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Fuel Pump pressure
richardh - 24/1/12 at 09:08 AM

Hi,
I'm using a new fuel pump linky just below the tank with my filter at the front (i know its best placed before the pump but i'm testing)
Pump is sending fuel to the front but my filter is barely containing fuel. Its a small clear one.

I have no leaks in the pipes.

My v8 i believe should run about 3-4 bar and i think the reason it splutters under load is the lack of fuel.

Do i just fit a regulator? Does pipe diameter make much difference?

Anything obviously wrong?

Thanks.


jeffw - 24/1/12 at 09:24 AM

Carbs or injection? 3-4 Bar is normal for injectors.


PeterV - 24/1/12 at 09:28 AM

That pump my not give enough pressure. The head height is important as well as the max pressure figure. The height between the lowest point in the system and the highest (plus any hill you go up) gives the head height. The higher the head the lower the pressure will fall. Maybe worth fitting a more powerful pump and regulator.

Try taking the fuel pipe off the carb end and see what comes out as you raise and lower the pipe. Should be a gusher not a dribble


richardh - 24/1/12 at 09:37 AM

Cheers, will try that.
I've not measured exactly but from visual inspection the feed from tank is at the bottom and the pump sits just underneath with about a 45 degree angle down. then it goes pretty flat along chassis until the front suspension turret (rangey rovey) and then up in a gradual sweep.

total height difference from lowest point to carb is less than 1metre.

I'll check the pressure in the manual as i don't want to blow the carb seals etc.

Is it best to regulate near the carb intake?


PeterV - 24/1/12 at 10:14 AM

Nearer the carb will give the best result at the carb, which is where you want the correct pressure. As Jeffw says 3-4 bar is injector level not carb but may be regulated down. My fuel injection system pump can deliver up to 8 bar and when I'm running high BHP 300+ 4.5 Bar is needed (fuel injection with turbo).
I had a few issues getting the fuel pressure sorted, you can read about it here Linky
May give you some clues or ideas.


minitici - 24/1/12 at 10:36 AM

The small clear plastic fuel filters always look like they have a lot of airspace in them - even when the pump is working correctly.