Something interesting happened during my "racing-around" in the last few days. Let me describe in detail.

I was toying around with an Audi S6 at the toll, revving my engine to about 4-5k RPM... then finally when I let the clutch out completely and stepped on it in 1st gear... the engine continued to rev like the clutch was disconnected, and the car barely moved. I immediately pushed the clutch back in and out again, and everything was fine ever since. Right away, however, a smell of "eggs" penetrated the car. Oops, did I burn my ACT 2600 "heavy-duty street" clutch ?

Anyway about 1 minute later a biker tells me through the window that my car might be leaking oil because of grey smoke coming out of the exhaust. I immediately pull over in fear of an engine problem.

I have my friend rev the engine and anytime it goes over 3-4k RPM grey smoke comes pouring out of both exhausts. Damn! I call my shop and tell my man Narv the story. He says to check the oil, and to try driving it if it runs. The oil looks fine, no leaks anywhere, and I drive the car home with blinkers on going 45. My friend who followed me later said I was blowing small amounts of smoke the entire way to the shop.

So here's the interesting news... they checked the car all over, including the downpipes. Nothing. They ran a compression test on all cylinders... they are all in the steady 180's! (Normal). The car runs fine and the smoke has now disappeared.

I'm about to go pick the car up... now I'm really curious WTF it was. I almost thought it was related to the clutch assembly somehow but the shop assures me its not possible?

Anyone have any ideas ?

 

Dont know if you saw my post . But I had a problem with very thick smoke when recording a hard run with the Vortech .Although not related to yours...it confused the chit out of me what it was . Comp check was fine and hasnt done it since . We think it was oil coming out of the dip stick and dumping on the headers . Hope you find the problem

 

Gurgen will probably chime in here. He will have a suggestion for you.

--Steve

 

yup, he found a problem with the routing of the PCV that was causing some smoke. It was smoked for a while....and I guess it has since stopped.

 

Yeah, that was my first guess. Blowby! Get a catch can and rig it up. Only about $50 for a nice one.

 

gq: was the problem he found specific to the PE kit or was it on a Greddy kit? I have not installed PE kit so I dont know what they did with the PCV. I have never had a problem with the way greddy does it in their kit, and its how pretty much all turbo cars do it anyway... is the PE kit doing something wierd?

-Charles

 

Hey Charles,

Gurgen problem was with the PE kit. Not sure what the resolution was for Gurgen.

The PE kit does cap off the passenger PCV and use a breather filter instead. Dunno if that will cause the smoke???

 

What the hell is blowby ? Heh...

And why can't I find that thread of Gurgen's about PCV ?

Thanks guys,
-slay

 

It was recent. Try searching for "Guys...got a problem"...something like that...That was the title

 

With the PCV attached you will have a vacume applied to the crankcase to help the rings seal. If you were pulling anything through the valve you could always put a filter or catch can on to filter out the oil vapor. However, if you've pulled it and vented to the outside air you no longer have any vacume helping the rings. Who knows, maybe it was enough under just those circumstances to blown or suck some oil into one of your cumbustion chambers. It might also be possible that you pulled some oil from your turbo(s) or SC supply line if you're running either of those?

 

Found it


https://my350z.com/forum/showthread....threadid=90056

 

Hey Guys, Slay

Just saw this thread.

Yes, this seems to be specific to the PE, due to the stupid way they route the PCV system on the d-side rocker cover.

Check out this thread on th eG35 site, a lot of guys had interesting suggestions: http://g35driver.com/forums/showflat...&part=all&vc=1

Here is the deal, if you look on the little tube that comes out from under the lower intake manifold, you will see that it is capped off with a rubber cap/plug (if your kit is installed as per PE instructions). That is where the PCV valve connects via a hose. Now, the problem with having this hose connected the way it normally is, is of course the pressurising the crankcase during boost operation. Normally, this is the case, as the PCV valves are not very efficient one-way valves on most cars. Hence, PE decide to connect the PCV valve via its hose to the nipple/port on the p-side intake tube. Now, this is a bad design, as at idle the crankcase will not see the -20inHq vacuum, but only a very slight drop below ambient (as the filter is pretty wide open).

Luckly, in our case (the VQ35), these pcv valves are very good one-way valves (to over +25 psi according to some very knowledgeable engineers who tested this very valve). So, the way Greddy does it, whether it is accidental or on purpose, is correct; i.e. they do nothing to the PCV valve connection and only reroute the d-side, as that one does not have a valve and is a straight shoot through some baffling.

So, Slay, you simpy have to reconnect the p-side hose and plug the intake tube port instead. Also, get a catch can, as I intend to do.

My problem was however a little different from yours... as you can see from my posts in the links above.

Any suggestions on good catch cans? Should I use filters in line wth the catch cans? I intend to route both ports (both rocker covers) through the cat can.

Gurgen

 

Hey Gurgen,

Thanks for the explanation. The way Greddy has it is also the way I've seen in many other turbo cars. That's why during one of our meet, when you mentioned about the PCV being capped, I was curious in seeing how PE did this. However couldn't come up with a logical answer why it was design this way.

Jeff

 

Gurgen thank you for the informative and detailed response.

I will print it out and show it to my shop who installed the kit, hopefully they'll be able to take care of it for me.

What happens if I don't install a catch-can ?

 

Then you'll be eating blow-by.

 

You are welcome guys.

Sharif, do you have a catch can?

Jeff, jsut a tiny correction, for complete clarity. The PE does NOT cap off the PCV valve at all, it only connects it with the intake tube rather than the lower manifold (<2 mmHg vs. -20 mmHg vacuum). the former is obviously under too high an absolute pressure to effectively keep the crankcase under a vacuum. What IS capped of is the tube that used to connect to the PCV valve via the hose. Essentially, you need to reconnect the PCV hose back to the stock location, and use that cap to close off the now-uselss port ont he intake tube.

Now, which catch can do I get? Cusco, Greddy, etc.

 

Slay, this is VERY easy to do. You can complete it in under 2 minutes. Could save you the trip to the shop.

 

Thanks for the clarification Gurgen. Now that makes sense to me. I need to get a catch can as well.

 

cool!

 

No I dont...I was actually just make a joke with Slay2K...that..I guess..nobody got.

I dont have a catch can yet...I just have my PCV setup the way Greddy said to do it. Havent had any problems. What is the benifit of having the catch can? Does it just keep the crap and gunk out of the intake manifold?