Power Steer Cooling - Lines and Order

[takai]

Just trying to decide how to route the lines for my PS cooler.

The stock method seems to be:
Pump -> Rack -> Cooler -> Reservoir -> Pump

But im considering going
Pump -> Rack -> Reservoir -> Cooler -> Pump

The only problem i can think with this is that the plasticreservoir gets the full brunt of hot PS fluid from the rack and it might crack/leak. But i dont think the overall heat of the system will be greater (especially that ill be using a finned cooler rather than the stock loopy lines).

Do people think that the order of it going around, and the heat in to the plastic reservoir will make any big difference? Or will it be fine?

[big_zop]

Is it going to make much of a difference to the way the lines are routed on the two options?

I would probably perfer to go through the cooler first before the reservior as it would seem to be kinder to the reservior but have you considered measuring it (got a multimeter with thermocouple input?) to see if its going to make much difference.

Most dry sump lubricating systems are set out the first way too - that way for hill climb cars, they can heat the oil reservior and not have it cooled before going through the engine, enabling the engine to get proper lubrication from limited running.

[takai]

Yeah, this is just a daily driver though. The lines will look like spaghetti in the first instance, and relatively tidy in the second.

[big_zop]

Realised it was for your daily - thinking of little things while still sorting out the wiring? Got a pic with the rough layout of everything and have you considered moving things (within reason) to accomodate?

[jazae86]

I'm guessing the reservoir almost feeds the pump under gravity?

In the factory system, the pump 'pushes' the oil through the system.

I think your modified system requires the fluid to be sucked through the cooler. In the extreme, the reservoir sits full of oil due to restriction of oil cooler and the pump sucking air.

[roadsailing]

I'd keep it as per factory

[takai]

Hmm, The JZ setup has the PS pump on the intake side, but since i dont have a JZX81 PS reservoir i have to have the res on the exhaust side. I guess i could run it back and forth with a bit less hose than i was expecting to need, but its not as nice as just making one big loop around the engine bay.

P.s. rs/sbs your new nick confuzzles me
P.p.s. wiring is 99.9999% done. Just have to test the sucker.

[roadsailing]

oh yeah, here is a bit of theory why you don't want the cooler after the reservoir:

The cooler will be a pressure restriction (maybe not that great, but a restriction nonetheless)

if the cooler is after the reservoir (which isn't pressurised) then it will dribble through it, and the pump might have a harder time sucking through it, as it will be used to big gulps from the reservoir.

(or something like that)

I'm trying to cut down my online user names, sick of the old one. i wish those assholes at PF would change my handle too, probably just as well they haven;t yet, who knows what it would end up as!

[takai]

Yeah, i think ill just do it as stock. Might bend up a metal return line to make life easier, because a rubber line across the entire engine bay is guaranteed to be annoying.

[Mos]

Hmm, The JZ setup has the PS pump on the intake side, but since i dont have a JZX81 PS reservoir i have to have the res on the exhaust side.

I don't get that. Make a bracket, put the reservoir near and above the PS pump (where it should be) and you don't have a problem (with anything, including cooler location, system layout, copious amounts of lines, etc).
The fluid is gravity/vacuum fed into the PS pump. If you have even the slightest leak on any of the connections it will suck in air - sometimes spring clamps on not-new hoses are not enough.
BTW, I had no PS cooler on the 2JZ and everything survived without problems (reservoir was on the passenger side strut tower).
Mos.

[takai]

Without a new washer bottle there is nowhere to fit the res on the passenger side.
JZA80s have it as an integral part of the pump, wheras the JZXs have it on the strut tower. Sweet pain in the arse.

[Mos]

Without a new washer bottle there is nowhere to fit the res on the passenger side.
JZA80s have it as an integral part of the pump, wheras the JZXs have it on the strut tower. Sweet pain in the arse.

You're saying this like I don't know .. There not much room, but there's enough... stop making excuses
I had the metal reservoir off the Aristo between the strut tower and the intake manifold. There's more than enough room to do that and it was mounted on rubber isolators too. Admittedly the plastic reservoir is larger in diameter but there's no reason you couldn't use a metal one.

But.. haven't you relocated your cruise control actuator? meaning you should have bucket loads of space?

Mos.

[RobertoX]

To get the most heat out of the liquid it is best to have the liquid going through the cooler when it's at its highest temperature. (larger heat differential means more heat flow through the cooler). Obviously this point will be just after the fluid has been doing all the work in the rack. If you are mixing the hot fluid with the less hot fluid in the reservoir and then putting it through the cooler the system wont be as efficient. Therefore, imo, option 1 is the best.
Also as Mr shinny said, the pump may not be designed to suck through a restriction...

[PlacentaJuan]

joel had his res getting too hot to touch without a cooler after a good drive in the hills.

io couldnt believe how hot it was.

[takai]

Problem solvered.
JZA80 PS res sits ontop of the pump, and ill just feed the LP return from the rack through a cooler before it goes to the res. It means the same amount of plumbing as option 1 in my original idea, but without the gheyness of having to suck through a cooler.