timcodon

timcodon - I just got this G37-Sedan recently. I used to drive a stick-shift only cars, where I have to use my left-foot for the clutch, and my right-hand for the stick. But I am very new to this automatic / manual transmission on the G37. I read the manual, and tried to switch between auto and manual. In the city-traffic, I tried to drive in "D", "DS", and M modes. But in "Manual-mode" I had hard time trying to time when I should push-up to switch to higher gears, and when I'm stopping, I just let the down-shift to occur on its own. Later, I found I better just use "D" in city, then when I get to high-way, while the car is still drivign fast, I would switch to "Manual", so I push to the 7th gear.

Why I want to do this? on a 300-miles long round-trip, when I drove in M-mode (of course in 7th gear), I got 31.5mpg. On my way back, I used "D", I got only 28.4mpg. So I would like to acheive its maximum potential benefit: don't have to deal /w manual in traffic, but want to get max mph when it's on highway.

Q: I wonder, if there is anyone out there doing what I "plan to do". And whether, if it's safe/ok to drive this way as a routine or will this create more wear-n-tear on my transmission than trying to get better gas milage?

Anyone has an opinion? BTW, my city/hwy combined, I got around 19, so that's why I try to find ways to raise to 20-21 (combined).

RedG37SNC

I'm surprised in D mode it doesn't go to 7th automatically once you're cruising. In D mode it should always go to the highest gear once you're cruising on a highway. If that's really the case then put it in DS mode and when you get to cruise speed force it to 7th which will put you in M mode and cruise away. When you look like you're going to be coming out of cruise, just move the shift right and left real quick to re-enter DS mode and let the car manage it until you're back in cruise and then force a shift to 7th to resume.

timcodon

I don't know it does or doesn't get to 7th in AT mode. But I just "assumed" it didn't, becasue otherwise, why do I get so much mpg different between using "D" and "Manual" on my 300-mile round trip?

Your suggestion sounds good, have it at "DS", so it's already ready for "M", then use "M-7th" on hwy, then cancel "M" by going to "D" (then go back to "DS") and re-ready for "M". If this is not too much for auto trans to take it, and for everyday's driving...

I'll try it out, and let everyone know...

Thanks.

SkyMG37x

I know Texas is flat, but is it possible that you're outbound trip had more downhill bias, hence better fuel economy compared to the return trip which had more uphill bias? That might explain the 3 MPH difference, especially since 31 MPH is much higher than the car is rated for.

Reno-ID-Doc

Timcodon, I employ nearly the same style as you do! What a coincidence. Personally I prefer MTs but the G37x Intelligent AWD does not come in MT, and in our area there's a real practicality of having AWD since we have a lot of snow days. I value AWD above all.

Here's are some pearls I have:

I basically leave it in 'D" mode for worry-free / thought-free driving. Perfect for that city driving. I still have a habit of putting the trans in "neutral" when I have decelerated enough (<10-15 mph) & this gives me a closer feel with the brakes without the AT "pulling" you forward when you release the brake pedal. I don't put in in "neutral" if I anticipate that after decelerating, I would need to accelerate within a short period of time.

In highway driving, where I could get more intimate with the tranny, I put it in DS mode, in anticipation of getting it into manual mode. However we should take note that by just putting it in "DS" mode, there is a downshift of -1 gear that occurs momentarily (DS = current D gear -1 gear). This is also evident because the car travels roughly the same speed but the RPMs go higher.

What I do then is after I momentarily put it into "DS" mode, I immediately upstroke & flick the shifter to the (+) direction. Anything then that we do, putting it into (+) or (-) direction would be now manual.

Because of the rpm matching, downshifts can occur while decelerating without you commanding it. It's a bit eerie since downshifting is a manual thing we're used to before. I guess we just have to accept this.

Like you I am still trying to find the best upshift points. I guess it would be tricky first since you have to contend with 7 gears. In my previous MT experience, I have had a 5MT car, and a 6MT motorcycle. The best teacher would actually be your G37 as well. In a way you could conversely learn the shift points by learning how it downshifts. (I am surprised that most common intersection curves are handled well by the G37s AT at gear nos 3. I would have erroneously thought that it would be at gear nos 2. Also, I've noticed that gear nos 1 is indeed a launcher, but the 7AT likes to get away from 1 as soon as possible). I'm still learning all this time. I have to admit it's fun having a 7AT teach me shift points.

popcornten

I think it's funny you're thinking so much into this. I have the '08, so it's just a 5AT but I use the manual mode 98% of the time (I wish I had a stick). I switch off between paddles and the gearshift just depending on the mood ha. I'm at about 20,000 miles and don't see why it should hurt the transmission. The only thing could end up hurting is continued downshifting at higher RPMs, which I've begun to do a lot more since I've instilled my Stillen cat-back and I LOVE the sound on downshifts! Other than that, I pretty much just let it downshift as I come to a stop, unless I'm looking for passing power on the highway or something and I'll drop it down myself (I honestly wouldn't want the 7AT since I drive M mode, there's too many gears to drop to REALLY get into the power band and get goin)

Upshift points - just depends on your driving. If I'm just leisurely driving I'll upshift as fast as possible (usually before 3K rpm). If I'm really going at it, shift no later than a couple hundred RPM before the limiter or you'll hit the fuel cut-off.

