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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Anyone have or seen a cross sectional expanded view of ZR1 LS9 dry sump oil tank?
trying to understand why using the clean air vent cap and routing then through my catch can stopped the excessive oil carry oil that was getting in air filter (discharge point of can in question)
because your oil tank was being pressurized through the pcv air line and pushing oil into your intake but now it appears that line is capped off so oil can no longer get to the intake?
Sorry for not being clearer - the stock vent is capped off that used to go to front can BUT now have “clean air” cap on oil tank replacing stock cap - this has a vent line off it that ties into the same catch can as the stock vent fitting did - so the path to air filter is still there - just using the clean air vent cap tie point vs. the stock vent fitting built into top of sump oil tank.
want to know if stock vent fitting is a dip pipe or how it looks inside of sump tank to better understand why this fix so effective - 630 wHP running E-85 - which generally generates more crank case gases than running pump gas.
Not an explanation of the dry sump, but a few years ago I went to a dual catch can setup, one of the cans never had anything in it. Here's a couple threads discussing why. Unfortunately some of the graphics have disappeared. But the gist is only one of the cans is effective. The other is receiving clear air.
Sorry for not being clearer - the stock vent is capped off that used to go to front can BUT now have “clean air” cap on oil tank replacing stock cap - this has a vent line off it that ties into the same catch can as the stock vent fitting did - so the path to air filter is still there - just using the clean air vent cap tie point vs. the stock vent fitting built into top of sump oil tank.
want to know if stock vent fitting is a dip pipe or how it looks inside of sump tank to better understand why this fix so effective - 630 wHP running E-85 - which generally generates more crank case gases than running pump gas.
Got it. I think it was @MTPZ06 that posted a picture of the inside of a tank to one of my threads a little while back. Let me see if I can find it.
A Z06 and ZR1 are completely different. NA vs. boosted....
For a Z06 At WOT the intake up to valves is at vacuum. Any leakage through valve guides will suck air back in from sump
and draw air from filter as described in these threads.
a ZR1 at WOT is at 10psi boost all the way to intake valves - any leakage on valve guides will send flow forward to sump and thus into air filter. This was problem I was seeing - on successive WOT pulls - the can between sump tank and air filter was filling and with twisting through corners - did not take long to burp over into intake. Have K&N CAI intake and filter and the tie point for this vent will actually drain down to filter vs. into throttle body. Thus would burp oil out after a few minutes (also screwed with MAF as it will get some oil mist on it as well).
using the clean air cap on tank causes almost all the oil to drain back into tank vs getting carried forward into catch can (again early data is clearly less oil in can now). Running E85 even more crank case vent gases are present since is much less dense than pump gas (appr 35%)
How is a z06 any different than a zr1 when it comes to blowby through the piston rings? Both will make the sump tank become pressurized and the only outlet is at the intake filter.
Cylinder blow by will go through the valley vent - i’ve Separated the valley vent from the valve cover vent as shown here - cylinder blow by will go same route but what’s different is flow off of valve covers as described previously - pressurized LS9 vs. vacuum LS7. That is can that was getting full.
Flow direction can be both directions in both systems...
I have mine setup the same way you have in your drawing and also found the most oil was on the valley cover to throttle body line. I removed the second one that goes between the oil tank and air filter as it was always bone dry. I have the aviaid insert in the tank though which adds an oil scrubber...so I am sure that helped.
The thing is - the valley cover hole is actually tiny - dont let the tube size mislead you. This is why flow goes backwards in either system as it is easily overwhelmed.
The valley vent will get flow from piston ring leakage and normal breathing during running - the valve cover vents Will generally see flow from leaking valve guides and normal breathing that occurs. Per folks at Prospeed who’ve tuned lots of e85 high power engines - vent flow off of heads goes up significantly while running E85 especially at WOT and full
boost - Just has stock vent setup off of sump tank so the clean cap is doing just what it needs to do. (So far).
you have part number for the Aviaid insert piece?
i’ve always gotten more oil on valve vent can - maybe valve guides need inspected if I can’t control it with the clean air cap. The excess flow only started after swapping to E85
Still getting high oil vent addressed - current catch can system is really undersized for HP level now hitting - the smaller lines from valve cover vents are getting a very high flow rate at WOT - Prospeed is going to install their larger catch can system and larger vent lines/connection. System comes with a fender mounted drain so can be dumped before each track session to minimize any chance of overflow on what will now be an atmospheric vented system vs. closed loop back to intake/TB. A Have ruled out any engine problems causing high vent flow compression good and no leak down - excess flow around valves not issue as problem only shows at WOT and not all the time.
Still getting high oil vent addressed - current catch can system is really undersized for HP level now hitting - the smaller lines from valve cover vents are getting a very high flow rate at WOT - Prospeed is going to install their larger catch can system and larger vent lines/connection. System comes with a fender mounted drain so can be dumped before each track session to minimize any chance of overflow on what will now be an atmospheric vented system vs. closed loop back to intake/TB. A Have ruled out any engine problems causing high vent flow compression good and no leak down - excess flow around valves not issue as problem only shows at WOT and not all the time.
I have always used #12 an from the valve covers to a Peterson catch can on wet sump systems or to the dry sump tank. The vent should also be sized the same sized on dry sump. The lines should also not form a trap for fluids. This is very tough with the limited space on a vette.When you start making HP and road racing band aid stuff will not work. You may be looking at a true 3 stage dry sump system in your future.
Prospeed can uses -10AN fittings from valve covers to can (double stock diameter) also getting the Aviaid tank insert and pan trap door baffle inserts. Working through problems as they come up - all getting addressed - one step at time
Hopefully above will be enough - but only time will tell. Car is 630 wHP currently and will get pushed to 750-800 wHP if all systems in check - but only after thrurough check out at COTA and some full sessions with all sub 2:30 laps or so.
car is a cornering beast and over 2 G’s will be the normal on fresh tires....car is easily capable of going under 2:15 currently - driver mods still being worked out....
04-15-2019, 01:31 PM
ZR1 dry sump oil tank expanded view
