Catch cans (turbo cars)

[Donor]

Ive searched

What would be the best CC to use on my 4agte? Im thinking just running a line to the can with a breather mounted, would i need to run a line from each rocker cover or just one? Do cans on turbo motors require a vacuum to purge or not nessesary????ta for the help

[Ae92typeX]

Ive always run a vacuum line on various engines to prevent fumes which always manage to get into the car one way or another.

[Donor]

Thanks, how would you run a vac line to the can? wouldnt boost psi blow the can apart? Im thinking of running one line to the can via rocker and being done with it

[Ae92typeX]

can have a one way valve on vac line...even though I cannot recall if I did have one on last car (and still had no issues)
but either way, with a breather, it wont blow the canister.
See what other opinions are, but I hate catch can fumes floating around.

[matt dunn]

The main performance reason for fitting a catch can is to prevent the vapours from entering the engine as they cause detonation,

So why fit a can and then run it back into the intake anyway??

Matt

[RedMist]

The main performance reason for fitting a catch can is to prevent the vapours from entering the engine as they cause detonation,

So why fit a can and then run it back into the intake anyway??

Matt

It could be used as a condensor. But you would be better off using professional condensors.

However I wonder if anyone has ever dynoed a low breathing 4age with a catch can installed. Theoretically they should be increasing windage and reducing HP, as the block isn't under vacuum.

[Ae92typeX]

The last time I used it, it was in the sense of a condenser. The catch can certanly did work, but I do understand the point of preventing vapours.No doubt I was getin some.

[Bazda]

I think the Motor sport of NZ rules is what ever cc your car is thats what teh catch can has to be.

[pc]

If fitting a catch can, fit it to the motorsport rules... otherwise you might have a problem if you go to the track. I can't remember the rules, but will cut & paste from other sources.

(a) Engines up to and including 2000cc shall have a minimum of 1 litre catch tank capacity.
(b) Engines exceeding 2000cc shall have a minimum of 2 litre catch tank capacity.
Turbo engine = engine cc * 1.7

[Mr Revhead]

i dont run a vacuum, was going to fit one then when i emptied it the first time and saw how much water and crap was in there i decided not too.

[sergei]

I have an idea of electric vacuum pump sucking it out all the time, but I can't source one... I think it will give good results becuase it will decrease pressure behind the pistons thus increasing pressure difference on power stroke, also it will seal the piston ring better, the oil seals will seal better as well.

[Ako]

Don't a lot of the V8 boys run an exhaust valve thingy?

I should explain that. Breather goes out into exhaust, the vacuum from there is a constant vacuum gas evacuation sorta deal going on.

Though that makes sweet f-all sense to me - isn't there POSITIVE pressure in the exhaust?

Well done mark, you've just confused yourself.

[Mr Revhead]

yep they run the breather into the exhaust.
which is why so many of them get real smokey at the top end.
i beleive it works like extractors.... the gas rushing past the opening of the breather sucks the fumes out.

[Donor]

The main performance reason for fitting a catch can is to prevent the vapours from entering the engine as they cause detonation,So why fit a can and then run it back into the intake anyway??Matt

thats what I thought! but all the cans on trademe have two tubes welded to them ........WTF aye? maybe this collects oil mist in the can so reasonably clean air is sucked into the in/man???. Im thinking these are only for n/a motors???

Don't a lot of the V8 boys run an exhaust valve thingy?

Yep I got given a valve that goes between the hose running from the rocker cover to exhaust, thinking of running one on my ccan but dunno if I really need to?

Well done mark, you've just confused yourself.

Well im the one thats getting confused i think

Do I need to run two lines into a can with a breather or will one be fine? thanks

[RedMist]

I have an idea of electric vacuum pump sucking it out all the time, but I can't source one... I think it will give good results becuase it will decrease pressure behind the pistons thus increasing pressure difference on power stroke, also it will seal the piston ring better, the oil seals will seal better as well.

I have two American high power, power steer assist vacuum pumps here, apparently perfect for what you are proposing. I thought of doing the same thing... hence the pumps....but I have additional sump issues... so dry sump for me.

[RedMist]

The main performance reason for fitting a catch can is to prevent the vapours from entering the engine as they cause detonation,So why fit a can and then run it back into the intake anyway??Matt

thats what I thought! but all the cans on trademe have two tubes welded to them ........WTF aye? maybe this collects oil mist in the can so reasonably clean air is sucked into the in/man???. Im thinking these are only for n/a motors???

Nope its not for any motor. Its pure bling. You're pressurising the can with no release... stupid. Or if the expect you to use it as a collector, then its just a silly design, you want to spool the air around and around something cool to condense the oil vapor.

Don't a lot of the V8 boys run an exhaust valve thingy?

Yep I got given a valve that goes between the hose running from the rocker cover to exhaust, thinking of running one on my ccan but dunno if I really need to?
[/quote]
The v8 boys do this because either they are regulated and cant dry sump, or are very old school. Exhaust excavators dont work very well at all. Its hard to generate enough vacuum, especially with a low capacity engine.

Do I need to run two lines into a can with a breather or will one be fine? thanks

The more flow you get into the catch can the better. I run two very large lines and have found that I dont get the traditional bigport issue of the head filling with oil anymore.

[sergei]

PM me with the price for pumps, that if you want to sell them...

[dash]

a crankcase venting system maybe what you're looking for.
Solved problems for Total Seal rings on our 2.6 starions, whose PCV has been considered 'marginal'.
Guys even swear they 'felt' power increase with the krankvent
http://www.krankvent.com/

[RedMist]

Butt dyno strikes again.

What is a vacuum valve?

It appears to combine the worst of all worlds. It appears to use partial intake vacuum, so not as powerful as the stock system. still vents to intake, and it combines the common bling issue of sucking raw shyte back into the head on block vacuum situations, such as starting.
Interesting that they dumped the specially designed bling shape for "racing" applications.
Anyone dynoed one?

[sergei]

I was looking at Z3 other day at work and I've noticed it had a electric motor attached to a pump looking thing which is connected to a tube going through a valve to rocker cover.... It looks like they have a pump sucking out from rocker cover from stock.