oil pump for modified engine

[rex-leggy]

So ive been researching for a while now on here and other forums and from everything ive read there no real conclusion on whats better .

Im looking for an upgrade from the standard 10mm pump .

There's 2 options the 11mm or the 12mm

http://forums.nasioc.com/forums/showthread.php?t=1411649&highlight=11mm+oil+pump.

Thats where my main info came from . From what they are saying the 12mm pump has a higher pressure (85psi) then the 11mm @ 6000rpm .

But the 11mm flows more @ 6000rpm but with a lower pressure (56.8psi)

So because i have little knowledge on this sort of thing im hoping someone can shed a little light .

At a higher rpm of say 7500 is the pressure more important then flow.

Assuming that there is adequate oil supply

[Koom]

Firstly, consider that most of the American sites have knowledge based on cars running AVCS.

Are you running a late model motor? Does your engine require the extra flowrate of a bigger oil pump?

If not, you could end up just heating up the oil as the pump will need to bypass any extra flow that the engine isn't requiring.

Has your engine been rebuilt with bigger clearances?

General guide is to have 10psi for every 1000rpm i.e. 85psi for 8500rpm.

You basically need enough oil pressure to maintain a film of oil on the bearings at the highest rpm that you are going to run at. Then your pump must be capable of supplying enough oil to maintain that pressure given the flowrate that your engine needs i.e. if you have loose clearances on your bearings, you'll have a higher flowrate of oil through the motor, need a bigger capacity from the pump.

In general, for a GC8 era motor, a 10mm pump can supply enough oil to maintain the oil film on an engine with ~factory clearance @ factory rpm limit (remembering that some of those motors had an 8300rpm limit or thereabouts).

I looked into it and decided to continue using a 10mm pump on my current build. Going to tidy up the casting around the pump outlet and the bypass but otherwise just bolt it and and be done with it.

[rex-leggy]

 Koom said:

Firstly, consider that most of the American sites have knowledge based on cars running AVCS.

Are you running a late model motor? Does your engine require the extra flowrate of a bigger oil pump?

If not, you could end up just heating up the oil as the pump will need to bypass any extra flow that the engine isn't requiring.

Has your engine been rebuilt with bigger clearances?

General guide is to have 10psi for every 1000rpm i.e. 85psi for 8500rpm.

You basically need enough oil pressure to maintain a film of oil on the bearings at the highest rpm that you are going to run at. Then your pump must be capable of supplying enough oil to maintain that pressure given the flowrate that your engine needs i.e. if you have loose clearances on your bearings, you'll have a higher flowrate of oil through the motor, need a bigger capacity from the pump.

In general, for a GC8 era motor, a 10mm pump can supply enough oil to maintain the oil film on an engine with ~factory clearance @ factory rpm limit (remembering that some of those motors had an 8300rpm limit or thereabouts).

I looked into it and decided to continue using a 10mm pump on my current build. Going to tidy up the casting around the pump outlet and the bypass but otherwise just bolt it and and be done with it.

im going to have to find out clearances when i pick up my shortblock so dont have those details as of yet.

was just thinking with the work done to the engine /possible bigger valves springs,retainers and porting ect.

then a bigger pump to supply oil till say 9000 rpm would be nice .

not saying ill get there but as you say if the tolerances and all other factors let me im going to want to be safe

[vorigan]

pumps normaly flow greater volumes on lower psi

oil pumps all come with a flow versus presure thus running up that higher rpm also means they get closer to cavertating,if your intended to run a motor that hard dry sump would be worth considering.

also running that hard you need to look close at water pump/power steer/ alternator rpm, for the water pump 6k is normally as hard as you need to spin them thus undersize pulley is a must done so with my open bmw also found airating the power steer was an issue at that rpm.

[Stoffa]

I ended up using a 11mm oil pump on my engine, my builder (collier motor engineers in levin) wanted to run bigger oil clearances, so I bought acl race bearings with 1 thou' bigger clearances (HX part number) they took a bit more off the crank and I ended up with .07mm (.0027 inch) on the main bearings and .06mm (.0023 inch) on the big ends.

Once assembled they like to fill it with oil, plug the turbo oil feed and any open galleries and use a high torque drill on the crank bolt to bring up the oil pressure. My engine ended up with 85psi@500rpm using a 30w mineral running in oil, that was with the std shimming the 11m oil pump comes with.

As my new pump also has a high flow im using a moroso sump with higher oil capicity as well so if the oil take its time to drain back I should be fine, Currently I've got 5L in my sump and it reads just under 1/2 on the dipstick. So 5 1/2 - 6 Litres all up I think.

So unless your running huge clearances like me you probably wont need a bigger oil pump.

