Boost leak test and trange results...

[dxbtune]

Originally Posted by Raceghost

Has any one thought simple...?

Any one ever felt the air that comes out of these power pumps that run on electricity vs. the ones that are in a big air tank. It looks the a little travel unit... I am no expert, and am not claiming to be, just read through the post, visualized, inspected, and have a theory...

That little air pump probably gets real hot. I would have to say that hot air rises. One, could a valve be open, and as the air goes through the blower side of the turbo, could it be warm enough to rise through the exhaust, or through the oil line, to bubble any where that is up. 2nd thing, its pressurized, which makes it move or travel that much faster, fill every ounce of open space, even if it is the minutest of cracks. Doesnt matter which end of the mattress the pump blows air, it all pressurizes the same. Oil may be thick, but oxygen or compressed air still rises through it. And if you think about a valve that only moves one way in circulating system, could this be a design flaw by Mitsu, and they actually reversed the valve so it opens up stream, instead of down stream...I would doubt this one.

Then I read this:


I would imagine that even with the ic pipe off, that it could still be something in this area. Just because the UICP is open, he still has it sealed, if you think about it, the butterfly on the other side to the intake, is sealed as well. A seal is a seal, either way, air still travels the same way, and I would imagine that you answered the question with this idea. Good job dude. So I second your theory, and would bet by doing a TDC, or whatever closes the valves the most, should help test this theory. Then if no leaky leaky, you have your anser.

Just my 2 cents here.

The air you get from tanks comes out cold because of the air going from a high pressure atmosphere to a low pressure atmosphere, that's an adiabatic process off topic but interesting enough to write...

I can understand your way of thinking with the air going into the hot side and into the head that way however, the hot side and cold side are def isolated from each other...

Im leaning towards it going through the oil feed or return line for some strange reason... check valve in there or something... dunno

[slvrr]

Firt you need to put the intercooler piping back together. Then put the motor at top dead centerand put your tester on the compressor housing in place of the intake. Its coming in through the head.

[Evoryder]

looks like you have air coming through the valve cover, exhaust side. Test properly through intake side of turbo block off mbc and pcv off intake manifold, you dont' want air under the valve cover. Also like others said make sure motor is set at tdc or 30degs after TDC that insures valves are closed.

[dxbtune]

I appreciate all the help on this however, it seems to me that the majority of people are set in their ways of boost leak testing...

Im doing my boost leak test in 2 stages

1st- the intercooler and piping
2nd- the system as a whole

I have created a closed system with the piping as shown in the picture, and there is no reason to get air in the valve cover unless there is a special system (check valve) or my turbo oil seal has blown...

I'm leaning towards the check valve because
A-no white smoke
B-no oil in piping
C-the air pressure im compressing WAY less than the oil pressure so logically if its a bust seal then oil will flow into the piping like a burst dam under idle or low boost conditions and i neither have A or B above going on...

now that i have clarified what im concerned about hopefully we can get past the TDC of the motor as thats totally isolated form what i am testing...

air is getting in there through the only oil/air contact and that would be either the oil inlet or outlet to cool the turbo...

I was told that big turbo kits come with a different bolt going to the head and a nozzle in it or something and perhaos they put back the original one...

going to investigate...

[INEVOIX]

I'm new to EVO's but far from new to turbo DSM's.

If you're determined to do your "2 stage" boost leak test, the obvious thing to do next it to eliminate the turbo from the equation. Build another tester and test just the piping and intercooler.

I would lay 10 to 1 the air is getting into the line through the turbo's seal. This does not mean it's bad though. My 50 trim would do the same thing but No oil would leak, etc. There were also tons of others on the DSM forums that had the same exact thing happen to them.

If memory serves me correct, the theory at the time was once the car was running, no air would make it past the seals since the oil pressure was higher than the typical boost being ran. But that was just a theory everyone at the time was tossing around.

Like I said, to narrow it down to the turbo, eliminate it from the equation all together and test again. If you're not getting any oil into the piping, I wouldn't worry much about it. My 50 trim ran years like this and performed extremely well.

Good luck

[Fast_Freddie]

Tom when i boost checked my car it did the same thing... although I do have a catch can installed... Just connect a hose to the valve cover breather port and plug it with a bolt, and continue the test, also you may want to set the engine to top dead center as all valves will be closed then. It is just air being forced into an open valve. How much are you pressurizing the system to? Alos did you get those parts yet... please tell me yes!

