 12hr trophy for a fourth straight year. The winning car also gained a podium finish at the international tarmac rally Targa Tasmania months later

What's a bonnet?

An Australian hood.

Yeah I know... kinda joking. It could be british too.

Good buddy has a Land Rover that I'm rebuilding. He says, "lets get the bonnet off." I say, "in this country, in this garage... it's a fucking hood!" :rofl:

What the fuck is a hood?

:rofl: Touche