Hey guys. New to the c7 game and I was wondering if anyone had issues with carbon buildup on the intake/valves since the motor is direct injection and not port injected. After some internet research I've seen some guys do seafoam or some rendition of that down the intake behind the MAF sensor, but that just pushes all that junk down into the cylinders and into the oil. I know bmw cars have to have the valves cleaned every so often and I'm hoping that's not the case with this car. I'm hoping I'm just overthinking the whole thing and I can just drive the car and enjoy it!

 

I haven't seen any posts with this as a problem. If you have to pull the intakes/heads for some reason, that's a great time to clean up the valves and ports, but I haven't heard of anyone pulling parts just to clean them.

 

There a few threads on here with information if you search.

Summary: This is not typically an issue on the LT1/LT4 platform in stock form. Once you start modding the car, especially adding boost to the LT4, its a good idea to get a catch can.

 

Great! Thanks for the feedback

 

A catch can helps with valve stem carbon build up?

 

More boost on the LT4 increases crank case pressure and the catch can help alleviate that along with reducing oil consumption due to the increased crank case pressure.

 

FWIW, I try to stick to Top Tier gas if I can get it. It's been a little trickier since C-19.

 

Gas doesnt matter since it never see's the intake valves on these engines.

 

Good point regarding the valves. Are the DI injectors "self cleaning"?

 

How does a recirculating catchcan help with crankcase pressure? It doesn't help at all. It helps to capture suspended oil droplets and gather them into the can. Now a VTA setup DOES help (although it isn't actual legal) as long as you vent everything. it iI'm assuming that is what you were referring to?

 

A catch can also allow ventilation under WOT where crankcase pressures are higher, especially with more boost. I'm not here to convince anyone about anything. Turn up your boost and don't run the proper catch can setup and you might just pop your front or rear crank seal due to crankcase pressure.

 

I have boost on mine and was thinking about a catch can. I rarely ever go into boost tho. A suprcharger is useless on the street.

 

Oh man that is a good one. I needed a laugh this morning.

 

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some people install a catchcan which voids your warranty.since all factory c7 warrantys are over you can do one.instead i pull my supercharger cover once a year and wipe up the oil that collects in there.it is a easy job and takes only about 20 minutes.
see my post with pics how to fix.
Annual Pulled The Supercharger Cover For Cleaning - CorvetteForum - Chevrolet Corvette Forum Discussion

 

Increasing boost with pullies, to the point where a catch an is a good idea, also voids the warranty. Also, cleaning out your supercharger once a year does nothing to assist with oil vapor hitting the back of the intake valve. Your intake valves are no cleaner than if you hadn't ever done your annual maintenance. I don't knock you for loving your car so much that you enjoy doing this. It is great and there is nothing wrong with it. But I wouldn't want other readers to get the impression this sort of thing helps in any way.

 

So you are stating that having oil in your supercharger cover which is forced and by vapor on top of your valves which coax up is not a problem and getting the excess oil out of there and cleaning your supercharger doesn't help anything. So on that basis then why put a catch can in that prevents oil from supercharger which the catch can prevents from going in there .contradictory. I've learned in life in an ounce of prevention is worth a ton of cure and cleaning your supercharger out once a year is it ounce of prevention.

 

No, I'm saying that the oil you are seeing in your supercharger when you clean it up, is the result of oil vapor already constantly making it across the back of your intake valves whenever the engine is running. What's left in the supercharger turned into droplets and pools up in the supercharger and hasn't made it across the intake valves yet. So you cleaning it up does nothing to stop the oil vapor that is already constant. But good news is, in stock form, it really isn't a problem for the LT4 because it does not inherently have the valve coking issue that other DI engines have. It is also why we use DEXOS 2 oil which resists getting stuck to the back of hot intake valves. Will what is in the supercharger make it into the intake tract if left there long enough? I imagine yes at some point it would or already does. But in the grand scheme of things, its a very small amount of the oil/vapor that hits the intake valves.

A proper catch can, will reduce the constant oil vapor and catch it in a can, and then additionally vent the crankcase when the car goes into boost. A catch can is a good idea when adding mods to the LT4 for the crank case ventilation so that you do not pressurize it so much that you pop your front or real main seal. It also has the benefit of helping keep oil vapor out of the supercharger and intake charge when you turn up the boost as more oil vapor is created. The factory PCV was designed deal with factory boost levels.

Again, I'm not lambasting you for your prevention procedure. There is nothing wrong with doing an annual clean up. But your valves will look identical to someone that doesn't follow your annual process and I wouldn't want any one reading this thread to get the idea that cleaning the blower on an annual basis would be a solution to a non existent issue. I think you demonstrate what most Corvette owners have, a high level of appreciation for having the means to own a Corvette. And you want to take very good care of it. Nothing wrong with that at all, sir.