with only 9K left on my warranty I decided today to do the crank case vent mod. I basically made a catch can that vents to the atmosphere but will not coat my jeep with oil or leave spots on the driveway.

then I got carried away and built a new air filter setup. it's not the best design by far (draws hot underhood air) but I thought I would share some pictures and some 'lessons learned' for any like-minded CRD owners on the board.

the catch can is a 1 qt oil bottle stuffed with a rag and vented with a hole at the top. the crankcase vent line goes into the bottom. that way all the vapors have to pass though the rag to vent out the top, hopefully stopping any oil droplets and collecting the mess in a nice disposable container.

as far as the stock intake, when the crank case vent line is re-routed it leaves a 1/2" hole in the intake pipe that must be plugged up, rather than plug it I decided to replace the entire intake. I'm logical like that. the stock air inlet hose is very small in diameter and has a total of 4 bends, including the airbox plumbing. so I installed a 2.5" stainless steel mandrel elbow and no other bends. the MAF housing was sawed off of the stock air box lid and happened to be just the size for a 3" inlet AEM universal dry-flow filter. this filter was $35 at advanced auto parts and supposedly has a very high filtering efficiency to compliment it high flow rating. the filter is made in the USA as well.

I did have to lengthen one of the heater hoses that was in the way. I simply drained 2.5 gallons of the coolant, pulled the old hose off, cut a longer hose and put it all together. unfortunately the new hose has a kink in it due to the tight bend, but it should 'steam' itself into the correct shape after a while, atleast I hope.

this is an overall shot of the new intake system and catch can:


here is the vent line that goes into the disposable catch bottle. the tubing is 3/4" and the metal part is aluminum tubing, also 3/4"


this is a close up of the new 90 degree bend. it follows a different path than the stock intake, as you can see the one heater hose is kinked a bit. it's amazing how much better it looks with a proper intake bends.


I have only taken it around the block once, as a shake down run, so i don't have a complete review. however, I can say this intake is ALOT louder than the stock intake, especially when the turbo is in a transient, such as idle to load and load to idle. otherwise it sounds about the same. the noise is not very pleasant, unfortunately, and if I or the wife can't stand it I will be installing the 3.7L airbox.

I hope to report, perhaps after the new-year, and then again after a week of my normal work commute on any mileage increase or decrease and heat soak issues.

Any noticeable power increase? Got a video or sound clip of the engine from idle to redline with the cai? I'm taking your word that it is A LOT louder than the stock airbox I would just like to listen to exactly how much louder and whether or not it is a "nice" loud. Thanks for the mini review though and the mod looks great. Kudos to you.

_________________
Jason
2006 Jeep Liberty CRD Limited
No Modifications to date.

Aren't you picking up hot air from the engine compartmant instead of cooler air from the outside?

_________________
2006 Libery Sport CRD, Lt Kakhi, nicely equipped
*****GDE Hot Tune at 38,879 miles
*****Stock TC.....for the time being!!

Being a test engineer, I dislike giving positive results with just empirical data, so to be safe, I don't know if it gained any torque. that, and If the truck did pick up a few lb/fts, I won't know it because I never floor it. I did a little more driving and I isolated what was making all the wracked. Apparently, between 2100 and 2400 RPM, at part throttle only, the compressor is right on the bring of surge, so it has a 'card in the spokes' kind of sound. this is a good thing because the engine is boosting at part throttle, giving good performance and it speaks to the effectiveness of the Garrett VTN turbo. it is pretty loud though and sounds like it is coming through the ventilation system, if I explain the sound away the wife might ignore it. or so I hope.

at near-WOT and idle I didn't hear surge so it's only audible during 'around town' type driving. nevertheless, I made the below modification in hopes of sealing in the sound a bit.




I said in my first post that the design was lacking, but I agree. Since then, I crafted a 'air box' out of a rubbermade container to seal out underhood air as best as it can.

I wish I had a blue one..

just a quick parts list

vent parts:
1' of 3/4" emissions grade hose
section of 3/4" aluminum tube
used oil bottle
rag

intake parts:
plumbing grade 2.25" coupler (thin walled)
2.5" diameter, 90 degree bend with 2" leg on one side only
2.5" to 3" coupler
AEM intake filter
small piece of vacuum hose (for filter restriction sensor)
rubber maid container
1' of 3/4" heater hose
4x 3/4" hose clamps
1' of 1/4" drain hose (for radiator draining)

total cost ~ $85

Just thought that I would throw a few comments out there from some the standpoint of impact on engine running...

