Over the weekend I was doing some reading on the 02 airbox mod, and folks reporting a boost in mileage from it. I went out and checked mine on my 2006 CRD (stock box) and found that at 7500 miles my filter was out and out filthy (great that the dealer checked this before putting the Libby on the used market).

Anyway, I recall reading a number of folks who believe that the stock airbox/filter does not allow the CRD to breath freely enough, and hamstrings our power a bit.

A little anecdotal experience. On Friday, I filled up my CRD with B20, and did my regular commute home (7 miles on interstate, slower traffic, average speed of roughly 60 mph.) Reset my trip computer at the start, average 27.2 mpg for the trip. I drive this route regularly, and this is about what I always get.

So on Sunday morning, I did the ORM and swapped in a new filter. Yesterday evening I drove the same route, same speed, with a 29.6 mpg average.

This is a pretty small sample, and not scientific, but I was quite suprised. The ORM likely made a substantial difference in and of itself, but based on the reports others have made of seeing mpg jumps when they swapped over to an 02 airbox (which I believe came more from the new air filter than the airbox), I am thinking the size and efficiency of our air intake may be one of the biggest constraints on the CRD's fuel economy and power.

Has anyone experimented with a larger box?

Did you happen to do the same test with only ONE of the modifications? Unfortunately, they do different things (one limits the overall combustion gas volume and one affects the temp and volume of O2 in the combustion mix). I did just the ORM and got about a 2mpg increase but it's really hard to say which does what if you have more than one moving part (I never liked multi-variable calculus...)

Also, it's important to note that many of the folks who do the ORM have reported excessively high readings for about half a tank on the EVIC, so your results might differ in a few days.

Dan

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

Are people hand calculating their numbers? I have yet to get better than 24MPG on 80% freeway driving 65MPH...

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Feb/2006 Silver Sport 4x4 CRD

"hand" calculate and get 29+ going 70-75.

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http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic

I have started using this chart to keep track of mileage:

https://www.fueleconomy.gov/mpg/MPG.do?action=mpgEdit2

The reason I like it is that it is easy to use and won't let you "cheat" if you go by true odometer readings. The inaccuracy of fill up calculations is minimized after you have done at least 5 or 6 fill ups. Makes it easy even if you do partial fuel ups.

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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

Hmmm, just logged in and tried it and for my partial fill-ups, it seems to be wildly inaccurate (and I did select to use that method). Any dea what the formula is for the calculations?

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

Does the '02 airbox actually flow better, or does it just reorient the intake to make it less susceptible to the elements?

- Chris

the 2nd half is correct.. it keeps the air filter cleaner.... Read: it just maks a better seal

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05 CRD
3" Rough Country Lift
SAMCO SPORT Hoses
Magnaflow Muffler (12226)
CAT 2 Fuel Filter
Fumoto Drain Valve
EGR replaced at 50K
in service 8/31/04
Sold 7/21/10 125k miles
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Paved Roads, another form of unnecessary government spending...

My results are completely non-scientific and should obviously be taken with a grain of salt. I was just curious if anyone has experimented with installing a larger/more efficient airbox.

In searching through old-posts about the 02 airbox mod, a number of people reported improved mpg. But the 02 box does not offer increased air flow (in fact, it may actually be less). Other folks have pointed out observations related to the ProVent mod that seem to indicate that as our air filters clog up, a pretty significant increase in pressure is created throughout the intake system.

I suspect that if increased mpg and/or power is occuring after the 02 airbox mod, it has more to do with installing a fresh, clean filter than with the box itself. Given that our engines are air-hungry turbo diesels, and that the box we are stuck with is the same one used in the gasser Liberty, it might be worth some experimentation. Also, I saw several references to Chrysler engineers referring to the CRD's airbox as "marginal" for the application. It looks to me as if the straight-through snorkel that CRD's come with was an effort by Chrysler to boost airflow vs. a standard Liberty intake.

Anyway, I was just curious if anyone has tried transplanting a bigger or more efficient airbox into a CRD Liberty.

It is just simple math...the first plug in will yeild nothing...after that it should be correct after any complete fill up.


MAKE SURE you post under "my Fuel Purchases"

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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

I used a larger filter: http://liberty.eurekaboy.com/airintake.htm

It seems to use less throttle than it used to and you can hear the turbo more. I haven't driven the Jeep enough to check on mileage changes (good motorcycle weather ).

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My Jeep Liberty page

ORM, air filter mod, and less restrictive exhaust has increased my 'everyday' driving 3 mpg.

And your basis for this statement of "fact" is what, exactly? A grain of salt?

If you read all of the calculations on the old posts concerning this subject, you'll find that the 02 and up snorkel design has slightly more area (based on measurements) in the main snorkel opening than the 05 design. Not to mention that the airflow path on the snorkel design is straight through the hood gap straight into the snorkel, down through a smooth curved path, into an interior opening that is larger than the 05 circular design.

Then there is the matter of the convoluted restricted airpath that the 05 design introduces, all while capturing significantly more dirt and free water in the airbox. And last but not least, after nearly a year of using the snorkel design, I have yet to experience rainwater in the bottom of the snorkel design, which was a constant experience with the factory airbox - and the filter stays cleaner much, much longer.

