Krank Vent -- worth it
Melting Slicks
Joined: Mar 2002
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From: Tx
Originally Posted by diynoob
Of course the valves won't draw vacuum... neither will the intake manifold to be precise... what I was trying to get across is I didn't know the valves would allow that much vacuum to be created in the crankcase.What kind of funky sounds did you hear on decel?
The sound was some type of squeek. My guess was air going in the front seal, but it was impossible to track down since it would only happen on pretty heavy decel. I figured that much vacuum was not a good thing.
Thread Starter
Supporting Vendor
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From: http://www.mphparts.com 800-364-1975
Hrmmm... Quick, how are you running your KV? Are you still using the OEM PCV valve behind the KV? I prefer to run the KV w/o the OEM PCV valve since I think that will work most efficiently, but I could see that drawing lots of vacuum quickly and also potentially leading to other air metering issues since it's behind the MAF. This will save me some experimentation time, thanks for the response 
Bill -- no fair, you'll get to play with yours before I can play with mine
Seriously though, I am impressed -- I'm not sure what's on the inside of the Krank Vent (they say aerospace technology...) but somehow they have overcome the simple check valve designs with flappers or *****/springs. Props out to small companies like that who innovate and bring cool stuff to market.
Bill -- no fair, you'll get to play with yours before I can play with mine
Seriously though, I am impressed -- I'm not sure what's on the inside of the Krank Vent (they say aerospace technology...) but somehow they have overcome the simple check valve designs with flappers or *****/springs. Props out to small companies like that who innovate and bring cool stuff to market.
Team Owner
Joined: Mar 2003
Posts: 96,496
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St. Jude Donor '03 through '17
I've been running one on my Harley for years. With a 14.1 C/R on the bike it works like a charm, the other option was to put relief valves in the head which I didn't want to entertain.
Probably the best $100.00 mod you've spent on the car, Tony.
Probably the best $100.00 mod you've spent on the car, Tony.
Drifting
Joined: Aug 2005
Posts: 1,314
Likes: 3
From: Simi Valley CA
The krant vents are great systems. Running 35 psi on my "little" 4 cyl. with no problems.
Ted is a great guy also.
It's the yellow car about half way down....
http://www.et-performance.com/gallery.html
You can also pick up a KV at www.kdmperformance.com
Tell Kelly that Ivan sent you.
Ted is a great guy also.
It's the yellow car about half way down....
http://www.et-performance.com/gallery.html
You can also pick up a KV at www.kdmperformance.com
Tell Kelly that Ivan sent you.
Last edited by Yellow03Z06; Nov 28, 2006 at 01:46 PM.
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
Originally Posted by DRK-SYD
Will using the KV eliminate the need for a breather and or catch can?
Thanks
Thanks
I haven't even heard of a Krank Vent before. I always assumed that vacuum was good and boost was bad, insofar as engine longevity is concerned. Now I hear about this and I'm all confused. I already have a breather and I'm not sure if my vaccuum line from the valve cover to the throttle body is capped. I am looking to add a catch can, alky setup and high perf. fuel pump and now I hear about some check valve. Where does it all end
I guess a ported oil pump and dual roller chain is all that would be left to do before a forged motor becomes necessary.
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From: http://www.mphparts.com 800-364-1975
Originally Posted by DRK-SYD
Will using the KV eliminate the need for a breather and or catch can?
Thanks
Thanks
The reason for the breather is to ensure that crankcase pressure doesn't build up. Crankcase pressure can lead to blown dipsticks, blown main seals, and other nasty issues. An unfortunate side effect of the breather is that you get little to no vacuum in the crankcase, which can lead to part throttle blowby (not as good ring seal) and some decreased performance.
With the KV, you can build crankcase vacuum and avoid crankcase pressure. Unlike a breather which just allows air to always pass, the checkvalves in the KV only allow air to pass in one direction (per valve). So the way you hook them both up allows vacuum to be built providing better ring seal, and vents crankcase pressure if it ever builds up (rather than venting all the time).
I am going to run a catch can on the KV valve between the intake manifold and the PCV nipple on the valley cover and just vent the KV valve on the valve cover to a small breather. Eliminating the breather entirely should be OK since air will only come out and it won't allow contamination into the valve cover, but I also don't want oil spurting out of the line coming from the KV unrestrained.
