[335dsleeper]

Originally Posted by TDIwyse

Found some threads on the exhaust evac systems in diesel trucks. Seems like a mixed bag.

http://www.dieseltruckresource.com/f...cuation-47609/

http://www.dieseltruckresource.com/f...-system-44803/

Something interesting to me was some were adding one or more sources for fresh air to enter into the crankcase to replace the fumes as they get pulled out (hopefully, although some who tried exhaust evac got pressure so they abandoned the approach). Also, there was concern regarding too much vacuum as well as too much pressure.

From the looking I've done, it doesn't seem like the M57 has a path of fresh/filtered air to replace what is pulled out the crankcase. Or am I just not seeing it?

Not apples to apples but, no mention of exhaust fires, which is good. I'm surprised some saw too much vacuum, especially in a streetable exhaust. I'm not sure how exhaust size, engine size or multiple turbos effect the vacuum level.

As for the pressurizing of the crankcase, I just dont see how that is possible when using a check valve. I mean, it's sole purpose is to eliminate the possibilty of exhaust pressure making its way back to the engine. I have seen quite a few threads/ videos where guys arent using them, which I don't understand why you wouldn't. A check valve is required. A properly installed check valve should completely remove the possibility of pressurization in the crank case.

Not sure if the m57 requires a fresh air supply. I'm sure you'd be the one to test it.

As you can see by reading this thread, there are a lot of opinions and myths that are getting questioned as there appear to be people running this evac successfully in many different platforms including diesels. For a guy like you, that designed his own fuel controller, I'm pretty confident if you tested this, and identified "fresh air" being an issue that you'd quickly find a way around it.

These parts are required to actually run/ test this successfully.

Quality catch can with filter media
Quality oil resistant hose
Venturi adapter
Check valve like this

http://m.advanceautoparts.com/p/carq...-cv8/5012791-P

[335dsleeper]

Originally Posted by Nadir Point

Sure, but were I to explore something like that I'd certainly take a cautious, staged testing approach.

Never a good idea to let too much smoke out of your car.

Absolutely

[TDIwyse]

As a point of reference on what the OEM intake snorkel generates for crankcase vacuum ... I can directly measure it, which is what I was doing here to get MAF measurements beyond what the OEM MAF can read: http://www.e90post.com/forums/showthread.php?p=19151585

Looks to me that at >51 lb/min of airflow the vacuum is approaching 6 inHg on my setup.

[335dsleeper]

Originally Posted by TDIwyse

As a point of reference on what the OEM intake snorkel generates for crankcase vacuum ... I can directly measure it, which is what I was doing here to get MAF measurements beyond what the OEM MAF can read: http://www.e90post.com/forums/showthread.php?p=19151585

Looks to me that at >51 lb/min of airflow the vacuum is approaching 6 inHg on my setup.

I'm glad you mention the OEM CCV set up creates a vacuum, there was some confusion in a different thread regarding that fact. Thanks!

I'd love to see you do the testing, you obviously have the knowledge, ability, tools and clearly like to tinker... it would be awesome to see actual data.

I think 14-20inHg is ideal for power generation, but as discussed depends on many factors. I bet you could find the ideal vacuum for your set up, which would be awesome to see if you could gain a little power.

[TDIwyse]

Originally Posted by 335dsleeper

I'm glad you mention the OEM CCV set up creates a vacuum, there was some confusion in a different thread regarding that fact. Thanks!

I'd love to see you do the testing, you obviously have the knowledge, ability, tools and clearly like to tinker... it would be awesome to see actual data.

I think 14-20inHg is ideal for power generation, but as discussed depends on many factors. I bet you could find the ideal vacuum for your set up, which would be awesome to see if you could gain a little power.

I did take measurements, but didn't post them. The amount of vacuum I was able to get was very low. Not anywhere close to what the OEM setup generates.

There's a couple videos here of testing OEM crankcase vacuum with a small manometer under startup and very light acceleration: http://www.e90post.com/forums/showpo...&postcount=320

In that thread I caution about using a manometer, as I ended up sucking the fluid into the dipstick when just starting to get into the boost ... Did an oil change after that... and moved to a much taller manometer after that.

With the exhaust venturi setup I tried, there was never more than a few inches of water vacuum (or a couple tenths of an inHg ... the intake snorkel generates almost 6 inHg, so it's ~20-30 times more) on the manometer. That's not to say it's not possible to find a better implementation that will pull more vacuum than my initial attempt. But it didn't look promising to me, so I never continued looking into it.

