fuse rating for fuel pump?

[PHATR32]

hey guys,

ill be installing a larger fuel pump in my gtr, and plan on running a fat cable from the battery directly to a relay then to the fuel pump.

I need to know what rating fuse i should use near the battery in case of shorts etc?

thanks

steve

[MonstaS4]

A fuse is to protect the wiring, so you need to size it to whatever cable you decide to use. If you buy it from an auto 'lecky, they'll tell you what size fuse to use.

[Sydneykid]

Hi PHATR32, easy question, not so simple answer. The current actually varies according to the fuel pressure. Of course the fuel pressure varies with the amount of boost.

So I have a little rule of thumb, that the electronics guru's will no doubt tell me is wrong, but it has worked for me so far. The standard GTR pumps is rated at 190 litres per hour, and I say that's about 190 watts of power. Divide that by 14 volts and you end up at 13.5 amps. Walbro rate their 190 litre per hour pump at 12.5 amps max current, so the "rule of thumb" is not too bad.

When we use a Bosch 044 rated at 330 litres per hour, divided by 14 = 24 amps. So I use a 30 amp fuse, relay and appropriately rated wiring.

Hope that helps:cheers:

[PHATR32]

thanks heaps for the info sydneykid.

ill be installing a bosch 044 so i guess a 30amp fuse it is then.

will make sure to take pics of both the wiring and the installtion of the pump and make some sort of a tutorial etc.

thanks again

steve

[Turbine]

30 amp fuse works on my beast as well PHATR32

Turbine

[R32-GTS]

I just did this upgrade on my r32 gtr. I used 8 guage cable , bosch relay and a 30amp fuse.

Brought the voltage up from 10.8volts up to 13.7

[PHATR32]

13.7? is that a direct line from the battery?

all 3 of my previous cars including the gtr have all read around 14v.

either way, its what the bosch needs so itll be what the bosch gets

steve

[R32-GTS]

14volts through the factory wiring ?? Are u sure. The most my old r32 had was 11.3 throug hthe factory wiring and the gtr had 10.8.

[PHATR32]

no, i meant i got 14v directly from the battery after running a cable to it. the factory wiring barley got me 10v

steve

[R32-GTS]

Ok yeh well 13.7v to 14v is bugger all difference. The alternator only charges at 13.9 volts so i got .2 volt drop from the front of the car to rear. Not too bad.

[PHATR32]

yeah, .2 wont make any differance.

steve

[R32-GTS]

Just hoping the single 044 can support 500+ rwhp. How are u setting it up inside the stock cradle ?

[PHATR32]

yes, Im going to try to get the best posible position inside the tank to avoid fuel surge aorund corners etc. Ill also be using a fuel strainer.

Ive read a few posts where people use cable ties to hold the pump in place, personally i dont think thats a good idea, so ill be using large hose clamps.

Ill see what happens when the time comes.

steve

[R32-GTS]

I'll go get some pics now of how i''ve done mine. You will find cable ties are the only things that will fit in there.

[PHATR32]

thats weird cause ive seen a pics of one with a clamp?

steve

[R32-GTS]

Heres some pics of how im doing mine. MIght install today.

[PHATR32]

awesome pics man.

where did you get the strainer from?

steve

[R32-GTS]

Thats the strainer off the factory gtr pump. I''ve set it up so its all sits in the cradle like factory. The strainer is a weird shape to get right to the bottom of the cradle so it dont starve of fuel.

[pnblight]

Just hoping the single 044 can support 500+ rwhp. How are u setting it up inside the stock cradle ?

i cant see why it shouldn't as the std pump and wiring will surport 530rwhp and you have upgrade wiring and pump ,the rest of the system will be the question (injectors and fuel control etc)

but i thought r32-gts you were looking for alot more than just 500rwhp?

[R32-GTS]

Your on a dreamboat. The highest i could get out of the stocker was 420rwhp with same injectors as you and same computer. Same as everyone else 400-440 seems to be the limit of a good stock healthy pump .