Curious to know what your opinion is on installing an oil catch can on a DFI + PFI Lexus engine.

I know that it is a must-have thing for a direct-injected engine because of the carbon buildup issue. Direct and port injected 3.5L V6 has port injectors cleaning up intake valves so in theory it might be completely useless.
However, after reading some relevant discussions, it seems that burning of oil in the chamber also causes a drop in fuel efficiency, as motor oil seems to decrease octane number of the fuel in the combustion chamber, resulting in a noticeable drop in fuel economy.

https://www.silveradosierra.com/thre....399506/page-2
https://www.rr-racing.com/Lexus-Air-...isxaos0002.htm

 

Leave stock. Playing "engineer" is something you do on a clapped out 25 year old Civic, not a modern premium make car. Leave a modern car as designed and just change the oil often. Not worth the risk of playing with stuff on a car you're supposed to enjoy white-gloved, going to work etc. Same thing I told BMW forums for a decade when they want to create catch can contraptions out of generic parts from the internets. Because man-things.

You're creating a problem in your mind which does not exist. Just enjoy the car and have nice dinners on the weekend. the car works for you, not the other way around.

 

Carbon buildup problem is a well known problem both in DFI and PFI+DFI community.
Here is a good summary of what it is, specifically for the DI engines.
It wasn't simply made up by me.
It is also well known that well designed catch cans do work very well at stopping oil vapor from getting back into the intake system.


changing oil does not remove nor does it prevent the problem, simply because it is the not what causes it in the first place.
Modern cars lose a lot of efficiency because they are made to re-burn stuff that was not meant for combustion.
It was NOT a good engineering decision, but rather politicians forcing engineers to design something ****ty.

My logic is very simple - if I can help my car run another 100-150k mile run while staying healthy, it would save me a lot of headache and financial pain in the future.

 

I don't think the oil catch can solution really benefits the 3.5L motors since you guys have the port fuel injection which is constantly cleaning the cylinders. I would just leave it alone. Catch can, I would assume, benefits the 250 and there are people selling the 2nd gen IS250 with 150k miles without it.

 

If you're racing or doing a lot of "spirited" driving get it.. If not, don't worry.

 

I probably do 20-25% driving spiritedly. I will think on that. Thanks guys!
Replaced the PCV valve yesterday at 68k. It looks fine to be honest, but it was a bit dirty. At least it did not require me to remove the intake like it was on my late Corolla 2011.

 

Someone posted a picture of the catch-can and how much oil it "catches". I was surprised.

I am sure you will be too with some spirited driving.

 

yea, that was pretty much my reasoning too, after I saw how much oil collects in there just in 1-3k miles... It is like a 1/2 - 1 cup of contaminated oil per one oil change interval that needs to be burned.

 

Just for reference....

 

Here is another one where he actually shows how much oil the can catches on his GS F.

 

Mate, no contradictions in both cases... there will be blow-by just cause of how ICE work in our engines. The difference is that engines without PI will see carbon buildup, engines with PI will see significantly less and engines with PI and with oil catch can installed might see even less carbon buildup. The amount of oil caught in that oil catch can shown in your video you shared does not automatically mean that all of that will be crud up, coz that's where PI comes in with the fuel spray. On this page below, it shows a photo of a 110k miles intake valve of a port injected engine and to me, it is mighty clean and the engineers have solved the problem.

https://www.enginelabs.com/news/vide...ect-injection/

 

This video is also very interesting and much more explains how oil ends up in the OCC, rather than just showing there is oil.

Part 1:
Part 2:

 

I mean, it does not mean all that amount will end up as deposites. But what it does show is how much of it needs to go through the combustion chamber as part of normal engine cycle. Something that should not have been done like that to begin with.

Some of it will be burned, some will add to the deposits on the combustion chamber upper portion and pistons, some of it will go through the cats clogging them, and some will be exhausted....
The latter will potentially cause cancer and something else, a cause-effect pair which we dont know about yet, because "experts" have not "blessed" us with their opinion.

 

Right. I mean, anyone who understands what a PCV valve is for, knows how oil ends up in the can or in the intake manifold.
Interesting videos, however one argument he is making is - manufacturers did not install factory oil catch can, hence it is deemed not necessary. Injecting oil vapor in the combustion chamber was not necessary either, yet the government forced engineers to do it, so that argument is flawed on that end, as it is not a pure "engineer good, do not engineer bad" logic, since it is tainted by the politics

For the same reason, they can be forced to minimize the amount of necessary maintenance needed in order to meet regulations.

 

just to add that scotty kilmer is perhaps the worst youtube personality who one should turn to for automotive advice.