MPG using a No Gallons and trip

SCKJCRD · **Posted:** Tue Sep 12, 2006 11:20 pm

I drove a 400+ mile trip over Labor Day. My first "road trip" in the CRD. Fuel mileage was 24.4 mpg (not odometer corrected), actual calculated, not EVIC, with probably 90% highway driving at indicated 75 mph. I discovered that when my speedo indicates steady 75, my gps unit shows about 72.5. When I had traveled 100 miles according to the highway mile markers, the odometer only showed that I had gone 93.8 miles. Speedometer reads faster than actual, but odometer reads lower than actual. That makes my real mileage 26 mpg, with the original "MOPAR factory air" at 33 psi in the tires.

2,700 miles since new, so I'm optimistic that fuel mileage will increase. And it's comforting to know that I have a 3 yr, 38,380 mile factory warranty.

KenJennings · **Posted:** Wed Sep 13, 2006 6:52 am

My normal daily drive which is about 90% highway is scored by the computer at 25 to 26 mpg, but hand calculation at fillup always reports 21 to 22.

The best ever was on vacation in July -- hand calculated 24.8 mpg. This was done with 3 adults, one rug rat in a car seat, and the entire cargo area and one rear seat filled with luggage. Driving was mostly 65, but there was about half an hour of stop-n-go through a construction area, and a couple side trips and rest stops. It had about 5,000 miles on it at the time.

oldnavy · **Posted:** Wed Sep 13, 2006 8:03 am

I still think that there are several reasons why there is some people who just can't get over 23/24 mpg as well as some who can't get past 27/28 mpg.

1. Quality of fuel. I use a B2/B5 mix of 49 Cetane fuel, while most only have access to 40/42 cetane fuel. A 40/42 cetane fuel with 20% biodiesel will only be about 44/45 cetane max, and it will most assuredly lower mpg compared to what I use.

2. Driving styles. It is hard to believe how much this effects this vehicle. Driving 75/80 mph in this vehicle will drop you mpg's like a rock. at 65/70 I can get low to mid 30 mpg's, but 75/80 drops me into the 24/27 mpg range. Excessive use of the torque in town (it's so much fun) can drop us from 22/23 mpg to 17/18 mpg. I have been guilty of doing this, it is more fun to hotrod then my Magnum. I drive more for mpg when driving the CRD on the highway, the Magnum I just fly low and don't worry about cost or mpg's as the car is so much fun and comfortable at the same time.

3. Injection Pump timing is off from the factory and needs to be reset. This also can knock the mpg's in the head and effect overall preformance, including 0>60 time as well as mpg's.

KenJennings · **Posted:** Wed Sep 13, 2006 9:54 am

oldnavy wrote:

I still think that there are several reasons why there is some people who just can't get over 23/24 mpg as well as some who can't get past 27/28 mpg.
...
3. Injector timing is off from the factory and needs to be reset. This also can knock the mpg's in the head and effect overall preformance, including 0>60 time as well as mpg's.

The injectors arrive from the factory already screwed? Is this common knowledge? How can we tell? (And how do we convince the Dealer it needs to be adjusted under warranty?)

Milner · **Posted:** Wed Sep 13, 2006 11:16 am

oldnavy wrote:

I still think that there are several reasons why there is some people who just can't get over 23/24 mpg as well as some who can't get past 27/28 mpg.

1. Quality of fuel. I use a B2/B5 mix of 49 Cetane fuel, while most only have access to 40/42 cetane fuel. A 40/42 cetane fuel with 20% biodiesel will only be about 44/45 cetane max, and it will most assuredly lower mpg compared to what I use.

2. Driving styles. It is hard to believe how much this effects this vehicle. Driving 75/80 mph in this vehicle will drop you mpg's like a rock. at 65/70 I can get low to mid 30 mpg's, but 75/80 drops me into the 24/27 mpg range. Excessive use of the torque in town (it's so much fun) can drop us from 22/23 mpg to 17/18 mpg. I have been guilty of doing this, it is more fun to hotrod then my Magnum. I drive more for mpg when driving the CRD on the highway, the Magnum I just fly low and don't worry about cost or mpg's as the car is so much fun and comfortable at the same time.

3. Injector timing is off from the factory and needs to be reset. This also can knock the mpg's in the head and effect overall preformance, including 0>60 time as well as mpg's.

I have to agree totally with 1+2. From my experience with every diesel vehicle I have driven, both hold very true. In my PSD I consistantly got 1-2mpg better from supplier A than I do supplier B. Winter fuel (additives) here really kill milage aswell. As for #2, It is so hard for me to drive mellow in any turbo diesel....they are just so dang fun!
Also, #3 seems to be a pretty consistant issue in most diesels too. Almost all but the most extreme re-programs will show some milage increase. Again my best point of refference is the PSD world....I have 6 dif programs in mine from econ to all out stupid. My 5th=extreme/race will yeild the best milage, even better then the econ program IF I can keep my foot out of it.

