would a FIT benefit on a catch can?
 

looking at the picture again... would a catch can be of benefit? and being that I'm waiting for my top fuel intake, it sure do make the rather bland engine bay look pretty non the less...

http://www.bosmobil.com/uploads/kale...1288641290.jpg

Certainly not a bad idea. Helps keep funky stuff from your crankcase building up in your intake manifold and ports, but you still have an EGR for emissions so that is still inevitable.

More of a necessary item on boosted applications, but a nice piece to have on any piston engine. But it can help diagnose if you are starting to get excessive blow-by from combustion.

Sometimes on cars that do not have a catch can) you might pop the dipstick out with bad rings or if you have out of round bores (OOR), bad valve seals, etc. ecause the combustion blows past the rings enough to push oil out. The dipstick happens to be the least path of resistance usually.

This can even be dangerous if you are on a drag strip and oil is spraying everywhere when your at the top of 3rd gear...

Or if you lift the cylinder head or pop a head gasket... all that combustion pressure and volume is now traveling through the oil and coolant passageways and it will find a way out ;)

So this is where the catch cans come in for oil and coolant.


On an NA, some V8 guys even use vacuum pumps to help with pumping losses created through through this blowby. Many will attest to picking up power from this.

you do realize that in every informative response you make you touch bases and then some :)

thanks DSM... your are one handy dude in this forum :wavey:

^^ agreed.

10 char

short answer: NO.

reason: sad fact... it's slow get another car if you want to race.

You don't have to be fast to have a catch can.. :confused: You realize that oil vapors and other combustion blow-by gasses get sucked into the intake under vacuum and make you far more knock-prone? It also helps cut down on carbon and other forms of grime that build up in the intake tract and cylinder head?

Also meant to point out in my initial response that EVERY piston engine has blow by, just to what extent is the question. Thats why we all have PCV's...

Agree.

To understand its purpose you have to understand blowby. Blowby exists in all cars as leftover combustion gasses that leak past your piston rings back into your crankcase. Pistons dont seal 100% thus some of this gas will escape. This causes pressure in your crankcase which is recirculated because of emissions regulations back into your intake system. This is especially a problem in turbocharged cars and constant high reving cars due to the excessive cylinder pressures. A catch can removes the oil and other contaminants and prevents them from recirculating. Blowby is recirculated for emissions reasons, but it can cause quite a few problems. Oil gums up intakes and intercoolers, making them less effective. Blowby that is mingling with your air/fuel mixture can lower its effective octane, not only lowering power potential but also encouraging detonation. Lets just say you want to eliminate as much of this as possible.

The reasons why I just installed a catch can is do to the fact that I track my fit constantly and canyon run. My fit runs constantly at high revs during long sessions. I have found about 3 table spoons of oil coming from the pcv line in my PRM instake every time I cleaned it at about 5k miles.

Here's mine =D

Attachment 39371

well, catchcans are usually used in race apps (high rev's) so that's why i mentioned. if you want to know if the stock car can handle hard driving, ive tested it the last 3yrs on my GD.

i drive my GD very hard at times (borderline abusive) and no issue. :)

... oh and even at borderline abusive hard driving, the car was in slow motion to me. :) if you have a turbo i think that changes a story a little bit but on a stock engine running high rev's, no issues.

you may not notice it if you don't check your intake regularly I do because I live out in the desert constant dust and sand is a issue.

but your right about the race application =D I just figured I would extend the life of my motor by keeping my valves from looking like this at 60k miles :)

Attachment 39367


Here is what I saw when I checked my prm intake after 10k miles found about 2 table spoons of oil the rest was trailing up the maf into the manifold. Which is why I decided to get a catch can :)

Attachment 39368

This is not a debate.. this is a fact of a piston engine. There is blow-by. Not every car has it to the same extent, even between seemingly identical cars.

Again, this is why you have a PCV.

Doesn't matter how fast you are going. The Valve is there for the purpose of alleviating pressure in the crank case. And like the example of the V8 guys using vacuum pumps, it is the same reason that your PCV is plumbed back into the intake.

