Is there any way increase MPG for M45?

[ken in az]

I think driving habits and tire pressure are the easiest and most effective ways to improve mpg in your M.

[dvan]

One thing you can do to save some gas that I didnt notice anyone mention is to manual shift to 5th gear when you're cruising at highway speeds. You can use 5th by itself on the highway from 40mph or so and it should suffice for most passing/speeding up scenarios.

What happens most of the time in 'D' mode is when you want to pass someone doing 65mph, it usually downshifts to get up to speed. 5th gear by itself still pulls good at those speeds. I got about 24.5mpg doing some high way driving around 70-80mph.

[The00Dustin]

popping the car in nuetral is a good idea too. on my way home from work, i can get about 10 miles in on neutral. i work at 3000 ft above sea level and live at sea level.

You may want to check your state's laws on this one, I have read in an article (on Yahoo! or MSN) that it is illegal to put your vehicle in neutral while driving down the road in some states. I agree it can make a huge difference in an M45, I don't understand why the transmission drags so much, but it is ridiculous.

[ken in az]

You may want to check your state's laws on this one, I have read in an article (on Yahoo! or MSN) that it is illegal to put your vehicle in neutral while driving down the road in some states. I agree it can make a huge difference in an M45, I don't understand why the transmission drags so much, but it is ridiculous.

-1 for you

[Q45tech]

An educated engineer would always calculate the top gear ratio times diff gearing and correct for tire size to arrive at an RPM at say 60 mph then use engine displacement to arrive at a precise fuel use per mile at steady speed.

After all the ecu and O2 maintain a very very very precise use of fuel vs air to create a 14.7 to 1 AF ratio.

My 20 year old Q45 has a 3.538 x 0.694 or 2.455372 final top gearing with a tire rolling correction of 4.8% so 2.343 effective drive ratio.

1996 rpms at 60 mph.

Why magazine test usually show rpms at 60 mph so engineers can see what they are buying............easily without doing calculations.

Buying a car then complaining about it PROVES the buyer did an incompetent job of prebuy analysis. AND DESERVES WHAT THEY GET.

[ken in az]

An educated engineer would always calculate the top gear ratio times diff gearing and correct for tire size to arrive at an RPM at say 60 mph then use engine displacement to arrive at a precise fuel use per mile at steady speed.

After all the ecu and O2 maintain a very very very precise use of fuel vs air to create a 14.7 to 1 AF ratio.

My 20 year old Q45 has a 3.538 x 0.694 or 2.455372 final top gearing with a tire rolling correction of 4.8% so 2.343 effective drive ratio.

1996 rpms at 60 mph.

Why magazine test usually show rpms at 60 mph so engineers can see what they are buying............easily without doing calculations.

Buying a car then complaining about it PROVES the buyer did an incompetent job of prebuy analysis. AND DESERVES WHAT THEY GET.

Q45tech - stop acting like you are better than everyone else just because you can do math - it's tiring and nothing you said helped anyone. Oh, and you said those calcs would give a "precise" fuel use at steady speed? Uhhhh...I think you forgot some things there because I'm not sure you'd even get in the ballpark with those calcs.

Lot more to consider to determine fuel usage than just revs per mile. Try throwing in fuel temperature, more specific measurement would be density or the specific gravity of the fuel. Need to also acount for rolling resistance from the tire, more specifically is tire size and compound. Need to know aerodynamic characteristics of the car/truck, more specific is the CD or coeficient of drag of the vehicle at said speed. Atmospheric conditions will also play a role in fuel economy as well. Barometric pressure, temperature, humidity will all play a role in how much oxygen will be present in the air the vehicle consumes. What a lot of people sometimes don't consider is how much of a factor Tempurature plays in the way an engine runs. Temperature directly reflects the speed of sound. Why is that important? Because the opening and closing of the valves of the engine create a sonic pulse that can aid in the cars ability to create peak torque at a given rpm. Change this and peak torque is not where you caculated and now that requires additional throttle to maintain the same speed. Also consider ignition timing, to advanced and it will cause a degridation of performance, to retarded and it will alsy degrade performance. Both of which affect toque output which can directly affect fuel economy.

Although slight changes in each of these factors on their own are a minimal distraction to fuel consumption, but start adding things up and together they can start to affect the rate of fuel consumption for said vehicle.

Don't beat the guy up for asking, it's a legitimate question. I'm sure he knows what he bought and like others have said, he owns several vehicles. He was simply asking any way to improve fuel economy. Your elitest attitude will be what drives people away from this site.

