RotaMan99

HAILERS and NZ are not arguing with me. And whats the point of you coming in here? You are not helping anyone.

I already told everyone that you welded that piece for me. I have been screwing around with the OMP for about 3 years now. You going to come in here and ruin this thread too like you do all the other ones?

toplessFC3Sman

iTrader: (1)

Rotaman, you're correct, there isnt a restriction to the flow besides whatever pressure differential is being injected into, which at WOT is not very large, so the oil will never build up to 10 psi gage... i was just stating that as a theoretical maximum capability that would be greater than the max pressure differential that you'd see between the TB and the intake. Im not trying to state anything new, just to recap in different words to sum up my understanding of how it works.

RotaMan99

I do see what you are saying now, and I guess we will have to wait for my results. Basically to see if the OMP can build up pressure if the pressure in the intake starts to rise, which is basically what you are saying right?

Then again I can understand what HAILERS and NZConverible are saying as well which to me would make more sence, but I guess I will just have to test the maximum pressure the OMP can produce, if any.

RotaMan99

I believe he is talking about when the air is moving. Not when its still. NZ is absolutly correct on this. I may not word this correctly, but when air has to change direction, as in a bend, there is a pressure increase that raises the restriction. That line came from part of this PDF file on airflow.

http://www.donaldson.com/en/engine/s...ary/034973.pdf

I have been reading that for a little bit.

Also the intake runners are smaller then the TB Bore, so maybe this has an effect on the pressure drop as well.

HAILERS

Go look at a engine. Pull the rear side housing off.

Look at where the small hole is for the omp delivery. An apex seal passes over that hole. NOW it's in the intake chamber of the next rotor face.

That area increases in volume as the rotor moves. That causes a low pressure area until the next apex seal arrives at that small nozzle hole, whereupon it all starts over again.

I know the intake port is uncovered at the same time that *fist*apex seal passes by, but can't but help thinking there is still a low pressure area created as the area of the intake chamber increases in size. Lower pressure compared to the air at the top of the oil nozzle.

A little hard to prove inless I tap into the area below the nozzle with a gauge and compare that reading with the air in the hose on top of the nozzle (during boost of course). OR mabe just remove the nozzle and inatall a gutted one where I can read the pressure/vacuum and compare it with the air on top of another nozzle.

This thread will eventually die. Can't but hope so.

imloggedin

you know you like it. youre still posting info lol

RETed

It's easy to check this.
Since there are lots of vacuum fittings all over the engine, just stuff a boost gauge onto them.
See how much pressure is generate at each fitting.
There isn't that much variation between all the different points.
I've done this - have you?


-Ted

toplessFC3Sman

iTrader: (1)

what sort of gauge have you used, and what was its response time and sensitivity? To see a lot of this stuff you would need a high-speed datalogger (at an engine speed that would create boost anyway) with precision sensors and a few channels to monitor each source under identical conditions, not an autometer boost gauge or something that you move from nipple to nipple while trying to hold RPMs constant with your finger.

Of course there is a pressure difference from the TB to the intake. You said it yourself (in reference to the oil), you need a pressure difference to cause a fluid to flow. Well guess what, air is a fluid too, and the lower pressure due to the expanding intake chamber during the intake stroke provides a lower pressure than that in the rest of the intake, sucking air in. If there were no pressure difference, the engine wouldnt pull in any air.

Pressure loss in a flow is due to the head pressure loss of flowing around the butterflys and through the manifolds and past the manifold seams. Its basically a frictional loss of the air against the side of the manifold, but this is a different effect and is due to the air already flowing (not the reason that it is flowing). Im sure you've heard of pressure drops across an intercooler or something, right? same thing! However, the air is originally flowing because of the expansion (and thus lower pressure) inside the combustion chamber, and compared to this lower pressure, the head pressure loss of flowing through the manifold at WOT is insignificant.

Please, take a course in fluid mechanics (or even rudimentary thermodynamics!), it'll help you immensely

racerlinkfc

quick question im currently premixing can i switch to 2 stroke or will it cause engine failure?

Dinnercoat

If you're already premixing and NOT using 2 stroke then what are you using?

toplessFC3Sman

iTrader: (1)

hahah... wow, this thread needed a little comic relief...

Dinnercoat

We're only serious in the tech sections.

RotaMan99

I am deffinatly thinking about either taking a course for the hell of it or getting books or something cause I seem to be getting into places where I need to understand this area more.

