Outer Limits 4x4 Board

How critical is it to have the res above the suction side of the pump?

I have no room to put the pump down low, so im forced to put it up where the A/C used to be on my 1HZ engine.

The pump is a Trail Gear unit.

Cheers

if its to low you will have a problem with air being sucked in to the lines ..
also stops the pump from having to suck as hard to get fluid
if it does have to suck harder it takes away from the final pressure output

im in the same boat as im putting in a KRC pump with 2.5ltr res as its needed @ 1600psi . 14lts a min

Mounting the resivoir low should not distract from the pump output pressure or flow wise, nor should it suck air if all connections are good.

While mounting the tank higher than the pump is the desired way to do it, mounting it slightly lower should have no diverse effects. Just make sure the inlet/suction hose is of the correct size with no restrictions.

DO NOT mount the res below the pump! otherwise buy plenty of spares...

Yes it can be done, but you don't have the gear to do it properly. It would require an inline check (and bypass releif) to prevent back-flow as the vane type pump will drain back when stopped and this will leave the pump un-lubricated on startup, which will cause galling of the rear ring thrust plate and pump seal failure.

Hint: mount the res as low as functional, then intall a large(ish) diameter filller neck ~1"bore min. and have this a min. of ~1.5-2" above the top of the pump casing. that should give you enough NPSH to keep it lubricated (hopefully).

Cheers for that mad,

Pretty much what i was thinking. I think the trail gear pump is a gerotor style pump (much like a gear pump) than can deal with a bit of starving at startup. I think this is why they use them for engine oil pumps where the pickup is well blow the pump unit.

I dont want to cut another hole in the bonnet and have something elce sticking through it but if i have to i guess i will.

how about making a shorter but wider res? is there a possibility for cavitation on angles here?

1MadEngineer wrote:Yes it can be done, but you don't have the gear to do it properly. It would require an inline check (and bypass releif) to prevent back-flow as the vane type pump will drain back when stopped and this will leave the pump un-lubricated on startup, which will cause galling of the rear ring thrust plate and pump seal failure.

The pump requires minimal lubrication at startup, the residual oil in there would be more than enough.

Z()LTAN wrote: how about making a shorter but wider res? is there a possibility for cavitation on angles here?

Ideally You'd want the reservoir to be as tall and "skinny" as possible.
That way angles will have nearly no impact (especially if the pickup is at the bottom).

Joshy had a long-ish shaped one on his truck and it would starve on angles.
And consider both, front-back and side-angles.
He modified it to be taller and narrow, with pick-up on the bottom.
No problems since.