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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

I'd just assume the engineers who came up with a different airbox/intake design for the CRD vs. the gasser were trying to accomplish some goal beyond wasting time and setting up a new assembly process somewhere to produce the components. They may have done a lousy job at it, but I think their goal was to boost airflow over the stock design.

I understand the advantages of the gasser airbox design in terms of keeping dust and debris out of the airbox. I'm not trying to knock anyone's favorite mod here (and I'm actually shopping for an 02 box myself).

But I'd say both designs require air to travel a fairly convoluted path, and in any event, two air paths that direct air into a tiny filter in a air-hungry engine still leave you with the same problem -- a tiny filter.

I think we'll have to agree to disagree on the convolution aspect of the snorkel design. I don't see convolution on a path straight in and down, up high and away from road dirt readily collected by the 05 design, compared to 90 degree bends and no direct air path.

Filter size is an area I can agree with you - bean counters apparently have no pleasure in tuning machinery to optimum performance, or have enough conscience to not steal from their customers by shortchanging them in ways that most of them cannot identify directly. I have no doubt that most of them would not personally take miscounted excess change from a 20 dollar bill at a store, but they will implement subpar components and materials known to fail early and before expected industry norms.

As an example, I discovered an old web article from 2005/6 where Chrysler settled with the EPA for over a million dollar in fines, and CARB for another fine, along with a recall for 4 and 6 cylinder engines (the infamous 6 in the Cherokee and GC) due to emissions equipment failing long before EPA specifications.

The cost for that one recall was expected to be 90 million dollars. Then you have the ongoing balljoint recalls on the Liberty's, some Dakotas and who knows what else that they calculated a return based on a law of averages. Of course, there are the multiple egr valves and now TC's on the CRD's. You have to wonder what the cost of doing it right would have netted Chrysler in return sales, missing recalls and customer goodwill.

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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

The CRD is a marvelous machine once you fix the many engineering flaws that DCX handed us. We really like it now that we don't have the old torque converter lockup problem, with the ORM "fix", and soon with the Suncoast TC (should be picking it up tomorrow). The Liberty CRD had the potential to be much more than what was delivered to us. Fortunately with this forum, we are slowly addressing these limitations with our own time and money.

However, DCX did indeed lose sales in the long run, at least from us. When we saw the Grand Cherokee CRD, my wife and I both thought of the same line at the same time:

"Fool me once, shame on you. Fool me twice, shame on me."

We are waiting for the V6 TDI Touareg to come to the states for the 2009 model year. 27mpg mixed and a 7700lb towing capacity - gotta love a drivetrain with some real engineering and careful design.

- Chris

No matter what comes out down the pipeline, the Jeep Liberty CRD will be in a class by itself most likely. Price wise, I don't know if there will be another "buy" like this...

The only vehicle that would change my mind would be a Jeep Gladiator with a CAT 6 Diesel

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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

Stick with the OEM tire size and you will continue to get good results. Upsize like me and TDI4BY and expect a significant drop.

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'05 CRD Sport born on 06/20/05, bought on 9/23/05, L.O.S.T. on 9/27/05 - modding ever since:

Daystar 2.0" Lift, P255/70R16 Revos, Boulder Bars, Reese Front Hitch w/9k Hooks, Poison Spyder Rock Ring, MOPAR Skids/Bug Shield/Roof Rails/Mats, WARN Hitch Shackle(Rear), 10k Hitch Hook(Front), Custom Tilt/Slope Meter, Ammo Box Mod, Rotella T 5W-40.

Back to the top. I have been running the ORM for several months and noticed a bump of about 2mpg as a result. Abotu a week and a half ago I installed the '02 air box. The filter was CRD air box dirty but not done for and I had not found a local source yet for the AMSOIL filter so I put the old one back in. I have not seen a mileage gain since the air box change so I would suggest that the new filter may be a factor but primarily the ORM.

I do think that btween filter changes the '02 has to make a difference because the CRD box allows it to clog prematurely or to get soaked and reduce air flow.

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Dave

'06 CRD Limited, Lt. Khaki, MOPAR Slush Mats/Skids, DrawTite Front Hitch, Mag Lite, Yakima Bars, Thule Bike Rack, Fumoto, ORM, 245/70 Revo 2

Wish list: Lift, Boulder Bars, Something Bigger in the Front and Back, More Lights

I run the 245/70 Fortera's most of the time and get about the same mileage results as the MTR's but even those are wider than stock.

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Feb/2006 Silver Sport 4x4 CRD

I think the goal of the design of the stock CRD box was to try and get some kind of half-assed "ram air" effect going, using the position of the opening in the grill and the flow of air around the Liberty at highway speeds to boost the availability of air to the engine. When I pulled it, my filter had bits of dried grass, dead bugs, and dandelion seeds in it.

Volant and a few other companies make really nice fully enclosed high-flow intake systems for the big diesel cummins, duramax, etc... pickups. Wish something like that existed for us.

I'm contemplating giving a higher-flow filter a try in the existing Liberty airbox. Something like this:

http://www.autotrucktoys.com/liberty/Mo ... 6C480.aspx

Or maybe an Air Raid high-flow filter element.