thesnowboarder

iTrader: (15)

I know alot of higher hp motors around here have Boundary Engineering's billet gears, which i was planning on using myself. I stumbled upon a high flow pump that Travis has created.

Boundary Engineering

My motor is coming to an end, and i want to make sure i have made all the right choices for safety. This will be a tracked and street driven car that will see quite a bit of boost. I am looking for about 300whp and don't ever want to pull my motor again.

Bottom end will consist of
M-tuned Rods
Supertech 8.7:1 slugs
APR bearings

I was planning on just using the billet gears, but after seeing the high flow pump i am debating if i should go with that for an extra safety margin.

What are you thoughts guys?

neogenesis2004

iTrader: (12)

I'm indifferent on the thicker gears. I think stock thickness is fine, but then again more can not hurt. How much it helps I think is negligible. You can acheive those higher pressures by simply shimming the oil pump relief with washers or having tighter clearances in the housing. I'd like to see a graph of differences in flow btw the two.

JayL

iTrader: (12)

It also appears that not all of these oem oil pumps are created equally. I would do this just to know exactly what I'm getting if I had to do it all over again.

neogenesis2004

iTrader: (12)

If you are properly clearancing the gears in your oil pump and measuring the relief spring according to the manual, then I would wholey disagree with you. They will all end up the same.

hustler

iTrader: (6)

i get enough oil pressure at 7k rpm that my stocker is fine.

TravisR

iTrader: (9)

The increase in pressure is from flow increase. Basically every bearing's load bearing capacity is based on how much flow, not pressure, that goes through the bearing. When more pressure is available you get more flow. The same principle is used on a MAP sensor of the car. Where do you get more flow into the motor 100kpa, or 30kpa? Samething with the bearings. Up the pressure, and the flow automatically goes up.

The gears are actually 30% larger then stock, and although I can't be sure you would run 30% more flow, I would imagine 25% would not be out of question. It would be tough to test though. Need a variable drive, high power electric motor, a special hook up for it, a flow metering system and lots of oil. I could easily spend as much money testing it as I ever would make on them. Just trust there is no replacement for displacement, and all your basically doing is increasing the displacement of the pump.

neogenesis2004

iTrader: (12)

None, the less. The stock gear area is made to support it to redline at a minimum. Increase the pressure by shimming the relief spring to support a higher hp ceiling and I see no issues. Hell the 600whp miata thats floating around out there is using Bill Wilners gears and those were made to stock width. So I know the stock width can support plenty of flow.

Its a great product, but I don't see the necessity considering the higher cost.

TravisR

iTrader: (9)

Well the stock gears are running flat out at that point. The relief valve isn't supposed to pop until 90psi. So whatever pressure your reading isn't because the relief valve is cutting the flow, its because the pump can't support anymore.

While there are high horsepower motors out there running ok, I know that at least FM was interested in reselling these gears for their high output motors. Its preventative, and if your upping the pressure up on the rod by three to four times, it might be a good idea to upgrade. I have no evidence to support the bearings are beyond their limits, but I can't believe the original design intended 390ft/lb of torque through the motor.

Joe Perez

iTrader: (8)

Everyone read this again, because I think people are missing it.

Once your oil is all nice and warmed up, the pressure relief valve should pretty much always be closed. Shimming the spring will only cause your oil pressure to increase when the engine is cold and the oil thick, which is pretty much exactly when you don't need a lot of extra oil pressure.


I recently ordered a set of the stock sized gears for Jessica, and the reason was that I'm worried about oil pressure when cold. As it is, my oil pressure tends to run >90 PSI (the limit of the gauge) when cold, and I worry that the relief valve might not pass enough volume to prevent it from running even higher with a larger pump.

Thoughts?

neogenesis2004

iTrader: (12)

If this were the case then please explain why a motor with stock gears will run 50ish psi on the gauge at redline. Then when shimmed with 1 or 2 thin washers with run 70psi at redline.

I have done this, so I can say that it does in fact happen. So I think your 90psi comment is nothing but conjecture.

TravisR

iTrader: (9)

Well, tell me this, why does your car run 90psi cold, and 50psi warm? Viscosity drops, flow goes up, and pressure goes down. We know the factory relief valve systems limits at 90psi, if this were not the case the car would run 90psi cold, and 90psi warm.

y8s

iTrader: (8)

someone suggested I run a stiffer spring in my wastegate to help spool...

isn't that the same thing?

ZX-Tex

iTrader: (15)

Oh, sorry, back to your regularly scheduled thread

neogenesis2004

iTrader: (12)

I never said anything about cold or hot. I'm referring only to full temp oil. If the only change that was made was the oil pump's relief spring being shimmed then viscosity of the oil does not come into the equation.

TravisR

iTrader: (9)

Yea but what I'm saying is this: If the relief valve was the piece that was limiting pressure, then wouldn't cold also be limited to the ~50 psi? If cold is limited by the true relief valve pressure, and hot was limited by the same relief valve pressure then they should have the same pressure hot or cold. That would mean that regardless of what the car is doing the limiter is the relief valve.

Look at Matt Andrew's graph. You can see at the same point Matt's car is running 37 psi, and the new motor with the higher flow oil pump is reading 53psi. These are the same relief valves at two different pressures. While I understand your evidence I also have my own that states the relief valve is not the limit on flow. Its right out there in number form for you to see. Same relief valve assemblies with the same pressure relief location, and the the high flow oil pump adds extra pressure/flow. How do you explain that?

neogenesis2004

iTrader: (12)

I don't think we are disagreeing on the fact that the high flow oil pump increases pressure by additional volume alone.

I am simply pointing out that if you are trying to increase oil pressure to increase your safety net on a high hp or high rpm motor you can shim the spring with stock width gears. People have been doing this with miatas for over a decade.

I won't even begin to argue over viscosity or other fluid properties. I'm no mechanical engineer. I just know what I'm talking about from personal experience and the experience of many others.

matttheniceguy

I suspect this is due to some leakage of the stock releif. In an ideal case the releif wouldn't leak at all until 90psi, where it would open as needed to maintain that 90psi. In reality it will leak, and as the spring and seats wear there is more and more leakage at a lower pressure. Shimming the pump (or replacing it) will redice this leakage so you get more pressure.


A 0W-XX weight oil should help keep oil pressure from being to high when cold. I had a 90 with a fairly worn oil pump (think it was leaking relief actually) that I ran 0W-50 in quite successfully. I'm in the "warm" part of Canada, but I still made it though several winters with -10C temps or so without the pressure being terrably high on startup. A 0W-20 or 30 might help a fresher oil pump.

j_man

Then why the Mazda 323 rally cars in the World Rally Championship were running different springs? Spring was different, pump was the same as the one in the street engines.
And they don't run their engines cold when racing

Stock relief pump is 5 kg/cm^2 (71 psi)
The version for the race cars is 6 kg/cm^2 (85 psi)

IIRC there were reports from people (who replaced the stock spring with the race version) about increased oil pressure

neogenesis2004

iTrader: (12)

I decided to open up my service manual pdf. Here is the page on the tech specs of the stock oil pump. Definitely says the stock spring is 50-64psi with full temp 30W oil.

I'd say the reason Joe's pressure is so excessive is because either his relief spring is messed up (siezed somehow), or hes running some thick oil.

j_man

Then it is even less than 5 kg/cm^2