Oil Pump Question

[Byrdman]

On the 919 Dual Sport (XR900R), I'm running a remote oil filter. It's going to be plumbed with about 28" of hose back and forth.

I'm concerned that the size of the hose (1/2" ID) and the length is going to really make the oil system inadequate. I'm thinking about over driving the oil pump to speed it up and then modifying the pressure bleed valve to allow slightly higher pressure.

The stock oil pump drive is underdriven (25 to 26 tooth sprockets) at about 91% and the pressure is capped at 71psi @ 6000rpm. By flipping the sprocket ratios out (26-25 teeth)with stock sprockets from a 600 Bandit I can get it it overdriven at 104%. Then with one additional shim I should be able to get a few more psi out of it.

What do you think Stan, Dean, other knibblers? Any issues that I'm just not seeing?

[cbrxxquad]

Once it is full, the lines and filter, don't think there is any effect to the length. most of the lines in the engine are about that size. I have done the same thing on many vehicles, without any consideration.

However, what your doing is correct, and I would do it more for the engine anyway. I run a 100 lb relief valve, and tighten the clearances on the pump end too. Might want to make sure the oil filter will not bypass at that pressure though.

[mikesail]

Once it is full, the lines and filter, don't think there is any effect to the length. most of the lines in the engine are about that size. I have done the same thing on many vehicles, without any consideration.

However, what your doing is correct, and I would do it more for the engine anyway. I run a 100 lb relief valve, and tighten the clearances on the pump end too. Might want to make sure the oil filter will not bypass at that pressure though.

It does seem like fluid flow is mostly set by the diameter of the pipe, the length is not too important. This would probably change when the flow is turbulent, I suspect that this case is more like laminar flow. But I'm not a fluid guy......

I will say that the issue at hand is the amount of oil flow, and whether this engine can flow enough oil to cause a pressure drop in a 1/2 inch line. I think that your average chevy v8 will only use this size line, and I have to believe that it flows much more oil. By looking at the size of a bike oil filter, it is apparent that it is not expected to flow nearly as much oil as a big v8. I'm sure you are fine with a 1/2 inch line, but the only thing that answers your question 100% is an oil pressure gauge at the block.

Do understand that the oil pressure you develop is directly proportional to the torque load the pump will incur. That is to say that increasing the pressure from 50 to 100 will double the torque load, and thus energy lost in the pump.

Stan, oil filter bypassing is from the differential pressure, right? It doesn't care what the absolute pressure is, just what the filter sees depending on viscosity and flow, si?

Jeff, is there a reason to believe that you need to change the pump gearing? As long as you are developing whatever pressure the relief valve is set to, any overdrive will simply cause more oil to divert past the relief valve. If you want more pressure at idle, then it makes sense to change the gearing I suppose.

Most oiling troubles seem to be because of momentary loss of pressure or contamination. I saw the guts of two engines blown at Bonneville last year, a Busa and a Chevy, both had some debris in the system which caused the failure. I think a consistent and reliable system is key, the pressure setting not such a big deal.

[Byrdman]

Thanks guys.

Mike, I had considered smaller diamter, hard formed oil lines but I didn't want to create so much pressure that flow would divert past the pressure valve. That's why I wanted to increase overall flow and pressure to make sure I had enough oil flow and pressure throughout the system.

I guess I really won't know if I have a problem until I run her as is but I wanted to get a plan in place if..........

[cbrxxquad]

oil filter relief valves work on differential, but, low back side pressure compared to feed side will generate high differential. I have seen filters blown off too. Around 120 psi. But that was with non-relief filters too. Just don't want the oil to not be filtered. Most filter sites will give information on this, and the rate.

I think they are meant to relieve due to filter being dirty, but will relieve just due to pressure too. Any time I do a out of spec pressure system I do remove the relief type filters. But most filters never see 40 lbs. Race filters and engines commonly see 100 or more.

[EVLXX]

Thanks guys.

Mike, I had considered smaller diamter, hard formed oil lines but I didn't want to create so much pressure that flow would divert past the pressure valve. That's why I wanted to increase overall flow and pressure to make sure I had enough oil flow and pressure throughout the system.

I guess I really won't know if I have a problem until I run her as is but I wanted to get a plan in place if..........

In my opinion, this sounds like it would be your best choice.

[cbrxxquad]

I have been thinking about examples, and the oil cooler lines on the bird come to mind, but then there is some quads with external oil tanks like the 400ex and Cannondale with flex lines. Harley does too. Shit I have external filters on my 8.1 sub, that are 6 foot long and 1/2 " id.

Maybe a little larger feed and a little smaller return.

