Direct Injection Intake Valve Coking

[c4c5specialist]

HI there,

Oil windage is due to the fact that oil is still slung around the crankcase, vapor with oil droplets is still present that is pulled into the PCV system for burning. Many people believe that this is the ONLY factor with carbon fouling of the intake valve, this is incorrect.

If PCV vapor was the only issue or a major issue, you would have a wet, droplets forming on the valves, not a dry carbon chunk type residue that is what we are addressing in this post. This wet, droplet formation would therefore coat the valves and you would never see this dry carbon deposit, ONLY WET.

This is why understanding ALL factors shows us that catch cans, cold air induction, fancy services with heavy repair bills are just NOT needed.

Plus if you have the dry sump system, you have a HUGE catch can on your car already, the oil sump tank itself.

Allthebest, Paul.

 

[Hib Halverson]

I found "c4c5 Specialist's" posts on this subject very interesting and to some extent they have better educated me (as Paul's posts sometimes do) and "calmed" my concern about the "coking" issue on the Gen 5s.

Obviously, if coking is a significant issue, as the back side of the intake valve becomes "gunked-up", intake air flow at is going to become restricted during WOT operation.

Generally, you have to be a very sensitive person to be able to feel even a 10% decrease in torque output and most people can't feel much until the change is 20% or better. Plus, if there ever is a problem with intake valve coking such that there is a measureable decrease in performance, the change is going to become very slowly so not only is it hard to feel a change of less than 20%, but the change will come so slow that, even if the driver does have a sensitive "butt dyno", they'll likely not be able to feel the change over time.

I suspect borescoping the engine or removal of the intake manifold for inspection is likely going to be required to assess any coking problem.

 

[red-vette]

I fail to understand how 88861803 will accomplish anything, since the fuel is injected in front of the valves with DI. Can you kindly explain how you get this product on the coke-impacted areas of the intake valves?88861803 Upper intake and combustion system cleaner - See more at: http://www.corvetteactioncenter.com...l?highlight=valve+coking#sthash.UNRqG6Qz.dpuf

 

[c4c5specialist]

I fail to understand how 88861803 will accomplish anything, since the fuel is injected in front of the valves with DI. Can you kindly explain how you get this product on the coke-impacted areas of the intake valves?

HI there,

That product is not added to the fuel tank, NEVER put that in the fuel tank.

That product is atomized at the front of the throttle body as the engine is running and is pulled through the intake system with incoming air and will wash the backs of the valves as it is pulled into the cylinder.

"Fogging" is the term that we use.

Allthebest, Paul

 

[Blue260]

:confused huh......!