Oil Pressure Regulator for Turbo?

[Ceddy]

Since we kind of have issues with oil pressure, I was wondering if anyone has ever seen this done?

Using orifices, kind of puts us in the dark ages of drilling out Carburetor Jets, technology wise.

I think the ideal setup would be a reducing regulator with a vacuum port like AFPRs have, so you would have lower pressure at idle and higher pressure in boost. This would enhance spool time and turbo bearing safety.

The external oil pressure regulators are widely used in oil sump systems.
I haven't found any in a small size (-4AN) with the pressure range we need yet.

Prince Adjustable Oil Pressure Regulator ~$60

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How Reducing Regulator works:

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[delta448]

Interesting idea; how would you suggest to do the oil plumbing?
I suppose it would depend on the pressure when unregulated and the demands of the individual CHRA?

 

[Ceddy]

The Oil Pressure Regulator has 3 lines.

One goes to Oil Filter Housing, one to Turbo Oil Feed, and one gets plumbed into the oil drain.

You would set the Regulators pressure to the Turbo Manufacturers Recommended Max Pressure or a little less.

 

[dsmfa9nutter]

A properly sized restrictor as spec'd by the manufacturer is all that's needed for any large aftermarket turbos as it's not pressure but volume that causes problems. Too much volume pushes oil past the seals and causes smoke. You can run 100psi of oil but if it's going through a hole the size of a pin head, it won't be a problem as the volume is severely limited.

 

[Ceddy]

A properly sized restrictor as spec'd by the manufacturer is all that's needed for any large aftermarket turbos as it's not pressure but volume that causes problems. Too much volume pushes oil past the seals and causes smoke. You can run 100psi of oil but if it's going through a hole the size of a pin head, it won't be a problem as the volume is severely limited.

I have to disagree with this, OEM Manufacturers Spec Pressure Requirements not a restrictor size(exception being BB CHRAs). Excess pressure is what causes seals to leak.

Restrictors reduce volume and pressure, but the problem with them is they behave differently with different feed pressures.

 

[crimsondragon]

I have to disagree with this, OEM Manufacturers Spec Pressure Requirements not a restrictor size(exception being BB CHRAs). Excess pressure is what causes seals to leak.

Restrictors reduce volume and pressure, but the problem with them is they behave differently with different feed pressures.

And where do you think that excess pressure is coming from if volume is limited?
If a CHRA drains quicker than it can fill up to cause overpressure, seals will be fine. Just as long flow isn't restricted so much to cause wear on the bearings.

 

[Ceddy]

Excess pressure comes from the feed pressure being to high. Pressure in the CHRA will never surpass the feed pressure ever if the drain is completely block off.

A restrictor doesn't provide a constant pressure or volume flow, it varies with the feed pressure, which isn't always consistent with our cars, and can vary a lot from idle to revlimit.

I was just wondering if anyone has seen this done. If Kiggly's HLA Regulator is only a hundred some dollars, I think a turbo regulator could be made for the same price or less.

 

[dsmfa9nutter]

Pressure doesn't matter when the volume is restricted to the correct amount. You're really overthinking this.

 

[delta448]

It's the old Toe-May-Toe / Toe-Mah-Toe debate.
Pressure and volume are -almost- interchangable here; have too much volume and you get too much pressure, have too little pressure and you get too little volume and vice versa. Why are we arguing so intently about terminology?

Bernoulli Equation

 

[dsmfa9nutter]

I'd rather have 10psi on a gallon of oil than 1000psi on an ounce of oil.

 

[delta448]

Yes, but we're not at the extreme ends of the spectrum here.

Regulating pressure will affect flow volume, but in this case we're not trying to choke the flow completely, just slightly reduce the maximum energy it imparts on the seals at peak rpm. As long as the oil pressure difference across the CHRA and volume of oil available are always enough to not allow the oil to coke for lack of flow, a pressure regulator should work just fine. Or am I missing your point?

 

[Ceddy]

I think a regulator will better protect and help the turbo better perform then a restrictor. Especially with some Brands that are prone to blowing seals or destroying bearings, on our cars.

With a constant pressure you will also have a constant flow(determined by the size of the feed lines), which is a plus.

I haven't been able to find much info on this though, mainly just for cars with a oil sump system, or a separate turbo oil system.


SkyLine owner who was blowing seal with restrictor, regulator fixed:
Turbo Oil Pressure Regulator - Skylines Australia

 

[dsmfa9nutter]

Hey, if you guys want to waste money on something that's not needed, that's your perogative. I never understood why people painted their interiors neon pink either.

 

[delta448]

If it's not needed and offers no benefit, I wouldn't do it. I definitely won't be painting any interiors anytime soon, (though for some reason the thought of pink trim does excite me?) I'd be much more likely to install a disco ball and reupholster in shag and velvet before painting anything in there a neon hue.

But if I had a reoccurring issue with blowing turbo seals due to high pressure, I think I'd rather rely on a pressure regulator than on a fitting with a tiny orifice drilled in it to reduce the volume flow. Some Holsets use a pretty darn large drain and IIRC, are rather picky on the oil pressure range recommended for them to operate within. I think oil starvation might become my concern with fittings, wrong oil viscosity and the cold climate where I live.

 

[dsmfa9nutter]

If it smokes, you just need a smaller restrictor.