The MAF sensor is linearized for the air flow through the production air box. Now that you're flowing simply through the AEM filter, the linerization will be quite a bit different as I've had to deal with this issue with our calibration at Rose-Hulman. The ECU monitors the drift of the airflow compared to the setpoint to adapt itself and/or monitoring for leaks, and the inaccurate linearization now will possibly lead to CELs set for no reason.

Also, make sure that you completely seal the airbox 100% from the engine compartment if you leave the filter in that location. There were already issues of the intake air temps being too high in certain scenarios with the production box, and that set-up will manifest those issues greatly. You won't see them so much during the winter, but come summer time you will see a great decrease in performance as the computer reduces the fueling amount because the intake temps are too high. The cooler air that you can get into the compressor the better off you'll be, and make sure you fab up a rubber seal of sorts so that it's completely isolated.

The surging noise that you hear is the vanes of the turbo closing when you tip out of the throttle and also the compressor on the verge of making lots of boost at that engine speed. The engines I work with at Rose at waste-gated turbos (fixed geometry) and do that as well during part throttle until the turbo is completely spooled up. The ECU calibration is set to eliminate this when the production airbox is installed but with your set-up now the parameters will be very wrong in terms of hiding the noise. Reason you hear it is because the vanes are mostly closed at this engine operation point so that the boost pressure will follow the setpoint correctly.

The hose that you had to change and is now kinked is the bypass hose to circulate the coolant before the T-stat opens. If that hose is kinked, you risk steam pockets forming in the cyl. head during warm up from lack of circulation which will spell disaster as these engines with the cast aluminum head don't respond well to overheating. I would recommend fixing that very soon. I'd take a ride by Advance Auto or AutoZone and seeing what molded hoses they have which will at least help make the bend.

My CRD had this "surge sound", or as others have nick-named it, turbo-bark, since day one. It always happened when accelerating, then letting off the pedal slightly. It was a loud metallic rattle sound. It disappeared with the last flash that reduced power somewhat. It used to be quite an ugly sound and frequently would startle passengers not used to it.

Your explanation is the first time I've ever seen it acknowledged. Ford PSD owners have it as well, but some don't and it is quite a sound. It makes you think that the transmission is grinding a gear when it happens, except its under the hood. Some of the Ford PSD owners were trying to figure out why with 2 identical PSD's, one would have the sound and one wouldn't. They never did come up with a good explanation.

_________________
2005 LTD CRD RB1 NAV/Htd Leather seats/Amsoil EA filters
SunCoast Mega Trans & Billet TC/PML pan/Aux cooler
Fuel cooler/Lift Pump/10um Pri/Racor R490 2um Sec Fuel Filters
IronMan Lift/Shocks/Provent/Moog ball joints/ V6 Airbox/Fan/Hayden
Cobalt Boost/EGT/Oil/Trans/Volt gauges/Aeroturbine 2525
Yeti Hot Tune/Odessey 65/Samco's/Michelin Defenders

darn computers! Sorry you did all that work for nothing. Sure looked good though. I especially like the rubbermaid surround.

_________________
2005 sport crd-SOLD No regrets

Would we benefit from insulating the air box (on the outside) with reflective insulation?

_________________
Founder of L.O.S.T.
2006 CRD Sport
Mods: GDE Hot Tune w/ 364#@2000rpm/Air Box /3" Str8 Exhaust/ASFIR Alum Skids/245-75R-16 Cooper STT PRO/OME LIFT w/Clevis & 4 Spring Isos/AirTabs/Rigid 10" S2 LED/4xGuard Ctr Matrix Bumper
Drag Strip:Reac=.1078_60ft=2.224_1/8=10.39@64.8mph_1/4+16.46@80.8mph

Anything that you can do to reduce the heat of the air coming in is beneficial. One of the best things to do is try and get the snorkel of the airbox that's at the lower leading edge of the lower box into cleaner and more fresh air. Trying to get it to a better spot behind the grille or somewhere would be good.



The reason why things like this come up is due to variability in the parts supplied to the assembly line. In the case of the variable geometry/nozzle turbos on the CRD KJ, we only have a certain number of vehicles to work with for calibration and so we don't always see the extremes. We usually try to compensate for the largest majority we can, but some things are just more out of spec than others and hence more noticable sometimes.

