Crank Case Evacuation Using Stock Baffle

[SOADweskey]

I didn't want to clutter up 99gst_racer's thread about his really nice setup so i made this one to show another way to increase ventilation size.

Currently I have my system set up to exhaust scavenge in the first bend of my down pipe which is 2.5"( This did not work so it goes back into the intake). I still have not had the opportunity to hook up a second MAP sensor to log the vacuum or pressure in the crank case yet. I'm hoping that will happen in the next week or two after I finish school and get my HX-35 installed.

Here is the start of me laying out what part of the valve cover I wanted to remove.

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Here is the section cut out and prepped for welding. I used a Dremel with a cut off wheel to remove the section.

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Here are some shots of the aluminum block I made to fit in the vacant section. The only thing not shown in these pictures is that I was able to remove more material from the section of the block that sits inside the valve cover to improve airflow to the vent. I made the decision of how much to remove once I was able to set the block in place in the valve cover and see how much of the block would be inside the cover.

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This is a comparison of the new vent sitting next to the stock vent.

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Here are some shots of the valve cover finished and the catch can.
The catch can is a Saikou Michi Stage 2 catch can Product Page

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[dsm-onster]

NICE!

 

[black_gst]

looks good wes cant wait to see some logged values

and just to state the obvious the check valve is mounted to the DP correct?

 

[99gst_racer]

Looks good, man.

I can wait to see some test numbers with it. I rigged up a fitting about 4 years ago to test the exhaust for a vacuum. It threaded into an O2 sensor bung and had a vacuum nipple on the other side. I never got around to testing with it though.

 

[SOADweskey]

looks good wes cant wait to see some logged values

and just to state the obvious the check valve is mounted to the DP correct?

Yes in the last picture the part with the hex and the larger circular area that contains the valve is a one way check valve so that the exhaust can not go into the crank case.

It threaded into an O2 sensor bung and had a vacuum nipple on the other side. I never got around to testing with it though.

That sounds like a good plan as I have an unused O2 bung I can use for that.

 

[99gst_racer]

That sounds like a good plan as I have an unused O2 bung I can use for that.

If you think you can put it to use, PM me your address. I'm not doing anything with it.

 

[_1466_]

Looks great!

 

[97gst_spyder]

Why do you want more vacuum for the catch can?

 

[1995gsx20g]

Why do you want more vacuum for the catch can?

to remove more crankcase vapors

 

[RiGs2G]

Good job Wes, I like this idea better then the intake getting all oiled up. Do you still have the PCV valve working? I have a simple vaccum gauge that you could borrow, if you need it to test this thing out.

 

[Calan]

Just out of curiosity, why do you still have the PCV in place with this setup?

It's not really doing anything at this point, other than providing a small amount of vacuum to the CC under low-load driving (and a path for oil to reach the IM). Since there is no longer a source of fresh air for ventilation, it really isn't needed with your pressure relief setup.

 

[SOADweskey]

Good job Wes, I like this idea better then the intake getting all oiled up. Do you still have the PCV valve working? I have a simple vaccum gauge that you could borrow, if you need it to test this thing out.

Thanks Mike, I have access to a cheapy boost/vacuum gauge that I plan to use to test it. 99gst_racer is sending me an adapter for an O2 bung to measure the vacuum in the exhaust and when I do that I am also going to set up an oil cap with a fitting to measure the inside of the crankcase. And yes my PCV is working.

Just out of curiosity, why do you still have the PCV in place with this setup?

It's not really doing anything at this point, other than providing a small amount of vacuum to the CC under low-load driving (and a path for oil to reach the IM). Since there is no longer a source of fresh air for ventilation, it really isn't needed with your pressure relief setup.

Part of it is laziness and leaving it in was easier than blocking the holes off. Another part is I figured the more ventilation the better and if some oil finds it's way into the intake manifold it really shouldn't matter to much.

 

[Calan]

And yes my PCV is working.

Well... not really.

In order for the PCV valve to work as designed, there needs to be a supply of fresh air flowing into the CC during off-boost conditions, to replenish the oil/hydrocarbon vapor that the PCV draws out. With your can inlet tied to a check valve and the exhaust, that source of fresh air has been removed. So very little if anything is flowing through the crankcase to ventilate it. (Sort of like putting the palm of your hand over the end of a vacuum cleaner hose). You will still get a small amount of flow through the PCV valve, but it won't be much.

Besides the differences in available vacuum (whatever that is; looking forward to your testing)... maintaining ventilation would be the main reason for running the vac source off the turbo inlet vs. the exhaust. But if you are going for max pressure relief and not worried about oil contamination, then it's not really an issue.

