G35 5AT vs. G37 5AT RPM's @ 80mph
 

Just bought a 2006 G35 Coupe with the 5AT. Love the car, everything except the RPM's on the highway, I typically cruise around 90mph (well, in all the cars I have owned in the past 15 years) and this thing is driving me crazy at above 3300RPM's at 80mph. There doesn't seem to be any issues with the torque converter not locking or anything, so it seems that this car literally is just geared this short. I have started driving my 1997 Ford Explorer (4.0L SOHC) for highway duties because the G is just too wound up over 80mph.

Just curious, I had no interest in modifying the final drive to anything shorter like most people, looking to go taller, maybe the 3.3FD out of the Sedan, BUT, considering I can actually afford, just barely, an 08 G37 (if I flip this car and add a little cash; unfortunately I have committed to buying cash) is the 2008 5AT similar to the previous generation sedan, or does it have the same final drive as my coupe (and final gear ratio in the trans)? I ask this because I have tried to search this topic for at least an hour, and I came across one person that cited that they were somewhere around 2900-3000rpm's @ 80mph in the 08 G37 AT.

Not interested in 6MT's, did that for 7 years in my Legend Coupe, liked it but not for a daily driver. Anyone have experience coming from G35 to G37, or just have a 2008 G37 that they could tell me what RPM they are at @ 80mph...2900-3000rpm's would be acceptable, not great, but acceptable, and I don't want to put money into the G35 final drive, probably a grand to swap the differential, and who knows what kind of issues I might run into (ABS sensors, computer issues, etc...). Thanks in advance.

Trying to understand why ur even worried about what ur rpms are or why u would cruise @ 90 mph.

The first concern is Increased engine wear, but more than that, I have never had a V6 that was so wound up on the highway, reminds me of my old 1996 Honda Accord 4-cyl (noisy above 80mph), I can easily see why they switched to a 7 speed auto on the G37. I was wondering if the G37 5AT was any better? I notice that the 03-05 sedan has a 3.3FD which seems correct, 80mph @ 2900-3000rpm's.

Cruising at 90mph is what I have always done, the speed limits are 75mph on the highways in AZ and most surrounding states, 80mph is common, 90mph is where I usually stay in the less populated areas. In my old 2003 Maxima, I used to have to purposefully slow myself down to keep from getting up over 100mph, hard to believe that was a 4 speed auto; really wide ratios I guess :) Just thinking about it, hoping to get closer to 2900-3000rpm's. Was thinking if the 5AT in the G37 was coupled with a slightly taller FD, or taller final gear ratio, it might get me closer to where the engine doesn't sound so wound up.

I'm in the surrounding state of CA and the limit is 65. Go slower.

Wow, 65mph, that's terrible, that would drive me crazy. Anybody own a 37 5AT that can comment if it's closer to the 3.3FD or the 3.69FD rpm's. More simply, does anybody have a G37 5AT Coupe that can tell me what rpm's they are at at 80mph?

Off topic, I can steadily cruise around 120-130mph and still get passed like I'm standing still. German autobahn ftmfw!

Life is gonna be rough when I get back to soCal.

Use this:
http://www.car-videos.net/tools/spee...B1=Recalculate

With the info from here:
http://infinitihelp.com/models/2008/...ifications.php.

Gotta Change that premier avatar pic to the one without the rail!

Having come from V8 cars that turn 1500-1800RPM on the highway at 80-85MPH, jumping into a G35 did surprise me because of how high the RPM's were on the freeway.

In my sedan, with 3.3 FD, my RPM's are 3000RPM at 80MPH. I was concerned,but after 150K miles of driving at 3000RPM for hours at a time, nothing bad ever happened.

Stay on top of oil changes and fluid levels and you should be fine.

Yeah, 3000RPM's is acceptable, I am at 3200-3300 at 80mph. Well, looks like the 5AT G37 really isn't any better. I should probably wait until I can afford the 2009 model with the 7AT.

Good call! Thanks brotha!

Every AT I've heard of outside of the 37s is 3.3 unless someone swapped it with a 3.5 or worse a 3.7 (or 4.08 if memory serves) for more down low. You know- to pretend the car is fast.

^The 06+ had the 3.5

Weird. I have an 06 and I'm a 3.3.


(Edit: Taken for granted since it's what I was always told... looks like I may have been mistaken in this statement)

This is a pretty interesting as I can't seem to find out what is going on with the final drives in the AT's. Info is actually pretty hard to find, I feel like I am missing a "sticky" thread on this, but, if I have this right, 03-05's have the 3.3FD, 0-60-07 have the 3.69, 08's also have the 3.69, and the 09 7AT's get the 3.3FD. again. The 3.5/3.69 seem good for the 6MT but puts the AT at RPM level that is just too high, for those of us that cruise at speeds between 80-100mph. With the 3.69, this car needs a 6th gear.

Looks like I should have got an 05, not looking forward to ripping the diff out my "new" car, but anyone have a 3.3FD for sale? That way I can get back to more "sane" highway RPM's.