OK, I know I was on here just a few months ago preaching that everyone should run out to autozone and slap breathers in place of the CDR and Oil filler tube... Well, I'm here tonight with a new perspective on these performance marvels, they're junk. In haste, I tossed my old CDR cannister (stupid) and the hoses, but I was fed up with the oily mess under the hood. All I could find was a piece of heater hose that just happened to fit nicely into both the intake boot and the valve cover. So now instead of a crankcase depression regulator, I now have a crankcase evacuator system. And you know what? The stinking thing runs better now than it ever did with the stupid breathers. No more smoke from under the hood when you come to a stop light, boost comes up quicker, a touch more power even, no more stumble on free-rev, and it warms up faster too. I just thought I'd share this, and apologize incase anyone out there is cursing at me because the bought these stupid things.

It takes a man to do what you just did. Kudos.

Actually this is no supprise as most high powered drag race cars now run vacuum pumps on their motors. Pulling a vacuum on the engine aids in ring seal, cuts horse power loss of oil droplets circulating with the crankshaft and rods. Some pull up to 20 inches but most pull 12 - 15 to keep from starving the oil pump. Another advantage is no oil leaks on the engine. The bigger the engine the bigger the horse power increase.

Tell me more of the this thing you call Negative Crank Case Pressure.... I understand concept...no understand how you did it.

I've noticed several signatures with "dual breathers, negative crankcase pressure". Never asked what it was. I've got the F motor. Are these mods that only apply to EGR motors?

Negative Crank Case Pressure. Sounds like it was an easy mod with some benefit. How exactly do you accomplish this? My truck is running fine. If it ain't broke, why fix it? Should I leave it alone, or is negative crank case pressure worth the effort? :confused:

All I'll say is...

Well said, TDG.

Negative crankshaft pressure works even better with stainless piston return springs.

The 5068 camring deal will be the next to go I am sure.

im with joispoi on this one....tell us more so we can understand!

DieselPro, you know the stainless piston return springs work better with the resistor spark plugs in the diesel......right?

5068 camring deal will be the next to go I am sure.
I'm pretty sure the cam ring is there for good. I still don't know which PROM I have as far as whether it calls for a 5068 or 5521 series pump. But I can say that I have seen these trucks run with a 5521 pump where a 5068 came out. When I tried to set mine up to mimic what a 5521 pump would do with a 5068 cam ring, it didn't work, I had to adjust the optic sensor to almost exactly to where it would be if it were a 5068 pump. So I think that now I have the cam ring that I'm supposed to have.

im with joispoi on this one....tell us more so we can understand!Its simple. That CDR or 'tuna can' is no more. Now I have just a hose from the valve cover to the intake boot for the turbo. The CDR's purpose is to keep crankase pressure between ~1psi pressure and ~1"Hg. No more CDR means that the turbo can now suck the crankcase freely, developing a partial vacuum.

why would they put the tuna can there in the first place? I mean, what is the reason for maintaining a specific pressure if partial vacuum is more beneficial? Any possible negative impact if removed??

Why did GM want ~1 PSI in the crankcase anyhow?

Sorry to keep this thread at the sophmore level, but won't that crankcase evacuator set-up increase oil consumption? Also TDG, you said that the turbo spools up faster and it has a touch more power....any idea why this is? (Not doubting, just seeking nollij)

You said the breathers are junk, I never looked into them, but I'm guessing that they vent the crank case into the under hood air, not the air intake tube??

You said that the truck runs better with negative crank case pressure than it did with the breathers. How does it compare to stock?

Its simple. That CDR or 'tuna can' is no more. Now I have just a hose from the valve cover to the intake boot for the turbo. The CDR's purpose is to keep crankase pressure between ~1psi pressure and ~1"Hg. No more CDR means that the turbo can now suck the crankcase freely, developing a partial vacuum.First TDG thats takes guts around here to stand up and say something ain't working well. WELL SAID :exactly:

Now with your new setup are you worried about your oil usage going up?

The reason that the CDR canister is there is to regulate crankcase vacuum. Too much vacuum can cause dirt to be sucked in past the seals and can cause seal leakage. Too high crank case pressure can cause leaks from pressurization and will wear out the seals from increased interface pressure and distortion of the lip.

If you have a backfire there goes your oil pan.