But I do employ the same school of thought. I prefer it be in top gear in M mode while on the highway because it's got plenty of passing power and I don't have to bother with unnecessary D-mode downshifts looking for a gear when you try to pass.

What part of Houston?

Chapinb

Theres a reference point somewhere in the manual for both aggressive and MPH-minded driving for the mph to shift. Section 4 or 5. In that same area, it also states that you should be in 7th for ANY non-aggressive highway-speed driving. Based on mpg, seem this is about 55-60+. The manual isnt around me at the moment so I cant dig up the pages.
The AT should shift to 7th. In my short time driving, it it seems to up-shift about as soon as it can during normal driving, Ie, it up-shifts at the lowest RPM that the car will manually allow us to shift.
Also, if your looking to do a quick downshift on the fly in D mode, you can still use the paddles (if you have them) and it will return to normal D after a few sec

lange74

Your car goes to 7th gear, the thing is, when you want to shift yourself, you have to put it in DS mode first, which downshifts to 6th.
So if you don't feel the shift, you might be thinking that you were in 6th all along. As far as your Mpg go. I just think many factors influenced it other than the gear being selected.

Also, I don't see the benefit of using the manual for upshifting. Anyway, if you are going slow in D, the trans is programmed to optimize fuel efficiency and if you go fast, it will shift at redline like you would try to do with a manual. So why do it yourself?

I usually use it for downshifting. Let's say I'm waiting for the right moment to pass another car, I'll put it in the best gear so the car is ready and I won't be subject to the 2 seconds it takes for the tranny to downshift.
Also, I'll downshift before going in a turn so I have all the power ready to make a fast exit.

w0ady

iTrader: (1)

ya this seems like a lot of wasted time/effort...

like pop, i drive in manual 99% of the time. if i want better gas mileage, i shift around 3k otherwise im usually shifting just before redline. there is a slight lag of about 500 rpm so you have to learn to time it. as for downshifting, mots of the time i do it myself for engine breaking.

and i would NEVER shift a car into neutral while on the road. you never know what could happen and when you need to accelerate.

mike55912

I know if your in D mode in the coupe and you have the paddles, if you just hit the downshift it will downshift to the gear you want then automatically go back to shifting for you.

terrycs

iTrader: (37)

For me, D shifts too early

DS (agressive) shifts too high for daily driving (close to redline)

DS (non agressive) shifts just like D

So M gives me the best of both worlds with more control to determine what "feels" like the best time to shift is. In my 5AT, I usually shift between 3K and 4K depending on engine load.

It sure would be cool if the AT can be custom programmed!

JohnEnglish

Wow talk about effort. I just leave it in D 99.9% of the time. Sometimes if I'm bored I put it into DS and play around with the gears.

Mr_Ryte

Out of curiosity, did you record your avg speed coming and going?

Bluesmaster

+1
The tranny responds pretty well to throttle inputs in D. It is certainly programmed to save gas and upshift quickly under light acceleration.

timcodon

Hi everyone,

I've done some experimental. I now believe the car is in 7th on highway in D mode (by measuring the rpm while it's in D, vs in Manual). There is a correction on my original post, I said one way it was 31.5mpg, but actually it was only 30.1 when driving in Manual (vs 28.4 when driving in D). I found out that there are so many other facters determining the mpg, such as uphill/downhill with-wind/against-wind, etc. Thus I came to conclusion that it is NOT worth the effort of doing this crazy stuff in a long run...So I now just leave it in D 99.9% of time. Occasionally, I want to have some fun, the I do it in manual for a short wile, or in DS. But then I put it back to D, and use D almost all the time now...

I still have the transmission jerkiness issue, and making appmt with Inifiniti to load new sw update (Thanks to Brynomon user with his post).

Bottomline, many other factors effect mpg a lot more than my switching between D & Manual, so I stopped doing it. Factors I found effecting mph: how I drive, aggressive or gentle, staying idle in traffic lights too long (or fast food) vs just a smooth highway home.

So, all, please don't do crazy thing, as I orginally planned on doing..it's really not worth the effort to improve mpg.