Looking at some programming for the CRD, but I want to break it in first so I can get a true feel for improvements....

Cowcatcher · **Posted:** Wed Sep 13, 2006 12:28 pm

With respect to driving style, one thing for me about the CRD is counter intuitive. I find that mileage is better if you accellerate to max speed sooner rather than nursing it. In other words stomp on it, get the TC to lock sooner than later then settle into cruise speed.

oldnavy · **Posted:** Wed Sep 13, 2006 1:57 pm

KenJennings wrote:

oldnavy wrote:

I still think that there are several reasons why there is some people who just can't get over 23/24 mpg as well as some who can't get past 27/28 mpg.
...
3. Injector timing is off from the factory and needs to be reset. This also can knock the mpg's in the head and effect overall preformance, including 0>60 time as well as mpg's.

The injectors arrive from the factory already screwed? Is this common knowledge? How can we tell? (And how do we convince the Dealer it needs to be adjusted under warranty?)

Sorry about the misprint, I meant to type Injector Pump Timing.

gsbrockman · **Posted:** Wed Sep 13, 2006 2:52 pm

oldnavy wrote:

Sorry about the misprint, I meant to type Injector Pump Timing.

The CP3 utilized in the CRD does not require any "timing" as all it does is pressurize a common rail, from which electrically fired injectors atomize and inject the fuel into the cylinders.....

I thought we have touched on this once before........

Greg

oldnavy · **Posted:** Wed Sep 13, 2006 2:57 pm

gsbrockman wrote:

oldnavy wrote:

Sorry about the misprint, I meant to type Injector Pump Timing.

The CP3 utilized in the CRD does not require any "timing" as all it does is pressurize a common rail, from which electrically fired injectors atomize and inject the fuel into the cylinders.....

I thought we have touched on this once before........

Greg

CRS!!! I forgot all about CRD, so many years with old tech. So sorry. :oops:

We need a software program like VAG-COM for VW that will allow us to change via the laptop things like the injection timing and duration amoung other things.

kjfishman · **Posted:** Wed Sep 13, 2006 4:18 pm

jakemoore wrote:

i get 21-23 mpg no matter what. i wish i could do better. roof box or no, drive like jackass or grandma, in town or on highway. it doesn't matter. only towing a completely overfull uhaul brought me down to 17.

jake

ABout the same as above using odo and manually calculating. Then I read about odometer error and rest the trip to 0 and reste gps to 0 and found that that that in 10 miles the odo was reading .1 less miles. So if I put my college education to work that is 10 percent off. I have BGF AT KO's same size as factory but that doesn't mean they are a perfect match in size. So I check my mileage towing my boat to MArk Twain lake and figured 18 mpg. So 18 + 1.8= 19.8 not that bad, my v6 KJ dropped to 11 maybe 12 towing.

I was getting better mileage but 2 computer flases latter this as good as it gets almost 20 towing 24 unattached to anything. Best ever was a ont time 28 when fairly new on OEM tires.

jakemoore · **Posted:** Wed Sep 13, 2006 6:05 pm

Where did you go to college?

KenJennings · **Posted:** Wed Sep 13, 2006 6:21 pm

kjfishman wrote:

jakemoore wrote:

i get 21-23 mpg no matter what. i wish i could do better. roof box or no, drive like jackass or grandma, in town or on highway. it doesn't matter. only towing a completely overfull uhaul brought me down to 17.

jake

ABout the same as above using odo and manually calculating. Then I read about odometer error and rest the trip to 0 and reste gps to 0 and found that that that in 10 miles the odo was reading .1 less miles. So if I put my college education to work that is 10 percent off....

Ummmmmm. A 0.1 deviation out of 10.0 is 1%, isn't it? (But, I never finished college ;-)

)

kjfishman · **Posted:** Wed Sep 13, 2006 8:55 pm

KenJennings wrote:

kjfishman wrote:

jakemoore wrote:

i get 21-23 mpg no matter what. i wish i could do better. roof box or no, drive like jackass or grandma, in town or on highway. it doesn't matter. only towing a completely overfull uhaul brought me down to 17.

jake

ABout the same as above using odo and manually calculating. Then I read about odometer error and rest the trip to 0 and reste gps to 0 and found that that that in 10 miles the odo was reading .1 less miles. So if I put my college education to work that is 10 percent off....

