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Modena Grand Master

Modena

Posted
Posted
hm. what i usually do is when the tank is about half way, ill jump on fuel watch and see whether today or tomorrow will b cheaper, then i will fill up on watever the cheapest day is... im too lazy to do partial fill ups, just fill it to the top!

I didnt buy a skyline to worry too much about fuel anyway. :ermm::D

With current petrol prices, keeping a turbo (esp boosted) Skyline is becoming a bit of a joke.

Most of the guys and girls on here that own Skylines struggle to fill up a tank every week... add the rising interest rates and rent + food prices and so on and suddenly you gotta be crazy driving anything that has a bigger than 2 litres capacity :)

I just sold my Skyline after 2 years of ownership to buy a newish Corolla soon, I hope to be back to owning a Skyline... R35 GTR within 4-5 years when I can pay cash for it or at least 3/4 of it and drive it on weekends.

Corolla FTW :P

FATAZZ Grand Master

FATAZZ

Posted
Posted
heres another one , always fill 2 cents more so it gets rounded down. Times are getting tough :)

haha i like your thinking.

mines always on 1/4 tank(plenty to get to the servo)

i have a local BP that i always use,so being on 1/4 isn't an inconvenience for me as i have the BP's phone number and ring them

before i bother leaving home to find out they are out of Ultimate like most other servos.

And i only drive it weekends....work ute and excel FTW

rev210 Grand Master

rev210

Posted
Posted
I am sure your fuel pump will appreciate this... :stupid:

I see you aren't of the same view?

Are you assuming that the fuel at the very bottom of the tank (where the fuel pump pick up is acutally located anyway) is somehow worse when there is less fuel or are you talking about concerns due to some 'spirted driving' around a corner on semi comps and the fuel pump sucks up air?

I have found that getting more of the 'old fuel' out in this fashion allows for less moisture and degredation. I've found in fuel cells there can be some interesting sludge build up over a period of time with old fuel if it's left around. A well used race car cell, even an old one is a pretty clean thing (it gets emptied alot). The greater and complete aggitation of the fuel at the bottom of the tank when it is relatively lower seems to keep the tank cleaner. It's an easy idea to test with a pond. Smaller amounts of water will 'swirl' faster keeping the bottom of the pond cleaner. A deeper pong with the same pump will move much slower. In terms of sludge build up in cars fuel tank, the idea is the same. We all know octane levels drop and fuel generall degrades as it ages and it doesn't actually take very long. The practice of the ' top up' guarentees a higher proportion of older fuel in the mix and if coupled with a full tank the swirl is kept slow and the aggitation less.

Having said that I've just been going off what I know or think, happy to be enlightened. :domokun:

Modena Grand Master

Modena

Posted
Posted
I see you aren't of the same view?

Are you assuming that the fuel at the very bottom of the tank (where the fuel pump pick up is acutally located anyway) is somehow worse when there is less fuel or are you talking about concerns due to some 'spirted driving' around a corner on semi comps and the fuel pump sucks up air?

I have found that getting more of the 'old fuel' out in this fashion allows for less moisture and degredation. I've found in fuel cells there can be some interesting sludge build up over a period of time with old fuel if it's left around. A well used race car cell, even an old one is a pretty clean thing (it gets emptied alot). The greater and complete aggitation of the fuel at the bottom of the tank when it is relatively lower seems to keep the tank cleaner. It's an easy idea to test with a pond. Smaller amounts of water will 'swirl' faster keeping the bottom of the pond cleaner. A deeper pong with the same pump will move much slower. In terms of sludge build up in cars fuel tank, the idea is the same. We all know octane levels drop and fuel generall degrades as it ages and it doesn't actually take very long. The practice of the ' top up' guarentees a higher proportion of older fuel in the mix and if coupled with a full tank the swirl is kept slow and the aggitation less.

Having said that I've just been going off what I know or think, happy to be enlightened. :)

Ask yourself this, whats easier, sucking a slurpee that is still full or when its nearly finished? The same goes for your fuel pump...

The petrol also serves as a coolant for the petrol pump, so if you are running very low, you are not cooling it down effectively.

BTW fuel pumps are around 800 bucks brand new, if you can afford it easy then keep doing what you are doing. :banana:

rev210 Grand Master

rev210

Posted
Posted
Ask yourself this, whats easier, sucking a slurpee that is still full or when its nearly finished? The same goes for your fuel pump...

The petrol also serves as a coolant for the petrol pump, so if you are running very low, you are not cooling it down effectively.

BTW fuel pumps are around 800 bucks brand new, if you can afford it easy then keep doing what you are doing. :banana:

Ah I see, you have assumed that I meant low fuel to the point where air is being sucked in.

Thats an assumption beyond what I am suggesting (ie: I am not saying run your fuel down so you are at risk of stopping by the side of the road).

Hopefully you now understand what I am talking about in terms of 'sludge'. This sludge can not only shorten the life of the fuel pump but, buggers up injectors and other things as well.

This is why there is a huge market for 'fuel system cleaners' due to the practice of retaining old fuel in the tank due to the 'top up' mentality.

I my rather long experience of doing this over a few decades, but I think my explanation hasn't been put very clearly.

So to clarify. The concept of running the tank 'down' doesn't mean you run it down to vapours, thats pretty silly. But, running the tank down to a safe level ensures you have litte 'old fuel' retained in the tank and ensures better aggitation of fine particals that may settle to cause a sediment sludge. :)

Modena Grand Master

Modena

Posted
Posted
Ah I see, you have assumed that I meant low fuel to the point where air is being sucked in.

Thats an assumption beyond what I am suggesting (ie: I am not saying run your fuel down so you are at risk of stopping by the side of the road).

Hopefully you now understand what I am talking about in terms of 'sludge'. This sludge can not only shorten the life of the fuel pump but, buggers up injectors and other things as well.

This is why there is a huge market for 'fuel system cleaners' due to the practice of retaining old fuel in the tank due to the 'top up' mentality.

I my rather long experience of doing this over a few decades, but I think my explanation hasn't been put very clearly.

So to clarify. The concept of running the tank 'down' doesn't mean you run it down to vapours, thats pretty silly. But, running the tank down to a safe level ensures you have litte 'old fuel' retained in the tank and ensures better aggitation of fine particals that may settle to cause a sediment sludge. :)

Yeah but you need to keep the injectors clean regardless... so in the end, dont run your car dry but dont have that "old" fuel sitting there for years as well :banana:

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