tnbigdawg

im using a b16a oil pump for my lsvtec.....i'd like to know which one is better?

Doogie Howser

gsr pump

tnbigdawg

sorry i wasnt asking about the gsr pump, im asking about the LS and SI pump cause i have these two on hand.

thanks.

Doogie Howser

si

tnbigdawg

kool thanks for the reply man.

but i just thought of something though, are you saying the SI is better cause it is simply VTEC? or do you know so because of their output ratings (PSI's)?

oh well i'll just leave the SI pump in there because of the rpms i take it to(8.5)

thanks anyways.

Doogie Howser

i dont know the psi ratings but vtec pumps pump more oil because of vtec and being a high revving engine

BuddhaSiR

is there a difference between the oil pumps, besides being from different motors? the specs for the two are the same.

BuddhaSiR

how does VTEC create more oil pressure. isnt psi dependent on rpm and condition of bearings.

HPinXS

Oil Pressure is set by the by-pass spring in the pump it self, and bearing clearance within the engine also affects it, oil pressure is resistence to flow.All of the honda oil pumps have the same volume capacity, well not really, but they are really close, there are an early and late gear set, I believe they are 80 mm and 84mm(diameter),but their flow ratings are very close to each other.The capacity of the pump is set by the gear size itself(diameter and width and number of teeth and type of gears), a honda pump is whats know as a g-rotor style pump where one gear turns around the outside of the inner gear. A g-rotor pump is not really happy at high rpm because of its design, by this i mean from an efficiency stand point,it doesnt pump oil well and this happens because of the gear type,with out getting to technical,the g-rotor cavitates(creates vacuum pockets within the pump section that should be filled with oil,but cant due to its design) at high rpm and high is not as high as you would think(4500 rpm pump speed, which in this case is the same as crank rpm,pump is driven directly by the crank snout).There are people who will argue this point, but the proof is out there, that this is a problem.There are after-market gears sets available to stop gear breakage from the destructive forces of the cavitation,but all they really do is delay the problem,they too will fail eventually,these forces are so powerful that they literally erode small pits into the gears,which over time become larger,at the same time this is going on the harmonics from this process can osicilate the gears to their natural resonate fequency and cause them to just break apart, the cracks starting in the pitting in the gears.Sorry this got a little long,also this is not the only reason hondas break the gears,but I will try to continue this if you guys want.Hope this helps