03 M45 Gas Mileage

[sr79labrat]

Ok so I finally decided to grow up and start driving slow or should I say less agressive. I never knew that I could get such great gas milage in the M45. I used to get 17-18(city) taking it easy though I would punch it here and there to get around people. Since I have tamed myself for the first 80miles or so on this tank I am at 21.6(city) mpg and was up to over 22 last night. I still cruise slightly higher than posted speedlimits but accelerate constant and slower to the cruising speed. The only mod I have is a K&N air filter. I usually clean it well and barely oil it-sometimes I dont as I know some sensor gets caked with the oil from the filter. Either way I thought I would share as this saves me about $15.00(21.6mpg-17.5mpg avg=4.1mpg increase x 18 gallons= 73.8 more miles of range in the tank devided by 17.5mpg=4.2 gallons extra x $3.5 a gallon=$14.75 in savings) per fill up. Am I right in my calculation....seems an awful lot for just a small change in the driving I do!!!

Comments please! Thanks! Kyle

[Mark Linkous]

Hello,Really good info. I am currently at 16.0 according to the carputer driving 90/10 city/hwy. Last night I read a forum post from 2003 with a M owner lamenting spending $34.00 to fill up the tank. Almost hit $80.00 the other day...Cheers,mark
Modified by Mark Linkous at 11:06 AM 4/23/2008

[DRIPS]

Remember to reset your carputer for the fuel economy after each fill up in order to keep your history and also to keep the calculation accurate.

[peter_rabbit]

If someone is only spending $34, he's not filling the car up from empty. I fill my car up at 1/4 a tank from empty and i'm at $55. With my driving now i'm at 19 city 26 highway. So i get an average of about 400 miles per tank if i go all the way to empty.

[sr79labrat]

Remember to reset your carputer for the fuel economy after each fill up in order to keep your history and also to keep the calculation accurate.

I do this every time, and I reset the odometer to see the range and miles per tank. That is how I can calculate the difference in range. It is the only way to do it I think.

It is amazing what you can get with this car considering there is no northstar effect going on....or so we know. I hope to hit 22mpg 100% city driving this next tank.

KTW

[DRIPS]

Make sure you get on it full throttle sometimes to avoid excessive carbon deposits...these v8 motors need to be driven like one sometimes at the very least.

[DRIPS]

If someone is only spending $34, he's not filling the car up from empty. I fill my car up at 1/4 a tank from empty and i'm at $55. With my driving now i'm at 19 city 26 highway. So i get an average of about 400 miles per tank if i go all the way to empty.

what are you doing putting the car in neutral down hills?!!

[Mark Linkous]

Hello,Peter, I was referring to a post from 2003. It made me wince to think of then and now. I reset my econ display and trip odometer at each refuel.Cheers,Mark

[sr79labrat]

Refills are now almost $65-70 for me here in colorado. $80 is the going rate in some states? I thought about coasting in neutral down hills...haha Isnt it hard on the transmission? makes me laugh

Peace, Kyle

P.S. Dont worry about those WOT blasts...plenty will keep me sending smoke from the back tires in the round-abouts here. haha

[Manok]

I've seen 26 MPG before but this is straight highway at 70 with the cruise on for four hours.

I usually get 22 which is pretty good for a car this size.

[Mark Linkous]

Hello,Down in God's Waiting Room, Premium (93) is going for $3.85 a gallon. I added 20.1 gallons and it was around $78.00. That is by far the lowest I have run down the tank. Manok, your mileage is exemplary. And your actual mileage(odometer) is insane as well.Cheers,Mark

[sr79labrat]

Th

Hello,Down in God's Waiting Room, Premium (93) is going for $3.85 a gallon. I added 20.1 gallons and it was around $78.00. That is by far the lowest I have run down the tank. Manok, your mileage is exemplary. And your actual mileage(odometer) is insane as well.Cheers,Mark

That is nuts! $3.85!!! Then again it is 93, and I only can get the lowly 91. His is about what I normally get on the high side of 24-26ish. I had once averaged 29 for a whole tank coming down from the mountains...it was quite the moment....until I got pulled over for excess speed. Cops all ways have to rain on my parade! haha

KTW

[Double E]

Thanks for the reminder about resetting the avg readout at each fill up. I was thinking I was doing pretty good bouncing between 22.3 & 22.5 for the past couple of weeks ...but I should do a reset. It's been over 1500 miles since I reset it.

