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I was checking out a new 2017 GS in the showroom when I noticed the PCV hose routing was different than in my 2014 Stingray's LT1. Both are dry-sump. It appears that GM has now routed one of the hoses so that oil vapors now are directed back into the engine rather than into the intake stream. Could this be a response to the oil ingestion issue that created the market for "catch cans"? Does anyone know any GM techs who may be able to advise if a 2014 can be retro-fitted with the new hose routing?
My oil level is always in between the min-max line on the dipstick and have not had oil in the airbox or throttle body despite some hard track runs. Might be beating a dead horse but never saw a need for catch cans. However, this new hose route might be in response to oil in the intake?
Pic 1 shows the 2014 PCV hose routing (red arrows) connecting to the intake air box
Pic 2 shows the new PCV routing (green arrows) with one hose bypassing the intake system and ending into the engine.
Most of the oil ingestion is taken in from the dirty side. That would be from the Pcv valve at the crank case to just behind the throttle body. That the line that feeds aftermarket catch cans.
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Originally Posted by redline_c7
I was checking out a new 2017 GS in the showroom when I noticed the PCV hose routing was different than in my 2014 Stingray's LT1. Both are dry-sump. It appears that GM has now routed one of the hoses so that oil vapors now are directed back into the engine rather than into the intake stream. Could this be a response to the oil ingestion issue that created the market for "catch cans"? Does anyone know any GM techs who may be able to advise if a 2014 can be retro-fitted with the new hose routing?
My oil level is always in between the min-max line on the dipstick and have not had oil in the airbox or throttle body despite some hard track runs. Might be beating a dead horse but never saw a need for catch cans. However, this new hose route might be in response to oil in the intake?
Pic 1 shows the 2014 PCV hose routing (red arrows) connecting to the intake air box
Pic 2 shows the new PCV routing (green arrows) with one hose bypassing the intake system and ending into the engine.
Yes, it was indeed re-routed. Tadge explained the system recently:
The Corvette's dry sump tank looks relatively simple on the outside but the internals are really quite complex. The top third of the tank contains a PCV air/oil separation system. On the Corvette, PCV lines route from the valve covers to the air/oil separator on top of our dry sump tank. Oil from PCV air is separated and returned to the lube system through the oil tank. "Catch-can" systems that do not have a drain back path for separated oil run the risk of poor oil pressure performance over time as oil is removed from the lube system.
I do not have the information about whether the new design is easily retrofittable or not.
David...are the connections you have labeled "crankcase" actually the connections to the valve covers? All of this plumbing is clean side, correct?
Are there any changes to the dirty side? Or does it remain the route from the valley cover to the IM plenum via the fitting you sell a plug to allow rerouting the PCV flow externally?
yes the 3 spots on the valve covers port the fumes coming up from the crankcase
the green line 'fresh air' to the CAI tube is the only one I consider clean side that we never want to see oil in. the lines connecting the oil tanks and valve covers can carry some oil during normal operation
for the lt4 you are correct, the 'dirty side' / pcv return / suction side is not shown, is buried under the supercharger. I have some photos of that trhough my website. Lt1 cars and the gen5 trucks still have an external return from the valley plate pcv valve to the intake manifold
for my part to fix that (lt4 pcv) and catch can I supply instructions on the install / re-route.
Hmm, would think you need more than the part numbers for the lines. It's what under the lines that is key, baffels, one way valves etc.
This is a pic I made trying to determine what the lines did and where the filtered air was coming from for the PVC system. The line used in my 2014 dry sump that was bringing in filtered air to the crackcase from the air intake tube is no longer there. Found that line but can't be sure of the function of the others.
^^^
Yep, after two years with my Grand Sport I am collecting 75% of the PCV oil as I was in my early 2014 Z51 with the same Elite Catch Can using one Exit. Therefore the can is simple connected to the outlet from the crackcase to the inlet to the intake manifold. It condenses oil vapor on stainless ribbon and than drops to the bottom of the can. That much less going over the back of the hot intake valves to coke. Note the stainless ribbon is coarse so there is no significant flow restriction.
Initially thought is was about half but that is a measure of all collected by miles driven, ~3/4 oz/1000 miles.
New PCV system?
