Oil Pumps... which to use.

[smh0101]

So I heard that the SVX has an oversized oil pump... an 18mm to be exact.

I believe the Legacy Turbo one is a 10mm and the ej257 STi Pump is an 11mm.

So I'm pretty sure I "could" use an SVX pump, which I'm guessing would pump more oil...

Since I'm building this engine to last, and to put out some pretty high numbers would it be advantageous at all to run an SVX pump? More oil is better so thats why I'm thinking so. Or should I just run an STi pump?

And this will be on a newer built 2.5L.

[SLODRIVE]

More oil is only better up to a point. Running a way higher volume pump than what's needed is nothing more than a waste of horsepower. Even worse, in some cases you run the risk of actually running the oil pan DRY because the oil gets sucked out of the pan faster than it can drain back.

I personally don't see the reason for anything bigger than a 12mm pump, assuming you have the oil squirters intact. I'm only going to consider a 12mm if the rally machine gets an external oil cooler.

[PhyrraM]

Your using a non-oil squirter block and non-AVCS heads. The main reason for larger oil pumps on factory cars is to provide more oil for those features. Ever wonder why the biggest pumps are on double AVCS heads?

What did you set you main and rod bearing clearances to? If the are still the stock clearances, then there is no need for more oil in that regard either.

Use a new (or known low milage) 10mm pump and you'll never have a problem.

Too much oil and it can foam, heat up, pump dry, wear the pump or waste power. If you haven't added any reason to need a bigger pump, I don't see the value in doing so.