I think I might go every 2 tanks between resets though just so the occasional WOT "cleanout procedures" get averaged in a bit better...

I'm getting pretty good at not letting the RPM get over 2200-2500 as I leave from a light.

[ftwklg]

3.85 for 93 I would crap my pants and stock up, passed a gas station yesterday 4.17 for 91!!!! I gave the M to my wife to drive for a few weeks seeming how her commute is 4 miles round trip and mine is just over 50. And before anyone starts the you gave your wife your M to drive!!! stuff, she actually takes care of her cars unlike most female drivers.

[Mark Linkous]

Hello,Yeah, I have sadly seen $4.00 here as well. That was on the barrier island I live on which there are only two gas stations and charge accordingly. $4.17 for 91 is truly evil though. Cannot fault your logic in having your wife drive your car given the commute.Cheers,M.L

[jbillion]

I just filled up yesterday and broke the $70 mark for the first time. The light just turned on and I needed > 17 gallons. I am a somewhat aggressive driver, but I only get 14.5 mpg with about 90% city driving. I always calculate my milage using the trip odometer. I have 58K miles on the car and will be going for the 60K service soon. Does anyone know if I will see improved milage after the service?

[ftwklg]

I saw no improved milage after my 60K service, but then again my foot weighs about 100 lbs and its to hard to keep it off the floor. seriously I think I averaged about 17-19 all around, not bad in my mind because my last DD was a 07 4x4 silverado with the 6.0L chipped and exaust = 12-13 at best.

[peter_rabbit]

honestly no, what i'm doing is just normal driving. If i'm going down a hill i come off the gas. If i go up a hill i try to keep it to were the speed doesn't drop past 55. Once i'm over the hill i go back to 60-65. I try to keep the speed as constant as possible without using cruise control. Oh believe me, i drive it like it's a sports car at times.

[peter_rabbit]

Yes, i do the same. From what i heard about the cluster problem, i've been reseting on every fill up. i see what you're saying now, Man i wish it only too $34 to fill up. I would spend the extra money on donuts

[peter_rabbit]

3.85 for 93 I would crap my pants and stock up, passed a gas station yesterday 4.17 for 91!!!! I gave the M to my wife to drive for a few weeks seeming how her commute is 4 miles round trip and mine is just over 50. And before anyone starts the you gave your wife your M to drive!!! stuff, she actually takes care of her cars unlike most female drivers.

Here in St.Louis it $3.79 for 91. I think i'm going to have give the car to the misses for her to drive. She catches the train which is like 2 miles from her house. But that would mean i would have to drive her Focus. Nothing wrong with that but for some reason a 272lb(i've lost 5 lbs) 6'2' in a focus, just doesn't sound right.

[CakeDaddy]

Uummmmm... Can I please get ummmm $4.26 on pump 6 in that black car with the rims, please... ummm, thank you

Hmm… We are at $3.70 here in Albuquerque and 3.93 in some of the surrounding small cities, but I’m not complaining about it. My only gripe(sp) is having 4 different cars to put gas in. Oh, I'll be posting barrels of rice and crates of eggs on eBay to help with my gas price woes. Stay tuned and look for my eBay sales under food/commodities. LOL I’ve gotten use to the gas prices, but to stay on topic; I can’t remember the last time I filled the M up If I remember right, I recorded 19mpg’s, but I drive it like a limo 90% of the time.

This is my next gas saver. Looks better than the Larry David Hybrid Prius


Modified by CakeDaddy at 12:18 PM 4/23/2008

[sr79labrat]

You guys will love this...

91 V6 Acura Legend(W/ Turb0)...worst gas mileage 11.5 mpg

79 Firebird 350/350 over carbed at 6mpg

Glad to NOT be driving them now!KTW

[szh]

what are you doing putting the car in neutral down hills?!!

