Driv200

iTrader: (1)

Hey guys,

I come to this forum for education. Concerned my duel catch can return set up with E85 was watering down my oil too much, I just tried reverting back to a single STM race catch can and -6AN ports on valve cover. This swap took out my Buschur dipstick return line from 1st catch can.....and replaced with a non return dipstick.....into the new STM race can.

What happened: After 2 street pulls, the new catch can had a large amount of oil volume. The change would not allow me to completed a 20 minute road race session before running low on oil. We discovered the oil volume came directly from the dipstick tube line that connects to STM catch can. The other lines were free from oil.

Why is my oil from pan pushing up so much and forcing volume into catch can.

I initially thought I had bad rings and the oil was coming through the other lines.....but this finding shows it's pushing up through the first "escape" line which is the dipstick vent line into catch can????

EVOizmm

iTrader: (10)

over the past few years and various testing, this is what I've found to work best.

single vented catch can with enlarged port on the side of valve cover.
Accusump 2qt system
Run oil level on low mark on dipstick.

That combo seems to have worked really well for me. I can make several sessions before filling the catch can.

honda-guy

iTrader: (55)

i don't see how venting from dipstick would ever work. the dipstick tube goes down pretty low on the block, and when you accelerate, the would splash back probably near the level of the dipstick opening. and there's no baffle in the dipstick like there is in the valve cover. if you've ever have a dipstick pop on track, you'd know how much oil spit out all over your hood and engine. that's the same amount of oil that would dump into your catch can if you vent from there.

i have vent from the front balance shaft inspection hole before. seems to work decent but it's hard to get a large enough line in there.

as Andy mentioned, the best thing to do is open vent catch can with enlarged side port on the valve cover. remove the rear PVC and run that into open catch can also if you need more venting. ive always fill oil to the full mark or slightly over to reduce oil starvation.

i have recently went back to all stock motor and turbo, running 320 whp on e85. my setup is large side ports into open vent can. removed rear PVC and run it into open catch can. both my cans are all most full by the end of one track day, but it's about 95% water/ethanol, hardly any oil in it.