Official: What are your real world MPG Numbers

[ukwildcats]

psi mgp

The thread is ENGINE BELLY PANS, GOT ONE? And yes larry that is what i was asking was hot and cold psi. thanks! inflate them next chance i get

 

[GeneralZod]

It would be easy and cheaper to make one out of corrugated plastic. That way you can make a door/flap for oil changes and so on.

You can also complete the rest of the under carriage too. I would estimate a 5% gain on the highway doing this mod.

If you do not believe me, think about this... Your side view mirrors arrount for a 6% increase in drag.

Just don't cover the exhaust channles unless you enjoy huffing burning plastic.

 

[stoopid]

The tires rolling off the lot were all between 30 and 31 psi. So, for that first 1811 miles I had assumed all was well. After checking at that point I had them topped up to 37 psi.

I had the TPS come on after a few thousand miles (around the time we had out first cold spell this Fall). I worried it was a nail or something, nope - just slightly under inflated. Cold weather caused the tire(s) to lose just enough pressure to trigger the TPS.

Is 37 psi the optimum? Walmart said that's what they inflated my new tires at. Seems kind high. I usually just do 34psi on all 4. I believe over inflating causes uneven wear.

 

[Bogus]

I've been told to go by what the side of the tire reads by one person, and to go off the car spec by another.

I would think it's best to go by what the tire manufacturer says.

 

[mitdr774]

The number on the tire is max pressure. Would not advise running max pressure all the time.

 

[Bogus]

^Agreed.

 

[joe truck driver]

have to get new alarm... 2 of six legs in a hurry; 2nd leg-68 with driving rain and wind, 5th leg ....what i would call spirited(north of 70) . down to 42.3 on this tank. my full average is down to 44 ...about since purchase.

for tire pressure its best to stick with manf. numbers unless you check at the tires manf. numbers. they will help you go by weight if you want to dial it in complete. tire pressures will affect tread life so it would be a trade between milage, grip, and tire life if you go to far....and safety.

 

[ukwildcats]

I drove 451 miles today 30 miles city 421 miles highway and ran 93 octane and the dash reading was 41.5 mpg.I also inflated my tires to 40 psi.My calulated on the tank before this trip was 31.2 mpg the dash said 32.5. i did give one more shot of gas after the pump kicked off so that is most likely the difference.I am happy with this mpg i traded in my 09 malibu for this sonic.1710 miles now. changing the oil and filter tomorrow.

 

[Bogus]

for tire pressure its best to stick with manf. numbers unless you check at the tires manf. numbers. they will help you go by weight if you want to dial it in complete. tire pressures will affect tread life so it would be a trade between milage, grip, and tire life if you go to far....and safety.

 

[Larry]

Sidewall max rating is based on the tire manufacturer's testing, which may not be applicable to the vehicle the tire is used on. Things such as how fast you drive, how rough the roads are, and how much load is placed in the tires (which is increased signicantly in hard launches, high speed turns, and hard braking) all plays a role in the max pressure you should run in the tires. If you drive mostly short distances, moderate speeds (under 80mph), and don't drive crazy... then you should be able to use max sidewall. I use in between because I like comfort and I also like to drive spiritedly from time to time.

 

[sx sonic]

I've been told to go by what the side of the tire reads by one person, and to go off the car spec by another.

I would think it's best to go by what the tire manufacturer says.

Anybody that says the pressure on the sidewall of the tire is the RECOMMENDED pressure does not know what they are talking about and you should not heed their advice.

 

[ChrisJ]

The worst I have seen so far in the new Sonic is 39MPG average, which is also currently listed as my lifetime average over 1440 miles. My current displayed average is 45.5MPG.

38PSI in tires when cold as per manufacturers spec.

Our previous Sonic which was a 1.8 2LT auto hatch averaged 32MPG under the same exact conditions.

I drive around 90-110 miles a day.


We have no option in NJ but to buy E10.

 

[$ub$onic]

I've had 2 sonics already ?

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[ChrisJ]

I've had 2 sonics already ?

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I assume you meant "you've" ?

If so, yes.

This thread explains why.
http://www.sonicownersforum.com/forum/t4353/

 

[$ub$onic]

Lol yes sorry. And wow.

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[$ub$onic]

Oohhhh OK I remember reading it now sorry about ur luck hope u enjoy your new one

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[GeneralZod]

The worst I have seen so far in the new Sonic is 39MPG average, which is also currently listed as my lifetime average over 1440 miles. My current displayed average is 45.5MPG.

38PSI in tires when cold as per manufacturers spec.

Our previous Sonic which was a 1.8 2LT auto hatch averaged 32MPG under the same exact conditions.

I drive around 90-110 miles a day.


We have no option in NJ but to buy E10.

Turnpike or GSP miles?

I do the GSP to 287 so traffic is an issue.

 

[ungawd]

The door sticker shows recommended cold psi of 35. Cold is relative to the outside temperature at around 32 degrees Fahrenheit. Elevation can usually be tossed out of the equation unless a commute is from the top of a very large mountain to the bottom or vice versa. Elevation change will affect tire pressure to some degree. The max psi posted on the tire sidewall is 44. If one would happen to fill their tires to 44psi when the outside temperature was 120f, at 70f those tires could be at 39psi.

Personally, when the temperature outside is 70-85 degrees like it has been, I fill my tires to 2.5-3psi over cold. It is not unrealistic to see a loss of 2-3 pounds of pressure when the temperature drops from 80f to 32f. If you're carrying heavier loads the tire pressure will increase, so you should always check it frequently in that instance. For long trips where dramatic elevation changes can be common, it's also a good idea to keep tabs on it.

Where the temperature can fluctuate 40 or more degrees from night to day, I've found the 2-3 warm psi to be best practice, or mfg recommended cold when it's near freezing.

For those living with more stable temperatures, or during the months where they are stable for many of us, it's probably best as well to go for a mix of comfort and reduced rolling resistance. Preference would be key assuming the tires are maintained in the safe pressure zone.

 

[ChrisJ]

Turnpike or GSP miles?

I do the GSP to 287 so traffic is an issue.

31 > 78 > 287.

Some days I wish I was dead during my commute.



ungawd, I assume you have different tires than me as mine shows 38 cold. I have the 15" rims. Sure, the temperature fluctuates but the cold indication means when the car is sitting and the tires are at ambient, whatever that may be. I have to adjust my tires throughout the year, sometimes removing some in the spring, adding some in the fall and so on. Usually I'll see 39-41PSI after a trip. Right now temperatures are dropping so I will probably end up with mine around 40 PSI cold as I expect the typical ambient temperature to continue dropping. This way I won't have to add some in December.

 

[ungawd]

Well, I was half wrong, but still good in practice. Here, from TireRack, is as detailed explanation as one would want.

Most people mistake rolling psi as hot pressure and cold as anytime ambient. It's specifically low and high range ambient tempurates in the course of a day.

Based on that information, if your temperature variance is 30 degrees (40f low, 70f high), then your pressure variance would be approximately 3 psi. hot psi would be cold+3.

The tires I have are 205/50R17 that show a max psi of 44 on the sidewall; the door shows cold psi as 35.