[KarlBenzSF]

As I said in the title... I want to stay in the fifth gear in order to obtain lower noise and high MPG....

BTW, anyone has the torque vs. rpm diagram for the 2000 E320's engine?

Thank you!

Karl

 

[ohlord]

You don't

want to do that.Torque in gear is the way a car operates.Starting in fifth gear and keeping it there would kill your MPG not help it.Ideally you want it to shift at the torque peak in each gear allowing ease of movement in that gear to the next and so on.Ever drive a stick manual transmission?Try feathering the clutch and taking off in high gear,unless the car has gobs of torque you will fry the clutch,or stall it out,or the engine will lug along straining to come to the torque peak for that gear.Not conducive to high MPG.
Every automatic has a compromise to obtain comfort in shift quality.If you want to maximize MPG get a G force meter and shift in manual mode at peak torque in each gear just short of the highest attained mpg using your mpg computer.When you get to 4th gear shift into D and let the car modify the OD.
aintain the car properly.O2 sensors at 100k miles,plugs at proper intervals,Bump up your tie pressure 4 lbs on front and rear and keep them inflated properly.Keep a clean oem air filter in the air box.And drive like you have an egg under the gas pedal. And get a G-force meter and learn to use it.
:bowdown:

232 ft. [email protected] rpm(the answer to your other question)

The extra 200 lbs for your 4 matic is costing you a few mpg,so next time unless you really need 4 WD don't get a car with it installed.:thumbsup:

 

[JeffreyP]

KarlBenzSF

Sounds like you just want the car to stay in fifth gear in kickdown situation right?

 

[Figuero]

KarlBenzSF

Sounds like you just want the car to stay in fifth gear in kickdown situation right?

You can't really do that with an MB automatic. They don't operate like any of the true Tiptronic variants. You can only force a downshift, or delay an upshift, you can not prevent a downshift.

The only way to prevent a downshift to drive very conservativly and get a feel for when the transmission is getting ready to downshift, and then let off on the throttle a little.

 

[Figuero]

...you want it to shift at the torque peak in each gear allowing ease of movement in that gear to the next and so on........232 ft. [email protected] rpm(the answer to your other question)

Ohlord, with all respect, I'm sure you know that torque and HP curves are only valid at WOT with the engine under full load. With that in mind I don't see how they would apply when trying to maximize fuel economy. If that were the case you would be shifting a Ferrari at 5,000 - 6,000 rpm to maximum fuel economy.

As far as optimizing fuel economy in an automatic, I would recommend leaving it in "D" and simply use as little throttle as possible to get up to speed. Then drive "out in front" of the car to anticipate traffic changes and moderate you speed as to avoid using the brakes as little as possible. The brake is the biggest fuel waster in the car.

Short of using hypermiling techniques I think that's about the best way to improve fuel economy. (Along with your other maintenance suggestions of course....

 

[iluvjesus]

Another cheap way to improve MPG is to use neutral gear more often at the appropriate time.

 

[Figuero]

Another cheap way to improve MPG is to use neutral gear more often at the appropriate time.

Keep in mind two things.

Coasting in neutral amounts to towing with all 4 wheels on the ground and can overheat and damage your transmission. Check your owners manual, (maximum distance = 30 miles, maximum speed = 30mph). I don't know if repeated coastings over the years will cause damage due to the accumulated distance - but I would be very cautious about the 30mph warning.

The other thing is that when coasting in "D", I'm pretty sure there is a fuel cut-off so you might actually use more gas coasting in "N". Besides, it's not legal in many states.

 

[iluvjesus]

Thanks Figuero for the info. May I request you to explain why towing with 4 wheels on the ground will cause overheating and damage the transmission?

 

[Yacht Master]

If you go easy on the gas the trans will shift in to 5th at about 48-50 mph and stay in 5th down to 43-44. That trans & engine is all about adapting to the best possible combination for MPGs.

 

[Figuero]

Thanks Figuero for the info. May I request you to explain why towing with 4 wheels on the ground will cause overheating and damage the transmission?

I'm not qualified to go into detail but my understanding is that even though you are towing in neutral, there will be certain components of the transmission rotating. With the engine off, there won't be proper circulation of the ATF causing excessive friction and heat build up.

Thinking about coasting vs towing, it might not be as hard on the transmission as I first thought. With towing the engine isn't running, with coasting it is so the fluid would be circulating. So I'm not so sure it's an issue.

 

[iluvjesus]

thanks a lot.

 

[E430SportMB]

Try riding a bike. Put it on 5th gear and start pedalling . . . uphill. Ouch !

 

[ohlord]

With all due respect

not many cars attain peak torque or horsepower at WOT.Torque falls of well before that and hp is a function of torque.A g force meter used properly will indicate the peak torque in each gear(remember gears multiply torque)that is the function of the transmission.So it is not peak engine torque it is peak gear torque and G force generated.He wants to keep it in 5th gear even at 20mph thinking it will increase MPG.Use torque per gear to maximize mpg.Just as you can use it to figure out the max acceleration point in each gear for shift points at the track.
If you have ever driven a Ferrari,5 or 6 grand would be short shifting it:thumbsup:
Using a g force meter on one would work the same way.I am not saying stomp on it and get it to speed.I am saying if you manually shift the MB auto and do it at the proper rate you will achieve the highest mpg for each gear while getting to the max mpg in overdrive in the shortest most fuel efficient way possible.
Personally If they had left the rev limiter at 6500rpm the engine would be much happier
I race and I hyper.Racing is way more fun:thumbsup:
:bowdown:
599 Ferrari
Horsepower: 612 hp
Max Horsepower: 7600 rpm Torque: 448 ft-lbs.
Max Torque: 5600 rpm
Neither attained at WOT
12mpg combined,you don't drive them for the miles per gallon

 

[KarlBenzSF]

I want my... I want my... I want my MPG!!!!!!!

 

[KarlBenzSF]

leaving the gear at "N" on expressway is a pretty chinese way of driving....hahahah

I've remembered that one of my friends drove a E240 and got 33 MPG.... sadly they didn't came to the U.S.

 

[Figuero]

I think we might be interchanging WOT (Wide Open Throttle) with Engine Redline RPM. Sorry if I created the confusion.

 

[Kajtek1]

leaving the gear at "N" on expressway is a pretty chinese way of driving....hahahah

I've remembered that one of my friends drove a E240 and got 33 MPG.... sadly they didn't came to the U.S.

Why would you want such a louzy mileage here?

 

[KarlBenzSF]

I forgot to tell you guys here...

I'm getting 24 MPG in city driving everyday....