What exactly is a catch can and how does it benefit?

[FST300ZX]

I've seen some heavily modified cars using catch cans...What exactly does it do and how would it benefit a modified car?

This is the only information I could find on the net is:

"Catches blow-by gasses that can create damaging carbon and oil sludge build-up in your intake including your intercooler. Less oil in your intake also reduces the risk of detonation. An absolute must for any import with mild to wild tuning that is subject to blow by gasses."

What are blow by gases?

"Less oil in your intake"?? does this mean I can install a catch can on a non turbo car? LOL

[Instamatic]

Blow-by is positive pressure in the crankcase caused by combustion gases leaking past the piston rings. Even healthy engines have some degree of blow-by, as it's virtually impossible for the rings to form a 100% air-tight seal.

Thanks to the design of its PCV system (the system used to vent crankcase pressure), the Z has a peculiar problem where hard right-hand turns can put a fair degree of engine oil into the plenum chamber. Depending on how it's installed, a catch can help minimise oil ingestion under these conditions.

Oh and yes, you can use a catch-can on a non-turbo car.

I've seen some heavily modified cars using catch cans...What exactly does it do and how would it benefit a modified car?

This is the only information I could find on the net is:

"Catches blow-by gasses that can create damaging carbon and oil sludge build-up in your intake including your intercooler. Less oil in your intake also reduces the risk of detonation. An absolute must for any import with mild to wild tuning that is subject to blow by gasses."

What are blow by gases?

"Less oil in your intake"?? does this mean I can install a catch can on a non turbo car? LOL

[My_Fairlady]

Be carefull, the $350+ ones are no different to the $50 ones. Don't be fooled by brands in this case ;)

[Chrispy]

There is a differance in the proper expensive ones. The good ones have baffles built into them to slow the air down and allow the oil to drop out. IMHO buy the biggest cheap one you can fit and stuff it full of steel wool ;)

[rom-vg30dett]

or just do a pcv bypass :eek:

There is a differance in the proper expensive ones. The good ones have baffles built into them to slow the air down and allow the oil to drop out. IMHO buy the biggest cheap one you can fit and stuff it full of steel wool ;)

[rollin]

blow by gasses in effect lower the octane rating of the fuel you use as they enter teh intake manifold

[ZEDZY]

How do you bypass?

[yellow_300zx]

There is a differance in the proper expensive ones. The good ones have baffles built into them to slow the air down and allow the oil to drop out. IMHO buy the biggest cheap one you can fit and stuff it full of steel wool ;)

could that not resualt in steel wool ending up inside ur engine? :S

[Chrispy]

Anything's possible. I know plenty of racers that do it without adverse effect.

You can bypass the PCV's, but then you are venting to atmosphere. Stinky, and illegal.

[dieseldave]

You can use the defunked AIV tube. no catch can to gain the boy's in blue attention and it give the same benefit. As per what I did for the track car, in the picture below. The road car runs a catch can and PCV, though to meet the ADRs.
http://i283.photobucket.com/albums/kk283/E-Vade_photos/Engine%20and%20parts/91386831_gGm5B7IO.jpg

[Mclovin]

This is interesting cos I noticed today the amount of oil in the intake plenum while I had the balance pipe off. Is any oil in there normal or does it mean my PCV valves are stuffed? there was quite a bit in there and it looked like it had lumpy bits in it.

[Instamatic]

Oil in plenum = normal

Lumpy bits = abnormal

[jakiro]

Is there any good write-ups on how to install one of these suckers?

I've got a brand new Greddy one waiting to go in.

[ZXXXII]

ok i know on my old vl it used to make a difference if if the pcv was removed it ran like crap so doin a bypass wouldnt that to cause the vg to not run the best if it was just a vl thing then how do i bypass because that is one less thing doin to the manifold

[Chrispy]

There is a differance bewteen bypassing and just blocking off. If you block it off it will cause problems. And depending on design bypassing isn't much good either, like on the VH. You have one line connecting both valve covers, another joining them and going to the intake pre throttle and another joining them and going through a PCV valve into the plenum... Fun... You let the PCV vent to atmo then you'll have problems and it won't idle (like mine did).