55superbeetle

iTrader: (5)

So im working on a 5.3 lm7 turbo project. We have a lh6 DOD 5.3 as a spare engine and i have been told they have a higher volume oil pump than non-DOD engines. But i always see people putting a std oil pump in when doing a dod delete. So my question is, what are the issues with over sized pumps with ls series engines?

LLLosingit

iTrader: (4)

I don't think there is an issue other than the fact that a standard pump is all that is needed. High volume pumps are good for performance engine that have slightly larger clearances.

2000RATA

I run the Melling's HV pump. Extra bearing clearance plus 2 turbos to feed.

samdogmx

iTrader: (14)

I run the melling 296 model

Forcefed86

iTrader: (4)

Because they put out an excessive amount of pressure.(some say these higher pressure won't hurt anything, I dont' see the point) I run a 2008 5.3 with the DOD pump. I'd see 75-80psi on cold starts and peg out my 100psi gauge WOT warm. That was with 5w30 oil.

I cut 2 springs off the pressure relief. I see about 60 on cold starts now and 40psi warm at idle. Upper 80's hot.

great421

iTrader: (1)

Yep.

For me, however, it's the extra bearing clearances (on my stroker) plus only one turbo.

OP -

You'll hear from some folks that a HV pump (excessively) stresses the associated parts which are used to drive it (In my case, LT1/4 here, the oil pump DS and / or the oil pump drive itself) - this is indeed a valid concern.

Having said that, a second, more commonly articulated 'reason' is the fact that the HV pump uses too much HP to drive it (vs. a standard oil pump); and, to be fair, the HV might require (at the upper RPM ranges) an extra 2 HP to drive it, but, IMHO, this second reason (ie - excessive parasitic losses) is less valid.

(OP Please Note - I just said something was less valid - I did not say the rationale was NOT valid, only 'less' valid; but, in true LS1Techdotcom fashion, I expect that all subsequent posts to dwell on this non-issue and also to call me ugly and tell me that my mother dresses me funny. OP, I apologize in advance for all such posts.)

stock48

iTrader: (17)

Other than cost HP, and or suck a small capacity oil pan dry I don't see what a HV oil pump will hurt. I've always had plenty of psi and volume with the factory truck pumps.

The Alchemist

iTrader: (19)

When I was building my motor, I worked with my engine builder and decided to go with a HV pump. He spec'd the motor to account for the HV as he liked having a little extra clearances, and the hv pump assured that I'd have good pressure. He cleaned up and took time to make sure the drainback for the oil had a clear path, I also cut holes into the lifter trays to allow the oil to drainback quicker as well so I wouldn't flood the top of the heads with oil.

My oil pressure now sits at 38-40 on cold startups, and once fully hot and idling at 700rpm, it dips to 30-35psi.

Baconz28

These oil pumps seem to be a hit or miss to be honest. One guy will have good luck with it and the next one wont. That's why I call up the car shop and ordered and schunanns oil pump a while back for my build.

Forcefed86

iTrader: (4)

What is “high volume” about most of these aftermarket pumps? Do they have more or larger vanes in the pump? Are they really moving more volume at the same pressures? Or are they generally running more pressure? I know the DOD pumps use vanes that are .100 wider than the standard (non DOD) pumps.

Even the older LS truck oil pumps can be shimmed quite a bit to make up for lost pressure if needed. How much pressure loss is generally seen opening up a bearing clearance .0002-.0005? Shouldn’t the standard OEM pump be able to compensate for this with a few shims? I used 2 small washers and shimmed up my 2001 LM7 oil pump last year. I’d see 40+psi warm at idle (I do idle high around 900-950) and 80ish WOT. (untouched factory bottom end w/ 160k) Even that amount of pressure shouldn’t be necessary and I Don’t think shimming the pump did me any favors.

I’m not saying a performance engine built purposely with larger tolerances isn’t going to benefit from an HV pump. For most of us though, I’d think builds like Stock48’s prove it isn’t necessary (or beneficial) to run an aftermarket HV pump. An HV pump will cost additional power to drive. If that additional pressure/volume isn’t needed, your just pissing away horsepower. To me it sounds like more unnecessary Gen1 SBC “old school” engine builder tips that have bled over to the LS performance crowd. (I’ve been wrong before though….alot)

JAX04

iTrader: (17)

I almost pissed my pants when reading this lol

pewtered'Z

iTrader: (4)

For a bolt on car doing heads cam intake stock bottom end, on a 150 shot, should you use a new stock pump? High pressure or high volume?

coltboostin

Pressure and Volume are 2 different things. Also excessively high pressure can absolutely hurt things-and take away horsepower.

Are the passages or gear set physically larger in the HV pump-or is it the same size with a stiffer relief spring (just delivering more pressure)