[mikesail]

Thanks guys.

Mike, I had considered smaller diamter, hard formed oil lines but I didn't want to create so much pressure that flow would divert past the pressure valve. That's why I wanted to increase overall flow and pressure to make sure I had enough oil flow and pressure throughout the system.

I guess I really won't know if I have a problem until I run her as is but I wanted to get a plan in place if..........

A normal oil pressure exists only when the relief valve opens, the job of the relief/pressure valve is to set the pressure, right? Any restriction in the oil pipes downstream of the valve will only decrease the engine block pressure, and thus cause less oil to flow thru bearings, more thru the valve.

Hard lines will still need a piece of flex line to couple to the engine block. If you don't there is a chance that the line will crack due to vibration and work hardening. Since the cost of a flex line is mostly the fittings, you might as well go flex the whole way.

The only reasons to use a small line are things like size, cost, weight. As far as oiling the bigger line won't hurt, but 1/2 has to be overkill already.

What I really like about remote filters is the freedom to get a larger and common filter, and also mount it where it is easy to change.

[Byrdman]

Wow, that was some great information guys. Thanks for the expertise.

I just spent a half hour working with my local Napa guy and here's what I think I'm going to do.

We chose the largest hard brake line we could find and then found a few brake line adapters. The 1/2 hose fitting from the remote oil filter kit was just a smidge larger that the brake line so I'm comfortable.

I'm going to mount the remote filter to the right rear of the engine so two hard lines with several vibration supports along the way should work fine.

I'll add a shim or two to the oil bypass valve to increase the pressure just a tad, that should take care of any added resistance from the 28" lines.

Fluid doesn't compress, so the only cost of the lines is the additional frictional cost of the oil traversing them.

Why would diameter matter? Flex in the lines should be minimal. Once the lines are full and the air has been moved out, solid smaller lines would look identical to the pump or possibly have a slightly smaller pressure drop. (drop / cost are interchangeable in this context to me..) Even with some tight bends, the high PSI of oil pressure should experience a negligible pressure drop -- probably less than 1 PSI?

I think what you've proposed makes sense, Jeff. Bump it up slightly and let it flow. Worst case, you've over-engineered it and have very clean oil..

P.S. I claim to be no expert but I have been talking with experts on the subject quite a bit over the last couple of months, even as recently as yesterday, while trying to piece together a dry sump system for the XX. That particular expert said to put the largest lines I can into the plumbing to ensure the highest flow between the pump, filter, and tank. No smaller than -8 (1/2") and only smooth 180 bends if I need them. (Which I will probably need 135s)

My dry sump set up will have more than 28" of hose to traverse when it's done - close to twice that..

The problem with large lines is the time it takes to fill them at startup. After startup, the diameter of the lines is a non-issue but...........

[mikesail]

Fluid doesn't compress, so the only cost of the lines is the additional frictional cost of the oil traversing them.

Why would diameter matter? Flex in the lines should be minimal. Once the lines are full and the air has been moved out, solid smaller lines would look identical to the pump or possibly have a slightly smaller pressure drop. (drop / cost are interchangeable in this context to me..) Even with some tight bends, the high PSI of oil pressure should experience a negligible pressure drop -- probably less than 1 PSI?

I think what you've proposed makes sense, Jeff. Bump it up slightly and let it flow. Worst case, you've over-engineered it and have very clean oil..

P.S. I claim to be no expert but I have been talking with experts on the subject quite a bit over the last couple of months, even as recently as yesterday, while trying to piece together a dry sump system for the XX. That particular expert said to put the largest lines I can into the plumbing to ensure the highest flow between the pump, filter, and tank. No smaller than -8 (1/2") and only smooth 180 bends if I need them. (Which I will probably need 135s)

My dry sump set up will have more than 28" of hose to traverse when it's done - close to twice that..

Dean, am I misunderstanding you? Diameter matters because there is some finite flow rate, and the system will experience a pressure drop which the line restriction incurs. Also, the high psi of the system does not affect the pressure drop, only the flow rate, viscosity and line friction determine that. It is true that one can start with a higher pressure to allow for some line drop, but that is a different point.

How can you say that smaller solid lines would have a smaller pressure drop? In general a larger line will have less drop, right? It is claimed that poor fittings can easily cause the most drop in a plumbing setup, and critical systems use special smooth bent fittings for angles instead of cross drilled fittings.

Dean's oil expert suggests what every race guy will tell you, big lines and smooth fittings. I don't disagree, just think -8 is big for a street bike motor. For those wondering, the dash (-) refers to eighths of an inch, so brake lines are commonly -3, clutchs use a -3 or -4 since they flow more fluid, etc. BTW, the price gets to be pretty big as you get to -8 for the quality fittings but they sure are nice to see!

