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David...you may have missed the response in post #108 to your claim GM is installing catch cans. The nice picture you posted points to a clean side separator on the LT1 as found in the Camaro. The response tells how they do that and why in the response.
i absolutely see it, and it is a very fancy way of backing themselves out of a corner on the topic.
it is this translation->
"yes yes we know we have always said catch cans are bad, and now we are putting one in production, but ours is 'special' "
what part of it specifically would you like me to key in on otherwise?
if you look at wet sump engines before (millions of them gm has made) and these wet sump engines now it looks like this.
no catch can -> years of data and proof -> catch can
To each his own. It just depends on how warm and fuzzy you want to feel. If you feel a catch can can help remove the excess oil, go for it. I know every engine design is different, so some designs may benefit more than others. I chose to put one on my Ecoboost F150 because those twin turbo engines are infamous for a lot of blow-by. No complaints so far.
David...You are missing the detail of where that GM separator is located in the PCV system. It is on the clean side and will catch vapors pushed back when there is high crankcase pressure.
The dirty side is the same for the Camaro and Corvette engines which have a simple tube from the PCV in the center of the V and goes directly to the IM. There is no catch can there in either the Camaro or Corvette versions of the LT1.
The LT4 also has a direct path from the center of the V to the bottom of the super charger. You have built a very effective solution to route that externally to a catch can if desired. A much better solution than your competitor who rerouted the PCV system just to attach a catch can until they caught on to how you did and and copied your solution. It took several posts on the Forum to convince them how your solution worked.
David...You are missing the detail of where that GM separator is located in the PCV system. It is on the clean side and will catch vapors pushed back when there is high crankcase pressure.
this is true, i am not missing it, but the general consensus from gm all along is that oil consumption through the air intake is negligible. and here is the proof they have changed their tone.
a drain back tank is all that the red tape will allow, which unfortunately means only clean side oil can be returned. if they could do an external catch of the vacuum side they would.
catch can (of any type) vs no catch can is plenty of proof for me as a consumer and a professional that gm is no longer publicly or privately dismissing this as an issue.
have to remember not every gm or even corvette owner is a 'performance enthusiast' so nearly anyone questioning this will buy their explanations.. but not everyone
If that's proof, the Earth would indeed be flat. Proof would be no little or valve deposits on identical engines w/ catch cans vs. those without. That "proof" doesn't exist.
"- Tadge claims the ZR1 can shoot flames out from its exhaust
- NEW fuel delivery system- BOTH PORT INJECTION AND DIRECT INJECTION..."
Although this doesn't relate directly to Catch Cans, I can't help but wonder if it isn't speaking to the possible valve coking problem. And, if so, it leaves me wondering about the veracity of Tadge's comparison of the Corvette dry sump vs. Camaro wet sump oiling systems.
"- Tadge claims the ZR1 can shoot flames out from its exhaust
- NEW fuel delivery system- BOTH PORT INJECTION AND DIRECT INJECTION..."
Day
From the new ZR1 Thread: https://www.corvetteforum.com/forums...fo-inside.html
Yeah, I know... should have just let this thread die!
MeToo, but that is interesting! Following Toyota, with Port Injection & DI! Was predicting they would follow the Ford GT engine when the new mid engine was announced, but happened sooner!
Gasoline will pass over the intake passages and valves and reduce any carbon build-up to maintain high flow! Probably helps cool the air/fuel mixture as well at higher hp. Expect they will hype that feature to avoid talking about reduced coking! Just like the initial reason for no center air dam on the C7 Z51 was for rear brake cooling then later admitting it was to reduce the slight oversteer at high speeds when they require understeer for safety reasons!
Funny, when I was interviewing the manager of car dealer body shop that was certified to weld aluminum frames for Chevy, BMW and Mercedes, he raised the question of Chevy backtracking on their rhetoric re Aluminum Versus Steel! He relayed they were told Chevy will use an Aluminum frame on an upcoming truck model!
I noticed on a recent TV ad about their steel vs Ford aluminum truck bed floors it was stated by one of the Chevy actors, “well aluminum is good for some things but not floors!” Will be fun to see how they deal with the dialog about the properties of aluminum they have spent a lot of money arguing against!
I chuckle about the recent release of a low restriction air intake filter system for the C7 at SEMA. There were those who critized my addition of an aFe system posting, “if it was any good, GM would have used it.” (In fact I removed it from my C7 Z51 when I sold it and installed it on my Grand Sport!)
I have been thinking about adding a catch can. I have a 2017 Z51. I just watched a video that showed puddles of oil and they say installing one would eliminate that. The car was a 2014 Z51 with 5000 miles on it. This is a confusing subject with a variety of responses. SO basically it doesn't hurt to have one on if in fact it does little or nothing correct?
SO basically it doesn't hurt to have one on if in fact it does little or nothing correct?