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Le Mans Master
Joined: Oct 2005
Posts: 7,088
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From: Metro Detroit Michigan
Are you concerned about running maybe 16 inches of vacuum under cruise or decel? Are the crank seals designed for this?
What about losing the vacuum after several seconds of boost (no vacuum source), when you'd want it most for ring seal?
What about losing the vacuum after several seconds of boost (no vacuum source), when you'd want it most for ring seal?
Safety Car
Joined: Apr 2004
Posts: 3,932
Likes: 8
From: Hayward California
Originally Posted by DRK-SYD
Will using the KV eliminate the need for a breather and or catch can?
Thanks
Thanks
The one thing this wouldn't totally eliminate are the fumes bled from the crankcase from getting into the cabin... which, would have been needed relocating in the first place to get eliminated.
Arnel
Racer
Joined: Jun 2004
Posts: 265
Likes: 0
From: malibu ca
Originally Posted by DRK-SYD
Will using the KV eliminate the need for a breather and or catch can?
Thanks
Thanks
With a KV setup, you don't want a breather, you want the engine sealed up, so it will hold vacuum. I guess you could put a catch can between the valley cover outlet and the KV check valve to catch vapors, but how much air moves through the check valve once vacuum is created? My guess, and its only a guess, is that only minimal amounts of oil vapor can pass through the throttle body and be ingested into the motor with the KV system.
Last edited by Zrod; Nov 28, 2006 at 10:37 PM.
Pro
Joined: Apr 2001
Posts: 589
Likes: 0
From: Torrance CA
Originally Posted by diynoob
First, I'm not an expert and I'm just speaking from personal experience. I may be off base. If so I will happily accept correction
The reason for the breather is to ensure that crankcase pressure doesn't build up. Crankcase pressure can lead to blown dipsticks, blown main seals, and other nasty issues. An unfortunate side effect of the breather is that you get little to no vacuum in the crankcase, which can lead to part throttle blowby (not as good ring seal) and some decreased performance.
With the KV, you can build crankcase vacuum and avoid crankcase pressure. Unlike a breather which just allows air to always pass, the checkvalves in the KV only allow air to pass in one direction (per valve). So the way you hook them both up allows vacuum to be built providing better ring seal, and vents crankcase pressure if it ever builds up (rather than venting all the time).
I am going to run a catch can on the KV valve between the intake manifold and the PCV nipple on the valley cover and just vent the KV valve on the valve cover to a small breather. Eliminating the breather entirely should be OK since air will only come out and it won't allow contamination into the valve cover, but I also don't want oil spurting out of the line coming from the KV unrestrained.
The reason for the breather is to ensure that crankcase pressure doesn't build up. Crankcase pressure can lead to blown dipsticks, blown main seals, and other nasty issues. An unfortunate side effect of the breather is that you get little to no vacuum in the crankcase, which can lead to part throttle blowby (not as good ring seal) and some decreased performance.
With the KV, you can build crankcase vacuum and avoid crankcase pressure. Unlike a breather which just allows air to always pass, the checkvalves in the KV only allow air to pass in one direction (per valve). So the way you hook them both up allows vacuum to be built providing better ring seal, and vents crankcase pressure if it ever builds up (rather than venting all the time).
I am going to run a catch can on the KV valve between the intake manifold and the PCV nipple on the valley cover and just vent the KV valve on the valve cover to a small breather. Eliminating the breather entirely should be OK since air will only come out and it won't allow contamination into the valve cover, but I also don't want oil spurting out of the line coming from the KV unrestrained.
Safety Car
Joined: Aug 2000
Posts: 4,537
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From: St. Joseph MO
Cruise-In III Veteran
Cruise-In IV Veteran
Originally Posted by hpcubed
Don't you want a small amount of fresh air coming into the valve cover as you pull vacuum through the intake via the valley cover?
Melting Slicks
Joined: Mar 2002
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From: Tx
Originally Posted by hpcubed
Don't you want a small amount of fresh air coming into the valve cover as you pull vacuum through the intake via the valley cover?
There is no perfect answer, but I think a little bit of fresh air is a good thing.
