E92 335i (N54) PCV valve and Oil Catch Can Upgrade

[Herbmiester 909]

So now that I have owned my 335i for 2 weeks I am already in search of more power but before I do that I felt it was pertinent to address some of the N54's short comings. First and foremost in my mind anyway is the PCV system. The internet says that the PCV valve on the N54 is average at best and in some cases downright useless especially when boost levels are raised. This is also apparently a big contributor to the carbon build on the inlet valves which rob power reduce throttle response and effect fuel economy. With all that said I decide that for the price of an upgraded PCV valve and an Oil Catch Can it was cheapish insurance. 

The PCV Valve is made by RB turbo in the USA  http://www.rbturbo.com/products/accessories/rbpcv Shipping was $10 USD and it arrived 6 days after ordering it. 

The Oil Catch Can is made by Mishimoto and I bought this along with some M3 control arms from FCP Euro https://www.fcpeuro.com/products/bmw-black-baffled-oil-catch-can-mishimoto-mmbcc-n54-06cbe not sure on shipping as it was part of a bigger order.

The yanks say that with an upgraded PCV the need for a catch can is less. That said I chose to do both because I am OCD and think that DI engines need  super clean inlet systems. Your make think otherwise and opinions are like arseholes; everyone has one.

Fitting was pretty straight forward and it took my just over 2 hours with a few breaks for beer, sore back and a chat with the Hot chick who rides a horse on my property. The images below will show the main points you have to be aware of. I would say that if can do basic mechanical work this is well within your capabilities. 

There are a few videos on YouTube showing how to remove the cabin filter assembly but you start off with the cable wire harness. Pull up on the front tabs then remove, then use a small screwdriver and remove the tray from the main panel. I left my cable in the tray but the internet says to remove the tray. There is one cable left and it slots out the same way tray does, I found it easier to just remove the cable and leave the clip unit attached to the panel. 

The main panel is held on by 8mm bolts, 2 fine thread on the sides and 6 course thread on the centre section. You also need to remove the covers for the Brake unit and whatever it covers n the left side, these are held on with clips and toggles there are also a couple of toggles for the main panel in this area as well. There are also a couple of sensors on each side of the main tray remove them by unclipping and twisting out and lay then in the side gutters of the engine. Once bolts and sensors are removed just wiggle the panel out toward you and slightly upwmards. When its out it will look like this. Note the cabin panel filter comes out first then the main panel.

Next is the engine cover there are 4 5mm allen bolts, once these are  out the engine cover slide forward under the cables.

Next I replaced the PCV Valve, that's it circled in red. Use a 13mm spanner to get it off. The internet says that removing the rear fuel pipe makes this much easier, I would have to agree. It also makes it easier to get the flapper valve (next to it on the left off as well. The fuel is under pressure so you will get around 15-20 ml leak out so wait until the engine has cooled down before doing this. 

I then removed the flapper valve This has somewhat fiddly clip but be gentle as you need to reuse this part. The clip is best attacked with a couple of small flat head screw drivers. note the rear fuel rail is removed do not use excessive torque when reinstalling; it nips up tight with very little torque. 

Here is a top down of the PCV valve. This can be pulled out with a pair of long nosed pliers. 

Here are the two PCV valves the RB on the left and the stock unit on the right. Note the sock unit has threads but but it is just a push fit.  

To fit the new PCV valve  insert it into the housing and then screw it back in. Note there is a big O ring that in this case had stayed in the engine cover housing. Pull it out fit it to the screw in housing. if you leave it in the engine cover it will be a pain in the butt to screw it back in. Once this back in and tight the PCV valve upgrade is done. 

The flapper valve assembly needs to separated from the attached tube. Be careful;  I recommend using a hairdryer or heat gun to make the plastic pliable so it pulls off easily.  Once you have done this replace the flapper valve back on the fitting on the engine cover. 

The catch can hoses can now be fitted. The 180 degree hose is the outlet and it gets attached to the other side of the flapper valve hose port that was removed. Route the hoses to the front of the engine bay as per the photos further down.

This is how the two hoses will look when when fitted to the ports that were bridged by the flapper valve hose. 

Next screw the Oil Catch Can to the bracket with the supplied 2mm allen bolts and attach the bracket to the power steering reservoir. Now you can push the hoses on; the 90 degree hose goes to port marked out and the straight hose that is attached to the flapper valve goes to port marked in. There is no need to retaining clips as this whole unit is under vacuum not pressure. 

Put the engine cover back and dont drop a 5mm bolt into the engine compartment never to be found again. Fit the cabin filter panels back in place. fit the wiring harness tray and the side covers for the brake unit etc and your done. It should look a bit like this. 

Next up is the intake port/valve media blast and by then the downpipes, intercooler and charge pipe should have arrived. It will also have the M3 front control arms installed along with some Koni Yellows.

Edited October 23, 2016 by Herbmiester

[Matth5 471]

Maybe you should start a project thread with all the stuff you're doing.

Will be interesting to hear what difference you feel with the M3 control arms. Can't say I have any complaints about the stock ones I have but maybe I don't drive it hard enough.

[Herbmiester 909]

I thought about doing a project thread but wasn't sure if there was enough interest in the more modern BMWs. Maybe I will get the moderators to move it to the project section. I had the pleasure of driving a 335i and m3 on the same day the m3 front end was very accurate, the stiffer bushes in the control armsystem should tighten things up a bit and the extra camber should add some corner grip.

Edited October 24, 2016 by Herbmiester

[Olaf 3235]

Definitely interest, John.  

That catch can is a tidy addition to your engine bay.

I liked the "don't drop a 5mm bolt into your engine bay never to be seen again"

[Herbmiester 909]

Perhaps when I take off the drivers side wheel to install the Konis and the M3 Control arms I will find it. 

I will say that my E46 still pips it for handling but with shocks and arms etc the 335i might close the gap. That said I think the chassis is still very good but its really just a side show to the engine. What a great engine, just so much useable power everywhere.

Edited October 29, 2016 by Herbmiester

[Matth5 471]

3 hours ago, Herbmiester said:

I will say that my E46 still pips it for handling but with shocks and arms etc the 335i might close the gap. That said I think the chassis is still very good but its really just a side show to the engine. What a great engine, just so much useable power everywhere.

Think you have a good point there. The E46's are still great cars with wonderful handling. Took me 6 months to sell my E46 328i after I got my 335i. I'd take them on back-to-back drives on the back-roads out of Auckland. The E46 felt every bit as agile, maybe more, you feel a bit less isolated in it too which inspires more confidence. I also felt like it had better braking. Although my pads, rotors, fluid and lines were all near new on the E46 so that may have helped. 
The 335i took me longer to feel confident in, I was taking corners slower than in my E46 for a while. Once you get there though, its still a very agile car, it's surprisingly hard to lose grip in corners, you need some brute force from the engine to make it slide

I've never driven a 335i hard with stock suspension, only a test drive at a dealer. Find mine pretty sharp with the KWs, so I reckon those suspension upgrades should make yours feel more agile. 

MHD for the N55 is out now. Maybe next weekend I'll try out one of their tunes on my car

Edited October 30, 2016 by Matth5

[Herbmiester 909]

Yes probably not fair comparing it to a fairly well modded E46, so when the shocks and arms are done it will be a fairer match up. That  said my E46 even with its handling prowess would get slayed on the straights by the 335.