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pgwerner

Just Bought '05 Corolla - Mileage Is Awful!

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maybe the consumer report driver drove a corolla with the ECU that gives lower mileage. Or, he was paid to drive such that the mileage was low. Or, he picked the winter gas which reduces the mileage even more. Or, ...

Maybe they just make up the numbers and use them to sway the consumer to buy the model?

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trap

The milage reported by CR always sounds much lower than the EPA. I think the testers drive the cars as hard as they can.

 

BTW, Bikeman, using 20W50 oil, especially in corolla is insane. I like heavier oils myself and sometimes use 5W40 and 15W40 oils (not in corolla though), but 20W50 in modern car is just crazy. Last cars designed for 20W50 were made back in 70s (i guess). You are not only burning more fuel but possibly increasing engine wear in cold and startup.

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The milage reported by CR always sounds much lower than the EPA. I think the testers drive the cars as hard as they can.

 

BTW, Bikeman, using 20W50 oil, especially in corolla is insane. I like heavier oils myself and sometimes use 5W40 and 15W40 oils (not in corolla though), but 20W50 in modern car is just crazy. Last cars designed for 20W50 were made back in 70s (i guess). You are not only burning more fuel but possibly increasing engine wear in cold and startup.

It does not take long for my car to warm up and I drive 50 miles at 80 MPH. That puts a lot of heat on the engine and definitely heats up the oil. It gets thinner as it heats up and 20W50 is not an unreasonable oil to use, under those driving conditions.

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The milage reported by CR always sounds much lower than the EPA. I think the testers drive the cars as hard as they can.

 

BTW, Bikeman, using 20W50 oil, especially in corolla is insane. I like heavier oils myself and sometimes use 5W40 and 15W40 oils (not in corolla though), but 20W50 in modern car is just crazy. Last cars designed for 20W50 were made back in 70s (i guess). You are not only burning more fuel but possibly increasing engine wear in cold and startup.

It does not take long for my car to warm up and I drive 50 miles at 80 MPH. That puts a lot of heat on the engine and definitely heats up the oil. It gets thinner as it heats up and 20W50 is not an unreasonable oil to use, under those driving conditions.

when you use an oil that thick it can do bad things like starve the valve train of lubrication. even tho the car may warm up fast that oil is just too thick, yes you have more oil pressure but at the cost of volume since the oil pump cant push 50W oil through the oiling system as fast as it can push 30W oil. ive seen people spin bearings from using too thick of oil, they had awesome oil pressure and thought it was ok and then TICK TICK TICK TICK they had spun a bearing in the engine because the thick oil couldnt flow enough to keep things lubricated. use 10W-30 in your car and you'll be doing more good than running 20W-50.

 

 

the hot thing is a little misguided. oil viscosity is graded at 210F (or was it 180F?), its how fast a certain volume flows through a certain sized opening on its own. 20W is the oils free viscosity at 210F, free meaning its sloshing around in the crank case. the 50 is its viscosity at temprature when its being pushed between bearing surfaces and through oil passages. the little wax beads elonagate and cause a thickening effect that doesnt happen when its just sloshing about in the crank case.

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The milage reported by CR always sounds much lower than the EPA. I think the testers drive the cars as hard as they can.

 

BTW, Bikeman, using 20W50 oil, especially in corolla is insane. I like heavier oils myself and sometimes use 5W40 and 15W40 oils (not in corolla though), but 20W50 in modern car is just crazy. Last cars designed for 20W50 were made back in 70s (i guess). You are not only burning more fuel but possibly increasing engine wear in cold and startup.

It does not take long for my car to warm up and I drive 50 miles at 80 MPH. That puts a lot of heat on the engine and definitely heats up the oil. It gets thinner as it heats up and 20W50 is not an unreasonable oil to use, under those driving conditions.

when you use an oil that thick it can do bad things like starve the valve train of lubrication. even tho the car may warm up fast that oil is just too thick, yes you have more oil pressure but at the cost of volume since the oil pump cant push 50W oil through the oiling system as fast as it can push 30W oil. ive seen people spin bearings from using too thick of oil, they had awesome oil pressure and thought it was ok and then TICK TICK TICK TICK they had spun a bearing in the engine because the thick oil couldnt flow enough to keep things lubricated. use 10W-30 in your car and you'll be doing more good than running 20W-50.

 

 

the hot thing is a little misguided. oil viscosity is graded at 210F (or was it 180F?), its how fast a certain volume flows through a certain sized opening on its own. 20W is the oils free viscosity at 210F, free meaning its sloshing around in the crank case. the 50 is its viscosity at temprature when its being pushed between bearing surfaces and through oil passages. the little wax beads elonagate and cause a thickening effect that doesnt happen when its just sloshing about in the crank case.

 

I'll take your advice and switch to a lighter weight oil and hope that improves my engine performance. I will have to wait until I get better weather here, since it is the rainy season and I do my own oil changes. Will I notice any performance gains or better mileage? I do 100 miles a day and it won't be long until I need a regular interval scheduled change for the oil anyway. I will let you know how it goes.

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you COULD pickup a couple mpg. i cant really say for sure tho.

 

to put things into a smaller scale, if you have a lawn mower fill it with 30W oil (like it should be) and run it, mow some grass. then change it to 50W oil and do the same. on this small scale you can really see the difference between how the 2 affect the engines performance.

Edited by Bitter

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The milage reported by CR always sounds much lower than the EPA. I think the testers drive the cars as hard as they can.

