[TDIwyse]

Originally Posted by JDG

Thanks yet again TDI! looking good, I might pick up one of these tubes and a sheet of Kydex. This mod looks like it frees up a bunch of room under the hood.

I just used the kydex and pipe insulation because it was handy and scrap from another project. And its easy to drill holes and use zip-ties on.

Here's a pic of the provent in the engine bay on the passenger side with enough room to run hoses with the AEM/Silicone setup. The Provent isn't optimially shapped to fit here due to its in/out setup. I may look more at the BMS can you guys have been using or some other crankcase ventilation options that have a heating option.

[TDIwyse]

Some good info when dealing with crankcase ventilation.

http://pdf.cat.com/cda/files/3375381...EBW4958-02.pdf


Goes over equations on how much blow by to expect for a given power level on an engine, and the impact of blowby on engine aging. Gives equations on calculating recommended pipe diameters for given blow by amounts for varying lengths of runs (longer runs need larger diameter lines), impact of bends on the line length calculations, recommendations on orienting and sloping the runs to avoid pooling/freezing of condensing gases, etc.

[BB_cuda]

Originally Posted by TDIwyse

Some good info when dealing with crankcase ventilation.

http://pdf.cat.com/cda/files/3375381...EBW4958-02.pdf


Goes over equations on how much blow by to expect for a given power level on an engine, and the impact of blowby on engine aging. Gives equations on calculating recommended pipe diameters for given blow by amounts for varying lengths of runs (longer runs need larger diameter lines), impact of bends on the line length calculations, recommendations on orienting and sloping the runs to avoid pooling/freezing of condensing gases, etc.

I read through this tech article. The effective lengths on page 8 seemed confusing to compute so I sought out what I had learned in fluid mechanics as a college sophomore. I pasted in tables for feet and meters. I'm looking at a 1 ft hose run each way plus angle fittings. It is a huge hit in effective length to add 1 90° elbow to a 1 foot run. The inlet run will need (1) 45° [just like JDG has] + a 90° to point it to the passenger side. The outlet run will need a 90° to point to passenger side as well. As stated a few times before. I'm aiming for the BSM N55 mount on the front corner of the engine bay. Using 1/2" diameter values (following JDG's lead here), the inlet run effective length is 39.04" and the return effective length is 38.4". Those 90° pieces are 2.2' each!

[JDG]

BB, using your supplied chart there and my setup I am running approx. (equivalent) 10.5ft tubing. I am only using 1 90 degree(short radius) fitting with a 1/2id. this may or may not take into account the factory parts(hard tube and other parts)

Using a shorter run would be better but the options are limited so far. To be honest Im not going to over think this. I don't have an issue with the hoses or freezing, Im just going to enjoy my mod.

On a side note, non mathematical in use of the cat PDF, one must think that a positive vacuum(ingestive) would still produce better flow than non-ingestive. Non-ingestive is doable in a non EPA regulated area, just food for thought.

[TDIwyse]

Originally Posted by BB_cuda

...I pasted in tables for feet and meters...

Thanks for the tables.

[BB_cuda]

TDI:
Another place in the article that isn't clear. Page 7. The exhaust flow rate Q.They state 0.5 ft^3/hr bph and 1.0 ft^3/hr bph for a worn engine. Are we supposed to mutliply by estimated hp? For instance, say we tune up to ~350 hp. Would Q=1.0*350=350 ft^3/hr. It would have been good to have included the multiplication sign (*).

Recall a while back i mentioned a friend (named Flint) that was the "air handler" for 76L turbo diesel engine built by Cummins. Perhaps I will send this to Flint and get his take on the article. He spec'd the turbos/ intercoolers/many other things in his job there with Cummins (owned by Caterpillar).

[TDIwyse]

Originally Posted by BB_cuda

TDI:
Another place in the article that isn't clear. Page 7. The exhaust flow rate Q.They state 0.5 ft^3/hr bph and 1.0 ft^3/hr bph for a worn engine. Are we supposed to mutliply by estimated hp?

That's the way I understood it.

[BB_cuda]

For your amusement as I got silly numbers:
I ran the computations from the caterpillar tech article. I did it on metric as the units were not canceling out correctly doing it the English way. I used the following assumptions. I went with 350 hp=261 kW assuming a modest tune but with no EGR and no DPF operation i.e. tuned out (YMMV)
P=25.4 mm H20=.249 kPa
Q=[.04 m3/hr]*261=10.44 m^3/hr
L=77 in=1.956 m
S=1.08 kg/m^3

I rerranged the formula to: D^5=[L*S*Q^2*3.6E6/P] and then took the 5th root of it. Numbers seem to be garbage:
L=77''=1.96m yield pipe diam=82 mm=3.22"
L=24" (2) straight lines now=.6096m => D=41mm
L=8"=.2032 m => D=33mm

If the eqn in the cat article is right, we're gonna start blowing main seals soon :-D. I believe the whole thing is breaking down because of the assumed pressure. It is in the denominator so as the pressure assumption increases, the needed D will get smaller. I'm unsure of the 3.6E6 factor and where it comes from but was super careful to cancel all of the units out such that inside the expression came out to units of m^5. Thus after taking the 5th root would yield m. I had to decompose the units down to Newtons, kg, 3600s from hr, yadda yadda yadda. So, lots of places to go wrong for this mechanical engineer.

[TDIwyse]

I think those equations were simplified to the point that the units are not needed any longer. As long as you use the correct equation for metric vs english. So just plug and chug.

For example, if I throw in 340hp (->340 ft^3/hr for a worn engine using the CAT formula -> 5.6666 ft^3/min) and 5 feet of tube and want to keep 0.5 inH20 I get a pipe diameter of 0.65 inches. That seems reasonable to me.

