Good bye Good Mileage??

[bsams]

I didn't start paying close attention to my mileage until the end of June this year. Of course hot summer months = nice mpgs. Now that it's cooling off here in upstate NY I am noticing quite a significant drop in my mpgs. Now I know of course this is inevitable with the colder temps, but it seems like I am losing about 1mpg per 10degree temp drop. Is there a general rule of thumb for ambient air temps and how it effects mileage? Just curious... can't wait for winter!

[dkjones96]

MY mileage drops when it gets colder but that's because the car runs so much better. On a 20 degree morning I beat the poor car to pieces as opposed to a 105 degree day when it can barely get out of its own way!

[Jay2TheRescue]

Maybe rig up a winter WAI, and remove it in the spring to maintian your mileage?

-Jay

[Erik]

At some point the refineries switch us over to the "winter blend" which yields less mpg

[Jay2TheRescue]

Yes, but a WAI will help soften the impact of winter blend fuel.

-Jay

[KARR]

Try blocking the air flow that hits the radiator. I've tried it once and mileage increased in 10 mpg, on average. I've done nothing that could explain this increase so I suppose it really improves mileage. Last weekend I've made a new "blocker" that covers a bigger area of the radiator.

[SD26]

Originally Posted by Erik

At some point the refineries switch us over to the "winter blend" which yields less mpg

You beat me to it. Yes, winter blend fuels are different in that they will help the engine start in colder months rather than give the economy of warmer months. There are mandated periods of when those fuels need to hit the distribution chain and then when they should hit the street. I think they hit the marks pretty well.

[Jay2TheRescue]

Yes, a good grille block is usually good for an extra 10% MPG.

[FLAteam]

I've also noticed a drop in my MPGs...but its strange because Scangauge shows that I've been consistently getting 36-40 mpg per trip, yet this last fill-up yielded 34mpg. My cutoff is 4, which is 4 above 0 (my idle TPS) and its uncalibrated.

Could the cold weather be affecting how well the SG is reading my actual mpgs? Should I reset the ECU? I'm thinking seriously for a grill block soon...

[bowtieguy]

no need to wait until winter to do a grill block. i have ~3/4 grill block in temps higher than most. certainly positive or negative(over heating) results vary from vehicle to vehicle, however.

i was thinking of installing a WAI myself.

i'm actually hoping for BETTER FE during winter via limited a/c usage.

gotta add this as well...

in january, i'll think about you northerners while outside in shorts and w/out shoes playing w/ the kids.

[Jay2TheRescue]

I have roughly ~95% block on the beast, and it was fine in 100F + temps.

-Jay

[bsams]

Yeah I would like to install a wai and at least block the upper grille on my 3. The Only issue I have is the car is still under warranty. If anything happens to go wrong in the next 40,000 miles I don't want them to try to put the blame on me if they see I have modified the airbox to accommodate a WAI. Thanks for the replies!

[Jay2TheRescue]

For now do something that is completely reversible. You can save the agressive mods for later when the warranty is out. For example my WAI is nothing more than removing the lid from the air cleaner box and a piece of duct tape. It can be reversed in less than a minute.

-jay

[bsams]

I am beginning to think that it's not all about the weather... a couple weeks ago the local Express Mart switched from Mobil to Sunoco gas. Yes, Sunoco and it's lovely 10% ethanol... yesterday the weather was perfect...mid 70s... and my daily cruise control at 55 ride home from work was not giving me the numbers it normally did with this relatively warm weather... I can't blame the gas switch yet until I fill up again with either Mobil or KwikFill (both gave me consistent mpgs all summer long)... but it really has me wondering...

[Jay2TheRescue]

I'm actually doing pretty good on my current tank of Sunoco, but then again all fuel in this area is E10 so that really doesn't matter. I filled there because it was $3.25/gal which is far cheaper than anything else in the area.

-Jay

[BEEF]

almost 100% grill block on the old cav. just enough room to get my hand in to pop the hood.

that isn't really a fair statement since most of my cooling comes from underneath.

I used plexi-glass that you can buy from lowes. I did this on my wife's car with zip ties. if we ever want to take it off, a pair of dikes (diagonal cutters) will do the job in about 5 seconds. quick, simple, and completely reversable grill block.

also, depending on where your car takes the air from, you may cause a WAI by blocking off some of the grill. my car takes the air from the fender well but my wife's car takes it from behind the radiator. if she were to block off more of her grill, she would yield warmer temps.

all cars are different. pop the hood, see what you have, and go from there.

[Jay2TheRescue]

I took the lid off of my air cleaner, and duct taped over where it sucked the air from the fender. This coupled with the grille block gives me temps of up to 80F over ambient. All this and the grille block and air intake are completely reversible in under 5 minutes.

