Carpokes Porsche Forum

Does anybody have experience with an oil Catch Can for an '86 951? Thank you!

I ran one for a while but didn't "catch" much in it. I ended up opening the size of the hole on top of the AOS, which helped with pressure in the crank, and then concluded I didn't have much need for the catch can...

https://www.ievilenergy.com/products/30 ... ne-fitting

Will do the job at a good price. Solid build.

Depending how fast you’re filling that up, you might want to address the root cause which might be worn piston rings.

I have a relatively fresh engine, rebuilt about 6 years ago. I have practically no oil in the catch can. I think I had maybe half an inch after a year plus that included a track day. But I can’t say I was doing a scientific process to measure.

I'll chime in even though my car is the lowly NA. I've been running a baffled Mishimoto catch can now for a couple of years with my E85-only car, and the amount of water and yellowish "snot" it catches is surprisingly big. The climate might of course play a role here, we are well below 68 degrees F most of the year here in northernmost Europe. But I don't drive short distances or start the engine without always running it to good operating temperature, mind you.

Wespa wrote: Wed May 13, 2026 2:05 pm I'll chime in even though my car is the lowly NA. I've been running a baffled Mishimoto catch can now for a couple of years with my E85-only car, and the amount of water and yellowish "snot" it catches is surprisingly big. The climate might of course play a role here, we are well below 68 degrees F most of the year here in northernmost Europe. But I don't drive short distances or start the engine without always running it to good operating temperature, mind you.

Interesting. Is that typical for E85?

Thank you everybody.
I will check out Evil Energy.
My engine has been rebuilt and hasn't been started yet. We replaced the stock engine mount, which also provided separate oil returns from the turbo and the oil separator, with the mount from Speed Force Racing. Ran the turbo return back to the oil pan. Now looking at options for output of the oil separator.

Thank you again everybody. I will let you know what we go with and the result.

944m3 wrote: Wed May 13, 2026 5:33 pmInteresting. Is that typical for E85?

Hopefully someone more knowledgeable will comment, but I'd say it is quite typical, at least in cooler climates.

Tom wrote: Wed May 13, 2026 1:28 pm I ran one for a while but didn't "catch" much in it. I ended up opening the size of the hole on top of the AOS, which helped with pressure in the crank, and then concluded I didn't have much need for the catch can...

This seems to be the same outcome I keep reading about. People install one, find the 944/951 doesnt produce much and then return to the original AOS configuration, or enlarged opening. @Tom Do you still run the catch with the enlarged opening? Or what is your current setup?

spacecad3t wrote: Thu May 14, 2026 4:58 am

Tom wrote: Wed May 13, 2026 1:28 pm I ran one for a while but didn't "catch" much in it. I ended up opening the size of the hole on top of the AOS, which helped with pressure in the crank, and then concluded I didn't have much need for the catch can...

This seems to be the same outcome I keep reading about. People install one, find the 944/951 doesnt produce much and then return to the original AOS configuration, or enlarged opening. @Tom Do you still run the catch with the enlarged opening? Or what is your current setup?

I have the enlarged opening with the stock plumbing going straight to the j-boot -- no catch can.

These cars dont really have a PCV valve like on newer cars so not sure a catchcan is really needed. AOS is a more rudimentary setup and shouldnt really fill with oil much.

If your AOS is getting full of oil which is making you think you need a catch can, you may have excessive blowby causing too much pressure in your crank case that a catch can isnt going to solve (it will just fill with oil quickly).

If you have eliminated the AOS for some reason (custom setup or something) then a catch can can serve its purpose.