[Mark M]

I admit, the formula tripped me up, I tried to crack it for the last 25min. I've been out of school too long.

TDI, for ~300 hp engine with the equivalent of 12.125 feet of hose, what do you calc as the recommended diameter? Thanks in advance!

[TDIwyse]

Originally Posted by Mark M

TDI, for ~300 hp engine with the equivalent of 12.125 feet of hose, what do you calc as the recommended diameter? Thanks in advance!

I get 0.736 inch diameter with those numbers.

[BB_cuda]

Originally Posted by TDIwyse

I think those equations were simplified to the point that the units are not needed any longer. As long as you use the correct equation for metric vs english. So just plug and chug.

For example, if I throw in 340hp (->340 ft^3/hr for a worn engine using the CAT formula -> 5.6666 ft^3/min) and 5 feet of tube and want to keep 0.5 inH20 I get a pipe diameter of 0.65 inches. That seems reasonable to me.

Thanks TDI for setting me straight.

Okay, just following the formula now. I screwed up by not using inches of water for pressure as i was using psi and cancelling units. Also, screwed up using ft^3/hr instead of cfm.

anyway, using 350 hp, 77"=6.41', 350 ft^3/hr=5.833 cfm, I get D=.69". Sounds like I need 3/4" ID hose. I don't recall size of BMS OCC inlets/outlets. Wonder if 3/4" ID will fit.

[JDG]

3/4id will need some adapters to get a good seal. The pipe supplied with the can is 3/4" od. How are you using 12' of hose? I have mine run to the front of the engine almost to the back of it and use just a bit under 8'.

[Mark M]

JDG, to measure flow restriction, using the formula in the Cat document, the affect on flow for a 3/4" ID 90 degree elbow is the equivalent of 2.0625 feet of hose length.

So 2 elbows = the equivalent of 4.125' of hose + 8' of standard hose = 12.125' of equivalent hose length.

However, I will go on the record and say that to me, the best option for an OCC looks to be cutting the hard line right off the hockey puck and then using tubing to the catch can on the driver's side cowling and run the return back to the hard line. Guessing that can be done with only 1 90 degree elbow and about ~3' of tubing in total. But it will be non reversible since you'd be cutting the hard line.

I'm doing a ~2200 mile round trip down to the 12 hours of Sebring next month, so I'll be able to really rack up some miles and see how the BMS can performs.

[BB_cuda]

Originally Posted by JDG

3/4id will need some adapters to get a good seal. The pipe supplied with the can is 3/4" od. How are you using 12' of hose? I have mine run to the front of the engine almost to the back of it and use just a bit under 8'.

JDG, used 77"=6.41', not sure where you are saying 12 feet? [Edit, i see you were asking Mark, not me]

JDG, is the 8 feet the sum of inlet and return legs?

The 6.41 feet was really based upon 1 ft hose each way but added in (2) 90° long radius elbows at 2.2" each +(1) 45° elbow at 0.625 (negligible) =77".

Also, thanks JDG for the info on the BMS OCC connections. I found clear 18mm ID hose X 25 mm OD hose made of silicone. Perhaps this would be good in terms of seeing if OCC is really working [inlet dirty and hopefully cleaner outlet]. 18 mm converts to 0.71". I know this is silly. I was just googling for 18 mm hose and the clear popped up first. 3/4" ID would be more conventional but as you say flare fittings would complicate the install a little.

[Mark M]

3/4 ID hose fits the BMS can perfectly.

[BB_cuda]

Originally Posted by Mark M

3/4 ID hose fits the BMS can perfectly.

Thanks Mark, does the kit come with 3/4" ID hose? Did you jumper the electrical thing at the top of the ribbed hose? Seems i recall that is where you spliced into the breather system.

[TDIwyse]

Did some experimenting on the spare vent pipe I purchased. I cut it in two at the neck around the oil cap area where it's really narrow, and wanted to see if I could shape the plastic into something kinda round. Turns out, the material is heat moldable. This opens up some interesting doors for very short routing on the passenger side...

[TDIwyse]

Anyone have any data on the pressure drop across the BMS catch can at various vapor flow rates? Whatever pressure it adds really needs to be accounted for in these calculations.

Also, it would be a good idea to check the line routing for "low spots" where condensing liquids could pool and create blockage/restrictions. That CAT article talked about suggested minimum slopes to avoid this issue.

[TDIwyse]

Another question for you BMS catch can guys ...

Is this piece on the N55 catch can setup to fit into the "puck" on top of the engine that the vent pipe end slides into and has the one screw to hold it in place?

[BB_cuda]

Go back to my post at #231 where i show the N55 335i engine bay. The hardware you point to is installed at point C.

The N55 install instructions say this in regard to position C
2) Unscrew the two torx screws holding the PCV assembly to the intake pipe in position C.
5) Insert the BMS nipple in position C and tighten the OEM torx screws snug.

I think I see what you're up to. Tap in right at the puck outlet and then splice back in somewhere in the middle of the breather tube. Perhaps use the elbow that Mark got from Advance Auto or wherever it was. This would suit your want of aft of the AEM filter location and get the heat from engine/turbos and not use a heater. Splicing in on top may give you more room. You must be a creative/right brained person. This might in fact allow mounting onto the passenger strut brace if not too crowded.

Don't have any data on flow characteristics of BMS OCC. Terry ought to be following this thread now as he may be getting more indirect business.

[JDG]

Originally Posted by Mark M

3/4 ID hose fits the BMS can perfectly.

I apologize for my incorrect measurement earlier. Mark is right, I don't know why I though that the hose was 1/2 ID. Anyways sorry, and I also forgot to add for the 90 degree elbows when calculating length. Been a off day for me.