[ken in az]

One thing you can do to save some gas that I didnt notice anyone mention is to manual shift to 5th gear when you're cruising at highway speeds. You can use 5th by itself on the highway from 40mph or so and it should suffice for most passing/speeding up scenarios.

What happens most of the time in 'D' mode is when you want to pass someone doing 65mph, it usually downshifts to get up to speed. 5th gear by itself still pulls good at those speeds. I got about 24.5mpg doing some high way driving around 70-80mph.

Yup - If you ever watch your Tachometer when doing this you'll see something else going on in manual mode(at least for the M45's). In manual mode in 5th gear the torque converter will lock at 65mph giving you a direct drive at any speed higher than that no matter the throttle position. It won't unlock until below 60mph.

If you leave it in D, the toque converter will lock at the same 65mph but just a little bit more than slight pressure on the throttle will cause it to unlock and the revs will increase before downshifting.

Locked TC do 2 things. First, Direct drive to the transmission means no wasteful slipping. The slipping causes heat. Heat Kills and Revs use more fuel.

Leave it in 5th - just be aware that it's still in 5th before making an aggresive manuver that requires a downshift. No matter how hard you press on the pedal it will stay in 5th gear.

[bredtime]

Q45tech - stop acting like you are better than everyone else just because you can do math - it's tiring and nothing you said helped anyone. Oh, and you said those calcs would give a "precise" fuel use at steady speed? Uhhhh...I think you forgot some things there because I'm not sure you'd even get in the ballpark with those calcs.

Lot more to consider to determine fuel usage than just revs per mile. Try throwing in fuel temperature, more specific measurement would be density or the specific gravity of the fuel. Need to also acount for rolling resistance from the tire, more specifically is tire size and compound. Need to know aerodynamic characteristics of the car/truck, more specific is the CD or coeficient of drag of the vehicle at said speed. Atmospheric conditions will also play a role in fuel economy as well. Barometric pressure, temperature, humidity will all play a role in how much oxygen will be present in the air the vehicle consumes. What a lot of people sometimes don't consider is how much of a factor Tempurature plays in the way an engine runs. Temperature directly reflects the speed of sound. Why is that important? Because the opening and closing of the valves of the engine create a sonic pulse that can aid in the cars ability to create peak torque at a given rpm. Change this and peak torque is not where you caculated and now that requires additional throttle to maintain the same speed. Also consider ignition timing, to advanced and it will cause a degridation of performance, to retarded and it will alsy degrade performance. Both of which affect toque output which can directly affect fuel economy.

Although slight changes in each of these factors on their own are a minimal distraction to fuel consumption, but start adding things up and together they can start to affect the rate of fuel consumption for said vehicle.

Don't beat the guy up for asking, it's a legitimate question. I'm sure he knows what he bought and like others have said, he owns several vehicles. He was simply asking any way to improve fuel economy. Your elitest attitude will be what drives people away from this site.

What did you do? Copy and paste a Wikipeda article? Would you have preferred if he responded with "-1 for you" like you did to the other person who replied to this topic and was again trying to help out. Each person has their own way to respond to a topic, so stop bashing Q45 because he methods are different than yours. His post might not have helped you, but down the road someone might need that information. With 323k miles on his car, I can trust that he knows what he is talking about.

P.S. In case you have forgotten you don't own this forum.....he does.
Modified by bredtime at 5:57 PM 11/5/2009

[ken in az]

What did you do? Copy and paste a wakopedia article? Would you have preferred if he responded with "-1 for you" like you did to the other person who replied to this topic and was again trying to help out. Each person has their own way to respond to a topic, so stop bashing Q45 because he methods are different than yours. His post might not have helped you, but down the road someone might need that information. With 323k miles on his car, I can trust that he knows what he is talking about.

P.S. In case you have forgotten you don't own this forum.....he does.

Uhh...nope that was all just out of my head actually.

and the -1 for you was supposed to be a joke - just like that law that you mentioned. Really?? a cop is going to give you a ticket for coasting in neutral??

In case you didn't notice I was actually mentioning that his calculation was incomplete and there is much more involved in calculating fuel consumption other than basing it on "revs per mile @ 60mph" If you expect a 10% increas in fuel economy by switching your axle ratio then I've got some land in florida I can sell you for cheap - lol

If you believe what he's saying and don't believe me that's fine, but the way he goes about his posts are quite arrogant and elitest which is demeaning and probably doesn't make the OP feel too good about themselves. Really - did he get what he deserved??? Huh??? Did he??

Oh, and do you own NICO Q45tech? I don't see your name on this list...

http://www.nicoclub.com/staff/greg.shtml

[bredtime]

Uhh...nope that was all just out of my head actually.

and the -1 for you was supposed to be a joke - just like that law that you mentioned. Really?? a cop is going to give you a ticket for coasting in neutral??