[rex-leggy]

a dry sump would be nice vorigan but cant really justify the 4k + needed to do it .

ill wait till i get my shortblock back to check everything before i make the decision .

im guessing that because the pumps are positive displacement pumps then even if i go past 8000 rmp then i should be flowing more . even on the 10mm pump.

as for some of the terms being used .... i dont understand them so will have to find out what they mean

[rex-leggy]

should have mentioned that the aplication isnt for a ej20 block its for a ej22 ...... if that would make a difference.

i think the ej22 t ran more shims.

[Stoffa]

well the gobstopper still runs a 10mm oil pump so I dont think its that much of a problem, ask your builder what clearances he set it to

[BT]

 Stoffa said:

well the gobstopper still runs a 10mm oil pump so I dont think its that much of a problem, ask your builder what clearances he set it to

It's actually got a dry sump...

[Stoffa]

my bad, it must be another high powered subie I was reading about.

Doesn't a dry sump set up still use the factory oil pump on a subie? never really looked into them with much detail

[D-Style]

Its a balance between flow and pressure. Ive always gone for higher flow. no point having high pressure if you flow less than standard pump (which some after martket pumps have been known to do)

Ive dry sumped my last 2 engines and would never go back. If it takes 4k (you can do it for less) it still be money very well spent.

[D-Style]

 Stoffa said:

my bad, it must be another high powered subie I was reading about.

Doesn't a dry sump set up still use the factory oil pump on a subie? never really looked into them with much detail

No.

check out http://www.petersonfluidsys.com

You can also get semi-dry (or external pumps)

[rex-leggy]

 D-Style said:

Its a balance between flow and pressure. Ive always gone for higher flow. no point having high pressure if you flow less than standard pump (which some after martket pumps have been known to do)

Ive dry sumped my last 2 engines and would never go back. If it takes 4k (you can do it for less) it still be money very well spent.

if it can be done for less then its defiantly something id look at but the expense puts me off.

but pumps, lines, modified sump, tank for oil its alot of gear compared to a simple blot on pump.

the car will see the track as much as i can but will mostly be a weekend car..... unless i get serious

[Koom]

 D-Style']

[quote name='Stoffa said:

my bad, it must be another high powered subie I was reading about.

Doesn't a dry sump set up still use the factory oil pump on a subie? never really looked into them with much detail

/quote]

No.

check out http://www.petersonfluidsys.com

You can also get semi-dry (or external pumps)

The Cosworth (and a few others) Dry Sump setup for Subaru's use a 2-stage scavenge pump and then plumb back into the factory oil pump for the pressure side.

http://www.cosworthusa.com/store/pc/viewPrd.asp?idcategory=&idproduct=703

[funkytown]

is it worth putting a few links to the pictures in here koom? I know its been floated else where lately.

[rex-leggy]

just curious jon what pump do you run for your 300kw?

[funkytown]

295 actually.. but i run standard 10mm. my builder recommends next time i have it apart i go to the 11mm. would be a wise thing to do.

[rex-leggy]

 funkytown said:

295 actually.. but i run standard 10mm. my builder recommends next time i have it apart i go to the 11mm. would be a wise thing to do.

my mad . did he happen to mention anything about shimming it or just running the 11 as standard?

[funkytown]

11mm standard was the impression i got.. from a late model sti. they all bolt up.

[vorigan]

i did a GT1 sub couple a few years ago making 580hp wheel on 24psi( yes wheel) and we custom made the pump joining two 10mm internals together seemed to work well but alot of work

[Stoffa]

 vorigan said:

i did a GT1 sub couple a few years ago making 580hp wheel on 24psi( yes wheel) and we custom made the pump joining two 10mm internals together seemed to work well but alot of work

I talked to Jason about that, he said he actually took 3mm off each internal gear so ened up with a 14mm pump, but yes alot of work as the block needs to be machined to suit the bigger pump other wise it'll stick out too far on the crank.

[vorigan]

i was close but yes lots of work or buy the cosworth pump

[rex-leggy]

found out the bearing specs . mains .05mm and bigends .06mm

done a bit more thinking and talking to a couple of people and i thing ill be going with the 10mm pump with an extra shim to start with and see what the pressures like.

[Stoffa]

Same big end clearances as mine, just a little tighter on the mains.

Is that a 75mm stroke 2.2 or a custom 79mm stroker?

let me know if you need a shim, i've got about 6 oil pumps in my scrap pile.

p.s loving a technical discussion thread without someone being abused for being a muppet

[albaru]

 rex-leggy said:

the car will see the track as much as i can but will mostly be a weekend car..... unless i get serious

My car's seen a lot of weekend track time (not so much recently) and the baffled sump done the trick. Other than that it's just a normal sti engine.

Thinking about it some more it's probably got much less power (169kw) than you'll have so maybe not so helpful. ???