Because under vacuum it reduces pumping losses. The consequence is that you are dumping more filth into the engine than necessary, even though the EGR will do it anyways once you get a catch can.

But every little bit helps. Some applications see more benefit than others.

You can drive slow and still find one handy. And before you give me the whole "but if it was that important or a good idea why didn't it come with one from the factory?"

Well there is more to designing a car for mass consumption than simply what works best. Believe it or not.

In summation... on high revving engines, I think a catchcan would come in handy, not a must but wouldn't hurt either to have one.

Peak cylinder pressure is at peak torque or VEmax, considering the Fit (both GD and GE) maintains the vast majority of it's torque across the rev range (thanks VTEC):
http://hondanews.com/media_storage/JPG/09fit_pt_3.jpg

This means that Cylinder pressure is pretty much always high in the Fit, hence a a catch can is a smart consideration for slowpokes too! And exactly why our fellow FF member here can show in his pictures copious amounts of oil has made it all the way to his MAF sensor.

And getting anything on your MAF can do all sorts of goofy and annoying things. Everything from idle quality to power to mileage can be screwed up with a contaminated MAF or IAT.

so I guess my next question would be... which can? are these cans just the same as others?

DSM,

Do you think I can put a T-fitting on the feed line to the catch can so that the crank case and the valve cover can be routed to the catch can, Basically killing two birds with one stone? Or would there be pressure difference that might introduce unwanted pressure in the valve cover from the crankcase or vice versa?

Hope that I'm making sense here. LOL.

?????? ?? ???? why would you want to spend more money by adding a t fitting. Just use the catch as it was intended and if you want to increase its effectiveness you can baffle it :)

Well you basically just need something that has a drain at the bottom some sort of filter media like 000 gauge steel wool to collect funky stuff and take oil out of suspension. Then you need to look for fittings and lines big enough to accommodate the amount of air you expect to move.

If you just want something functional? Just about anything you find in a Summit or Jegs catalogue will do!

For super blingy I would call up places like JM Fab, Shearer or DVDT and they will make you something otherworldly. :D

On an NA Fit? -4AN or -6AN, I would just go straight to -6AN (3/8").

On a boosted Fit -6AN at the absolute minimum, preferably -8AN. I am having -10AN (5/8") fittings put on my 1G's valve cover this spring. I currently have almost no blow by even with looser (.0040") Piston to Wall (PTW) clearances for my forged pistons because they expand with heat.

But I am doing this in the event something happens I want it to collect what comes out so if I am on a standing mile track like the Maxton or Texas Mile at the top of 4th or 5th I don't spray oil everywhere and either start a fire or lose control. That is if they would even let me pass tech without one. ;)

Though the Land Speed guys at the Loring Timing Association in Maine are supposed to be far more strict...

Your making sense :) and you are exactly right, it would create a pressure differential and it would somewhat defeat the purpose of the can.

You should route them both through seperate lines to the catch can. Most of them have 3 fittings. One from each.

This way you aren't screwing with the metered air (post-MAF sensor on a GE) in the system, this would basically act like a vacuum/boost leak. Which would cause you to run excessively on a Speed Density computer like that in the GD. And on the MAF'd GE it could cause all sorts of annoying hiccups and driveability issues.

So PCV, Valve Cover and Intake all should get dedicated lines. The can is there to help alleviate the pressure in the crank case and cylinder head by using the vacuum of the intake.

Noxm09,

Because the valve cover also has a hose that goes to the intake tract.............

hmm really brb gona go look at this :hyper:

Yup! The valve cover and the crank case are connected through the oil and coolant passageways! But because they both have their own way of seeing blow by, through the valve guide/seal and past piston rings... they can each have positive pressure in different amounts, and this can helps neutralize that and collect any gasses, particles and fluids that would otherwise get sucked straight into the combustion chamber and either cause harm, hurt the burn process, or build up grime over time!