In case you didn't notice I was actually mentioning that his calculation was incomplete and there is much more involved in calculating fuel consumption other than basing it on "revs per mile @ 60mph" If you expect a 10% increas in fuel economy by switching your axle ratio then I've got some land in florida I can sell you for cheap - lol

If you believe what he's saying and don't believe me that's fine, but the way he goes about his posts are quite arrogant and elitest which is demeaning and probably doesn't make the OP feel too good about themselves. Really - did he get what he deserved??? Huh??? Did he??

Oh, and do you own NICO Q45tech? I don't see your name on this list...

http://www.nicoclub.com/staff/greg.shtml

I never said that I didn't believe you, nor did I say that I believe Q45 over you. The fact remains that you could have replied to his post by just stating that his did not finish his equations - would have been much more productive. But, like I said, everyone replies in their own way and if that is how you like to reply, thats cool.

And honestly, the OP did get what he deserved, I mean asking a simple question of how to improve fuel economy is fine but to then to complain:"i am complaining for Nissan's misjudgement. they shouldn't put 5 speed automatic.""But my friend's 2008 Lexus LS460 get better mileage than mine.""Nissan shouldn't put 5 speed automatic for 8 cylinder car!!!!!!!""M45 S those 4 letters made me blind......."

I could go on....

[ken in az]

Yeah I see your point...he kinda had it coming with those responses

And a friend of mine just bought an IS350 tonight and they get a rated 28mpg....she's a hairdresser so that car fits her perfectly - lol I kid I kid!

[AD1787]

I just completed a 2000 mile cross country trip in my M45 which averaged 66.7mph and 22.3MPG according to the trip computer. This was probably 99% highway miles.

[AD1787]

15000 miles a year20mpg - 750 gal x $2.80 = $210018mpg - 833 gal x $2.80 = $233316mpg - 937 gal x $2.80 = $2625

I'd rather skip one night out eating a month and just get in my car and enjoy the ride. Its so much easier to save a few hundred dollars a year on nearly anything else and just enjoy your car.

And to you answer your question, I have no idea if there are ways to improve gas mileage

[saeedakobiakov]

http://www.roadandtrack.com/ar...=4459h ... ...testsIS 350 will blow doors of M45. i would not race them if i were you.so is gs 460 had better times throu 1/4.toyota makes fast cars.my friends ISF was 12.5 @117, that's faster then new camaro ss at [email protected] faster then c63 amg.all i am saying there is no need to make fun of toyota/lexus.they are faster.i think supra always smoked Z.but try for yourself to beat the hairdresser with IS350, let us know the results.

[dvan]

saeedakobiakov,

R/T M45: 5.3 sec/13.8 sec @ 101.6MPHR/T IS350: 4.9 sec/13.5 sec @103.1MPH

Given this data, yes, the IS350 is technically faster, but .3 sec and 2MPH difference would be 'blowing the doors' off the M45? Wow

Besides, if you didnt know, Kenz M45 is highly modified and is considerably faster than a Stock M. So I would think he would actually beat an IS350 anyway.

Also, in the realworld, sometimes racing doesnt mimic mag specs/times. Check out this video of Stock 2004 G35 vs Is350 with intake/exhaust.

http://videos.streetfire.net/v...4.htm

G35 for the win

I would love to race an IS350, win or lose, just too see what happens. I bet from a roll it would be very very close.

[Q45tech]

Using current [$2.80] for gasoline is short term thinking at its worst.

Do all your calculations on $4.00 per gallon and you'll always be more than right. Include the hour waiting in line to refill or ration coupons.

Gasoline is never the majority in real cost to own even when it returns to $4.........Ins, tag, tax and M&R, annual depreciation always exceeds the cost of gasoline on expensive cars.

[saeedakobiakov]

stock to stock lexus is faster , period. there is not need for making any kind of jokes against more advanced lexus.toyota just more advanced then nissan.

[bredtime]

stock to stock lexus is faster , period. there is not need for making any kind of jokes against more advanced lexus.toyota just more advanced then nissan.

I'm sorry, but why are you on this forum?

[saeedakobiakov]

if i had money i would buy ISF in the hard beat.i just dont like people making fun of lexus, that is all.peace.,caug

[bredtime]

if i had money i would buy ISF in the hard beat.i just dont like people making fun of lexus, that is all.peace.,caug

Hey....this is funny :

http://www.youtube.com/watch?v=zmv1ty2p-H0

[saeedakobiakov]

gs 460, i said

[M45Runner]

gs 460, i said

Then, wait for M56 next year....