This morning I also coated the inside of a metal pipe with a thin layer of motor oil and used a propane torch on it. It would catch and stay smoking for a bit after removing the flame, but no flame thrower output :-)

[335dsleeper]

How was the venturi installed?

[Nadir Point]

The ~17-to-1 compression ratio means there's always going to be positive pressure in a running diesel crankcase. The only question is where it goes, or how it escapes. Whether or not it comes out naturally and goes somewhere of it's own accord, or is helped along by a vacuum seems unimportant. Any way it evacuates adequately without building an "over"pressure condition is fine. I cannot imagine how any "under"pressure or excessive vacuum on the exit side could cause a problem. If there was some way to determine you "did" have that "under"pressure condition, the stock CCV where it it exits the top rear of the engine could be converted into a filtered intake, but I doubt it would matter or make any difference. In fact, it would act that way all by itself if it was simply disconnected. But I would probably want a better filter on it in that case.

[DWR]

Originally Posted by 335dsleeper

As for the pressurizing of the crankcase, I just dont see how that is possible when using a check valve. I mean, it's sole purpose is to eliminate the possibilty of exhaust pressure making its way back to the engine.

Let's talk about how a check valve works. It can only setup a pressure differential. The differential is equal to the check valve cracking pressure. If there is exhaust pressure trying to make its way into the crankcase, then the crankcase can build pressure up to exhaust pressure plus the cracking pressure.

[DWR]

Originally Posted by Nadir Point

The ~17-to-1 compression ratio means there's always going to be positive pressure in a running diesel crankcase.

It has very little to do with the compression ratio. It has very much to do with the seal of the piston rings and valve guides/seals. For the later, boost makes a difference.

[TDIwyse]

Originally Posted by 335dsleeper

How was the venturi installed?

Post 374 has a picture. It's using the hole where the DEF injector used to be installed (the ecotune downpipe had this vestigial connection and an opening into the flow of the exhaust).

I've also made a PVC test pipe and used the redneck flowbench (shop vac and manometer) and played with alternate shapes/angles for a venturi vacuum config ... that also didn't look very promising. Especially if you get much of restriction in the flow, which causes the venturi to actually create pressure instead of vacuum. This is one of the things on the diesel truck links I posted that happened to the guy who added twin turbo's to his config. The extra power and exhaust flow actually caused his exhaust venturi to start pressurizing the crankcase.

"Well I will chime in on this subject.

I originally installed a moroso exhaust- crankcase evacuation kit being brought up in 2001 and even wrote a thread on it in TDR. I believe it was called, "loose the pill bottle." And it didn't give me any problems until I got into the mid 500 hp range.

Wannadiesel, Twins did not cause the evacuation system to suck so hard that it sucked the tappet cover seals in. Just the opposite. The system actually starts to give some back pressure after about 1600 rpm. "

[Nadir Point]

I'm going to start by running my catchcan drain back to the old DEF injector port. If it gets any backpressure we'll just call it LP EGR.

Hey, at least my environmental friendliness factor is going back in the planet's protective direction - no more black spots in the parking spaces, right?

[WreckerX5d]

Gauging some interest and studies others have done. Is there any restrictions with the current headers our cars have? If there is a way for American Racing Headers to design some new ones, would anyone be interested? Johnny showed there's a few Euro guys have replaced theirs but I'm not 100% sure if they fit ours (I don't see why not though).

[gtp900]

Originally Posted by Wrecker335d

Gauging some interest and studies others have done. Is there any restrictions with the current headers our cars have? If there is a way for American Racing Headers to design some new ones, would anyone be interested? Johnny showed there's a few Euro guys have replaced theirs but I'm not 100% sure if they fit ours (I don't see why not though).

Was there any proven gains with this mod?

[Whitbread]

No point in changing the header unless you're building an all out drag car and going single turbo. There just isn't room to do anything better flowing and still fit all the oem components.

[335dsleeper]

There's likely little to be gained especially for the cost/ time spent.

Camshafts and headwork would be an area to look at if you're interested in making more power post hybrid turbos.

Originally Posted by Wrecker335d

Gauging some interest and studies others have done. Is there any restrictions with the current headers our cars have? If there is a way for American Racing Headers to design some new ones, would anyone be interested? Johnny showed there's a few Euro guys have replaced theirs but I'm not 100% sure if they fit ours (I don't see why not though).