I find it hard to believe that the CRD lacks sufficient adaptive learning capability to eventually smooth over rough spots, in this case compressor surging.

my experience with turbocharged engines is pretty limited, but from my work with one in a ford vehicle, after as few as 30 minutes of driving the computer trims the MAF curve and such to make the car pleasurable to drive. I would be very disappointed if the CRD lacks that ability.

just a quick update, after talking with some powerstroke people and reading on their forum I found out that, among many other things, a TAG (turbo air guide) somewhat alleviates compressor surging. apparently the air just before the compressor is normally spinning and somehow that makes surging worse, so if the air can't spin it's better. so I added a TAG to my stainless elbow and in doing so almost eliminated the surging. now, even at full boost if I let off the accelerator petal it will slowly whistles down, instead of very loud surges I had before. however, if I very progressively press the accelerator pedal at about 2200 it will briefly surge once or twice before it goes to full boost. I am going on a road trip so I will evaluate if I find it a nuisance then.

here is a picture of the TAG



Also I was not able to find a proper "?" heater hose I wanted to accommodate my air intake. so I found a Goodyear brand hose guide that wraps around the hose like a boa-constrictor and smoothly guides the hose in the shape I wish. I'm very happy with it and it fixed the kink.

You can also place a spring inside of the hose to keep it from deforming.

_________________
2006 CRD Sport,
Born on 5-20-2006 @ 7:20pm
Jeep Green, Oil drain valve
Tow Package, Transmission skid plate
EHM2, ORM,
Current mileage 79,000.
Past Jeeps: 63 CJ5,
1994, 1995, 2000 Cherokee,
1995, 1997, 2003 Wrangler

http://www.dieselpowerproducts.com/tag

Wonder if these guys can manufacture something to fit our application.

_________________
Jason
2006 Jeep Liberty CRD Limited
No Modifications to date.

just got back from a 400+ mile trip and the new intake posted 23.6 MPG, about 1 MPG less then my best on that same route. given that it doesn't look like this intake is the secret to the better mileage I wanted, I probably end up putting the orginal intake back on in a few weeks. only with the crankcase vent catch can installed.

If you stick with your setup, I would move that catch can out of the "airbox" no sense sucking those fumes back in there if you dont have to.

So is there something to this turbo air guide? Is it just a noise reduction thing or are there some performance/longevity gains to be had with it?

_________________
It may be that your only purpose in life is to serve as a warning to others.

06 CRD Sport
Built 5/11/06
Jeep Green
Rocklizard diff cover
V6 Airbox

thats a good idea, but where to run another hose? under the car I guess. also, most of the gas that exits the catch can is like a white vapor, I guess that is mostly water vapor because it condesates into water. the oil seems to "drip" out of the ccv and soak into the rags in my catch can.

Also I replaced the orginal intake hose, as best i could. since i hacked the air box lid i had to leave the AEM filter on it. anyway, i noticed that the turbo surge is still very present, if not more so than with my goofy intake pipe. so yes, I think I will be emailing the air guide people, or making my own to work with the stock intake hose.

Don't forget that winterized gas gets less mpg's...was your other trip in the spring or summer?

_________________
2005 Black CRD Sport
All J CRD Frankenlift with 500 fronts, Boulderbars, and Superskid
Kilby Gas Skid
Yukon Rear Axles
265/75 16 TrXus M/T's and Bridgestone Revo's
Fumoto Valve
Aero Turbine 2525
Rock Lizard Komodo Bumper
Sundance Custom's Front Bumper

it was last summer, your right i would have to do a back to back to tell for sure.

I'm looking at installing an EVIC with instant MPG to help with my economy documentacion quest and I should be able to get better data quicker with an '02 EVIC installed, hopefully.

just a quick update. I am currently running the stock intake rubber hose, MAF section of the air box lid and a AEM filter.

previously I reported 23.5 MPG. that's with a mandrel bent 2.5" intake pipe, in place of the rubber hose, on a almost all-highway route.

this week I had my regular commute (that is typically less than all-highway in terms of MPG) it showed 24 MPG or .5 MPG better with the stock intake hose compared to the 2.5" pipe despite the different type of use.

before mucking with anything, in the last few months I had been seeing 21 to 23 MPG every tank.

Also I scored a dirt-cheap EVIC with instant MPG (2002 @ <$25). I will try to Tailor my speed to that which give the best economy. this is important because I drive 500+ miles a week and that adds up in fuel at the end of the year.