Should I Leave Fuel In The Tank?

[jjman]

Hi guys, just looking to get a bit of advice on what state to leave my fuel tank level in.

Basically, i have my GTST as a weekend only car which means it gets driven 2-3 times over a weekend and then just sits all week.

In doing this i have basically been filling it up with enough fuel on friday to last me the weekend then leaving it empty for the week before again filling enough fuel for use on that weekend.

My rationale for this is that I know fuel can go off after a period of time reducing the octane level etc. My car is tuned quite hard and iv been instructed to only ever put BP98 in it from a reputable shop. As such i do this and only with enough fuel for that weekend's driving so i always have fresh fuel in it. If i was to fill it up completely a tank would probably last me 1-3 months and im worried that fuel in the tank for up to 3 months would be gettting shitty and perhaps causing problems (pinging etc from the fuel losing octane level).

Do people agree with this rationale or is there an alternative reason to actually be keeping the tank full? (or fuller)?. Im wondering if always having less than 20% in the tank and usually it is sitting there with <5% in the tank will be encouraging corrosion in the tank or some other problem i havent considered...?

[blind_elk]

Fuel doesn't "go off" that quickly. I take about 2 weeks to go through a tank (BP Ultimate), and I've yet to notice any fall off in performance week to week.

[jjman]

as i mentioned above though- it would be up to 3 months that a full tank of juice would take to be used in my car. I know it wouldnt go off in 2 weeks.

also i doubt you would notice a drop off in performance even if the fuel was starting to go off. There would probably just be increased ping that you wouldnt be able to notice but would not be good on your motor. Hence my predicament...

[zoidbergmerc]

just keep doing what you're doing, it's fine.

The only bad thing about not having a full tank is the slight risk of fuel surge when you're going hard around corners and stuff. But skylines don't get it that bad anyway, not like WRXs which'll surge if you're under 1\3 and think about going around a corner.

[PM-R33]

I'm very much the same. Drive my car mainly on the weekend and just have about 1/4 of a tank in there most times.

Perfectly fine.

[EJD001]

Went to an SAU trackday at wakie last july, last lap and the fuel light came on, loaded it on the trailer and have driven it around the block once since then.. going to chuck 10ltrs in this weekend with some octane booster i think!!

[DVS JEZ]

Becarefull running the tank that low especially at the track. Unless u have a wideband Sensor connected when racing u will have no idea if the motor is leaning out.

[jjman]

mmm, i might keep that in mind as i down have some 'favourite corners' that have me at pretty high cornering g's for perhaps 8-10secs so perhaps not the best thing if the tank is very low or even empty (fuel light on)...

does anybody know if it is one side or the other that the pump draws from? therefore will be more likely to suck air under cornering 1 way or the other...

Edited April 1, 2011 by jjman

[Beer Baron]

there is no problem filling the tank and running the fuel for 1-3 months. also at say the 2 month point when it's a qtr full just top it up again. the fuel tank should have a check valve so it can breath out. the advantage of filling the tank is less air in the tank. being that the tank is under the car, and in a cool dark place with no UV or exposure to air it should last quite a long time. certainly 3 months would be no problem.

the other problem with running the tank low is it concentrates all the dirt/silt etc that is in the tank into such a small quantity of fuel and can cause contamination.

[jjman]

mm, food for thought on the contrary arguement. Might go for keeping it at at least over a 1/4 tank for the driving phase n also making sure i dont leave it too empty in the weekly garage time.

cheers again peeps