I recently had to take 3 trips for work. I opted to use the wife's CRD because it'll use less fuel than my Wrangler or my GMC.

Her CRD has a provent and a glasspack muffler. On all three trips ( about 400 miles round trip) i filled up with 40 cetane diesel at the local conoco. All the stations here sell citgo #2 40 cetane. I decided to booste the cetane by 6 points with powerservice.

The mileage results are as follows:

1st trip - average -75mph - 23.4 mpg ....not bad
2nd trip - average 85 mph - 22.5 mgs - that was expected at that speed.
3rd trip - cruise set at 70 mph - 25.6 mpg!!!

I don't understand how some people get 30 mpg but i'm very pleased with 25.6. This is all flat ground in south louisiana and texas. Temperature outside was about 90 degree and the AC was on at all times.

I too just ran a tank with 12oz of the PS cetane booster (summer version) and I got 270mi on the half tank, i usually see 240 at the 1/2 mark

I don't understand how it works, but this past weekend I drover 1300 miles on a round trip back from DC to NE Indiana. There, I was only getting upper 22s to mid 23. Then 1/4 into my trip back I finally broke into 25, peaking at 28.7, same driving style before.

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Ryan
2006 Ford F-250 PSD CC FX4
**GONE**
2005 Jeep Liberty CRD
SAMCO Hoses//GDE Tune//PML Trans Pan//TransGo HD Shift Kit//MBRP Exhaust

1986 2R Mustang SVO

Well, you didn't say how many miles are on the CRD. That impacts mileage. The best CRD mileage won't be seen until about 8 to 10 thousand miles on the clock.

You also don't specify if the Libby has any racks, lightbars, or different sized tires. Which will also affect mileage.

Additionally, how inflated were your tires, and what kind of tires were they? Was the vehicle a Sport or a Limited? (Limiteds are heavier, and SelecTrac ads rolling resistence)

And finally, and probably most relevant, your "slowest" speed you posted was, if you will note, also your highest mileage. Try the same trip at 60mph and you will probably break or come close to 30mpg...

The Liberty is horrendously un-aerodynamic. (0.421 cd) The energy required to overcome aerodynamic drag increases with the square of velocity. Drag only begins to be a limiting factor between 40 and 50 mph - before that you are fighting mostly rolling resistence.

This means that at 70mph you are consuming 75% more energy just to overcome drag than you would be at 60mph.

You also mention your AC was on the whole time which will lower mileage, and if your lights were on that will affect mileage as well...

Anyway - my point is that acheiving MAXIMUM mileage is a complicated formula that can be affected by tons of variables....

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http://www.pdxbiodiesel.org

And 40 cetane fuel can't help either. I bet after a couple tanks of B10 50 cetane fuel he could knock down 30 to 32 mpg doing 70 mph like my wife's CRD depending on weather. The PS summer and the highway miles could have helped clean her out and get the mpg's up.

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine

40 cetane, they can still call that diesel fuel? I bet that rattles in your CRD. A little biodiesel will go a long way to help that stuff.

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2005 Liberty Sport CRD, Lt Khaki, sunroof

Thankful to now be an EX-CRD owner.

That's getting close to bunker fuel or the old sea going heavy distillit back in the day.

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine

I'm driving to Washington D.C. next month and would love to find filling stations along the way who sell Bio-Diesel. I'm not sure I understand the Cetane thing though. Is that in Biodiesel?

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2005 Unlimited (LJ) Rubicon w/ 5.5" of total lift
Flat Fenders made by http://www.jpfaboffroad.com/

"Democracy is two wolves and a lamb voting on what to have for lunch.
Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin, 1759

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine

Actually they sell 38 cetane here ocasionally...lol. It's not posted on the pumps I just work next to the refinery.

The wife's CRD is a sport with stock tires..running whatever air pressure the factory put in them. It has 6000 miles on it.

As far as the rattling..lol..you're right...If we go through a drive through in it..i can barely hear the people talk to me over the clattering engine. These crd's clatter more than any diesel i've heard at idle when you use crappy fuel in them.

The power service helps though.

??? Can you please elaborate?

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2005 Unlimited (LJ) Rubicon w/ 5.5" of total lift
Flat Fenders made by http://www.jpfaboffroad.com/

"Democracy is two wolves and a lamb voting on what to have for lunch.
Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin, 1759

When in DC, try the Quarters K Citgo in Arlington, VA. It is right next to the Pentagon. They sell B20 and it is excellent fuel. I buy diesel there every chance I get.

Also try http://www.biodiesel.org/buyingbiodiesel/retailfuelingsites/ to fing biodiesel stations.

Power Service is a fuel additive that can increase the cetane number of your fuel and they also have a winter version that helps to prevent gelling of the fuel. it can be found at almost any Wal-Mart or most diesel truck truck centers on the interstates.

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine

Power service can raise the cetane by 6 numbers. It also increases the lubricity of the fuel with thier "slick diesel" formula.

I too don't understand how some people have gotten 30 miles per gallon. But when my CRD was still bone stock with no lift, tiny factory tires, and no roof basket, and engine was broken in good...I did manage to pull off a 26 miles per gallon tank myself. It was in the Fall last year before winter blend diesel hit the market, and I purposefully drove strictly the speed limit everywhere I went. And I hit an all time record of 460 miles or something like that on that tank of fuel. 26 mpg was the best my CRD ever did regardless of fuel quality or addition of Power Service. BUT...that is over double the mileage I was getting out of the Dodge Ram I traded on the Jeep. So I am a VERY happy camper with my mileage.

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2005 Stone White KJ Limited CRD 4x4
Off-Road Pkg
Trac-Lok
Emu 790s/948s
Skyjacker H7088s rear/Bilsteins front
15x7 Black Rock Lobos/31x10.50 Firestones
GDE HOT Tune + TCM Tune
Euro TC
CB radio
Thrush Turbo muffler
AEM DryFlow filter

I finally hit 26 with my last 2 tanks. Since winter began and since winter blend diesel was being used I only got like 18-19 mpg average. All at the same BP station.

My guess is that we are finally getting the nice summer blend.. Ahhh, feels so good, espically since diesel is hitting 3.20 a gallon!