Lets talk about FD oil pressure regulators

[JustJeff]

I'm considering doing an FD oil pressure regulator with my s5 13B turbo rebuild. FSM for FC and FD oil pressure:

FC
regulator relief = 71psi
For testing at 3000rpm = 64-78psi

FD
regulator relief = 110psi
For testing at 3000rpm all the FSM says is 51psi (min.)

Is there a downside to increasing oil pressure? Racing Beat in their tech section warns that using their race pressure regulator set 105-115psi will increase oil pump wear. Is this a real concern? Is the extra wear on the oil pump worth the benefit of increased oil pressure?

If I'm increasing oil pressure will the OEM oil cooler still cool as much as needed? Will oil temps rise? I've learned from watercooling my computer that too much pressure/flow can be a bad thing for cooling if the liquid does not stay in the radiator long enough to remove it's heat.

[RETed]

I've never had good luck doing that mod.
The engines would end up smoking more.

Any reason why you're looking at this option?
Only real reason to increase oil pressure is to increased redline on the engine, or if you're running serious amounts of power - i.e. over 400hp?
Other than that, there's no real reason to do this on a daily driven street vehicle.

The Racing Beat 85psi(?) street OPR upgrade is good enough for most applications.
It's reasonably priced too.


-Ted

[My5ABaby]

So for example, on a stock block TII with a BNR stage 2 (and supporting mods of course) that puts down around 300rwhp, would the Racing Beat OPR be an upgrade or just wasted money?

[Buggy]

I've done the FD regulator on my old FC and my Rx-4 engine. I've had no issues with either engine......

[diabolical1]

i've used the REW rear regulator in two of my engines now, a 12A i built a few years ago and a 13B i just put together. there was no smoking on the 12A and i should be able to report on the 13B once it goes in the car and is fired.

[JustJeff]

I've never had good luck doing that mod.
The engines would end up smoking more.

Any reason why you're looking at this option?
Only real reason to increase oil pressure is to increased redline on the engine, or if you're running serious amounts of power - i.e. over 400hp?
Other than that, there's no real reason to do this on a daily driven street vehicle.

The Racing Beat 85psi(?) street OPR upgrade is good enough for most applications.
It's reasonably priced too.


-Ted

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?

I'm running mostly stock S5 13B turbo. My mods are in my signature, that's alot easier than typing them out in threads. I'm looking more for reliability and longevity than added HP. If I can toss on some mods that are cost effective and won't affect driveability I'm interested. Somewhere down the road I may do a BNR or even find a core and start a new rebuild and have more fun with that engine.

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?

So for example, on a stock block TII with a BNR stage 2 (and supporting mods of course) that puts down around 300rwhp, would the Racing Beat OPR be an upgrade or just wasted money?

See above:
RB OPRs are $100
FD OPR iss $34 and is a 105psi regulator

I'm always suspicious when you can get the same thing for less cash. Hopefully some people will chime in with experiences, knowledge, etc.

[Monkman33]

How can you really wear the oil pump much more? it is always moving at an rpm dependent rate.

also, if the oem part will get you where you want to be, I'd go that route... especially when it comes to something critical like the oiling system. Oem parts have to take longevity into account.

[RETed]

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.com/videos/Oil_Pressure_Increase_With_Rear_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

[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.


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

REALLY? :banghead:

[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!

[RETed]

Side note:
The stock FC turbo and FD runs basically the same oil pump - 17.5mm width rotor?
So I don't think accelerated oil pump wear should be an issue.

The oil pump is typically pumping out close to 150psi - 200psi of oil pressure in the front cover - i.e. right after the oil pump itself.
This is why there's another OPR in the front cover (which most people don't mention).


-Ted

[TitaniumTT]

Isn't that more of a relief valve to keep the pressure from spiking throughout the system? IIRC the regulator that most people toy with is at the end of the line, where it should be, but extremely high pressures, cold start for example, would overpressurize everything before the OPR in the rear iron had a chance to react?

[RETed]

Technically, the rear OPR is a relief valve. :)

The front one is set around 150psi, IIRC?

It has to pump through the oil cooler (and lines), so that's why it's set so high?


-Ted

[TitaniumTT]

Yeah, you know what I mean :) Ones more of a relief, the other more of a regulator..... right???? Brian needs sleeeeeeepppppyyyyy

[diabolical1]

Isn't that more of a relief valve to keep the pressure from spiking throughout the system? IIRC the regulator that most people toy with is at the end of the line, where it should be, but extremely high pressures, cold start for example, would overpressurize everything before the OPR in the rear iron had a chance to react?

your posts have actually now given me some insight now into why my pressures on that motor reacted with increased RPM appropriately, but started to fall off shortly afterwards. all this time i thought it was the modifications i made to the e-shaft jets. now i'm thinking i might have simply blown out the front cover o-ring.

if i recall, that front regulator bypasses at 156 psi from the factory, it usually gets shimmed when you use the high pressure rear regulators.

[TitaniumTT]

Yes, it usually gets shimmed, but the last time I had the pan down I removed the shims hoping to lower my oil pressure and it didn't do a damn thing.

What are your pressures like? GENERALLY when an o-ring blows out the pressure is abysmal. Not sure why mine continues to seal

[diabolical1]

Yes, it usually gets shimmed, but the last time I had the pan down I removed the shims hoping to lower my oil pressure and it didn't do a damn thing.
somehow that doesn't much surprise me.

What are your pressures like? GENERALLY when an o-ring blows out the pressure is abysmal. Not sure why mine continues to seal
it's not a current problem. i had a blowout with that car and crashed it a few years back. the engine has been sitting in my garage ever since. it's just that i was never able to figure out what was going on.

from what i remember, idle pressure was normal. it would shoot up to about 80 psi (stock gauge) with throttle and just kind of sit there through the gears, but once i was cruising on the highway, it would slowly start falling. it never got critically low though. keep in mind, for most of the 2 or so months that it ran, i was limiting myself to 4000 RPM because of break-in on the new bearings.

[JustJeff]

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.com/videos/Oil_Pressure_Increase_With_Rear_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.

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? :banghead:

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.

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?