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

[RICE RACING]

DO IT!

Personally I have Never ever had a motor smoke due to high oil pressure!.

Every engine I build uses the 13B-REW rear regulator. I do MANY T2 based engines for various customers.

The higher oil pressure is a must in anything really if you want to bearings to live, especially when you are making an honest 450bhp. Any decent motor even stock ported will see 8000rpm all day long (most see 8500rpm) and when you combine this with 500bhp, let alone more power! you will find out the hard way why this level of oil pressure is needed.

Oil pump wear is never a problem, though you do loose some power running higher oil pressure, which is nothing compared to how much you will be making when you are justifying running the higher pressure anyway.

DO IT!

[JustJeff]

Originally Posted by RETed

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


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

A friend and I were talking about shimming OPRs and I read over Aaron Cake's page on it. I simply can't justify tearing into my FC OPR when I can simply buy an FD OPR for as cheap as they are. But that is the first I've seen pressing the OPR and...it just..um...seems wrong to do???

Once the engine is broken in I'll be pushing it harder than I had been prior to detonation. Before blowing up my engine I had bigger exhaust, increased boost, had upgraded my fuel...but I was waiting for Rtek S5 TII chips to come out of beta. Because I knew I was treading on thin ice I tried to keep a light foot.

With the rebuild and the Rtek I'll feel a little safer to redline more often. But it's still a near OEM setup that is mostly city driven. Sounds like most of the people doing this mod are building different engines than I am.

Originally Posted by TitaniumTT

I run an FD OPR without shimming the relief valve in the front cover and I see a steady 100psi cruising down the highway @ 4k. I'll see 130-140 psi on cold startup. I would like it to be a little lower. I'm in the category or higher revs and higher torque though so while I need the pressure, I have too much. Then again, I felt that the stock Cosmo OPR was a little on the low side.

Don't forget though, that I modded my oil pump so my pressure is higher than most because of that o-ring in the pump.

My pressure also gets so high that I constantly blow out the front cover o-ring. I've tried gasket, no gasket, proper o-ring, bigger o-ring. Doesn't matter what I do, first oil-change after removing the front cover, I always... ALWAYS find the o-ring in the filter, yet I still get those pressures. I also cleaned and bored all the passageways in the front cover so I'm sure my pressure is dependant on a few of the mods that I've done.

Next time the oilpan is down, I plan on swapping OPRs.

Next engine I build, I plan on making the oil pressure adjustable externally, and bypassing the front cover all together, the original front cover outlet will actually become the return dump.

One of the reasons that I believe the REW OPR is set so high is becuase they are feeding 2 turbo's and need a slightly higher pressure to get more volume.



REALLY?

What I don't like about this mod is that the higher oil pressure is going to look for the weakest link. Before my turbo swap I blew one of the cooler lines in my N/A. This was before I knew enough to do much work on my own. Regardless of who did the work, my engine compartment was an unholy slime pit. I hate the idea of loosing a hose with even higher pressure.

Originally Posted by RICE RACING

DO IT!

Personally I have Never ever had a motor smoke due to high oil pressure!.

Every engine I build uses the 13B-REW rear regulator. I do MANY T2 based engines for various customers.

The higher oil pressure is a must in anything really if you want to bearings to live, especially when you are making an honest 450bhp. Any decent motor even stock ported will see 8000rpm all day long (most see 8500rpm) and when you combine this with 500bhp, let alone more power! you will find out the hard way why this level of oil pressure is needed.

Oil pump wear is never a problem, though you do loose some power running higher oil pressure, which is nothing compared to how much you will be making when you are justifying running the higher pressure anyway.

DO IT!

I've read a little about power loss from higher oil pressure, mind explaining it so I'm understanding? But keep in mind that I'm not building an engine that is much higher than OEM power. I won't be seeing redline at every light and every corner. Is higher oil pressure still justified if I'm NOT running big HP?