I have a 10+ year old engine, oil consumption is just a part of life for this baby. Judging by the mess I witnessed while I was under mine, I don't expect to use any more oil than with the breathers or the original CDR setup.

By saying the turbo spools up quicker, I can now peg my 15psi gauge, where before I could only graze 14psi, it also maintains pressure a little better and doesn't drop off as sharply as the WGDC drops. This is because now the turbo has a small amount of positive pressure from the crankcase to feed off of, not a big difference, but noticeable.

I have a 10+ year old engine, oil consumption is just a part of life for this baby. Judging by the mess I witnessed while I was under mine, I don't expect to use any more oil than with the breathers or the original CDR setup.

By saying the turbo spools up quicker, I can now peg my 15psi gauge, where before I could only graze 14psi, it also maintains pressure a little better and doesn't drop off as sharply as the WGDC drops. This is because now the turbo has a small amount of positive pressure from the crankcase to feed off of, not a big difference, but noticeable.
I wonder if the extra performance is from the engine now burning more oil? I'd watch your oil level closely for a while till you see how this affects your oil consumption.

Carey

Its burning the oil it used to spray all over the engine. It can't suck any more blow-by than the engine creates, vacuum or not.

you could insert pcv valve in hose, and this would regulate crankcase draw and give check valve incase of backfire. should fit in side 5/8 hose. that would help prevent drawing water and dirt into c/c seals, pcv valves also have different spring rates, incase you want to test.
good job
keith

getting back to the tuna can, is it possible to adjust the vacuum setting on it?? I guess I'm thinking along the same lines as Keith's idea about the pcv valve. It never occurred to me that backfiring could be an issue. Has anyone ever had a diesel backfire on them? I've experienced that wonderful phenomenon with gassers, but never on a diesel. Then again, I've spent more quality time with gassers in the past.;)

In FAQs is a very good dissertation of how the CDR works and some tests on it

??? A diesel can't backfire, it happens in gassers because the fuel is mixed with air in the intake manifold. A diesel engine only gets fuel injected into the combustion chamber just before TDC firing.

I don't see any need to regulate crankcase vacuum, as long as your air filter isn't restricted, you can't draw even as much vacuum as is present between the turbo and the air filter.

Sometime ether will cause a backfire if conditions are just right.

Ether would be the exception, that would give you a fuel/air mix in the intake, but if your spraying ether in the engine your asking for trouble anyway, IMHO.

??? A diesel can't backfire, it happens in gassers because the fuel is mixed with air in the intake manifold. A diesel engine only gets fuel injected into the combustion chamber just before TDC firing.
Correct!

I don't see any need to regulate crankcase vacuum, as long as your air filter isn't restricted, you can't draw even as much vacuum as is present between the turbo and the air filter.
GM did. Don't let this be another bad decision. I would highly recommend reinstalling the CDR if you don't use some other system. My recommendation. Do with it what you like.

...I tossed my old CDR cannister (stupid) and the hoses...
I'll see how this goes, if it doesn't work out, I'll have to find a replacement.

What is the theory behind the breathers? Where are the performance gains coming from?

TDG- is it possible that you are getting better performance becuase you've added the crankcase vent as an additional air intake? ie. intake air is no longer limited to the airflow through your air filter, hence faster spool up? If that's the case, are you pulling dirty air through your crank case?

Thanks a lot TDG....I just replaced my TunaCan at a rate of $ 88.00 !!!

Now this thread shows up.......Censored

Even though I did not agree with TDG's suggestion on the breathers, lets give the guy props for thinking outside the box, and owning up to it when it didnt work like he thought. Ideas like that stretch our own thinking about these engines. And who knows, maybe someday someone will stumble upon something signifigant hidden in a stupid idea.

Or as Homer Simpson would say:

"The first step in failing is trying" ;)



:beerchug:

Tim

Would a check valve installed in this line work to keep everything flowing just one way and not the other??????
Yes TDG Thanks for helping us at least knowing where the box is.

Freeby.... 1 slightly used tuna can....
I purchased a new one a couple of weeks ago, there was nothing wrong that i could see but thought it due after 180,000 km's.

Yours for the price of shipping TDG.

TDG, your honesty ROCKS! Keep tweeking and un-tweeking as neccessary to move forward.