Lets talk about FD oil pressure regulators

[RETed]

Originally Posted by JustJeff

I'm considering the FD OPR simply because it's a cheap mod to put on while the engine is apart. $34 for the FD that I'm told and have read is a 105psi OPR. The RB OPRs are all in the $100 range. Am I missing something that would justify RB charging almost 3x as much?

Yes, that's the most compelling argument for going with the stock FD OPR.
Most of my (customer) builds are in the middle of a rebuild, so the additional $60 for the RB "street" OPR isn't that much difference, considering that we're usually working with a ~$2,000 budget for the rest of the parts.

You want cheap?
How about shimming your original OPR?
http://www.aaroncake.net/rx-7/shimoil.htm
You can also "crush" your original OPR like in this video:
http://www.rebuildingrotaryengines.c..._Oil_Regulator

Is the only benefit at high rpms when oil pressure tends to drop? Does the higher pressure equal to more flow, more cooling and more or better lubrication across the RPM range? Or is the only benefit to higher oil pressure at higher rpms?

Higher oil pressure is for proper oil lubrication of the oil journal bearings.
Not enough oil pressure causes contact of the bearings, and we all know this is bad.
Increased load from the engine increases the requirement for oil pressure.
This usually means increased redline revs and / or increased power output.


-Ted