Measuring crank case pressure

hardparker

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I've been putting some time into researching canbus sensor integration for the N55 DME. Mostly looking at what the EcuTek guys are bringing over from related successes on other platforms. It sounds like MHD is nearing those capabilities and some new features from BM3 are building the basis for canbus integration, too.

My applications would mostly be pressure and temperature sensors initially. True EGT, exhaust back pressure, compressor outlet TMAP, N55 LPFP rail sensor, etc. with canbus integration to the DME with native logging via whatever tuning platform that supports it. Ideally, with DME logic integration, replacing the modeled lookup tables for things like EGT and intercooler efficiency with actual live data. That's probably ambitious, but it would be nice to have.

Here are some related resources and products that would work.





 

doublespaces

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The 10an with 1/8 npt sensor port is here, I've got it hooked up to the intake pipe with a cap on it so I can measure the intake pipe vacuum under boost, if any
IMG_20200329_105832.jpgIMG_20200329_110236.jpgIMG_20200329_110257.jpg

Then after I'll move it to the crank case and measure, then connect the hose and measure again. Hopefully the resolution is fine enough to register some values.
 
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doublespaces

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In the intake under boost, you’ll see positive pressure.
I would sure hope not. Unless you are being facetious and referring to the intake manifold which would be obvious.

In the latter case I have two or three 10AN ports coming from the crank case. Tell me how many I need to use given my ring condition. Ideally I'd like to use just one if possible if it wouldn't create unnecessary pressure.
 

The Convert

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I would sure hope not. Unless you are being facetious and referring to the intake manifold which would be obvious.

In the latter case I have two or three 10AN ports coming from the crank case. Tell me how many I need to use given my ring condition. Ideally I'd like to use just one if possible if it wouldn't create unnecessary pressure.
I am saying that is you put the sensor in your manifold or charge pipe to measure vacuum under boost, you’re not going to see any. Maybe I misunderstood what you are planning on doing. If you’re trying to see max vacuum you’ll ever see in the cp/manifold, just let the car idle with the sensor plumbed. That’ll tell you how much vacuum it’ll apply to the crank case. Then measure what you’re Seeing in the crankcase via the oil cap.
 

doublespaces

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I am saying that is you put the sensor in your manifold or charge pipe to measure vacuum under boost, you’re not going to see any. Maybe I misunderstood what you are planning on doing. If you’re trying to see max vacuum you’ll ever see in the cp/manifold, just let the car idle with the sensor plumbed. That’ll tell you how much vacuum it’ll apply to the crank case. Then measure what you’re Seeing in the crankcase via the oil cap.

Look at my photo, the sensor is on the intake pipe, not the charge pipe.

With a decent filter I expect zero or little vacuum reading here, but some people think it's more than this at boost levels so I'm checking.

I think maybe you should read the text I've typed because you're talking to nobody with that info.
 
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Torgus

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Look at my photo, the sensor is on the intake pipe, not the charge pipe.

With a decent filter I expect zero or little vacuum reading here, but some people think it's more than this at boost levels so I'm checking.

I think maybe you should read the text I've typed because you're talking to nobody with that info.

What value is putting the sensor in the intake path? Like what meaningful data do you expect to collect? Unless the filter is a restriction of course, even then...
 

Panzerfaust

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He wants to see if there's any meaningful vacuum pre-turbo while in boost or if it's still effectively the same as just going VTA on the high side. His whole goal is to simplify the PCV system, so I'd imagine if he finds useful vacuum there he'd have that be his (sole?) crank case vent. Worst case scenario is he confirms what he already suspects. Science :)
 
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The Convert

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Look at my photo, the sensor is on the intake pipe, not the charge pipe.

With a decent filter I expect zero or little vacuum reading here, but some people think it's more than this at boost levels so I'm checking.

I think maybe you should read the text I've typed because you're talking to nobody with that info.
I did not look at the photos and “intake pipe” evoked the cp in my head. So, as stated when I said, “maybe I misunderstood what you are saying,” I did in fact misunderstand what you were saying. Not sure what the snippy bit at the end is supposed to solve, but you do you.
 
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doublespaces

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I did not look at the photos and “intake pipe” evoked the cp in my head. So, as stated when I said, “maybe I misunderstood what you are saying,” I did in fact misunderstand what you were saying. Not sure what the snippy bit at the end is supposed to solve, but you do you.

Probably because of the eyeroll comment you left, providing that oh so valuable information that my charge pipe will contain positive pressures. If you mean that as a genuine comment then that is insulting at best.
 

The Convert

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Probably because of the eyeroll comment you left, providing that oh so valuable information that my charge pipe will contain positive pressures. If you mean that as a genuine comment then that is insulting at best.
It was a genuine comment. How you choose to take a comment that was positive and informative, if I had not misread/misunderstood your comment, is entirely up to you. The fact that you chose to see it negatively says a lot.
 

doublespaces

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It was a genuine comment. How you choose to take a comment that was positive and informative, if I had not misread/misunderstood your comment, is entirely up to you. The fact that you chose to see it negatively says a lot.

Yes, it says you think I don't know the charge pipe has positive pressure in it. C'mon now. If anything you're being a smart ass and I can at least buy that. Telling someone there's boost in the boost pipe, that's ground breaking information.
 

The Convert

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Yes, it says you think I don't know the charge pipe has positive pressure in it. C'mon now. If anything you're being a smart ass and I can at least buy that. Telling someone there's boost in the boost pipe, that's ground breaking information.
I never put a temporary brain fart past anyone, and I don’t assume anyone knows anything. Let it go.
 

doublespaces

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I never put a temporary brain fart past anyone, and I don’t assume anyone knows anything. Let it go.

Sometimes when I wake up in the morning I say stupid shit but at least I know it's stupid shit.

In the intake under boost, you’ll see positive pressure.

This is 100% a troll comment or just plain old sarcasm, I can accept that. Trying to say otherwise is 'stupid shit'.
 

doublespaces

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What value is putting the sensor in the intake path? Like what meaningful data do you expect to collect? Unless the filter is a restriction of course, even then...

It's been said a benefit of routing to the intake cone for single turbo people is the 'vacuum' that is being pulled when the compressor is boosting. Obviously this is filter dependent but I'd like to see if there is any truth to it.

Secondly I'm going to measure crank case pressure when it simply is vta on a single 10an exit. If there is a positive pressure I'll measure with two 10an exits or a third exit (8an). There is going to be a diminishing return at some point and I'd like to see where that is. And of course measuring when the supposed intake pipe is "sucking".

I'm pretty sure I explained that poorly originally so that is my fault.
 

The Convert

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Sometimes when I wake up in the morning I say stupid shit but at least I know it's stupid shit.



This is 100% a troll comment or just plain old sarcasm, I can accept that. Trying to say otherwise is 'stupid shit'.
How many times do I need to tell you it was a serious comment. You believe whatever the fuck you want though. I’m done.
 

doublespaces

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He wants to see if there's any meaningful vacuum pre-turbo while in boost or if it's still effectively the same as just going VTA on the high side. His whole goal is to simplify the PCV system, so I'd imagine if he finds useful vacuum there he'd have that be his (sole?) crank case vent. Worst case scenario is he confirms what he already suspects. Science :)

It is almost like you read the first post.

I want to see what kind of actual restrictions these catch cans have. I want to see if there is benefit to using more than one venting port. I want to see if the intake pipe is actually aiding in this process. Hopefully it is clear now.
 
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