I know you were joking, but, just as a word of warning for those who might be tempted to do this.

Please DON'T put the car in neutral down even a gentle hill, or for any length of time (miles down a long gentle slope ... coming back from Lake Tahoe, for example). The ATF inside the transmission stops flowing, and the resulting heat buildup could be seriously detrimental to the life of the transmission.

For the same reason, the car should never, NEVER be towed with the drive wheels on the ground - don't let the tow truck driver convince you "Oh, it is in neutral"! Ideally flat-bed the car, and the next best thing is to dolly the wheels that are not in the air (front or back).

Z

[wbrian63]

Sorry - I don't think so...

If you leave the engine running, the fluid continues to circulate throughout the transmission. The engine turns the torque converter, the torque converter turns the pump, the pump circulates the oil just like it does when you're sitting in park. Only difference is that none of the clutches are receiving pressure to generate forward or reverse momentum.

You should definitely never tow or push the car more than a very short distance (i.e. to get out of harms way) with the engine off and the transmission in neutral - I agree here.

[Double E]

wbrian63,

Can you refrence/document that information for us?

If not, I'm more inclined to believe info from, and do further independent verification of, the moderator's (szhosain's) contribution (having thousands of posts and) having previously guided me to good information.

My change in driving habits rests on your being able to back up your info.

Thank in advance.

[marosari00]

At $3.80 a gallon here in Melbourne, I made it finally to 403 miles to the tank. It was scary, thinking I would run out. But after this my next goal is to reach 410. I'll carry the gas can with me...

[sr79labrat]

That would be awesome! Just remember it is supposed to be hard on your fuel pump...just in case the car doesnt start back up for some reason.

What is everyone elses MPG?

K-Dubya

[szh]

wbrian63,

Can you reference/document that information for us?

If not, I'm more inclined to believe info from, and do further independent verification of, the moderator's (szhosain's) contribution (having thousands of posts and) having previously guided me to good information.

My change in driving habits rests on your being able to back up your info.

Thank in advance.

Turns out that Brian (wbrian63) is right.

I did some research and asked some experts who I thought had told me what I said in my post. They corrected me ... without wapping me on the side of the head too hard.

As long as the ATF is moving, then heat buildup will not be a problem. Personally, I would prefer not to move it to neutral ... the savings just coasting in gear should be good enough (according to my informal down-slope experiments with this) ... but you can do choose to put it in neutral down a slope - as long as the engine is still on, of course!

Z

[szh]

Here, by the way, is some info that is important to keep in mind.

Automatic Transmission Fluid Oxidation

Automatic transmission fluid will provide 80,000 miles of service before oxidation occurs under normal operating temperatures of about 174°F. Above normal operating temperatures, the oxidation rate doubles (useful life of fluid is cut in half) with each 20° increase in temperature.

The approximate life expectancy at various temperatures is as follows:174°F 80,000 miles 195°F 50,000 miles 212°F 25,000 miles 235°F 12,000 miles 255°F 6,250 miles 275°F 3,000 miles 295°F 1,500 miles 315°F 750 miles 335°F 325 miles 355°F 160 miles 375°F 80 miles 390°F 40 miles 415°F Less than 30 minutes

This information clearly shows why transmission oil coolers and the various maintenance intervals are recommended for non ideal usage.

Above 270°F, the metals inside the transmission will warp and distort in varying degrees depending on the severity of overheat. Because this damage occurs and fluid life is so seriously impaired, rocking out of snow, mud or sand should never exceed a very few minutes.

Personally, I like to do a full transmission flush every 30,000 miles, so I am assured that it has the best conditions to operate under. Cheap insurance to extend the life of the transmission and avoid expensive replacements!

Z

[Double E]

Now we have a useful forum gentlemen!

Thanks to the MOD for the research and verification.

...and to wbrian63 for providing additional useful information.

Since the last fill up, I'm averaging 22.3 MPG and expecting 410-415 miles per tank.