-Jay

[philip1]

I have a 90% lower block and an 80% upper block on my car with a HOT air intake on the 90* day we had last week my coolant stayed at about 204* and my intake was 140*. No over heating and great numbers for a great huge beast of a car.

[BEEF]

mine has hit 179 IAT but here lately has struggled to get in the tripple digits with 60-70 degree days. the morning is much worse than the afernoon. 40-50 degrees in the morning.

a little warmer lately has pushed me up to 115 or so for IAT.

I am thinking on adding more shielding just for the winter to keep temps higher. I will just have to remember to take it off for the summer.

[bobc455]

Originally Posted by Erik

At some point the refineries switch us over to the "winter blend" which yields less mpg

In the past, I heard that this happens on September 15 in Massachusetts, although I've been unable to substantiate it. I also can't seem to find out when they switch back to summer blend.

-BC

[SD26]

Originally Posted by bobc455

In the past, I heard that this happens on September 15 in Massachusetts, although I've been unable to substantiate it. I also can't seem to find out when they switch back to summer blend.

-BC

I think that is the start of the modification of the blend, but it is changed also a month or two later. Summer blends start around March? It depends upon where in the country you are too.

[shatto]

1. You might check with your Amsoil dealer. http://www.amsoil.com/products/promo...aranteeWeb.pdf
Their P.I. gas treatment guarantees MPG improvement.
Worth a try, don't you think?

2. I get my gas from Costco because it costs less. Here they get it from; Tosoro, Shell, Chevron, Unocal and Exxon. Whichever is cheaper. It all has the Costco additive package when it goes into the truck. Gasoline that comes out of the refinery is essentially the same.
So, I suggest you fill at a high volume station so you are getting fresh fuel, and pay the lowest cost you can find.

3. And, sometimes you may experience a drop in MPG. This may be because the refinery made too much high octaine and sold it as regular to the station to get rid of it. Putting higher octaine than recommended in your tank reduces MPG.

[theholycow]

Originally Posted by shatto

Putting higher octaine than recommended in your tank reduces MPG.

I don't think I've ever heard of that. Can you explain it more?

[Jay2TheRescue]

I've heard that before, but I don't think I've ever seen any data to back it up. Personally I feel that all things being equal (Ethanol content, additives, etc) the difference in mileage would be statistically insignificant.

-Jay

[shatto]

Fiat 1500 Station Wagon, Chrysler 300, Volvo DL, Honda Accord, Pontiac LeMans, GMC Sonoma, Dodge Dakota, Honda Prelude.
Simple 4-Banger to sophostocated 4-Cylinder, Original Hemi to....well, I havn't done it with the new Tundra.

At least one full tank of gas on I-5 between San Francisco and Los Angeles or between Los Angeles and San Francisco.
"The Grapevine" is the mountain pass between the LA Basin and the Central Valley and the rise is to 4,000 feet or so, the rest of the trip is nearly sea level.

Dividing miled drove by gallons consumed, gas mileage has always gone down using higher octane than recommended.

[theholycow]

Any guesses why? As I said, I don't recall ever hearing of anybody else who observed that data, but it's interesting if true. It behooves us to find out why; this is the sort of thing that eventually leads to a new strategy, modification, or idea, once we learn the concepts behind the observation.

A first simple guess would be that the additives required to raise the octane dilute the gas, but I doubt that the percentage of additive is enough for that.

[shatto]

Simply; The engine is tuned for the lower octane gas.

[theholycow]

That doesn't tell me anything about why it gets lower FE on high octane gas.

What does that mean, besides compression ratio / timing?

What is it about higher octane rated gas that makes it produce less power in an engine optimized for lower octane ratings?

[BEEF]

this is the explination that I heard, is it true? I don't know.

with higher octane gas, the engine must advance the timing. depending on your engine, your ECU may only be able to advance the timing so far or if you are carburated, you have to adjust the timing. I assume they are talking about the spark plug fire. most modern engines do this automatically and I can't see where it would be an issue.

do I have data to back this up? no

I was having issues with my riding mower and I was asked what kind of gas I put in it. I usually just fill the container when I fill my car and yes I usually put premium in my car. I have been putting regular in it lately because stations around here still don't have premium. they are starting to get midgrade back in stock.

this was just a "for what it's worth" statement. take it for what it is. just something someone told me. true? false? I don't know.

[Jay2TheRescue]

My dad always used premium in his lawnmower and tractor because they were initially built for leaded gasoline. His logic being that regular leaded gasoline had higher octane than your standard 87 octane does now.