Catch can...worth the cash?

[anmracing2]

The purpose of the PCV system is to route the oil fumes out of the crank case and back into the intake to burn off during combustion to help with emmisions. Since you need vaccum to suck the air/fumes out of the crank case, it acts like condensation. If you are hard on the car the fumes turn back into oil before burned. That is why you get carbon build up. These catch cans take the oil out and let the air run through instead. Edit: spelling issues

[FNBADAZ06]

Well, my .02 on this.... I ran 2 stroke dirt bikes and jet skis in my youth. Fouled plugs were just part of ownership, but more interesting was the amount of unburned oil that was sent out the exhaust.....VERY noticable on a jet ski as you could see the oil film on the surface of the water. Talking about my car now....an LS7. I don't spend all of my time at WOT or my days lapping the race track, but I do my fair share. If these oil vapors are making it into the intake and are pooling, some of it is also making into the combustion chamber and expelled out the exhaust port. What lies just down stream from your exhaust port ??? Your first set of 02 sensors which are responsable for setting your Long Term Fuel Trims. And if these get coated with a cooked oily coating via the ingestion of oil vapors to the point where they no longer read properly ? A possible trimming (reduction) in the amount of fuel being sprayed through the injectors. Less fuel, combined with the same amount of airmass coming down the throttle body equals a lean condition. Lean condition leads to detonation. If the 02 sensors, in combination with the MAF sensor, determine the fuel trims of the injector, which in turn equates to your AFR, it seems that it's in your best interest to protect the 02 sensor from ANY type of contamination if you desire to have the engine run as effienctly as possible. I've got to believe that over some duration of time, combined with the quantity of oil vapor pulled into and expelled from the combustion chamber, this has got to be to the detrement of the O2 sensors. The catch can is just another "insurance" item I will be adding to the car to remove as much oil from the induction airstream to stack the odds in my favor that the engine is going to run at peak effenciency when I push the car. How's THAT for some serious bUllsh!t !!!

[Two Fangs]

Let's not get too crazy here. If the fuel trims are affected to a large degree,the car will pop the SES light. Chances are, if you had that much of an oiling issue, you would already have "cat efficiency low" and "O2 Sensor not switching" codes as well. And, furthermore, when you are on the car hard, the PCM doesn't care what the O2 sensors have to say, anyway. Not banging on ya, Victor. I love you to death, dude. Just trying to keep this in perspective. EDIT to add info.

[FNBADAZ06]

Let's not get too crazy here.

If the fuel trims are affected to a large degree,the car will pop the SES light. Chances are, if you had that much of an oiling issue, you would already have "cat efficiency low" codes as well. And, furthermore, when you are on the car hard, the PCM doesn't care what the O2 sensors have to say, anyway.

Not banging on ya, Victor. I love you to death, dude. Just trying to keep this in perspective.

I did say it sounds like some serouis bullsh!t, didn't I ?

In all honesty, I will be installing a catch can for my car, as I've seen first hand the amount of oil it has trapped on fellow C6 Z06 owners that frequent HPDE's on a regular basis. As far as the O2's are concerned, at 40K miles it appears that my front 02's are ready to be replaced as my LTFT's are constantly going deep into the - % numbers on both banks....to the point that the car is intermentitly tripping a P0175 on both banks.

I'm told this only happens when fuel trim meet the -25% range for two seconds are greater. The car is constantly trimming fuel and never really settles on 0 +/- 5% .

[Two Fangs]

That is correct. Sounds like they could use replacement. Interstingly enough, when O2 sensors become clogged, they cannot sense oxygen in the exhaust any longer (duh). Well, when they can't sense oxygen, guess what they tell the PCM? "I'm rich, beeotch" So the PCM then does what?Leans the car out. So yeah, when the trims go rich, and cutting fuel (-25%) doesn't solve the problem , DING! SES light.

[FNBADAZ06]

That is correct. Sounds like they could use replacement.

Interstingly enough, when O2 sensors become clogged, they cannot sense oxygen in the exhaust any longer (duh). Well, when they can't sense oxygen, guess what they tell the PCM? "I'm rich, beeotch" So the PCM then does what?Leans the car out.

So yeah, when the trims go rich, and cutting fuel (-25%) doesn't solve the problem , DING! SES light.

You GOT IT !!!

Intersetingly enough, the issue is exasperated on my car by the adition of the KillerBee/Beehive CAI combo.

The greater volume of air commands roughly a 5% increase in fuel (according to Jim)...adding to the excess fuel that the front O2's are already "reading", commanding a LARGER and lasting fuel trim....close to -16 % on average according to my logs. After a steady state highway cruise, the -25% threshold is met and sustained for that minimal two second interval.

BING....CEL...and a set code of P0175 for both banks !!!!!

You can guess what a -25% fuel trim does when you go part throttle or load...DETONATION, and a pulling of timing

My recent education suggest the front O2 sensors are the closed loop feedback for the ECM.

The rears O2's are making sure the cats are working properly.

At 40K miles, I would have expected the O2's to NOT be in this condition, but we know that the LS7 is programmed to run on the rich side from the factory.

That begs the question as to why both O2's are beginning to show signs of deteriation to the point of affecting LTFT's...solely from the factory "rich" tune ?

[Two Fangs]

Your recent education holds true. I would not put too much stock in oil being at fault for the front O2s going south, I would put a rather substantial amount on the fact that when you remove them,they will not be oily (If of course, I were a betting man). It is more than likely age, and well, funk from gas additives like MMT.

[FNBADAZ06]

Your recent education holds true. I would not put too much stock in oil being at fault for the front O2s going south, I would put a rather substantial amount on the fact that when you remove them,they will not be oily (If of course, I were a betting man). It is more than likely age, and well, funk from gas additives like MMT.