 

[logic]

Ceddy, did you ever locate an appropriate adjustable oil pressure regulator? (I was searching for exactly this, and your thread apparently has a bit of google-juice. )

 

[Ceddy]

Ceddy, did you ever locate an appropriate adjustable oil pressure regulator? (I was searching for exactly this, and your thread apparently has a bit of google-juice. )

The external regulators for dry sump oil systems look like they would be a good match. They are adjustable for the pressure range we need. And are fairly small in size. I was waiting for a cheap one to pop up on ebay, they're fairly expensive new.

A few companys will custom make them for the pressure you need, but they are industrial, laboratory grade type of things and cost about the same as a new turbo.


Example of Dry Sump Remote Regulator:

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Edit:
I was playing with the idea of adding a vacuum nipple to the chamber where the spring is in, that way under vacuum you would have less pressure and under boost more pressure.
But the diaphragm/plunger is probably to small, the 1:1 AFPRs have a large cross sectional size diaphragm.

 

[logic]

Interesting idea; I think I'd be inclined to supply a fixed pressure to the turbo and be done with it though. Otherwise, it seems as though by adjusting pressure based on manifold pressure, you'd be recreating the same problem we're trying to fix here, no? Unless you're suggesting basing it on crankcase pressure, to overcome drain resistance?

Just noticed that Canton and Peterson Fluid Systems both have an (identical-appearing; there's so few original manufacturers anymore it seems) oil pressure regulator, but only in -10 and -12AN inlet/outlet sizes. *sigh*

I did a bit of digging at mcmaster.com, and came up with a couple of pressure relief valves that come close, but they're back in the $60-80 range, and again, they're huge.

 

[Ceddy]

Its all just theoretical, would have to calculate rising rate ratio from diaphragm size.

But, 1:2 Ratio, 20 psi base oil pressure:
-20 inHg = 15 psi oil pressure
0 psi = 20 psi
20 psi = 30 psi
40 psi = 40 psi

Or something like that... (Just an idea)


I tried searching for a regulator for a drag bike sump system, be more the size we need, but couldn't find anything.

The Canton and Peterson type ones with -4AN reducer fittings should work.

The mcmaster ones all looked a little to heavy duty and huge.


There is stuff from parted out NASCAR cars on ebay sometimes, I'm going to try to pick one up this spring to test out.

 

[dsm-onster]

If it smokes, you just need a smaller restrictor.

But then you may have too little flow for spool up. Some turbos "get on load" VERY fast. Like the bolton hx35. They require a MINIMUM of 30psi oil pressure with the proper drain (to net the correct minumum flow) on load.

 

[logic]

Yikes, I happened to look up the pricing on those Canton units (which, now that I look at them, look like they're just Aviaid regulators); $100ish is the best I've seen.

Perhaps something simple and DIY: a rudimentary ball-and-spring valve (same principle as a manual boost controller)?

(By the way, we're not the first to need something like this. The MX6 community had a member named "Toastier" who sold what was essentially an adjustable restrictor; not a real bypass, but something you could dial in a bit without requiring disassembly; something like an inline pressure gauge fitting would probably allow you to replicate that with a bolt and a nut. Also, apparently RX-7s have the same problem we're trying to solve, only much worse, but they have OEM hardware that they simply mod for the task.)

 

[logic]

I ended up ordering the bits to make my own regulator from McMaster, which should hopefully arrive Tuesday.

We'll see how well this works out; the current paper design is a 1.5" wide by 5" long by 1" thick aluminum block, with 1/4" NPT ports for inlet, outlet and return, an 1/8" NPT port for pressure sampling, a 5/8" OD ball bearing and spring for the bypass, with a washer and bolt for setting preload on the spring. (Basically, just a slightly larger MBC, with a stronger spring.)

If it turns out to be a dud, at least I haven't spent much on it, other than a bit of aluminum stock. (Seems like metal is ridiculously expensive these days...)

 

[shadowdrag]

Just go to your good old ACE hardware store and pick up a 1/4" flare brass ball valve and hook it to the feed line and call it a day. Its like 3 bucks.

I used an air compressor to pre-pressurize and pre-set my ball valve to a max of 35-40 psi prior to install and works like a champ. Just make sure you have a good lock on the nob. It's like crack opening your gardening hose from the ball valve.


good luck

 

[logic]

Again, though, this is just a slightly more sophisticated restrictor. Better by far than just guessing what size restriction you might need, but unless it has a bypass (like a proper pressure regulator), you still run the risk of over-pressurizing at the turbo at high RPM, or if you're too aggressive about restricting flow, there's the risk of there not being enough pressure at idle.

Did you test your valve at your engine's lowest and highest pressures (ie. oil pressure at low load/idle, and oil pressure at your maximum RPM)? Doing so may be enlightening.

(You'll see that you don't "set" a restrictor valve at a given pressure like you do with a proper regulator: you merely set a percentage of reduction to input pressure.)

 

[gixrman]

Anything ever come of this? I run a HOLSET H1E and can see oil pressure sometimes at 100psi(cold) which is way over what HOLSET recomends. I run a restrictor and have even hooked up a OPG post restrictor just so I know what psi is going into the turbo. The problem is that when the motor is hot OP drops down to 10psi which is below what HOLSET recomends. So I was thinking of going this route
Electric Oil Feed and Scavenge Pumps that way I know the oil pressure is consistant. Yes it might be alittle pricy but less than replacing a turbo.