Blowing oil bottom mount turbo issues

[b1mmerk1d]

I run a bottom mount dual BB gt35 turbo from cx racing on a spa mani and it blows a shit ton of oil occasionally. Like fogging for mosquitos. I suspect it isn’t draining correctly, the drain isn’t a straight shot to the pan and could be improved & that it’s getting too much oil because there is no restrictor. Where should I go from here? Should I run a restrictor and shorten/straighten the drain hose or run a scavenge pump/ collection tank & maybe the restrictor too? I could also switch back to a journal bearing turbo.

[b1mmerk1d]

Cars an OBD1 M3 w/ an S52

[pbonsalb]

Use a restrictor in the feed line for the ball bearing turbo and make sure the turbo center is clocked so the drain is in the 5 pm to 7 pm angle range and goes downhill towards the top of the pan.

[dominator293]

try the above first, but if it still doesn't work i fear you'll need a rutbo sump and pump to drain the oil. That's the problem with bottom mount turbos. Also make sure your oil drain is above the oil level in the pan because that could be the issue too, have oil feeding back up the drain tube.

[pbonsalb]

The SPA and GT35R is a combination proven to work with a gravity drain if set up right.

[Mklock]

Vented turbowerx scavenge pump back to pan. Using this currently. Works great!

[pbonsalb]

Yes, Turbowerx higher end pump is one of the best. If you have no choice but to use a scavenge pump. I ran one for 5 years because it was necessary due to the manifold I was using, but I changed bottom mount manifolds and now use gravity drain.

[b1mmerk1d]

Use a restrictor in the feed line for the ball bearing turbo and make sure the turbo center is clocked so the drain is in the 5 pm to 7 pm angle range and goes downhill towards the top of the pan.

Just ordered the restrictor, gonna install it & Rex lock turbo as you said. Should work I have my drain going into the top of my pan

[wgknestrick]

Just ordered the restrictor, gonna install it & Rex lock turbo as you said. Should work I have my drain going into the top of my pan

The other thing to check is the ID of your drain fittings as some of the elbows greatly restrict flow depending on the size of the drills used (as do some of the flange/NPT adaptors). In general, you want to use the largest inner DIA everywhere on your drain for the ball bearing CHRAs. Oil leaking is an issue with flow in vs flow out. Just chamfering some of the leading ID edges of the fittings helps a lot too. Obviously, you want as much slope to the drain into the pan too. You cannot have too much drain flow out.

You can also have a bad CHRA, but that is your worst case scenario after you've addressed all the cheap things.

I really like this piece, but it's not cheap. Nice tight turn, eliminates the NPT ID restrictions, and large ID inlet. The hard tube based flange adaptors are good too if you can find one (or make your own) with a tight bend in it. Try to use .75" ID tube if you can, and .625" ID is your minimum.
https://www.thoroughbreddiesel.com/5...RoCH08QAvD_BwE

[pbonsalb]

That is a nice looking compact angled fitting! Pricey but could be worth it.