Here is the phone number for TMR, a local plumbing supply house for motorsports, (714) 771-1348 . They have built various lines for me in stainless braid, brake lines, oil lines, remote shock, power steering that's what I recall just now. Mike Torino is the owner, they have a daily clientel of race vehicle builders coming thru the shop. If they are not busy they will take time with you over the phone, I've always been happy with their knowledge and advice.

Jeff, if you do use solid lines, just be careful about the flare fittings. There are two different flares in common use, 45 and 37 degrees. they look similar at a casual glance but will not work well together. SAE uses 45 degree, AN spec is 37.

[mikesail]

The problem with large lines is the time it takes to fill them at startup. After startup, the diameter of the lines is a non-issue but...........

Depends on total volume and orientation - gravity is the only thing that would empty them, right?

Where in the circuit is the filter? Last is what I am accustomed to, so it shouldn't matter if it takes a few seconds for the whole system to pressurize as long as there is an adequate amount in the pan to pressurize the critical areas, right?

Fluid at these pressures moves awfully fast too, measured in milliseconds..

Dang, more comments to respond to.......

I presumed the filter was in the path from the pump to the engine oil gallery. If it is a bypass type of filter, then everything is a bit different, so which is it? A bypass filter would not be critical as to its plumbing.

Fluid moves fast at high presure, but the problem with filling large lines that have emptied is not affected by the operating pressure. The pump is a positive displacement pump, this means that a fixed volume of oil is pumped for each revolution. So it will take a certain numbers of rotation cycles to fill the system BEFORE pressure will build up. Oil flow is really quite low when an engine is cranking over. An Accusump ( which I think Stan uses ) will overcome this startup starvation problem.

[Byrdman]

Typical motorcycle engine has 2 pumps in the oil pump, 1 side is for the mains/rods/cams, the other side runs it through and oil cooler and filter.

Still think the biggest concern is placement in orientation, not line size.. If it never drains (much) it never has to refill (much). Look at cars. Top of the filter is at the top of the oil level at rest, typically irrespective of filter location.

The XX has a dual side oil pump, the 919 has a single rotor. It sends oil to the filter then back into the engine to do the work.

The problem with large lines is the time it takes to fill them at startup. After startup, the diameter of the lines is a non-issue but...........

Depends on total volume and orientation - gravity is the only thing that would empty them, right?

Where in the circuit is the filter? Last is what I am accustomed to, so it shouldn't matter if it takes a few seconds for the whole system to pressurize as long as there is an adequate amount in the pan to pressurize the critical areas, right?

Fluid at these pressures moves awfully fast too, measured in milliseconds..

On the 919, the filter is the first in line after the pump that's why I'm so concerned about time to pressurize.

[cbrxxquad]

Oil in the lines is relatively static, not that much flow, that is why there is pressure. The amount of oil flow is surprisingly low and the major drop is at the bearings. So the pressure is the same in all the lines and fittings and filter. If the flow was much the drop through the filter would open the relief, but it don't till the differential causes it to open. Been thinking about that for a day.

I did run a xx pump with an external motor in an assembled motor to see how much oil is used, or better yet, lost, through the bearings and transmission.

Drips from the rods, runs out the trans, and the restrictors in the oil galley for the trans side,,, the holes are maybe .060"

Flow is the main thing that shows pressure drop in the lines, no flow no drop. Relatively speaking.

I would be more worried about location of the filter.

[Byrdman]

I think using the small brake lines, a filter location roughly the same elevation as the original filter, and a shim or two in the pressure bypass valve is going to be part of the plan.

Then I'm going to run an oil guage to make sure I have pressure almost instantly at startup and there are no major dips across the rev range. If there are pressure drops, then we'll overdrive the oil pump.

Clear as mud?

[mikesail]

Apologies, but I am not going to argue against your last comments -- not educated enough in fluid dynamics to pretend that I can do much more than parrot what I have been told by people who build things like this or this. (And they have 2+ g's of acceleration for the 1st 60'. I trust their experience.)

Typical motorcycle engine has 2 pumps in the oil pump, 1 side is for the mains/rods/cams, the other side runs it through and oil cooler and filter.

Still think the biggest concern is placement in orientation, not line size.. If it never drains (much) it never has to refill (much). Look at cars. Top of the filter is at the top of the oil level at rest, typically irrespective of filter location.

Oh Dean, this isn't about fluid dynamics, just trying to help Jeff make a good choice. At least he isn't messing with a dry sump, those cause more problems than you can imagine!

