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amc racer
DTO Silver Member
Joined: 26 Jul 2005
Posts: 511
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 Posted: Sat Oct 22, 2005 8:21 am Post subject: |
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| rob92xj wrote: | | Mileage divided by fuel used. The overhead in my 03 is off by .03mpg when calculating the math, which most of them are no where near right. |
My overhead is off by an easy 2.5 mpg.
Still don't believe the 18 mpg unless all trips are downhill.
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69 AMC 12.79@105.9 4,200 lb barge with a 33 year old engine (Car Craft June/05)
99 Ram 2500 CC/LB CTD 4X4 , full Magnaflow stainless 4", Edge EZ, AFE
There's no such thing as too much truck.
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HankL
DTO Gold Member
Joined: 21 Sep 2002
Posts: 1402
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| Posted: Sun Oct 23, 2005 4:09 am Post subject: |
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The overhead trip computer gets its MPG estimation by timing how long the fuel injectors stay open, multiplying that by what it expects the injectors to squirt during each microsecond, then dividing by the miles the computer thinks has been driven.
If the overhead trip computer's MPG is way off,
that is usually a tip that either:
1. a least one fuel injectors is partially clogged
2. fuel pressure is either low (likely) or unusually high
3. the calibration of the odometer is incorrect
Nearly all the new, off the dealer's lot, Chrysler vehicles I have driven will go by mileposts on the interstate in less than 60 seconds when driven at what the speedo shows to be a steady 60 mph. |
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amc racer
DTO Silver Member
Joined: 26 Jul 2005
Posts: 511
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| Posted: Sun Oct 23, 2005 8:47 am Post subject: |
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Correct.
The fuel info overhead is only an estimate.
The only difference is that the unit doesn't expect any data. It shouldbe being supplied the injector pulse width directly from the pcm and yes, brand new vehices off the lot are off as far as fuel estimates.
_________________
69 AMC 12.79@105.9 4,200 lb barge with a 33 year old engine (Car Craft June/05)
99 Ram 2500 CC/LB CTD 4X4 , full Magnaflow stainless 4", Edge EZ, AFE
There's no such thing as too much truck.
NAMDRA Officer/Member#2923 |
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rob92xj
DTO Newbie
Joined: 29 Sep 2005
Posts: 34
Location: Fayetteville, NC
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| Posted: Mon Oct 24, 2005 12:01 pm Post subject: |
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| amc racer wrote: | | rob92xj wrote: | | Mileage divided by fuel used. The overhead in my 03 is off by .03mpg when calculating the math, which most of them are no where near right. |
My overhead is off by an easy 2.5 mpg.
Still don't believe the 18 mpg unless all trips are downhill. |
His Chevy is a03 1500 with 5.3L auto trans extended cab. My 00 was a 1500 4X4 off road 5.9L Auto it's mpg was acually 16.8 going from NC to NY on the highway.
My 03 is getting 12 mpg on our last trip from NC to NY with no load on it. Just had our clothes in the back seat. |
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nazbom
DTO Senior Member
Joined: 29 Jul 2005
Posts: 155
Location: Spotsylvania, Virginia (central)
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| Posted: Tue Oct 25, 2005 5:43 am Post subject: |
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You gotta love V-8 motors. they love the gasoline don't they?
_________________
2001 Ram QC Sport W/ Off Road package, 5.2 Liter, headers, Flowmaster 40 series Cat Back duals 2.5", Airaid intake, 35" BFG A/T, 4.10's, spray in Bed Liner, 2" leveling kit, Hypertech 87 Octane Program, Mobil 1, Synthetic Valvoline in Tranny |
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rob92xj
DTO Newbie
Joined: 29 Sep 2005
Posts: 34
Location: Fayetteville, NC
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| Posted: Thu Oct 27, 2005 11:47 am Post subject: |
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| nazbom wrote: | | You gotta love V-8 motors. they love the gasoline don't they? |
They really love to drink some fuel. Next truck will have a Cummins though. |
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nazbom
DTO Senior Member
Joined: 29 Jul 2005
Posts: 155
Location: Spotsylvania, Virginia (central)
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| Posted: Thu Oct 27, 2005 5:36 pm Post subject: |
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I worked for a cummins diesel shop that's where I got my respect for the cummins. The owner onlydrove Dodge diesels cause of that, I'd sure likde to have one but the price of diesel is sky high and can't be justified (the oil co.'sproffiteering)
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2001 Ram QC Sport W/ Off Road package, 5.2 Liter, headers, Flowmaster 40 series Cat Back duals 2.5", Airaid intake, 35" BFG A/T, 4.10's, spray in Bed Liner, 2" leveling kit, Hypertech 87 Octane Program, Mobil 1, Synthetic Valvoline in Tranny |
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rob92xj
DTO Newbie
Joined: 29 Sep 2005
Posts: 34
Location: Fayetteville, NC
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| Posted: Thu Oct 27, 2005 10:38 pm Post subject: |
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| nazbom wrote: | | I worked for a cummins diesel shop that's where I got my respect for the cummins. The owner onlydrove Dodge diesels cause of that, I'd sure likde to have one but the price of diesel is sky high and can't be justified (the oil co.'sproffiteering) |
Lets see my 03 Ram 1500 5.9 gas=12mpg at 65mph on the highway, 9mpg in town. My cousins 05 2500 5.9 diesel=17mpg in town,14mpg at 90mph on the highway |
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ofelas
DTO Diamond Member
Joined: 05 May 2002
Posts: 3053
Location: Unreconstructed Southerner
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| Posted: Fri Oct 28, 2005 5:53 am Post subject: |
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rob92xj - did you find your 2001 gave you better mileage? I get ~ 12mpg city & ~18mpg hwy at 70mph with 35s & 4.10 gears with my 2001.
