What vaccum lines can I cap off?

[my3awds]

I want to cap as many useless vaccum lines as possible to clean up the engine bay and let the intake burn a bit cleaner. I'm assuming both lines from each valvecover can be capped off and the middle engine bay bung. Can the PCV and the 2 lines that go to it from the engine be capped off? Also, can I skip the fuel pressure sensor and have a line go directly from the intake manifold to the fpr? I'm just trying to avoid any potential leaks. Thanks for any help

Manny

[Project_Legacy]

i dont think capping off the pcv line is a good idea. ive seen a dood put one of those breather filters on it, and it was leaking oil out of it.

[206er]

some have claimed that PCV gases can induce detonation so deleting them from the intake might help but DO NOT cap them off.
maybe run them to a catch can with a drain, and route that to the oil pan somehow.

[Project_Legacy]

yea thats a good idea. a catch can would be perfect.

[my3awds]

Oh ok. So I can cap off all lines except for fpr, wastegate, bov, brakebooster, and just catchcan the PCV.

[sammydafish]

WTF?

Why would you want to cap off any vaccum lines. None of them are useless. Each one serves a specific purpose, especialy the PCV lines. Don't cap them or dissconnect them. They need vaccum. The crancase needs to be under vaccum to ensure good ring sealing and it also helps to reduce pumping losses. Opening up the PCV lines will cost you power, economy and engine wear as well as be an emissions issue and is therefore illegal.

[my3awds]

Well, opening exhaust flow by deleting a cat or any performance modification these days can be considered an emissions issue and therefore illegal, but people still do it.

The only vacuum lines I wanted to remove were the emission lines, the ones that put oil or extra exhaust gases in your intake track. Again, coming from the dsm world, I've done this without any adverse effects (except for maybe the environment) and it has helped especially when you have a bit of blowby. This is why you see pretty much 0 vacuum lines on race setups. BUT, since the ej engines are designed differently I thought I'd ask just to be sure. Thanks for the warning.

[sammydafish]

Well, opening exhaust flow by deleting a cat or any performance modification these days can be considered an emissions issue and therefore illegal, but people still do it.

The only vacuum lines I wanted to remove were the emission lines, the ones that put oil or extra exhaust gases in your intake track. Again, coming from the dsm world, I've done this without any adverse effects (except for maybe the environment) and it has helped especially when you have a bit of blowby. This is why you see pretty much 0 vacuum lines on race setups. BUT, since the ej engines are designed differently I thought I'd ask just to be sure. Thanks for the warning.

your car is not a race car. Race cars have dry sumps so they don't need PCV, they have fuel cells so they don't have evap systems, they have high overlap cams so they don't need EGR. All of these things are not only emissions systems but they also help the performance of your car in some way. Your car also needs to operate in more diverse climates so there are control systems to compensate for that. Race cars have none of this because well, they are not street cars.

You won't gain any amount of performance in any way be removing any emissions system on your car save for the catalytic converter. That's the only emissions equipment that hurts performance and it can be elevated using a more modern unit. There are production cars making over 600hp though cats. Until you're over that limit, you've got not argument to remove that either.

[vrg3]

Your assumptions are wrong. Listen to Junior, he knows what he's talking about. Do not cap off PCV fittings.

But, you can simplify the plumbing of an EJ22T a little bit.

http://www.graphics.cornell.edu/~v/vacuum/

Put a check valve in hose E, H, or I that only allows flow towards the throttle body. Then you can remove the auxiliary purge valve, the tee, and hoses C, D, P, and Q (though hose B may need to be a little longer). You can then cap the nipple on the resonator and the charcoal canister.

Also, you can disconnect hose J from the resonator and stick a filter on the end instead. Then you can cap the nipple on the resonator.

I've done both of these to make it easier to build a replacement for the resonator.

And of course if you're using an MBC, you can remove hoses M, L, J, and K, and also the union fitting. Then you can cap the fittings on the boost control solenoid.

For the rest, just make sure you're using new quality hoses and that they're secured with zipties or something. There aren't that many.

[my3awds]

No, I wasn't arguing Junior's post nor was I justifying capping the PCV. I asked and already several people before him posted not to do it, so I wasn't planning to.

vrg3, can you explain where I made an assumption, and a wrong one at that? Not trying to argue with you but I am trying to learn. Does not the EGR recirculate exhaust gasses into the intake track for emissions purposes? I know the ej22t doesn't come with an EGR, but the 1.8 does. And many dsm'ers have made EGR blockoff plates to help a with a cleaner burn, and thats why I've done it before on the few DSM's I've had. Also for the PCV, doesn't it act as a waste, thereby putting excessive oil in the intake track?

True, there are 600hp factory cars with cats, but they have the displacement to do so +more. We're talking about 4 cylinder turbo cars here, not V8 turbos or 12s. I have yet to see a 400whp 4cyl produce that power without removing exhaust restrictions. Anyone who's anyone with a turbo'd 4cyl will likely choose a delete over a highflow if their goals are anywhere past 350whp. It just wouldn't make sense to add a restriction as simple as a cat. If you're going to alter your air:fuel ratio to gain your whp goals anyway, why not remove the cat? You are already going against emmission standards by using a piggyback, afpr, or standalone. So saying one needs at least 600hp before having justification for removing a cat due to emissions purposes doesn't make sense to me, especially with how hard it is to reach that goal as is on a 4cyl. I guess this is besides the point, so I'll just skip this.

Thanks for the graph and replys everyone. That pretty much answers my question about what can/can't be simplified under the hood. Even though it sounds like I'm trying to be annoying, I'm not. I really would like to learn more.

[vrg3]

I'm saying that the assumption stated in the original post -- that you can just cap off five of the engine's six PCV fittings -- is wrong.

I didn't know we were talking about EGR. I thought we were talking about an EJ22T. But, to respond to your questions about EGR, it can be harmful to an engine's longevity and performance to remove a factory-installed EGR system. I don't know about DSMs in particular, but properly done, EGR improves an engine's efficiency as well as emissions at moderate loads. Many cars with EGR removed will run poorly because of it. And at idle and at high load, EGR isn't used, so it usually doesn't affect peak performance one way or another anyway.

PCV does cause the engine to ingest some oil, but that is a side effect and does not outweigh its positive effects. I don't understand what you mean by saying it acts as a waste.

Do not confuse removing exhaust restrictions with removing equipment as a whole. A high-flow catalytic converter flows much better than the factory one but still performs the job. Choosing a cat delete over a high-performance cat (which actually isn't very restrictive at all) isn't the obviously correct choice.

Furthermore, 600 horsepower is 600 horsepower, regardless of the displacement of the engine producing it. 600 horsepower's worth of exhaust gas flows out the tailpipe of a 600hp V-12 just as it flows out the tailpipe of a 600hp L-4. The presence of a cat doesn't really have much to do with what size and shape the engine is.

But anyway... yeah.