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Fuel tank sump
Nitrogeno25 - 25/4/12 at 11:57 PM

I'm building my tank and trying to decide how big the sump should be. (I don't plan to fit an in-tank pump, nor an external swirl pot)

What is the common size for a sump to work (road and track)?

Thanks!

blakep82 - 26/4/12 at 10:46 AM

there must be some sort of mathematical answer, but basically is needs to be big enough to collect fuel as it moves around the tank, but not let too much back out on corners.
i am planning to get a sump added to mine, i'm thinking maybe 4" diameter, and about 1.5" deep, and a hole in the bottom of the tank slightly smaller, maybe 3" diameter so it leaves a lip round the top of the sump to make it harder for fuel to get back out
don't know if theres any common size really

garybee - 27/4/12 at 12:53 PM

Assuming you are running a fuel injection system...

Do you have a return to the tank? If not then you only need a sump/collector large enough to allow for what your engine uses during cornering. If you are running a fuel return, then your collector needs to be big enough to allow for what your engine uses plus the amount returned from the fuel pressure regulator to the tank (unless your return feeds back into the collector).

There is obviously a pretty large difference between these two figures so your type of fuel system is very important.

Nitrogeno25 - 27/4/12 at 01:11 PM

quote:
Originally posted by garybee
Assuming you are running a fuel injection system...

Do you have a return to the tank? If not then you only need a sump/collector large enough to allow for what your engine uses during cornering. If you are running a fuel return, then your collector needs to be big enough to allow for what your engine uses plus the amount returned from the fuel pressure regulator to the tank (unless your return feeds back into the collector).

There is obviously a pretty large difference between these two figures so your type of fuel system is very important.


Yes, return to the tank, I think I can make it to feed the collector. Engine is 2.0 Duratec on Jenveys. Fuel pump is a Bosch external 130l/h

Thanks!!

adithorp - 27/4/12 at 01:12 PM

The one on mine is cylindrical, approx 150mm diameter and 60mm deep so approx 1/2lt capacity. The hole between the main tank and the sump is about 75mm so gives a lip/baffle.The pick up is in the bottom and the return goesbackinto the sump. Never had the slightest stutter either on track or on mountain hairpins... even when almost empty. My only fear is it's so good I won't get any warning untill it's dry and used every last drop.

My previous tank (plastic) had a moulded sump with no lip/baffle, pick up in the side of the sump and the return into the main tank. It would stutter when cornering hard with less than a 1/8tank.

Nitrogeno25 - 27/4/12 at 09:19 PM

quote:
Originally posted by adithorp
The one on mine is cylindrical, approx 150mm diameter and 60mm deep so approx 1/2lt capacity. The hole between the main tank and the sump is about 75mm so gives a lip/baffle.The pick up is in the bottom and the return goesbackinto the sump. Never had the slightest stutter either on track or on mountain hairpins... even when almost empty. My only fear is it's so good I won't get any warning untill it's dry and used every last drop.

My previous tank (plastic) had a moulded sump with no lip/baffle, pick up in the side of the sump and the return into the main tank. It would stutter when cornering hard with less than a 1/8tank.


Thank you very much! This is what I need to know.