Agreed. On a serious note, I would not expect the sensor's to be oily, but there would be no way of telling just how much the burning of oil vapors DID contribute to the O2's early demise, along with a factory tuned "rich" state.

This O2 sensor might also explain why my car picked up 8+ rwhp and 2ft/lbs TQ when the x-pipe and ZR1 mufflers where installed. The adjusting of the LTFT to a leaner state, in conjuction with a (possibly) superior scaveging exhaust system has brought my AFR closer to a proper level...in effect, by proxy, "tuning" the car.

[Two Fangs]

Not without an empirical analysis that, by the time it was all said and done, wouldn't be worth it, LOL.

[FNBADAZ06]

Not without an empirical analysis that, by the time it was all said and done, wouldn't be worth it, LOL.

WORD

Some pretty solid bullsh!t though, you must admit !!!!

By the way...your statement above sounds like something Fox Mulder from the X-Files would make.....are you guys related

This O2 sensor issue might also explain why my car picked up 8+ rwhp and 2ft/lbs TQ when the x-pipe and ZR1 mufflers where installed. The adjusting of the LTFT to a leaner state, in conjuction with a (possibly) superior scaveging exhaust system has brought my AFR closer to a proper level...in effect, by proxy, "tuning" the car.

[Two Fangs]

I would say the gain was due to a more effective scavenge. Remember,the PCM doesn't care what the O2s say at WOT.

[Two Fangs]

By the way...your statement above sounds like something Fox Mulder from the X-Files would make.....are you guys related

Nah,I'm actually much more like Murdock from the tv version of the A-Team

[FNBADAZ06]

I would say the gain was due to a more effective scavenge. Remember,the PCM doesn't care what the O2s say at WOT.

I forgot....what was this thread about ???

I seriously think I highjacked my very first thread

[Two Fangs]

And you did it it grand style, LOL.

[FNBADAZ06]

And you did it it grand style, LOL.

Talk to you later Agent Murdock

[Bigfoot]

I've had my intake off before for other stuff. I noticed oil dripping out of the thing so I did a finger swipe.

I turned it to "pour" the oil out and it was significant. I changed it at this point for an LS6 and let it sit in the garage for some time before I gave it to Tim on a de-mod. Still dripped oil when I laid it on its side.

Catch can is needed. Again, I put mine through the RPM's on a regular basis.

[fourseventeen]

ok so if the LS7 runs rich...would this mean that adding the intake would make it run a little leaner? Yeah dont hassle me for the stupid question.

[FNBADAZ06]

ok so if the LS7 runs rich...would this mean that adding the intake would make it run a little leaner? Yeah dont hassle me for the stupid question.

Are you trying to "hijack" my hijacked thread ?????

Jay...the bottom line is this:

A properly functioning Catch Can will catch most of the oil that may find it's way into the intake tract.

What that oil does to the the AFR or performance of your car may be a little less clear.

YMMV

[fourseventeen]

ok so if the LS7 runs rich...would this mean that adding the intake would make it run a little leaner? Yeah dont hassle me for the stupid question.

Are you trying to "hijack" my hijacked thread ?????

Jay...the bottom line is this:

A properly functioning Catch Can will catch most of the oil that may find it's way into the intake tract.

What that oil does to the the AFR or performance of your car may be a little less clear.

YMMV

You didnt really answer my question you hijacker lol. So the car stock runs rich. So would adding an air intake kit and exhaust make the car run a little leaner or does it do opposite of that?

[Two Fangs]

At WOT, it really depends on the system. If the air comes through the air tube and where the MAF is located is larger, it will be leaner. If the area where the MAF passes through is smaller, it will run rich. This leaves out any dynamics that may change how the air passes by the MAF which may change the above general rule. It is really why a tune is recommended after installing a cold air intake.

[fourseventeen]

OK "F" it...guess when I get back from vacation ill have to call Nic and get the tune that I keep putting off

[Two Fangs]

I've had my intake off before for other stuff. I noticed oil dripping out of the thing so I did a finger swipe.

I turned it to "pour" the oil out and it was significant. I changed it at this point for an LS6 and let it sit in the garage for some time before I gave it to Tim on a de-mod. Still dripped oil when I laid it on its side.

Catch can is needed. Again, I put mine through the RPM's on a regular basis.

Dude, I am absolutely not discounting what you say, the LS1 and LS6 do exhibit some pretty serious nastiness in the intake. But this really hasn't been a nearly as big an issue since the crankcase ventilation got a re-design in 2005.

[Two Fangs]

OK "F" it...guess when I get back from vacation ill have to call Nic and get the tune that I keep putting off

I cannot think of a better person to take it to.

[Bigfoot]

Dude, I am absolutely not discounting what you say, the LS1 and LS6 do exhibit some pretty serious nastiness in the intake. But this really hasn't been a nearly as big an issue since the crankcase ventilation got a re-design in 2005.

And that's why I justified it by saying that on the LS1 I know it's worth it, but was not sure on the LS2, 3, or 7.

[HOXXOH]

Dude, I am absolutely not discounting what you say, the LS1 and LS6 do exhibit some pretty serious nastiness in the intake. But this really hasn't been a nearly as big an issue since the crankcase ventilation got a re-design in 2005.

And that's why I justified it by saying that on the LS1 I know it's worth it, but was not sure on the LS2, 3, or 7.

The LS3 block has the latest ventilation design. GM even did some slight changes in '09 to improve it again. That's probably why I only use less than 1/2 quart in 12-13K miles. It just not sucking oil through the intake.