rmurer

For those of you running a roots type blower and oil separators.

Are you only running one? or both?

Blown CS

I'm just running a passenger jlt and when I emptied it yesterday it was 1/3 full after 2 months of driving or 800 miles. I'm gonna pull my intake tube off to get a look at the throttle body to see if any oil is getting by since I think the drivers side also has some blowing by. Really think the best set up is both sides to a catch can vented to atmosphere.

silverstate777

I run the Moroso small body separator, passenger side only. This was written by Modular Motorsports Racing:

We have been getting alot of emails in regards to the difference between a separator and a catch can, so we decided to post so that others can make the correct decision when buying.

What most people call a catch can is actually just a separator, the type is truly defined by its location, if it is mounted inline with the PCV hose it is a separator. A separator ONLY works when the vehicle is in vacuum (NOT boost) this is because the PCV closes the moment the manifold sees any amount of boost, at this point the engine crankcase switches breathing from the PCV side to ONLY the air inlet side, the problem is the GT500 (and all other mustangs) air inlet side (from the valve cover) connects to the suction side of the supercharger, meaning the supercharger/turbocharger is now sucking the oil vapors originally being caught by the separator and now putting it into the supercharger and ultimately into the combustion chamber which causes detonation and lowers the octane rating of fuel within the chamber. When the vehicle is wide open this is the most important time to keep the oil vapor out, which unfortunately the separator is no longer doing. Kits such as the MMR Breather kit allows the crankcase to vent the power robbing oil vapor into the atmosphere at WOT by way of a filtered catch can that catches the oil and separates the air -Much like the separators on the pcv side. Some tuners prefer not to vent the valve cover to atmosphere as it can cause a lean condition at cruise if the vehicle has not been tuned for it. A breather however DOES NOT cause a lean conditon (tuned or not) at WOT or anytime in boost if the inlet tube is properly capped off where it originally joined to the rubber inlet hose between the TB and MAF.

We hope this explains the differences! Ultimately, the best combination would be to have both, but in the realm of performance the most important for your engine is the one that works under WOT which is the breather kit.

Questions, comments - we are happy to answer anytime we are online.

MMR
Modular Motorsports Racing

TommyV

"This kit is designed to vent the non PCV valve cover so that at wide open throttle the engine can breath and does not suck in harmful oil vapors that causes detonation and damaged engines in supercharged, turbo charges and Nitrous applications."

If a bunch of FI engines were blowing up because of oil vapors, these would be standard equipment. Me thinks they're just trying to sell their kit.

AlsCobra

I agree with you. Nothing is gonna blow up if you don't run a separator. With the velocity and pressure you're building up into the intake runners, that little bit of oil vapors won't hurt anything either. If you're running a full race car, just run filters. This is a truly useless mod and more of a PIA than anything. Your crankcase is connected and only one side will be sufficient also if you must buy this mod. Check your throttle body when you change your oil for build up and just drive your cars guys. Enjoy them. Too much Interweb researching and con artists trying to sell stupid mods. Geez