I looked on the forum but couldn't seem to find an answer (I know it should be out there so I am most likely an idiot).

Does everyone else notice that the automatic 2007 G revs really high when driving on the highway. I think I am at 3100 at 70MPH. Seems really high.

 

not mine, at 75MPH I'm at 3000. RPM's doesn't effect gas mileage at all, you can drop to 4th gear and watch the instant mileage and it shows the same.

The reason for 3K @ 75mph is that it puts you more in the power band instead of choking the engine at 2100, and a lower RPM will actually lower MPG.

 

I am not so sure of that ..... I would think that higher rpms directly impacts mileage.

If not, why did car makers even bother with overdrive in the first place ??

If that were the case,we can all drive in say 3rd all day (MT models can go upto about 90 mph in 3rd) and get the same mileage as now!!

 

I think this is one of the biggest drawbacks with the G35 setup. It's a great car, but the engine RPM at highway speeds is too high. Most of the other vehicles in this class get better mileage in part because of better overdrive ratios in the transmission. A lower RPM on the highway will almost always net you better gas mileage- 2100 RPMs will not put the engine under a lot of load under normal driving conditions. I have a 2005 3.5 SE Altima (auto) that runs at 2100 RPM's at 70 MPH/ 2400 at 80 MPH and with mxed driving, will get 26- 27 MPG. On a recent trip to Texas with all HWY driving I got 33.5 MPG (checked this manually- the computer is off by 1-2 MPG). It's hard to compare different cars but the G will not get close to numbers like this if the overdrive gearing isn't adjusted. The IS 350 has the same amount of power as the G ( with a minimum advantage in torque), has similar weight, but has better MPG- one of the main differences in the two cars is RPM's at highway speed.

 

I went to Boston this weekend in my X and that was a 220 mile drive 1 way. Doing aobut 80-100 mph, my rpm was around 3700-4200. Even inthe city on local HWY i notice the rpm runs alittle high but i thought it was due to the short gear ratio. But goin 80-100mph it should be lower cuz it in a higher gear. Don't know if this is normal or not. Also HIGH RPM=LOW GAS MILEAGE. Example: Try stompin on your car from red light to red light, and you see how much gas you lose.

 

thanks everyone. oh well, i guess i have to live with poor gas milage.

 

actually, to me, the rpms seems fine. in my old car at 80mph the rpm would be around the 3200 range. so i guess you can say im use to it.

 

I have done a few long Hwy trips and have avg about 23 - 24 mpg. I was cruising about 75 - 80 most of the way.
Mine shows an indicated 3K rpms @ 72 mph.
I assume mpg will go up slightly with more miles on the engine.

 

Not quite.. high rpms with wide open throttle means bad mileage.
high rpms with slight throttle can still yield good mileage with the engine always in or near the peak powerband. OHC engines are designed to run at higher rpms

 

what was your old car?

 

My son's M3 cruises 70 mph @ 3300 rpms. This felt really high to me the first time I drove it... but after some time behind the wheel... it feels right

 

99 a4 1.8tquattro auto. it was a dawg!

 

Ditto. The G35 revs are very similar to the G35, but just a pinch better and as such the mileage seems to be a little better.

 

i think you mean to say, "The G35 revs are very similar to the A4" and yes the mileage seems to be better, so far.

 

Thank you CarNutz, That's what I was trying to say in my first statement, but I alway forget to account for the extremists. A few hundred RPM's has no effect on gas milage, people shouldn't be sweating 3000 RM at 75mph. smashing the gas pedal or running at 7600 RPM of course is going to impact MPG, but a few hundred in the low range won't matter.