You're an idiot.

 

All this just confirms to me that Nissan/Infiniti needs an automatic 6 speed transmission with an overdrive gear for highway cruising. They could probably increase highway mileage this way by 3-4 MPG. It's interesting that they have fallen behind in this department. I was sure that the 07 G35 would have this feature to match Lexus/Acura/BMW, even Cadillac in offering a 6 speed slush box.

 

do any of you guys get this problem..?? if i am moving at 60 MPH my tach reads about 2K and the mileage is good...BUT the moment i go to 65 or 70 and above..it shoots straight to 2500. and then the mileage is terrible..iv driven my dads LIFTED nissan titan on big 22 inch wheels and BIG all terrain tires and can go 80 with the tach at 2000...

 

^I get my best gas mileage at about 80 mph rpms being at 3k.

 

Adding an extra overdrive gear may help MPGs slightly on the highway, but it's dependant on so many other factors like overall gearing, torque converter stall speed, engine size, weight, and powerband. I've been on the Lexus site and IS350 owners report about the same MPGs as most of us G35 5AT owners which is about 17-19mpg in the city and 26-29mpg. Same goes for the Acura TL 5AT owners. One downside to 6AT+ trannies is the gear hunting. It can get pretty annoying because the tranny as so many gear options that it will start second guessing itself. A 4AT often feels like they're always in the wrong gear and 6ATs can often feel the same way. Lexus and Benz owners with the 7/8 speed autos report quite a bit of hunting and jerkiness. The JATCO 5AT in the G/Z is definitely geared towards performance and the gearing is optimal for acceleration at most every MPH. It's also why the car performs so well for having a run of the mill DOHC V6. While rolling on the highway, leaving the car in 5th often results in enough passing without the need for a downshift. The Acura 5ATs are geared more towards economy and are much the reason why the auto TLs are significantly slower than the 6MT versions.

 

Because:

1) The Titan has a V8 with a good bit of torque in the low revs therefore it doesn't need as much gearing.

2) 22" wheel with big tires are most likely taller than stock therefore he's reduced the gearing of the truck over stock therefore lowering the operating rpm at 80mph.

3) Gearing a 5.6 liter V8 Titan like a 3.5 liter V6 G35 would result in some seriously bad mpgs and would probably make the truck slower because it would accelerate through it's useable powerband too quickly. Gearing a G35 like a Titan would result in soft acceleration.

 

Take that mpg and subtract 10 from it, thats what I always get.

 

not to mention horrible asian drivers.[/QUOTE]

Ya I hate those horrible asian car manufactures' too!!

 

i just got 160 miles with a little more than 1/2 tank =(

 

all highway driving!!

 

jesus...if i go 80 constantly..ill gulp down the whole gas tank...

 

I hear you Dave but I would hope that Nissan/Infiniti would do more than just add a gear and engineer the tranny for the vehicle. There could be a sport mode where 6th is locked out, there are many options to improve the MPG while preserving the performance.
I realize that we buy these cars for the performance and I really appreciate the capabilities, that's why I purchased. I'm not mad or angry, my car is delivering the mileage I expected. I am such a fan of these cars that I don't want to see Infiniti lose sales in the age of mileage when other manufacturers are addressing this with their new designs.

 

I just pulled down 29mpg on the way back from PA. 16.5 gals @ 480 miles. Best I have got to date.

 

WOOOOOOW. you're f'ing cool! NOT. you should be ashamed of even saying that on forum-- not to mention good admin.

 

just a quick question for you guys with good mileage..

i notice many of you say going 80 is the best for you
What RPM is your car running at 80 MPH?
Mine goes a little above 3k...is that what you guys get??