check valve not necessary - SRT Forums

betternyou · 04-28-2008, 09:40 AM

I was just perusing the agp section when i came across the check valve sticky.

AGP specifies using the 3/8" mcmaster-carr instead of the 1/4" valve.

I argued this to no avail a while back.

For what it's worth, I'm starting to wonder if their's really any need for a check valve if one's running 20ish or less psig.

The pcv valve, which in itself is a check valve, may leak a bit, but it shouldn't make a significant difference in boost level.

Plus, two check valves in line (pcv + aftermarket) can cause air flow issues.

It's also questionable whether a catch can is necessary.

Shouldn't cause issues, but only so much oil vapor flows thru the line, and most of it is harmlessly sucked thru the engine.

The oil that accumulates is on the output side of the ic, so it doesn't really do any harm.

Food for thought.

<edited for my_little_srt - didn't stop hitting enter but used capitalization which might help. thanks>

my_little_srt · 04-28-2008, 03:40 PM

why
do
you
keep
hitting
enter
after
every
sentence,
makes
it
hard
to
understand
what
your
saying

faceyournation · 04-28-2008, 05:42 PM

i never even bothered with a check valve either...

moparx12 · 04-28-2008, 09:16 PM

i just intalled a catchcan without a check valve and in a week and a half of driving everyday i havn't collected anything. could this mean the pcv is no good? or am i just lucky and dont get much blowby?

kagekun · 04-29-2008, 10:37 PM

I guess you dont NEED a check valve...but why would you want to trust the plastic pcv with holding boost if you dont have to, guess worse come to worse, its just another boost leak fix

**lilmike0450** · 04-29-2008, 10:39 PM

If you like boost leaks go ahead.

Big D's Blue 04 · 04-29-2008, 10:45 PM

They are definitely worth it! As I have tried to explain many times in the past, under boost the boost pressure will go back into the pcv track and into the valve cover since the factor PCV valve is a joke! this added crank case pressure will cause oil blow by from the fresh air line on the intake and its not good on the rest of the internal parts to have built up pressure like this.

Check Valve = Good!! If you need to know how to get one RFR sells them at a very nice price. Ramsey Family Racing

**lilmike0450** · 04-29-2008, 10:48 PM

yuppers...

Carentan'44 · 04-29-2008, 10:59 PM

A checkvalve isn't to stop a boost leak. A check valve is to keep pressure out of your crankcase which is bad, so put a damn $15 check valve on there.

Epic · 04-30-2008, 12:47 AM

Quote: Originally Posted by Big D's Blue 04

They are definitely worth it! As I have tried to explain many times in the past, under boost the boost pressure will go back into the pcv track and into the valve cover since the factor PCV valve is a joke! this added crank case pressure will cause oil blow by from the fresh air line on the intake and its not good on the rest of the internal parts to have built up pressure like this.

Check Valve = Good!! If you need to know how to get one RFR sells them at a very nice price. Ramsey Family Racing

Thats the check valve i have. i bough it off of ebay the only complaint i have is that the shipping took forever!

kagekun · 04-30-2008, 11:08 AM

Quote: Originally Posted by Carentan'44

A checkvalve isn't to stop a boost leak. A check valve is to keep pressure out of your crankcase which is bad, so put a damn $15 check valve on there.

The stock pcv valve is a pos, it leaks under boost. Weather that is leaks boost into the crankcase or leaks it atmo...still a leak you do not want

sti_zee · 05-01-2008, 12:48 PM

the stock pcv leaks very little (tested it myself)

certainly not a significant boost leak.

**Philth** · 05-01-2008, 12:52 PM

FWIW, I had a PTP check valve set up. Was having lots of blow by, as noticed in the coupler for my intake just before the turbo. Took the check valve out, cleaned the coupler, and it's tons cleaner after driving hard/going to the track.

Carentan'44 · 05-01-2008, 02:26 PM

Quote: Originally Posted by sti_zee

the stock pcv leaks very little (tested it myself)

certainly not a significant boost leak.

SRT-4s come with a factory boost leak, the point of a checkvalve isn't just to stop a boost leak. Fact is the PCV valve is a POS and you don't want any pressure in your crankcase, infact you want vacuum in there so put a checkvalve on.

BTW my pcv valve leaked 100%

sti_zee · 05-02-2008, 08:06 AM

Quote: Originally Posted by Carentan'44

SRT-4s come with a factory boost leak, the point of a checkvalve isn't just to stop a boost leak. Fact is the PCV valve is a POS and you don't want any pressure in your crankcase, infact you want vacuum in there so put a checkvalve on.

BTW my pcv valve leaked 100%

If your check valve leaked 100%, you'd get almost no boost.

Solution - buy a new one.

Also, you'll get better 'ventilation' from a slightly leaking pcv valve than a tightly shut check valve.

goes out the other side of the cam cover. no 'pressure.'