Thread Starter
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From: http://www.mphparts.com 800-364-1975
Originally Posted by QuickSilver2002
Yes, some fresh air helps circulate the system and take acid forming moisture out of the oil.
There is no perfect answer, but I think a little bit of fresh air is a good thing.
There is no perfect answer, but I think a little bit of fresh air is a good thing.
Melting Slicks
Joined: Mar 2002
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From: Tx
You can get a simple restrictor valve and ajust it to allow x amout of air in (available at any place that sells air tools). This will obviously change with engine load.. but you can set a specific vacuum on the crankcase at idle this way.
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From: http://www.mphparts.com 800-364-1975
Originally Posted by QuickSilver2002
You can get a simple restrictor valve and ajust it to allow x amout of air in (available at any place that sells air tools). This will obviously change with engine load.. but you can set a specific vacuum on the crankcase at idle this way.
When you logged crankcase pressure on your car did you see anything alarming in the crankcase at WOT? I was also concerned that perhaps the KV would not flow enough out of the case just because I don't really know what level of blowby is typical and how difficult it is to move it out of the motor.At one point I was considering getting a small wastegate for the valve cover since they are a known quantity -- a simple, high flow valve that opens at a boost pressure you define based on which spring you put in the housing. But it sounds like maybe, unless the motor is really unhealthy, the little KV does the job.
Melting Slicks
Joined: Mar 2002
Posts: 2,931
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From: Tx
No issues at all, atmospheric pressure at most. I actually have both of the valves doing the same thing on mine and one is pretty large. I used the old mcMaster checkvalve in place of the PCV valve.
Le Mans Master
Joined: Nov 2000
Posts: 7,391
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From: Chandler AZ
UPDATE:
DAYUMN that Krank Vent **** works! Too good! Gonna have to throttle incoming air into crank case at idle... just like what Quick was saying. Installed my setup this morning on my 06 Silverado with a Maggie... see pics below. Took it for a test spin and during normal driving conditions under decel I would hear this belt squealing sound. Note I was also seeing 22-24 inches of vacuum on my gauge where as under same situations without this catch can Krank Vent setup I saw 17-20 inches of vacuum. As soon as I put my foot back into the throttle the sound went away. Pulled into my driveway and turned off the engine... the sound persisted for a good 3-4 seconds AFTER the engine was off. Started the engine back up, and after a few seconds this squealing sound came back. I struggled to pull my oil filler cap off and when I did it sounded like pulling the hose off of the brake booster X10! Holy Vacuum Batman!! Hope I didn't hurt my rear main seal because that is definitely where the sound was coming from. Got some more work to do here... Anyways thought you guys should know...
DAYUMN that Krank Vent **** works! Too good! Gonna have to throttle incoming air into crank case at idle... just like what Quick was saying. Installed my setup this morning on my 06 Silverado with a Maggie... see pics below. Took it for a test spin and during normal driving conditions under decel I would hear this belt squealing sound. Note I was also seeing 22-24 inches of vacuum on my gauge where as under same situations without this catch can Krank Vent setup I saw 17-20 inches of vacuum. As soon as I put my foot back into the throttle the sound went away. Pulled into my driveway and turned off the engine... the sound persisted for a good 3-4 seconds AFTER the engine was off. Started the engine back up, and after a few seconds this squealing sound came back. I struggled to pull my oil filler cap off and when I did it sounded like pulling the hose off of the brake booster X10! Holy Vacuum Batman!! Hope I didn't hurt my rear main seal because that is definitely where the sound was coming from. Got some more work to do here... Anyways thought you guys should know...
Thread Starter
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From: http://www.mphparts.com 800-364-1975
I just installed mine on the car last night and gave it a test drive. I saw the same thing you did Bill, except for instead of getting a noise, I got a HUGE puff of smoke when I let off. It went away after 3-4 seconds of cruise. Something has to be done to modulate the vacuum somehow. Not sure what the right solution is but the car is not happy with that much vacuum in the crank case.
I'm still happy with the valve though, it opens easily and flows a ton of air. The overall system will need more than just a couple of KVs though.
I'm still happy with the valve though, it opens easily and flows a ton of air. The overall system will need more than just a couple of KVs though.