Do I really need a catch can

[The_Phantom]

I'm not sold on the necessity of these things. Do any of the major automakers sell cars with these included?

No, they don't. But somehow over the years amongst enthusiasts, it has become a "necessity".

I personally have never owned one and do not see the need for them. If it were a major threat, manufacturers would supply the car with them as they have to honor their warranty. Obviously, none (or at least not enough) are failing under warranty for them to deem it necessary.

OP, that's not normal. You have a seal issue for sure.

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[ahl395]

I don’t think a catch can does much for engine protection, I was against buying one but ended up with one anyway. Once I put the Procharger on my car I had oil coming out of the head unit from the PCV system pluming the oily PCV air into the intake. Now with the catch can installed it barely comes out of the head unit anymore. Was an oily mess and now it’s much better.

Make sure you keep an eye on the catch can. I had the same thing happen with my UPR catch can once it filled up (mostly with condensation, mixed with oil). I switched to a larger catch can that wasnt recirculated into the intake so it was impossible for it to make it's way into the Procharger.

 

[Genxer]

I'm not sold on the necessity of these things. Do any of the major automakers sell cars with these included?

Ford Performance offers them for both the Coyote and the Voodoo, and they don't seem to sell junk/useless things.

 

[armykyle1 [HACKED ACCOUNT]

Is it a necessity? No. Does it hurt anything? No. Can it help with deposits in the intake and valve tract? Most likely yes. With the new engines, the port injection isn't the primary fuel delivery anymore. This can and has lead to more build up on the intake valves. GM definitely had some issues with their new LT motors.

 

[BlueThunder]

Ford Performance offers them for both the Coyote and the Voodoo, and they don't seem to sell junk/useless things.

People need to get away from saying "the necessity" of these things. Nobody is saying your engine is going to die if you don't have one (well, a few goobers might). You don't "need" it. But they definitely do work (some to a much greater degree than others) at keeping extra oil/water vapor/slurry mix from going back through your intake. It's really not natural when you think about why these valves came about.

It's debatable if it's just a peace of mind item where you think not having one will definitely cause excessive buildup and cause problems or failures over time. But if you're chasing tenths or even hundredths of a second, I'd wager that having extra oil and water vapor coming through your air intake is going to cost you something.

 

[bootlegger]

Is it a necessity? No. Does it hurt anything? No. Can it help with deposits in the intake and valve tract? Most likely yes. With the new engines, the port injection isn't the primary fuel delivery anymore. This can and has lead to more build up on the intake valves. GM definitely had some issues with their new LT motors.

GM DIG has no PFI to assist. Big difference.

 

[GT Pony]

I think the only subject that gets more discussion and debating is motor oil and filters. That said, I do use a catch-can, and it keeps enough oil out of the intake to make it worth while to me.

 

[CEHollier]

I think the only subject that gets more discussion and debating is motor oil and filters. That said, I do use a catch-can, and it keeps enough oil out of the intake to make it worth while to me.

Agree. Initially I didn't install a catch can. After getting a new short block I decided to install it. I too get enough oil out of it to justify it's use.

 

[Loki-GT]

I am bewildered . Did Ford port inject the 302 for 2018 or not . Also there is supposed to be a redesigned baffle plate .

Wait . Start using an additive to your gasoline like Redline . Change that oil out . Your running catless and headers so your back pressures are increased . Check valves and CC . ....GOOD LUCK ..

How does removing cats and installing headers cause back pressure?!?!?

 

[Loki-GT]

A catch can isn't going to prevent that. Sounds like you were running E85 for quite some time. E85 has very poor detergency, as only the 15% gasoline is actually treated with detergent. Ethanol is a solvent, so it should actually clean things up. However, the corrosion inhibitors used in the ethanol are known to cause intake valve deposit. It is my suggestion is that you either run a full tank of high detergency 93 octane E10 (like Shell or Chevron) every once in a while, or add an ethanol friendly detergent additive to your tank. I believe PEA (Polyetheramine) is ok in ethanol.

BTW, I don't see a need to have a catch can, unless you are boosting. The stock engine has been thoroughly tested, and if blow by were an issue, it wouldn't make it through validation. IVD and injector deposit buildup is almost always an issue with poor fuel quality or low detergency.

THIS, this is exactly what I was looking for, a well reasoned explanation. I've built plenty of engines back in the day and in place of breathers used catch cans because I could build them myself and mostly to keep a breather from dripping oil than anything else.

 

[TGGT]

How does removing cats and installing headers cause back pressure?!?!?

Right !

 

[Loki-GT]

No, they don't. But somehow over the years amongst enthusiasts, it has become a "necessity".

I personally have never owned one and do not see the need for them. If it were a major threat, manufacturers would supply the car with them as they have to honor their warranty. Obviously, none (or at least not enough) are failing under warranty for them to deem it necessary.

OP, that's not normal. You have a seal issue for sure.

Playing devils advocate, perhaps they know that these engines will last a specific duration average with hopes of trade ins or? I know plenty of Mustang owners who have well beyond 100 or 150k miles on them so I don't believe this but figured I'd ask.

 

[Brian V]

How does removing cats and installing headers cause back pressure?!?!?

I Have already answered this .. go study exhaust velocities and tuned headers .

 

[Loki-GT]

I Have already answered this .. go study exhaust velocities and tuned headers .

Maybe there is a misunderstanding, in 35 years of building engines or modifying them I have never, ever heard or experienced reducing back pressure actualling increasing it. I don't need to study exhaust velocities to know that removing cats and increasing diameter of pipes increases airflow and reduces back pressure.

I'm not trying to be a jerk, I also Googled it and nowhere could I find a website where they stated improving exhaust airflow also increases back pressure so maybe they're all wrong?

 

[Brian V]

You do understand that there are velocities to exhaust pressures that are being released through an exhaust manifold .. headers need to be designed according to these velocities for a proper flow rate . Just going bigger does not mean you are evacuating these flow rates with out creating back pressures into the intake ,, 35 yrs ,, there are 2 velocities of pressure at each exhaust cycle .

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