Hello everyone. Im considering purchasing a used infiniti m37x or m56x. I like that there are a decent amount of performance upgrades for the m37 forced induction, tranny etc.. and the stillen cat back exhaust for the m56 sounds great. Anyway I would like to know if I was driving in ds automatic mode and cruising along at 25mph or 50mph will the car downshift to the lowest possible or correct gear if I floor it? m37 or m56. The videos ive seen on you tube when the car is cruising and the person floored it it stayed in second gear when when the car I guess should have downshifted. I am not sure what mode those cars were in but it wasn't manual. I couldn't get my last car to downshift worth anything while crusing when I needed it. I would not like to have the same issue with my next car and I really like the M.

my car downshifts when I accelerate hard

The M56x takes off like a raped ape. It will DESTROY pretty much any other car you encounter on the road unless you live in an area where everyone drives V8 powerhouses (Corvettes, BMW M-series, AMG Mercs, etc.). It pulls and pulls hard all the way to the speed limiter at 142

Hell, even the M37 would decimate the family minivan next to you

I've noticed in standard mode in my m37x that when I'm going around 50 on the highway and need to make a move and really mash it I get lots of RPMs but no shift down or catch for a couple seconds. It's a bit annoying. I've quit just mashing and started accelerating more gradually and it gets me up to speed more quickly than mashing for some reason. I haven't tried in sport mode. I only use sport when i'm on a nice winding stretch and want to enjoy that.

I've got an M37 that I keep in sport mode all the time and I rarely ever have an issue with downshifting. In fact, more often, if I mash the pedal briefly for a quick start, and then lay off, it keeps it in a lower gear, like the tranny is expecting me to keep accelerating. I think normal mode is quite a bit different and I really don't prefer its shifting patterns, which is why I keep it in sport.

On another note, I also have a '13 QX56 and I will agree that the 5.6L V8 is a beast. Even with all the with of the QX, I still think I can outrun many cars and almost all SUV's. It would probably be a little terrifying to drop that engine in my M. Only real negative that I've seen/read on the M56 is that the additional weight of the engine over the V6 makes it less agile on the twisties than the M37. I bet the M56 guys would have an opinion on it, though.

This is probably a silly question/side tangent... but running your M in sport mode all the time.... Are there any factory or forums recommendations against this for long periods of time? Does it adversely impact handling in wet conditions? I'd love to run sport mode 24/7... The decrease in gas mileage doesn't matter to me... I just want to make sure I stick to the road and don't do any long term damage to the transmission/drive train? Like I said... Silly question but I baby my baby.

Don't laugh...I spent probably the first 9 months of ownership in normal mode. I was saving sport for "special" occasions. I don't know what those were, but usually it was when I was near the end of the tank of gas and didn't care what it did to my mileage. Eventually, I decided to leave it in sport mode full-time and I became addicted. I can't stand normal mode for longer than a few minutes and miss the sport shifting pattern. And don't get me started on the uselessness of the ECO mode!

Sport definitely changes the personality of the transmission, and not just on the upshifting. In sport mode, I find that the transmission more readily downshifts on hard breaking. I love braking hard in a corner and then accelerating our of the corner. The transmission is almost always still in a low gear that doesn't actually require a downshift, so the power is right there to punch it. I also believe, if you have a "Sport" model (I do), that it also makes minor adjustments to the suspension for more sport handling. No matter what mode I use (normal or sport), I can spin my tires and get sideways if I turn of the electronic nannies, so I don't think it will make a difference for you either way. Obviously, with an "X", this likely wouldn't be an issue. Personally, I live in Texas and other than the increasingly rarer occurrence of rain, I don't have to concern myself with road conditions much.

M35austex wrote:Only real negative that I've seen/read on the M56 is that the additional weight of the engine over the V6 makes it less agile on the twisties than the M37. I bet the M56 guys would have an opinion on it, though.

I haven't noticed anything of the sort. This M56x handles better, stock, than my M35x did, stock. Of course, my M35x at the time of trade-in was on coilovers...but once I get those on the M56x, I'll be golden.

withomps44 wrote:This is probably a silly question/side tangent... but running your M in sport mode all the time.... Are there any factory or forums recommendations against this for long periods of time? Does it adversely impact handling in wet conditions? I'd love to run sport mode 24/7... The decrease in gas mileage doesn't matter to me... I just want to make sure I stick to the road and don't do any long term damage to the transmission/drive train? Like I said... Silly question but I baby my baby.

