I have read many things about snow mode in these forums which leads me to a lot of confusion. Everything I am seeing is that it only effects the car under 12 MPH or so. This is odd to me because when driving on the highway, I decided to flip the switch and I felt a huge shift in the car, as if more power went to the front. I would turn off snow mode, but it wouldn't seem to change back until I let go of the throttle and came back onto it.

So does snow mode in fact shift the torque above 12 MPH in 2007+ G35x sedan? If so, does it also decrease throttle response at these speeds?

 

You don't specify what year of car. Important; sedans changed in 2007 but kept G35x badge. But the platform changed to V36; I don't know if the ATTESA system features changed then too.

Former 2006 sedanX owner here. The "Snow Button" locks the car into AWD. It should only be used in the snow; do not use it on dry pavement. You will cause additional stress on the system because when cornering, the wheels are locked and do not adjust rotation to the different turning circumferences from the inside and outside cornering wheels. This is explained in the Owners Manual. If you don't have one for your model year, download one from the web. They are available at NicoClub and other locations.

When the "Snow Button" is not selected, on dry pavement the AWD is engaged up to 16 mph, and then begins to transition to RWD only, and the car handles like a RWD sedan. I believe it also re-engages when the system detects traction issues.

 

Sorry, I am referring to a 2008, so V36.

 

You're not actually going to hurt anything because the X models have open differentials front and rear, the center is a viscous coupling which technically could eventually overheat if you did a very very long continuous circle. Your MPG will suffer significantly in snow mode because it's always sending power to the front rather than biasing up to 100% to the rear like it will in normal mode.

There weren't any changes (that I'm aware of) to the ATTESA-ETS system from the V35 to V36 chassis.

 

Right, I am not really concerned whether or not there will be damage. I am just wondering what it's actually doing since every thread says that it goes back to the normal torque ratio after 12 or so MPH. This is odd to me because going on the highway at around 60 or 70 MPH, I do in fact feel a change in the car when turning on snow mode.

 

Yes that's correct, the snow mode is mostly just so you can initially START DRIVING in AWD. Otherwise it has to wait for the rear to slip before it starts biasing power to the front. The system is constantly biasing power at higher speed, I can't remember the actual split but with snow mode off it's like F/R 5/95 at launch then 0/100 at speed. With snow mode on it's 50/50 at launch then 25/75 at speed I think.

Keep in mind those numbers are considering no wheel slip at all, as soon as it detects slip in any condition it can bias up to 50/50 depending on how much slip there is.

 

Interestingly, there are two different owners manuals for the 2008, depending on the VIN number. They are available for download at infinitihelp.com if you are registered.

Thanks Cleric for straightening me out on the open differential. The 2006 owners manual talks about the dash light blinking fast if the differential oil overheats; that was this issue I was thinking of when driving at speed with snow mode engaged.

The 2006 manual also notes that engine power is "controlled" when snow mode is engaged, to reduce wheel spin. I wonder if that is what OP is feeling when flipping the switch at speed.

 

Well the VDC system is separate (but works in conjunction) to the ATTESA system.

ATTESA controls power transfer through the center carrier/transfer case viscous coupling (that's the diff that the overheat light is referencing), it also controls the ABS brakes to clamp the wheel that is spinning to send power through the open front/rear differential to the non-spinning wheel.

VDC limits engine output by pulling rpm to keep the wheels from spinning wildly, it will still allow some spin (or a lot more if you click the VDC off button on the dash).

The snow mode might also be recalibrating the APP pedal input to the ECM to not be so aggressive, ramp up a lot slower, etc.

Computers = magic