Hmm, interesting and controversial subject! Read the posts on this thread and you'll get a feel! There are many other threads on the subject.
I had one on my September 2013 built C7 Z51 and captured about 1 oz of oil every 1000 miles (many with them report about the same thing.) Took it off when I sold it and put it on my Grand Sport. Now I collect about 25 to 33% the amount. GM has made improvements and added a more complicated PCV system. They did that for a reason. However puddles of oil in the intake manifold from normal driving-doubt it!
Does it stop all coking-NO. Does it reduce the coking by collecting and allow you to dump some of that oil before it gets to the intake manifold- YES.
Will it cause a problem? IMO not if you install a one outlet can and empty it and not allow the collected oil to accumulate.
If you don't want to read that much, install the "can" properly (which the PDF outlines,) and are not sure if you will empty the can periodically. Don't bother to add it! There is a risk re warranty that you should consider.
I don't have a dog in this hunt as I trade car frequently. If the catch can is necessary to ensure long engine life and performance, why wouldn't all the car manufacturers install them? They certainly are not expensive and could be cleaned w/ each oil change at the dealership.
One could argue that they (the car companies) don't care about the customer down the road after the warranty runs out, but then one could further argue why recommend oil changes, radiator flushes, or transmission fluid changes. Most cars could likely go past factory warranty w/o having any maintenance done before a problem occurs. This would keep the manufacturer off the hook for repairs and on the customer.
So I know the above paragraph is hyperbole, But why would they ignore a catch can if it was truly a necessary addition?
I'm with you Top. No dog in this hunt but I do realize that most car manufacturers don't want you to stay in the car for too long. They would rather have you trade up the old clunker for a new shiny one, especially a Corvette. Not saying this is a GM master plan, but I'm sure the longevity conversation has been had in the financial and marketing rooms of all manufacturers. Buy one car and keep it for 25 years or buy five cars in the same time period. What would your sales target be as the CEO of a car manufacturer? Making cars that actually last long are not really a top priority of the car manufacturers.
I cleaned the catch can today. I wanted to see if any gunk actually comes out of the clean side of the CC. I first put one end of the Qtip into the inlet (dirty) side of the CC then put the other end of the Qtip into the exit (clean) side.
No one has said here that the catch can is a 100% fix. But if you look at what it does catch let just say this I sure in the hell would like that much what ever amount it is in the can then in the dam t.b. & intake & that.
If you dont want one that is cool dont put one in. But I see your stupid statement here it cant won't help. If it catch's any of the blow by it has helped.
GM did do a big chg on the system in 2016 cars made it diff & better for the vette. Robert
Last edited by robert miller; 05-03-2018 at 11:08 PM.
I installed one on my C7 and it's loaded with oil every time I look.
16C7Z51, don't you know, you can't say things like that (that CC's can be effective at reducing oil vapor ingestion into the fuel intake system) around here! Nobody cares about how much oil you're preventing from being reingested. By the way, my CC will be here in a couple of weeks. Can't wait to get it on and see what I collect.
Foosh, you know a lot about many things, but this is clearly not one of them.
The Elite system on my built C6, which I tracked extensively was regularly full of oil. Same on my C7 Z51. Guess what I'm putting on my 2018 Z06 Z07?
The Moroso system on my 2014 RAM 1500 5.7L Hemi dumps oil each fill up. It isn't coming out of nowhere, and I'd much rather have it in my can than burning in my intake system.
I can't recall whether you track your vehicle regularly, but if do and you're not adding oil then good for you; you are truly the exception. If you're just tooling around on the street then your argument carries no merit.
Your argument that 'if there was an issue, the factory would come with one installed' is like saying, 'if stainless LT headers really helped performance, then they'd surely come from the factory'.
You lost credibility here, man.
Longtube headers are for "offroad use only" which is why they aren't, and can't, be sold on a new car. Apples and oranges.
Personally I could care less if other people agree with the benefits of a CC.
As for me I have seen too many videos of intake manifold/valves choked full of carbon build up to dismiss the problem with GDI engines. And it does not take a rocket scientist to understand if you vent dirty gunk via the PCV valve without benefit of fuel injectors blasting the intake valves with gasoline+additive you will get carbon build up...DUH.
One other point, before I added a CC my exhaust tips turned black pretty quickly, within 500 miles. Since adding a CC I have taken road trips adding 2000 miles during the trip and they were still shiny. After noticing this I disconnected the CC and the exhaust tips got black again. That's all the prove I need.
An even more interesting observation is that there is zero evidence that valve coking causes performance problems on LT1/4 engines. They've been around now for going on 6 years.
Yes, there are a lot of ugly pictures and problem reports from DI engines designed and built by other manufacturers, but not on GM DI engines.
11-08-2017, 11:27 AM
Nobody cares about how much oil you're preventing from being reingested. By the way, my CC will be here in a couple of weeks. Can't wait to get it on and see what I collect. 
