Is it right just because a lot of people do it?

 

This is wrong. If what you said was true, then oil would bypass the oil cooler and the oil filter.



The path for oil flow is:

Pickup from the oil pan and pumped through the front cover, where the front regulator lies, to the oil cooler lines. Oil goes through the oil cooler and enters in the rear iron. Oil passes a Y, with one path leading to the OPR and the other leading up the rear iron to the oil filter housing. Oil reneters the engine through the oil filter housing after being filtered, and spilts again: one side of the Y flows through the rear iron to the rear stationary gear, which in turn enters the eccentric shaft and feeds the rear oil jet. The other part of the Y enters the engine upper dowels, which flows to the front iron. At the front iron, the stock turbo oil feed is taken. Oil flows down the front iron to the front stationary gear, with a small line taken off of this to lead to the metering oil pump, via a small path through the front cover. Oil again enters the eccentric shaft (if the thermal pellet is open), and oil is injected into the front rotor via the oil jets.



The oil path does NOT split after the front OPR. ALL pumped oil goes through the oil cooler and oil filter, and has a chance to be bled off via the rear OPR. OIl is fed to the front irno ONLY through the dowel pin.



Even the Haynes doagram will show that :P

 

Here is a front iron.

Oil is picked up at E, pumped through the shown passage to A. The line associated with B is just a drilling passage; the oil passages were machined, not cast.

You can also see where the upper dowel enters the iron at C, and the flow path to the front stationary gears. D is another blocked drilling passage.



As you can see, there is no flow from the oil pump directly to the dowels, now would this makes sense.

Thus, if your oil cooler becomes a complete retriction, the engine bearings get ZERO oil.

 

so, shim or not shim?

 

****. I guess I should have refreshed my memory before posting...

 

Follow the manufacturer's recommendations. Your best bet would be to check pressure drops through the oil cooler lines, fittings, and oil cooler itself, and then determine if the pressure drop is less than the difference between the regulators (I certainly hope its less than 36 psi :O), but this is more of an undertaking than most people will do or care about, and so following directions given by the retailer is best.

 

Hmrm it wouldn't be TOO hard to find pressure drops?

at least over the oil cooler is fairly easily.. get a spare banjo bolt, drill and tap the top of it and bobs your uncle you can measure the pressure drop!!

This gives me an idea.. when my motor is running I might do this.. Since I already have a drilled and tapped banjo bolt. (oil for turbo)



Finding the drops elsewhere in the system would quickly get a bit more trickey though...

 

I guess keeping the system with a close to stock ratio between front and rear regulators would make sense. Still though 80 psi of pressure drop in the factory system? or is the front regulator only there for emergencys or soemthing?

 

Its a safety device in case something else fails in the system.

You wouldn't shim anyway with an 80-85 psi regulator; only the 110 psi race regulators.

 

im going to use and FD regulator