CAMS regulations: catch cans

**StuC** · 21-09-2009, 10:33 PM

I'm helping a mate out with his Evo4 track car and have been loking through the online cams regulations regarding catch cans. It has to be 2litres but is there a reg on whether or not it has to be closed in or can it have breathers on it etc:

I'm probably gonna knock something up myself as most off-the-shelf items are a lot smaller than 2 litres. Any ideas?

Cheers, StuC

**takai** · 21-09-2009, 10:50 PM

Can be either closed in or with breathers. Breathers must be filtered, although many scrutes dont care.

**Billzilla** · 21-09-2009, 10:51 PM

It'll be closed and have to have a breather that won't let fluid out.

**StuC** · 22-09-2009, 07:05 PM

so filtered breather (little k&n) on top at highest point so as not to let oil out if it gets too full.
something like this???

cheers guys

PS:havent used MS paint since grade 6. fun times!

**kaido** · 22-09-2009, 07:32 PM

it only has to be 2L if it breaths to atmosphere (via a filter)..
if it plumbs back into the intake system it can be a catch can of any size.

from cams manual
---
15. if fitted with any crankcase breather discharging to the atmosphere, each breather be vented into a catch tank
of minimum capacity of two litres for engines up to 2000cc or three litres for over 2000cc. Regulations for
competitions on unsealed surfaces may waive this requirement;"
----

and yeah if breathing to atmosphere those little K&N filters on the top are suitable.
but the diagram youve drawn is wrong, you dont need both a pipe back to intake, and a breather... you do one or the other.

**Billzilla** · 22-09-2009, 10:33 PM

Originally Posted by StuC

so filtered breather (little k&n) on top at highest point so as not to let oil out if it gets too full.
something like this???

Yep looks pretty good mate.

**MWP** · 23-09-2009, 12:19 AM

Originally Posted by kaido

but the diagram youve drawn is wrong, you dont need both a pipe back to intake, and a breather... you do one or the other.

^^^^ Correct.

If you can adequately filter the crankcase gas in the catch can (steel wool, fine mesh, etc), then do the non-vented & back to intake manifold.
You can also then run a can under 2L according to the quoted text above.

**StuC** · 23-09-2009, 05:41 PM

ah, ok, that makes sense now. i read it in a hurry. If a clsoed circuit with no breather (inlets to can, outlets to air intake), can cacn be any size
if it has an external atmo breather then it doesnt have to go back to the intake however it must be of a 2 litre capacity.

I need to have a look under the bonnet again to see what the space options are. i only had a quick peek at the hill climb.I'll check after Rob Roy when i put new bradid lines on it.

Another question - do the hoses have to be braided or is normal oil-resistant hose fine?