[dxbtune]

Originally Posted by INEVOIX

I would lay 10 to 1 the air is getting into the line through the turbo's seal. This does not mean it's bad though. My 50 trim would do the same thing but No oil would leak, etc. There were also tons of others on the DSM forums that had the same exact thing happen to them.

If memory serves me correct, the theory at the time was once the car was running, no air would make it past the seals since the oil pressure was higher than the typical boost being ran. But that was just a theory everyone at the time was tossing around.

Ok this is some sense of comfort...

I'm 100% sure the air is getting into the oil return line as I removed and plugged the oil inlet (top pic) and am still getting the same result...
the air is going through the return line to the sump 2nd pic (blue is the direction of flow)

With that done, I reconnected it and proceeded to check for oil deposits inside the turbo outlet... not a drop of oil! clean as a whistle as you can see in the below underside pic... this would rule out a torn badly damaged seal as it would gush out with the oil pressure.




I have come to the conclusion and reading from what INEVOIX has said it is quite possible that with the engine running it creates a seal due to oil pressure...

I'm not to pleased with the fact that i'm getting air shoved into my sump because i want the pump to suck in 'air free' oil to properly lubricate the system and not suck up gulps of air in the process (if it is indeed a leak or a faulty seal design)

Now ok, it would make sense to re-connect all the hoses and do the standard TDC boost leak test as it would all be sealed as a whole.. but the fact of the matter is that in that process the leak coming from the turbo oil return line would be camouflaged especially if everyone says to plug the catch tank line...

Air leaking past the valves and pressurizing inside the head cover could be easily mistaken with what i am experiencing right now...

I'm curious to know if someone who ripps these big turbo's apart could give some insight on the design of the oil seal if there a check valve incorporated in it or what

[dxbtune]

Originally Posted by Fast_Freddie

Just connect a hose to the valve cover breather port and plug it with a bolt, and continue the test, also you may want to set the engine to top dead center as all valves will be closed then. It is just air being forced into an open valve.

Hey Bud, im doing a 2 stage test not yet testing the intake manifold and vacuum lines for leaks..

I need to get over this first and understand why air is getting through to the sump then into the valve cover and its a one way leak with no oil getting into the turbo (or its totally normal and no one realized this before as its not common to do the boost leak in 2 stages)


The parts are in my office and i will pick them up and install the wide band after I go through my checklist (boost leaks,plugs etc) and ready for my race gas tune...

Thanks again for shipping them over bud...

[dxbtune]

Right, so someone with an hks 3037 or a bigger turbo setup please go do a 1st stage test like i did and see what gives...

Oh so i dont get flamed... 1st and 2nd stage test is just name for reference

Common now... don't you want to know if your rides doing the same

I bet it will turn out to be some design feature with the gt series twin cooled turbo's...

[crcain]

Attention Boost Leak "Gurus"

TDC has nothing to do with this guys issue as his UICP is blocked off!

ALSO! Putting any cylinder at TDC will guarantee that both intake and exhaust valves are open in one of the cylinders. Meaning not ideal for a bost leak test. Have you ever heard of valve overlap? Do you understand the 4-stroke combustion process? Apparently not.

[dxbtune]

bump

[TTP Engineering]

Get a real boost leak tester and hook up your UICP back to the manifold. You cannot flow sufficient volume of air through a tire valve stem. Get a quick disconnect with a valve and hook it to a real compressor and tank.

[dxbtune]

ten four

[R/TErnie]

Originally Posted by TTP Engineering

Get a real boost leak tester and hook up your UICP back to the manifold. You cannot flow sufficient volume of air through a tire valve stem. Get a quick disconnect with a valve and hook it to a real compressor and tank.

If you need that much flow to find a leak YOU'RE DOING IT WRONG.

OP, the reason why you're pressurizing your crankcase is because your seal on the compressor side of your shaft is being overpressured and is pushing air past the oil seal. As someone has already told you this.

You have a pressure differential across your oil seal and your oil pressure will be higher than your boost pressure... making a nice seal. However you have no oil pressure and you're putting 20psi of pressure against the seal.... thus it leaks.

To the people who haven't experienced this with the stock turbo... the turbo's have different shaft sealing designs.

Search for the "Wattard" engine thread on FSAE... good read.

[dxbtune]

^ thank you for clarifying that...
the car is all put back together and running smooth like a baby

Cheers