[fiveliterbeater]

What did you do? Copy and paste a Wikipeda article? Would you have preferred if he responded with "-1 for you" like you did to the other person who replied to this topic and was again trying to help out. Each person has their own way to respond to a topic, so stop bashing Q45 because he methods are different than yours. His post might not have helped you, but down the road someone might need that information. With 323k miles on his car, I can trust that he knows what he is talking about.

P.S. In case you have forgotten you don't own this forum.....he does.

Modified by bredtime at 5:57 PM 11/5/2009

so......are you sleeping with Q45tech now? do you guys grab beers together on sat nights now? Ken just happened to beat me to the punch line cause i was getting ready to unload on Q45tech myself cause the info he provides is simply USELESS

....and since you like to defend him so much, let me ask you , when you bought your Q56, your Acura and your M, did you go into the dealership asking the sales guy if he could "calculate the top gear ratio and then multiply the diff gearing?"

.....or better yet.... did you ask him if he could "correct for tire size to arrive at an RPM at say 60 mph then use engine displacement to arrive at a precise fuel use per mile at steady speed."?

i cant believe you're even listening to a guy who owns a dinosaur of a car combined with good math skills, and then magically answer any car question he feels like...

i mean that's like me telling John Force that i think i could drive a top fuel drag car better than him because i've read all about drag racing in books and i also own a passenger car myself.

and to the "copy and paste" comment...believe it or not ...there are people out there that are self taught, and have picked up knowledge through trial and error and lots and lot and LOTS of fri and sat nights at the track asking questions and picking up knowledge on the go from more experienced car guru's. REAL GURU"S (im talking to you Q45tech) , not wannabe's who sit behind a computer with a mouse in one hand and a math book in the other....

that's all i can think of for now......

p.s. and by the way, i believe AZHitman owns the forum, not Q45tech. Mods correct me if im wrong

[fiveliterbeater]

http://www.roadandtrack.com/ar...=4459h ... ...testsIS 350 will blow doors of M45. i would not race them if i were you.so is gs 460 had better times throu 1/4.toyota makes fast cars.my friends ISF was 12.5 @117, that's faster then new camaro ss at [email protected] faster then c63 amg.all i am saying there is no need to make fun of toyota/lexus.they are faster.i think supra always smoked Z.but try for yourself to beat the hairdresser with IS350, let us know the results.

OMG.....another Jacka$$......let school begin...class is in session

the term "blowing doors off" is a term you use when a stock honda civic DX gets beat up by a.....ummmm.... i dont know... a Mustang GT. (4+ cars) to say the least.

but an IS350 that has an average 1/4 mile time of 13.6-13.7 @100mph vs an M45 that has an average 1/4 mile time of 14.1-14.0 at 99-100mph IS NOT BLOWING DOORS OFF!

how can 3/10ths of a sec (which translates to 1/4th of a car length ahead of someone) be considered BLOWING DOORS OFF???

i mean, then what would you say when you're precious IS-F actually races an M45? whats your terminology there? blowing doors off again?

and yes, toyota makes fast cars.......but there is always faster....

proof you ask? why certainly sir! i'd like to see you're top of the line IS-F , compete with a car you may have heard of....... GT-R

now that, capt. dufus...would not simply "blow the doors" off an IS-F.......but it would ANNIHILATE it! plain and simple! your friends 12.5@117 is no match for an 11.0 @129....

and an IS-F faster than a C63 AMG? you might wanna call motortrend and caranddriver and tell them they made a mistake cause the IS-F actually came in 3rd against the C63 AMG and the M3. so you and your "friend" should make a trip to LA (here is the address: MOTOR TREND6420 Wilshire Blvd. Los Angeles, CA 90048-5515) and then to MI ( CARANDDRIVER 1585 Eisenhower Pl, Ann Arbor, Michigan 48108) and tell them that you disagree

Sorry to knock you off that cloud you were sitting on when you typed up your post but i had to.

Now don't get me wrong....i LOVE Lexus vehicles. i think they make awesome machines (i've owned 2 in the past) , but they have their limits. Supra's are amazing machines and always will be, but, as long as there is competion, there's always gonna be a faster car out there...PERIOD!

p.s. id like to see your precious IS350 against a G37.....


Modified by fiveliterbeater at 9:39 AM 11/9/2009

[Kosmos]

Here is a tricky question. If say we would take out of the M and IS all the insides (sets, carpet, electronics...) and race them again, who will win? To my understanding the weight of the M would be reduced more then the IS and just enough to get that head to head race )))

And by the way to the Lexus lover... IS-F is a performance car that comes in last within it's class. I don't suggest you dreaming about it. Try the M3 now that is a legendary and recommended with time performance vehicle. Truly to say I see Lexus as a girly brand now days too many stylish lines. The previous IS though was a masterpiece of design! Do you remember the speedometer looking like a fancy watch?

