Is it bad for fuel pressure to get low on a CAMMED sv6

[Adeel123]

Hi guys and girls.
I have a cammed sv6, and I was told not to let fuel get below 1/4 in the tank due to low fuel pressure otherwise “[my] engine will blow”. Now my question is, is this true for all driving conditions or just racing conditions?

 

[J_D 2.0]

It’s not wise to let your fuel get below a quarter tank. The pump relies on fuel for cooling and that cooling works a lot better when the pump is fully submerged.

That’s a lot more likely to be the case if the fuel is always over a quarter of a tank so keeping it over a quarter tank will extend the life of the fuel pump.

 

[vr304]

That’s a load of bollocks mate your fuel pressure isn’t going to drop and blow your engine because your below 1/4 of a tank lol but as above it is better for the fuel pump to keep it above 1/4 if you can but don’t panic if you happen to be running low, your only risk is running out of fuel

 

[Skylarking]

As long as there is some fuel in the tank, the pump will keep fuel pressure at the required level and the engine wont have any issues with leaning out and burning holes in pistons. If fuel is so low that the pump starts to suck air, you’ll feel the engine loose throttle response and a smart person would take that as a hint his fuel warning light is actually telling him the truth…

It’s not really an issue running the tank another 50km past the low fuel warning light (other than the fuel may pick up crud at the bottom of the tank requiring fuel filter changes - an expensive service item on VF commodores)…

Racing on a track with WOT is a different situation. For such racing, the fuel pump needs to be dimensioned so it is able to flow the required fuel at the required pressure. Going lean at WOT isn’t conducive to long engine life but if that occurs it‘s more probably the wrong pump for the task is in the tank.

Oh, and the manufacturers didn’t add a low fuel warning light so you wouldn’t get stranded by the side of the road with an empty tank. They added a low fuel warning light to warn the driver he needs to fill up sooner rather than later, because if he doesn't fill up soon his fuel pump may overheat and the fuel pump may die. Without the warning light ,there would be lots of warranty claims but the warning light gives them an out clause…

 

[07GTS]

pump should be in the factory pot which even if fuel is lower then pot it should be full with the returning fuel filling it and shouldnt be able to leak out so pump is always surrounded by fuel (in theory)

 

[Brettly-2008]

Just FYI: 'Low fuel' warning is approx. 10.5 litres remaining and 'Very low fuel' is approx. 2.5 litres.

 

[Immortality]

Low fuel, fuel surge and sucking air was an issue with early EFI Commodores. Holden actually solved that problem with the 3rd generation models (VT onward) with a proper fuel pump/ fuel bucket arrangement inside the fuel tank.

 

[Adeel123]

pump should be in the factory pot which even if fuel is lower then pot it should be full with the returning fuel filling it and shouldnt be able to leak out so pump is always surrounded by fuel (in theory)

So does adding a Cam change any of the responses given in this thread? ie. Due to Cams, fuel must be kept at higher level than a standard VF/VE

 

[07GTS]

just check on the duty of the injectors it may only shift a little for the extra needed for a camshaft, id just treat it same as stock as they test theres for most driving conditions, as its a fuel pump there is also fuel constantly running thru it to keep it cool

 

[Skylarking]

So does adding a Cam change any of the responses given in this thread? ie. Due to Cams, fuel must be kept at higher level than a standard VF/VE

Not in terms of amount of fuel in the tank… the pump will still pump fuel at the flow rate and pressure it’s designed to deliver even with the low fuel light on…

However, performance upgrades raise a different question in that what rate of fuel flow does the modified motor require? followed by yne related question can tne existing system cope with the newer higher flow rates?

After all, mods put a higher fuel flow requirement on the fuel system since the engine can produce much more power than standard. And that’s because the crux of all mods is to get more air into the engine as you can then squirt more fuel to produce more power. But such may require upgrades to the fuel pump flow rates, pipe sizing, injector flow rates and such. The aim would be to be able to supply the required fuel flow without hitting any limits. Limits tend to be seen when the duty cycle for either the fuel pump or injectors are maxed. Pipe sizing also has a play in it as a fire hose can carry more water then a small thin garden hose… If the duty cycle is at or near 100% at WOT, then something’s gotta give and that is usually loss on combustion control and mixtures going go dangerously lean which can be very bad for the engines (holes in pistons bad).

I don’t know if a cam upgrade would put large enough extra load on the fuel system where it can’t cope but usually the kits don’t include new p7 maps or injectors so one would think it’s ok. But it does get a lot more complex when adding a supercharger where fuel system components can be upgraded. Your tuner should be able to advise…

Just don’t accept bullshite concept that one needs to have at least a half full tank to have real performance. Never heard such crap about fuel tank levels from makes such as Ferrari, Porsche or even GM (with their new corvette) Good engineering will ensure all parts of the vehicle can perform as expected, including running safely with the low fuel light on