I trust your experts experience too, but I'll raise you one. I used to work on this many years ago

And then at Bonneville in 08 I put this bikes engine back together, some guy named Noonan

Not saying I'm a plumbing expert, I'm not, just trying to clarify what is important to Jeff. Every application has it's special requirements, as a drag racer G force must be the toughest. I'm sure you guys have that solved very well.

So far the topics covered for this oiling question have been quite varied. Startup time to pressure, line drop, vibration failures, cost, operating pressure, fittings, ....

So I called Earls plumbing today, they are the company that created the steel braided racing hose business, been doing this since the 50's or so. For a car they recommend either -8 or -10, a bike only -6 to keep the pressure drop in 3 foot of hose to less than 3 percent with 50 weight oil. he has seen a couple of bikes use -8, but saw no reason to do so.

Stan, if you ran a test for oil flow, did you apply a load to the piston? A big end bearing will use more oil as the piston loads are applied, since the crank will not be centered and the gap will open opposite the piston side of the bearing. I have a lotus engine which drops pressure considerably when you hit the gas from this effect.

Hope this has been helpful........

[mikesail]

I think using the small brake lines, a filter location roughly the same elevation as the original filter, and a shim or two in the pressure bypass valve is going to be part of the plan.

Then I'm going to run an oil guage to make sure I have pressure almost instantly at startup and there are no major dips across the rev range. If there are pressure drops, then we'll overdrive the oil pump.

Clear as mud?

1. startup time will be determined by how much oil has drained out, and also by the pump RPM. So overdrive would help there.

2. If there are pressure drops, you need to know why. Is it because the consumption of the engine is too high for the pump, or is it because the line and/or filter is restricting? For the first condition overdrive will help, for the second overdrive will not help only bigger plumbing.

[Byrdman]

I really appreciate all of the help you guys have given me. I should have clearly stated the questions and concerns I had in the very beginning but Mike did a great job of summarizing them.

FYI:

[Byrdman]

2. If there are pressure drops, you need to know why. Is it because the consumption of the engine is too high for the pump, or is it because the line and/or filter is restricting? For the first condition overdrive will help, for the second overdrive will not help only bigger plumbing.

The best bet would be a pressure guage right before and after the pressure bleed valve and one way downstream at the filter head.

Then I could identify exactly where any flow restriction is.

[EVLXX]

Metal lines will help cool, minor I know, but I like it, plus they will take any pressure flexing a lot better.

Then, if the Oil filter is to be mounted above the crank, wouldn't you want to mount it, filter down...

maybe that's not explaining it correctly...

Basically opposite the picture you posted. In order to keep the filter itself from draining off.

[Byrdman]

Then, if the Oil filter is to be mounted above the crank, wouldn't you want to mount it, filter down...

maybe that's not explaining it correctly...

Yes, I will hang the filter from the mount as to at least keep it full of oil when the bike is shut down.

[tomek]

Mehh,RX7s have filter on the top of the block,filter up,unless you punch couple of holes to allow air in,you have nice, messy oil spill during oil change.

In other words ,it won`t drain,I would not worry about orientation of the oil filter.

[Byrdman]

I hate that design, by the way.. Filter and oil cooler issues could cause reduced oiling to the mains/rods? Wow.. Spare oil pressure like what Stan has might be a safe bet, if there is room for it..

Agreed 100% It is a bass-ackwards design but how many 900RR are out there running fine?

I really like the XX oiling system with the dual pumps. It's safe and clean, maybe I'll try to wedge the XX pump in there! :icon_think:

[mikesail]

Mehh,RX7s have filter on the top of the block,filter up,unless you punch couple of holes to allow air in,you have nice, messy oil spill during oil change.

In other words ,it won`t drain,I would not worry about orientation of the oil filter.

The BMW Z3 engine had an upside down canister filter on top as well. An upsidedown filter will stay full just like a straw with your finger over it, you have to break the vacuum to purge it. I can't think of a single engine with the filter below the oil level in the pan, so they all would tend to drain if the system can flow. Some oil filters have an anti drainback flap, just to help with the startup problem.

>>>>>I really like the XX oiling system with the dual pumps. It's safe and clean, maybe I'll try to wedge the XX pump in there! eusa_think.gif

Don't know the real reason for doing two pumps, but a nice benefit is that the cooler runs at low pressure. Far less worries about leaks, and if it does you can just block off the pipe and keep going.

[cbrxxquad]

http://www.perthstreetbikes.com/forum/f16/...e-engine-96508/

This came up on my web site and thought it had a bunch of really good stuff pertinate.

[Byrdman]

That sump plate makes my pee pee feel funny................