I ran manual mode in my 07 M35x from 32kmi to 140kmi probably 90% of that time. No issues ever, and I even bounced it off the rev limiter a few times or, on the rare occasion I was in D, accidentally put the car into N at 60mph (went to shift up thinking I was in M and was actually in D, so N it was lol).

On the M56x, I just set the stick to sport and don't use manual. Too many gears, and 1st especially is very short IMO.

Wish I could get my new X sideways...car won't even do it very well in snow ...proof:

IlyaKol wrote:Well...my cast wheels took a nice hit today.

I was in a parking lot taking snow fall pictures of the car and as I was pulling out I turned off VDC, cut the wheel, and hit the gas. Even with 2" of snow, wheels didn't break loose. They grabbed traction and somehow, after 10 years of doing precisely the same things when messing in empty parking lots, I popped the TIRE off the WHEEL lol. I was like whaaaaaaaaa? I didn't even realize it (and just thought snow got packed into the wheel as it felt very similar) only to realize I had lost air in the tire. Road on it for like a quarter mile before pulling over. Wheel only had rash, that was it.

Holy s***... hahaa... GREAT pic though!!!

I just ran home to lunch on Sport and back... definitely noticed it in the down shift and blew through the on ramp and got to 80 like nothing. I might get in trouble in sport mode but I'm going to keep it there. Thanks!

Hahah, yeah. I was like WTF? I've been donuts for years and never had that happen before. I didn't even feel it cause of the snow till I started driving down the road. Put my spare on, drove back a quarter mile and right into Walmart. Guys remounted the tire and off I went, lol.

IlyaKol wrote:Hahah, yeah. I was like WTF? I've been donuts for years and never had that happen before. I didn't even feel it cause of the snow till I started driving down the road. Put my spare on, drove back a quarter mile and right into Walmart. Guys remounted the tire and off I went, lol.

Weird! Glad you weren't at high speeds.

Is the wheel width correct for the range of widths that this particular size tire uses? Normally, this kind of thing only happens to the stretched-tire folks!

Maybe the wheel was cold, and if you are using summer tires, the rubber may have hardened in the cold weather and caused the bead to pop off the wheel.

Z

I use Sport mode 24/7, and manual shift most of the time. No issues.

It does have a hesitation in standard. Car shifts mich nicer in spprt mode.

szh wrote:

IlyaKol wrote:Hahah, yeah. I was like WTF? I've been donuts for years and never had that happen before. I didn't even feel it cause of the snow till I started driving down the road. Put my spare on, drove back a quarter mile and right into Walmart. Guys remounted the tire and off I went, lol.

Weird! Glad you weren't at high speeds.

Is the wheel width correct for the range of widths that this particular size tire uses? Normally, this kind of thing only happens to the stretched-tire folks!

Maybe the wheel was cold, and if you are using summer tires, the rubber may have hardened in the cold weather and caused the bead to pop off the wheel.

Z

These were the same wheels/tires from my old M and I abused the crap out of them doing donuts in previous winters (same size, etc.). These are relatively new (had them put on this fall), so it's possible it was just a bad install job or what not.

Thanks for all the info! I like performance so this is really helpful.Just have to decide between the m37x or m56x. How are the maintenance costs on these two cars? Are they reliable? I know JD Power doesn't tell the whole story.

After about 3 years all I've had to do is oil changes. I had an FX45 for 5 years before that and only had to do oil changes and brake pads. I've owned several other Nissans in the past and never had any major issues other than expected wear and tear. Maintenance cost is much cheaper than my wife's old BMW I can tell you that. Even her new Lexus is costing more for oil changes than I pay at the Infiniti dealership.

I'm on my second M. Nothing more on either one other than normal maintenance and wear and tear. Same for my QX, so far. I think Nissan is pretty good for maintenance, particularly when compared to other manufacturers.

Second M here as well. The first one was a 2006 M45; never any issues, just scheduled maintenance, wear items and mods. The (current) M56S has had an electronic hiccup that the dealer solved, and the battery replaced; both under warranty. In both instances the dealer bent over backwards to make me happy. Other than that, just scheduled maintenance.

Second M as well. 07 M35x and 11 M56x as previously stated.

No major issues on either...and I had the 07 for 4.5 years. The only 'big' thing that happened on the 07 was the power seat memory module and steering rack had to be replaced (under warranty). Memory module was at like 40k and rack was at like 89k (I took the car off a jump accidently in the middle of nowhere at night, so it might have been the culprit lol).

That's great! Sounds like the M is pretty solid and reliable. That's great to hear. Once again thanks for the valued info.