[fiveliterbeater]

Here is a tricky question. If say we would take out of the M and IS all the insides (sets, carpet, electronics...) and race them again, who will win? To my understanding the weight of the M would be reduced more then the IS and just enough to get that head to head race )))

you know that's actually a tricky question and i'd be lying if i said i would know the outcome.

but now that you actually brought up that question, SportCompact did an article many many many years ago about weight reduction and how much of a difference it made.

what they did was (at the time) took a brand new 2001 Nissan Sentra and ran it down the track. i think it clipped a 17.xxx at 80 something miles per hour.

they then proceded to strip parts off the car little by little. and everytime they took a part off, thed'y make a quick pass to see if it made a diffrence. well, 20 some passes later, (and half a car), they managed to get the Sentra into the low 14's at almost 100mph!

it was really funny though cause they had a pic of the Sentra running down the track with no doors, no dashboard, no seats (just the driver seat), no hood, no trunk, no fenders... just basically the frame and the eninge going down the track

[ken in az]

Here is a tricky question. If say we would take out of the M and IS all the insides (sets, carpet, electronics...) and race them again, who will win? To my understanding the weight of the M would be reduced more then the IS and just enough to get that head to head race )))

And by the way to the Lexus lover... IS-F is a performance car that comes in last within it's class. I don't suggest you dreaming about it. Try the M3 now that is a legendary and recommended with time performance vehicle. Truly to say I see Lexus as a girly brand now days too many stylish lines. The previous IS though was a masterpiece of design! Do you remember the speedometer looking like a fancy watch?

The IS350 would win hands down. It already has a lower starting curb weight and is under-rated in the power dept to the tune of 320bhp stock. I believe the M45 is spot on in the power dept but it has a little mushier transmission.

Overall the IS will have a better hp per lb ratio and be victorious in nearly all feats of straightline speed. I'd have a hard time believing that an M45 could get down to 3300lbs from 4000lbs than the IS350 3500lbs down to 3300lbs seems more reasonable. I have been wrong before so don't hold me too it

IS350 does have some inherent stability control deficiencies - like you can't turn it off "at all!" So around a track it will limit the limits to which you can drive towards. Also, the ECU has not been hacked so no tuning options available either. Anyone that has tried to tune the 2IS has failed or only partially succeeded. Any tune that has been thrown at it eventurally gets learned out and resorts back to stock. Couple that with 11.8:1 compression and an already tricked out factory intake and exhaust, not too much to gain in the power dept. The M45 definitely has the tunability advantage there.

One other item that I noticed, the final drive of the IS is 4.08 gearing! 5th and 6th gear are both overdrive and 6th being .59:1 ratio is quite impressive. Lets hope the M56 shares a tall 7th gear so they can take advantage of the lower gearing off the line. This gearing is another reason why the car is so dang fast....it can get off the line quickly and still maintain a low cruise rpm for economy and longevity.

[saeedakobiakov]

I bet m56 will be slower then my frieds IS-F [email protected] number is real.do the serch and see who can beat in its class. please dont you gt-r. it is almost race car.we are talking 4 door onces.m3 slower, amg is slower.do the serch again.

[rsg123]

I bet m56 will be slower then my frieds IS-F [email protected] number is real.do the serch and see who can beat in its class. please dont you gt-r. it is almost race car.we are talking 4 door onces.m3 slower, amg is slower.do the serch again.

Why are you comparing apples and oranges? The IS is a small entry-level "luxury" sedan. The M is a heavier and much larger luxury sedan. I second the question: what are you doing in this forum?

[fiveliterbeater]

I bet m56 will be slower then my frieds IS-F [email protected] number is real.

....and your point being???? it probably will be slower capt. dufus! you're comparing two cars from two different categories you're comparing full size luxury against entry level sport luxury. what's the point of having a luxury car if i can't even get my "3rd leg" in the door??

do the serch and see who can beat in its class.

done!

http://www.motortrend.com/road....html

and another one...

http://lexusenthusiast.com/200...s-c63/

and just one more.....

http://www.caranddriver.com/re...tests

had enough?

please dont you gt-r. it is almost race car.

ummm....that's stated where? and if that's the case is the corvette a race car too now?

we are talking 4 door onces.m3 slower, amg is slower.do the serch again.

please see my reply in post #2 ....i think i've done enough research for you.

......thank you and please drive through