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| Quote: | | Blaming guns for crime is like blaming spoons for Rosie O'Donnell being fat |
http://www.cardomain.com/ride/283969
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amc racer
DTO Silver Member
Joined: 26 Jul 2005
Posts: 511
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| Posted: Fri Oct 28, 2005 8:23 pm Post subject: |
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| rob92xj wrote: | | nazbom wrote: | | I worked for a cummins diesel shop that's where I got my respect for the cummins. The owner onlydrove Dodge diesels cause of that, I'd sure likde to have one but the price of diesel is sky high and can't be justified (the oil co.'sproffiteering) |
Lets see my 03 Ram 1500 5.9 gas=12mpg at 65mph on the highway, 9mpg in town. My cousins 05 2500 5.9 diesel=17mpg in town,14mpg at 90mph on the highway |
This is how I can't justify a swap to a diesel right now.
Current ride is a 2500 BR long bed 4X4. Daily driving fuel mileage is 13 and change.
Worst mileage was 11.5 pulling close to 7,000 lbs of race car and trailer.
For the sake of calculation, I'll round down to 11 mpg as my average.
I drive 1,600 miles/month.
With yesterdays price of gas @ $2.57/gal, that comes to $373.93/mo.
Giving the diesel the benefit of the doubt, I'll use 17 mpg.
With yesterdays fuel going for $3.16/gal, that comes to $206.47/mo.
Fuel savings $77.46 in favor of the diesel.
I'm paying $150 and change per month on the note for the truck.
If I dump the gasser and trade for an oil burner, I don't expect the payment to remain the same to show an actual savings in the switch.
_________________
69 AMC 12.79@105.9 4,200 lb barge with a 33 year old engine (Car Craft June/05)
99 Ram 2500 CC/LB CTD 4X4 , full Magnaflow stainless 4", Edge EZ, AFE
There's no such thing as too much truck.
NAMDRA Officer/Member#2923 |
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nazbom
DTO Senior Member
Joined: 29 Jul 2005
Posts: 155
Location: Spotsylvania, Virginia (central)
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| Posted: Sat Oct 29, 2005 6:52 am Post subject: |
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Yeah, thr cost involved with switching, such as higher diesel price, higher truck cost, alot more oil per oil change, fuel filters, etc. does make it hard to swithch right now. The high price of fuel sort of turns the equation around economically.
_________________
2001 Ram QC Sport W/ Off Road package, 5.2 Liter, headers, Flowmaster 40 series Cat Back duals 2.5", Airaid intake, 35" BFG A/T, 4.10's, spray in Bed Liner, 2" leveling kit, Hypertech 87 Octane Program, Mobil 1, Synthetic Valvoline in Tranny |
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rob92xj
DTO Newbie
Joined: 29 Sep 2005
Posts: 34
Location: Fayetteville, NC
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| Posted: Sun Oct 30, 2005 6:16 am Post subject: |
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| ofelas wrote: | | rob92xj - did you find your 2001 gave you better mileage? I get ~ 12mpg city & ~18mpg hwy at 70mph with 35s & 4.10 gears with my 2001. |
My 00 got a lot better fuel mileage. It had a Mopar PCM, Mopar headers, Flowmaster exhaust, Airaid throttle body spacer, and a K&N FIPK.
Last time I towed my XJ to Uwharrie National Forest I averaged 8.4 mpg, open trailer with a 3500 lbs Jeep on it. That was a local tow about 2 hours away, 150 miles round trip. I bought the truck to tow my Jeep with but I am still driving the Jeep to the trails, due to how bad the mileage is.
Thats why the next truck will be a diesel. My wife was going to buy a 05 Liberty with a CRD but it was going to be a 6 month backorder and she needed a vehicle right away, so she has a 05 Liberty Sport with a 3.7L. |
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