Ummmmmm. A 0.1 deviation out of 10.0 is 1%, isn't it? (But, I never finished college ;-)

)

.01 is 1 percent or .1 is 10 percent

kjfishman · **Posted:** Wed Sep 13, 2006 9:02 pm

KenJennings wrote:

kjfishman wrote:

jakemoore wrote:

i get 21-23 mpg no matter what. i wish i could do better. roof box or no, drive like jackass or grandma, in town or on highway. it doesn't matter. only towing a completely overfull uhaul brought me down to 17.

jake

ABout the same as above using odo and manually calculating. Then I read about odometer error and rest the trip to 0 and reste gps to 0 and found that that that in 10 miles the odo was reading .1 less miles. So if I put my college education to work that is 10 percent off....

Ummmmmm. A 0.1 deviation out of 10.0 is 1%, isn't it? (But, I never finished college ;-)

)

ok 1 decimal point is signifigant, I think it was wishful thinking that my mileage is 10 percent better.. . 1 percent isn't much better.

litton · **Posted:** Wed Sep 13, 2006 10:17 pm

You may just need more data points. I clocked 427 miles on the odo and 450 miles on the GPS for a varience of -6%. If you have larger tires then the error may have been compensated for by the larger diameter. The speedo was constant at 3 mph low.

Reggie · **Posted:** Thu Sep 14, 2006 9:07 am

I get 20.5 to 21mpg constantly with only one tank at 25.9 mpg on a long trip. I've tested the fuel so that isn't an issue. Driving styles don't seem to change my MPG much. I run my tire pressure at 36 - 38 PSI. I've changed fuel and air filters already.

gsbrockman wrote:

oldnavy wrote:

Sorry about the misprint, I meant to type Injector Pump Timing.

The CP3 utilized in the CRD does not require any "timing" as all it does is pressurize a common rail, from which electrically fired injectors atomize and inject the fuel into the cylinders.....

I thought we have touched on this once before........

Greg

The timing is controlled by the ECM based on input from the crank position sensor. The mounting and machining error of the sensor and the wheel could combine to give one CRD a slightly advanced timing and another CRD a slightly retarded timing. Food for thought. ON has also mentioned fuel rail pressure and there was another thread where members with boost gauges noticed low boost pressures. Mine is a dog that smokes constaintly when accelerating. I'm wondering if I have a combination of these symptoms.

KJbob · **Posted:** Thu Sep 14, 2006 10:52 am

I've been regularly getting 24-25 mpg during warmer months. Bridgestones filled to 38 psi, about 50% highway driving at 63-64mph (w/cruise), another 30% highway doing 65-75mph, usually use Koch Gold "premium" diesel.

oldnavy · **Posted:** Thu Sep 14, 2006 7:24 pm

KJbob wrote:

I've been regularly getting 24-25 mpg during warmer months. Bridgestones filled to 38 psi, about 50% highway driving at 63-64mph (w/cruise), another 30% highway doing 65-75mph, usually use Koch Gold "premium" diesel.

In reality there is no such thing as "Premium Diesel". It can be real clean and not cloud till a 20*F and 40 cetane and still be premium diesel and give a CRD 25 mpg at X speed, where fuel that is real clean, does not cloud till 20*F and 50 cetane could give the same CRD 30 mpg. Those are just numbers that I stuck in there as an example and they vary greatly between vehicles. Cetane levels and BTU's is what means fuel economy in diesels, and when you use a higher cetane fuel (50 cetane) there is less engine noise.

DarbyWalters · **Posted:** Thu Sep 14, 2006 7:29 pm

oldnavy wrote:

Cetane levels and BTU's is what means fuel economy in diesels, and when you use a higher cetane fuel (50 cetane) there is less engine noise.

WHAT???

I can't hear you...let me turn off my CRD

oldnavy · **Posted:** Thu Sep 14, 2006 11:36 pm

DarbyWalters wrote:

oldnavy wrote:

Cetane levels and BTU's is what means fuel economy in diesels, and when you use a higher cetane fuel (50 cetane) there is less engine noise.

WHAT???

I can't hear you...let me turn off my CRD

Ok, ok so I'm tired from the 400 mile round trip today and didn't get the sentence structure correct. A 50 cetane fuel will really quiten down your CRD if you have been using rotgut 40>42 cetane fuel. My guess is that this will be another way to tell if you have bought ULSD, since it will be 46 cetane your engine will be notciably quiter. I have a friend with CRD that uses local station that is 40 to 42 cetane fuel and his engine is a lot louder then mine, due to 49 cetane and B2 fuel and I can not convince him it is fuel.

Watched the Pink Floyd Cocnert tonight again on PBS, it was their live concert from '94.

MPG using a No Gallons and trip

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