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Old 05-16-2019, 11:23 PM   #5
Glen e
Retired from Car mfrs....
 
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Drives: 2LT RS/HR-V
Join Date: May 2013
Location: /Fort Lauderdale
Posts: 10,048
Obviously GM is going to say that they don’t need a CC because their engines work fine without them. It has been posted time and time again.... there is a post that was over at the Corvette forum in 2014 when it was discussed whether it was warranty or not… a GM engineer answered indirectly......

Written to mike at Criswell when he asked one of his engineering buddies about this…

I was the one that contacted someone from the Stingray Consultant team from GM...Here comes is what he wrote back on this matter.

"The Stingray was evaluated with over one million development miles on 200 captured test fleet cars. There are tens of thousands of direct injection vehicles on the road from General Motors alone. During the evaluation hundreds of engines were literally torn down in to part piles and evaluated. There are hundreds of thousands of LSx family of motors (where part of this catch can hype started) on the roads and the many of these motors are running well past 250,000 miles without a catch can.

The cars have a 100,000 mile powertrain warranty and that includes mechanical failure of the engine. Trust me when I tell you that there are not reams of data (not even pages of data) on cars coming up lame because of oil at the MAF. It just isn't the problem that the "internet" makes it out to be. When you ask a GM Powertrain engineer about a catch can the reply is that the only thing you get is added weight.

In looking at the extra effort and added cost that went in to the Stingray, do you really believe for one second that if a $20.00 part attached to the engine would improve reliability, limit warranty claims and replacement costs, that GM wouldn't have put it on if it was necessary as part of their evaluation?

Every single GM engineer that I have spoken with told me in one form or another that a catch can is predominately a "gimmick" device created by tuners looking to make a few extra bucks on their engine modifications.

As a by-product of the PCV system, excess oil vapor is recycled to prevent it from leaching out in to the environment. It will condense back in to liquid if the temperature and environmental conditions are right. A catch can is an oil separator device. It allows the heavier oil in liquid to condense in the bottom of the can and only pass the air (gases) back. This is basically the same thing that is happening at the front of the MAF where most of the oil can be found.

The theory is that this oil in the intake system will collect on the valves and in the cylinders and cause excess carbon deposits. The catch can will reduce (not eliminate) oil pooling in the MAF.

Where the plan breaks down is that there aren't thousands of cars detonating because of the oil. As I told you on the phone, This isn't new. The engines are designed to deal with a quantity of oil mist presented via the intake.

You asked what I should tell the customer, my answer is I'm not sure because I don't know what his question is. If the question is is this normal? The answer is yes. If the question is should I put a catch can on? The answer is what ever makes you feel better. If the question is do I need a catch can? The answer is a resounding no. If the reply is that they saw it on the internet, apologize politely and tell them virtually every thread about it has started with a vendor selling a product or a consumer that was fooled by the hype and trying to make themselves feel better about their purchase by getting others to agree with them.

If he has concerns about his condition he should take the car to his dealer for evaluation.

Here is my standard response to the dozens of emails I get each year with a link to a thread like you posted (and often, that very same thread).

Simply stated, absolutely not on the catch can. It simply isn’t warranted for any street driven car. We can talk in more detail about it tomorrow and Dan will appreciate it as I’ve all ready had this conversation with him as well. Since the advent of the PCV system, cars have released some oil in places where it wouldn’t normally have gone in a fully sealed system. It ends up in vapor which condenses back in to liquid form in the intake path. As a result of that, the system is designed to ingest and subsequently digest some extra oil. Higher revving produces more oil and repeated higher revving (drag racer, track duty car, etc.) would be in the realm of uses that I might consider adding the can. Daily driving, occasional back road romp or stop light to stop light burst, not so much.

With all of that said, they won’t hurt anything. For those that don’t want to take my word for it, can feel comfortable adding it but it won’t make an appreciable difference in the life of the motor or the efficiency of the system.
If you dig deep enough in to forum information about catch cans, all roads generally lead back to a performance tuner, aftermarket part supplier or fabricator who has a vested interest in selling catch cans." Stingray Consultant


Mike Furman ~
"Be kinder than necessary, for everyone you meet is fighting some kind of battle"
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