RotaMan99

I really think thats how it works now that you got me thinking from reading yours and NZ's posts. Like I said earlier, this makes more sense to me then the OMP being a high pressure pump due to how slow the pumping action is and since the tolerences are not that tight.

CyberPitz

The only reason I screw with trying to fix MY OMP is because I don't think I'll be able to take off the UIM and put a blockoff plate there...then put it back together.

RyoFC3S

iTrader: (1)

I have, and it cost me a lot of money in rebuilding my engine. I started noticing my compression was getting worse and worse over a period of about a month, and I finally figured out it was because my OMP was working intermittently, and getting huge air bubbles in the system. Finally my compression got so bad that I had to pull the motor (I think it was about 20psi on 1 rotor and 60 on the other).

Once the engine was apart, all of the apex seals on the 20 psi side were flattened out (deformed), and it was obvious that they were not receiving ample lubrication and were being ground down against the rotor housing surface.

Since then, I blocked off my OMP and now premix. It costs an extra few cents per gas stop, and takes an extra 30 seconds-1 minute to do. Easily worth the sacrifice to save yourself from what happened to me (and as Ted says, a healthier engine).

My $.02.

toplessFC3Sman

iTrader: (1)

Rotaman, the "please take a course in fluid dynamics" thing was not directed at you, but in general I recommend it anyway. I still think that the OMP could function as a (relatively) high pressure, low flow pump, even if its never asked to in normal duty, but i think its kind of a moot point by now.

RotaMan99

Oh I know. I actually should have said that but I know it wasn't directed toward me. Your statement just reminded me thats all.

Im still going to see if I can get any pressure out of it.

Did you check to make sure all the o-rings were not leaking? When you say it was working intermitantly, how did you observe this? The only thing in the S4 OMP I can see possibly getting stuck is the plunger with the spring at the front of the OMP, but I think that would still be a long shot.

If it was pumping in air bubbles, then the OMP was working, there was just a leak some where. Atleast thats how it sounds to me but I never looked at your motor or OMP at the time.

Hellkat

Ultra-Low Flow Pump utilizes external gear technology.

May 11, 2004 - Compact micro annular gear pump minimizes pulsations for smooth, constant flow. It helps conserve valuable liquids such as flavorings, reagents, solvents, inks, dyes, and cleaning agents. For maximum dosage accuracy, rotors provide tight flow rate control, even at differential pressures to 1,160 psi. They allow pump to dispense volumes down to 0.5 µl and handle flow rates from 0.3–288 ml/min with accuracies within ±1%.
Taken from a company who manufactures hydraulic gear pumps.
Example of extremely low flow, high pressure pumps.

Hook up a psi gauge to output of an omp line, then rev all the way past 3000 rpm. then tell us what you get.

RETed

For the record, it was a Haltech E11 datalogging in realtime @ 200Hz.
Sure, there are variations, but for the most part all the fittings were within 1 to 2psi of each other.
Negating all the weird fluctuations due to intake dynamics, it's close enough.


I invented fluid dynamics and thermodynamics!
muHAUHauAUHAhauhUHAHUAHUAHUHUAHUAuhA


-Ted

toplessFC3Sman

iTrader: (1)

1 to 2 psi is more than enough to get a pretty large amount of air moving, and even if you're running 5.5 lbs of boost (S4 stock), 2 psi is 10% of that, so i'd say its substantial, not close enough.

RETed

Car was running around 10psi to 12psi of boost.


-Ted

RotaMan99

So I did some testing on the OMP but I was not able to do all of what I wanted to do.

What I did do was block all but one output of the OMP and hook an air pressure gauge up to it, since the air in the small amount of clear hose I was using would have to be compressed, the gauge should show a reading.

So I started spinning the pump and to my surprise, the pump would not even syphon the oil out of the resi. The pump will only pump while spinning in one direction so I thought I may have been spinning it backwards so I went the other direction and found I was right before.

I then removed everything including the pressure gauge and started to spin the omp and sure enough, it started to syphon the oil out of the resivoir. I blocked the holes and added the pressure gauge again and the fluid would not move at all and would actually at time get pushed backwards.

The test I wanted to do was hook up 4 old injector lines to the omp and install the other ends onto a manifold with one output which would be hooked to a pressure gauge, unfortunatly I didn't have any spare lines, I though I did, I figure this would be a better test.

Since I couldn't get the OMP to build any sort of pressure at all, or even get it to syphon with restriction, I say the "high pressure' portion of the OMP is busted.

RotaMan99

My post actually went through?

Another test post few hours later

toplessFC3Sman

iTrader: (1)

hmm... good to know