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samtheman
Dodge Dakota
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11/29/2004
11:52:40
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 Subject: Winter mpg question!
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I drive a 03, 5.9, 3.92rear, 4X4 QC. Daily driving in town and 40 mile round trip to work (hills) I get 15 plus change even using the AC. Interstate trips here in PA I'll get over 16 (I think in a "level" state I'd get 17!) However, now with the temps only down to the 30s so far, I can't get 15. My intake is plumbed directly into the fender well and totally insulated to the TB. So my question is: does my engine stay in the warmup loop to long because of the insulation or is it winter blend gas or both? By mid winter (based on last year) it will be down to 12-13mpg. I don't sit around letting it warm up by the way.
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furball69
Dodge Dakota
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11/29/2004
15:18:47
| RE: Winter mpg question!
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Probably the cold air. Cold air is more dense with oxygen so the O2 sensors will think the mixture is lean and richen up the fuel. Ever notice vehicles have more power when it's really cold out?
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ethanolic
Dodge Dakota
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11/29/2004
18:21:08
| RE: Winter mpg question!
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The 10% ethanol is the main culprit. That and colder fluids in trans diffs bearings etc... All vehicles will be in warm-up loop longer because of the cold,not because of your insulation, common sense. All these add up to losing mpgs.
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not true
Dodge Dakota
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11/29/2004
18:40:23
| RE: Winter mpg question!
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furball the O2 sensors will NEVER see the cold air coming in. They are in the exhaust pipe and only see after burn temps, and those don't change due to weather.
ethanol whatever, Not true either. The gasoline I buy says 100% gasoline and since where I live is right next door to Penn. It would have that option too. Unless of course you arre dumb enough to buy the stuff with ethanol, but then your summer milage is less too.
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mikec041
Dodge Dakota
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11/29/2004
19:30:32
| RE: Winter mpg question!
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When I lived in NY every Oct. thru April they change the gas to a "winter blend" that reduced my MPGs by about 2 or 3 MPGs.
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Turbostang
Dodge Dakota
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11/29/2004
19:30:35
| RE: Winter mpg question!
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Furball was on the right track, but I think he ment the MAP sensor..
Plus..Colder fluids in the driveline hurt too.. And even the fact that cold air is denser and less easy for a truck to push thru, probably hurts a little..
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furball69
Dodge Dakota
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11/29/2004
19:32:35
| RE: Winter mpg question!
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Why is it that when someone disputes something logical they hide behind a lame nym?
I never said anything about the o2 sensor detecting the incoming cold air O2 level. More O2 coming in will mean more O2 going out as well.
If it's not true, how would a nitrous system benefit anyone without any other mods? All nitrous is is oxygen, if the engine doesn't know it's there how does it know to pump more fuel in to the cylinder?
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ethanolic
Dodge Dakota
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11/29/2004
21:28:39
| RE: Winter mpg question!
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Ethanol is now mandatory add YEAR ROUND in NY (and Conn or NJ, i forget which). Tuners hate doing the fuel trims with ethanol. Ethanol fools the O2`s a bit on the rich side,which leans out the mixture when you need more to make up for the blends loss of thermal efficiency.
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Bob Lincoln
Dodge Dakota
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11/29/2004
22:27:22
| RE: Winter mpg question!
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There are two main causes, one of which has been mentioned, and one overlooked. Most NE states use a winter blend of gas, and the labeling at the pump does not change. But the other main factor is that it simply takes longer for the engine to warm up, so it runs richer for a longer period of time. My Dak warms up in less than 2 miles in summer, takes 4 miles in 30-40F temperatures. I lose over 1/2 mpg.
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furball69
Dodge Dakota
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11/30/2004
00:46:30
| RE: Winter mpg question!
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Ask any drag racer that knows anything about anything, well, no, ask a top fueller or funny car driver about cold air and air at sea level as opposed to higher elevations. That's all I'm saying.
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eddy
Dodge Dakota
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11/30/2004
08:39:57
| RE: Winter mpg question!
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My 4.7 Quad 4x4 goes from averaging 14-15 when it's warm to 11-12 when it gets colder.
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furball6969
Dodge Dakota
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11/30/2004
14:09:03
| RE: Winter mpg question!
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this one slipped me before, but intercoolers were invented to do the exact same thing I described; cool the air charge to make it more dense, and therefore give you more power.
A turbo and colder, more dense air in and of themselves will not give you more power, neither will nitrous, it's the fact that there is more oxygen going into the cylinder and therefore out the exhaust that makes the computer compensate by pumping more fuel into the cylinder. Otherwise the engine would run lean and destroy itself by burning holes in the pistons.
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Ted
Dodge Dakota
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11/30/2004
16:47:36
| RE: Winter mpg question!
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Here are the main culprits:
Ethanol in fuel - many northern states mandate it
Higher aerodynamic loss due to colder, denser air
Higher pumping/throttling losses due to colder, denser air
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Ed
Dodge Dakota
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11/30/2004
19:23:07
| RE: Winter mpg question!
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Research first before you go off about something you know little to nothing about.
Quote "neither will nitrous, it's the fact that there is more oxygen going into the cylinder and therefore out the exhaust that makes the computer compensate by pumping more fuel into the cylinder."
Additional fuel is added at the same time through a seperate pump and solenoid. It is not computor controlled.
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android287
GenIII
11/30/2004
20:14:37
| RE: Winter mpg question!
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Colder air make the engine run more rich = less mpg.
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furball69
Dodge Dakota
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12/01/2004
02:36:44
| RE: Winter mpg question!
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"Additional fuel is added at the same time through a seperate pump and solenoid. It is not computor controlled."
Dude, do you know what a PCM is, and what the purpose of all those sensors on an engine is? Obviously not. PCM = powertrain control module, in other words a computer.
O2 sensor in the exhaust tells the pcm that there is too much o2 in the exhaust which means the engine is running lean which is dangerous for the engine because a lean engine can burn holes in your cylinders. So pcm tells injectors to spray more fuel unto the cylinder.
Who's spouting off about something they know little or nothing about?
"Additional fuel is added at the same time through a seperate pump and solenoid. It is not computor controlled."
that is laughable.
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furball69
Dodge Dakota
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12/01/2004
02:39:23
| RE: Winter mpg question!
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that should read 'burn holes in your pistons' not cylinders.
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Crow318
Dodge Dakota
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12/06/2004
15:41:40
| RE: Winter mpg question!
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Furball,
You are right if you are talking about a "dry" shot of nitrous. And Ed is right if you are talking about a "wet" nitrous shot. The "dry shots are usually limited to 50 hp or so, as that is all a factory computer can compensate for. Anything larger requires an extra fuel injector (usually located close to the nitrous injector)
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Crow318
Dodge Dakota
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12/06/2004
15:44:12
| RE: Winter mpg question!
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Oh, and it can be controlled by either a solenoid like the nitrous, or a computer regulator that comes with the kit. Most use the solenoid.
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ONE
Dodge Dakota
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12/06/2004
16:24:11
| RE: Winter mpg question!
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FIGHT FIGHT! KICK HIM!
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WTF?
Dodge Dakota
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12/07/2004
11:06:16
|  RE: Winter mpg question!
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Let's not argue, children. Can't we just get along? BTW my Dodge pickup (WS-1500 3.9, 5 speed manual) gets 19 in the summer and 16-17 mpg in the winter. The Durango (4.7, 5 speed auto)gets 15-16 mpg in the summer and 13-14 in the winter. As far as I know this is a common problem and you can't really do anything about it.
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