 

[Imback]

Wouldn't a regular AN fitting be the same. Instead of having to cut that square out and make that block?

 

[SOADweskey]

If you do the regular AN fitting either thread in or weld on it usually requires the removal of the baffle as it is to close to the top of the valve cover to accommodate such a large fitting. I have seen the weld on used successfully but as the larger hole was drilled the drill bit scraped and pushed on the baffle. It worked but was very close plus once it was drilled it was hard to remove all the shavings.

I like my method (which I stole from Jack's Transmissions) as it guarantees no damage to the baffle and it makes it much easier to clean up inside the baffle.

 

[SOADweskey]

I have not fully tested it yet but the initial results of the exhaust scavenging are not promising. Tonight I found time to modify an oil fill cap with a cheap sunpro boost gauge. I didn't have a chance to do a full pull as I just was checking on my way home but when boosting from 11-15psi I had 5psi of pressure in the crank case.

I will be switching the vent line from exhaust scavenging to the intake on Friday and running a comparison to see if it is better.

I also got the fitting from Paul to put into my extra O2 bung to actually see if there is sufficient vacuum in the exhaust so I will try to give it a shot measuring that but I think total results in the crank case are the most important.

I switched over the line coming out of the catch can to the intake today. I'm only tuned enough to run like 17psi right now. (Tuning the car at RRE this weekend) But at that 17psi I had no pressure in the crankcase. It may have had a bit of vacuum but it is hard to tell as I used a cheap Sunpro Boost gauge that doesn't have much resolution.

So basically I found that the exhaust scavenging is not effective on a DSM. At least not on mine which is a 2.3l with an HX35.

 

[Scott McIntyre]

I have the Moroso parts but haven't welded it to the downpipe yet...

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I'd be interested in knowing the full specs on your exhaust... 2.5" downpipe -> cat? -> 3" catback? -> straight-thru muffler?

It would also be interesting to know if you experienced enough vacuum from the exhaust scavenging to actually open the check valve at full boost, and to learn the vacuum reading from the exhaust scavenging line alone (i.e. not oil cap).

 

[SOADweskey]

Here are my exhaust specifications. RRE downpipe (2.5" first bend to 3" flex and 3" from there back), the fitting is welded into the 2.5" first section of the pipe, 3" high flow cat, 3" Espelier Cat Back (80mm if you want to get technical).

I still have not hooked up the fitting to just measure the vacuum in the exhaust. I will be tuning the car this Sunday and if all goes well I run that test once the car is in running shape to really hit some boost.

If I have time I also have a test pipe so I could see if removing the cat will make any difference.

 

[Scott McIntyre]

That would be great!

I have a 2.5" O2 housing, 3" downpipe, no cat, and 3" cat-back with a straight-thru muffler, so I'm guessing back-pressure would be less (no cat). I just haven't had the opportunity to weld the pipe nipple on the downpipe yet (read: lazy).

 

[SOADweskey]

Testing is being delayed by that fact that I had a piston stop being round in shape on the dyno. I'm currently tearing down the motor so a new set of pistons can be installed.

 

[Lofty]

Can anyone explain why the valve cover breather is good routed to the exhaust? I no get it

 

[99gst_racer]

Can anyone explain why the valve cover breather is good routed to the exhaust? I no get it

If the exhaust gas is traveling fast enough, it will scavenge and pull on the crankcase to evacuate it. Works great on older V8 muscle cars. It's good because the engine doesn't re-consume the filthy crankcase air/oil/fuel/water that you're pulling out.

 

[Calan]

Testing is being delayed by that fact that I had a piston stop being round in shape on the dyno. I'm currently tearing down the motor so a new set of pistons can be installed.

That sucks man. What type of pistons and what was the cause?

<<< paranoid 2.3L stroker dude.

 

[SOADweskey]

The pistons are Wiseco 6-bolt stroker pistons, non HD. It was not the pistons fault though. I think I damaged the ring landings a few months ago from one of the first pulls after the engine was broken in. I still had my old timing map from the 2.0 loaded in (16* advance by 6000 RPM) and even with the 5031 on straight wastegate it made about 18psi of boost. After this the compression was about 140psi in cylinders 1 and 2 and 165 in 3 and 4. Once I tuned the car on a dyno after that I found that with 91 in the tank the car only likes about 4* of timing at 18psi.

This time it was knocking like crazy from the get go we were at only 15psi and 5* of timing with e85 so I figured it must have been phantom knock so I turned off the knock sensor. That would be when the piston in cylinder 2 completely let go.

 

[gsxeclipse97]

I have this same problem but my engine is not all that old.. I replaced the pcv also where do you find this gasket that. Is it possible that the baffle is clogged and causing the pressure to build up?