 

BTW, Bikeman, using 20W50 oil, especially in corolla is insane. I like heavier oils myself and sometimes use 5W40 and 15W40 oils (not in corolla though), but 20W50 in modern car is just crazy. Last cars designed for 20W50 were made back in 70s (i guess). You are not only burning more fuel but possibly increasing engine wear in cold and startup.

It does not take long for my car to warm up and I drive 50 miles at 80 MPH. That puts a lot of heat on the engine and definitely heats up the oil. It gets thinner as it heats up and 20W50 is not an unreasonable oil to use, under those driving conditions.

 

With this type of driving, the oil temp should be fine, unless you overload the car, tow, or go uphill all the time. But even then 5W40, or 10W40 would be plenty of reserve, remember totota specifies 5W30. I would be more worried about ATF temp, as I clocked up to 250F in corolla driving 85 MPH with AC in hot summer (90F ambient). The ATF was dark when changed at 30000 miles. I will put ATF cooler in as soon as the drivetrain waranty expires.

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I have formed 2 hypotheses regarding this topic from reading many forums and tons of postings. Please note I have not had the opportunity to validate either one yet.

 

First a little background:

-2005 Corolla S

-Bought new April 2005

-Manual Transmission

-Wife's car

-New England/Upstate NY weather patterns

-30sec or less warm-up times

 

This is our trip car, so we take it for 500mile trips between MA and NY. With a fill-up at either end, checking MPG, every time; Best = 42, Worst = 32. Best was during moderate to warm temps without A/C. Worst was winter driving with snow.

 

During this past winter, now hopefully coming to an end, I have seen very inconsistant MPG's ranging from 38 to 32. This has bothered me because nothing from the driver/maintenance end has changed.

 

Hypothesis 1:

The engine in the Corolla is very tiny and the large engine compartment provides lots of space for airflow. Is it possible in winter weather the engine does not reach proper operating temperatures due to too much cooling/ventilation?

 

Hypothesis 2:

As I have read, and makes sense, the colder the air intake the more fuel required for proper engine combustion. If one were to alter to a warm air intake, reroute intake to inside engine compartment, would this help MPG? Year round? In winter season?

 

Thoughts?

:D

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Winter time is a hard time to gage fuel economy. For one, any time you drive in snow, slush, rain, ect, it is resistance on the tires. Anytime you have a hard wind, you can get lousy fuel economy. It can also come down to winter fuel formula's.

 

The EPA numbers can be had, but only when the roads are dry and the wind isn't moving much. Also summer fuel has less aditives and you should get better fuel economy on that.

 

We've been averaging 32-43MPG, but latly, it's been all in town miles. I'm sure I can get that 40+ again this sumemr when I got on a longer trip.

 

I know your never suppost to go by the fuel gage to figure out fuel economy, but even this last tank now that the roads are clear, I can tell when I'm getting good fuel economy. When I get over 100 miles per 1/4 mark on the gage, then we are doing good. On bad tanks, it reaches about 85-90 miles per 1/4 mark. I use math to figure out what it really is, but I can tell on the gage and tripomitor if we are doing good or not. I wouldn't be surprized if this tank is more like 36-38MPG. We went spent some more time on the HWY this tank.

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One thing that bothers me about cars sold in US that they dont display instant MPG, except for a couple of hybrid cars. Many or not most cars in Europe have it standard. If we had that instant feedback, people would learn quicly to save tons of fuel. A test drive while buying a new car would have a different meaning.

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Agree!

I have seen this technology on many high $ vehicles (i.e. - Acura MDX, Corvette, Chevy Avalanche).

 

I'm in the process of researching OBD-II to laptop devices so I can monitor this and, hopefully <_<, any other data the ECU can provide. Then maybe I'll attempt to validate one of my hypotheses mentioned earlier.

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Hypothesis 2:

As I have read, and makes sense, the colder the air intake the more fuel required for proper engine combustion. If one were to alter to a warm air intake, reroute intake to inside engine compartment, would this help MPG? Year round? In winter season?

 

Thoughts?

:D

This is an interesting proposal - warming the air to help with MPG. Actually has been done in the past with mixed results, not neccessarily with poor fuel economy - the test mules have all shown increased MPG, mixed results with the end product with blown engines and whatnot.

 

There are a few systems that advertise mixing some exhaust gas with the intake charge - so called hot vapor engines. Sounds good in passing - but doesn't quite work with todays systems (can't bend the laws of physics and chemistry).

 

Though there is some benefit to heating the air/fuel mixture - modern gasoline blends do not fully vaporize until heated above 450 degrees F. If you could heat it up that high, gasoline would readily vaporize. Problem is that the fuel injected into the engine also modulates the temperature - want to cool things down, add some more gasoline or mix in some exhaust gases. Too high of a combustion temperature and you run into a problem of autoignition and detonation - hence all the blown up engines with most of these mods. Though there are a few out there that swear by this method - I've yet to see one run consistently with these shortcomings.

 

Just for the curious - read up on the "Hot Vapor Cycle Engine, The Adiabatic Engine" that Smokey Yunick came up with decades ago. He presented a test mule for demonstration that blew up - but he blamed on substandard parts and oil control issues.

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Very interesting....Yet another innovative technological accomplishment that never made it into the main stream. But, it kinda begins to validate my hypothesis on a WAI.

Warmer air = more combustible = less fuel required

 

Now.....Please correct me if I'm wrong but in today’s cars timing is controlled by the ECU. Therefore, if you were to increase the intake air temp altering the point of detonation the cars ECU should automatically adjust.

 

Like what a knock-sensor does to adjust for different fuel octanes.

:rolleyes:

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