M35 Using Snow Mode For Better Fuel Economy

[jpave]

Has anyone tried using the snow mode for better fuel economy.

I have noticed it cuts down the boost?

What else does it do?

Also does anyone know why my stag jumps forward if i have the snow mode on and i turn the car off.

[RBPOWA-(TJ)]

snow mode from what i can work out, doesn't use first gear, so it stops any wheel spin.

so if you are stuck in snow, you can pull out with easy.

jumping forward i wouldn't know. but would driving around on snow mode be good for the car ? some whiz will be here shortly to clear that up

[xRHETTx]

would snow mode leave the car in gear so that you don't need to use the handbrake? ie so it doesnt freeze on.

[andy65b]

probably has more to do that it is locking the center diff and causing some binding(windup) of the diffs. It is probably releasing this windup as you turn off the car and it releases the diff lock.

[lachlanw]

just put a boost gauge on it and drive it to the most vacuum you can . or get an avcr and look at injector duty cycle . directly tells you how much fuel you using

[jpave]

my nav unit already as the fuel economy on the screen

Just wondering if anyone knows what snow mode does and weather its ok to drive around using it

[lachlanw]

it takes off in 2nd gear like someone else said . a lot less traction brreaking torque than first . i wouldnt drive round with it on the whole time . your just riding the torque converter . how do you see it using any less gas than simpley not using your foot better . ?

[zei20l]

sorry it doesnt take off in 2nd gear. its constant 50:50 torque split. and yes ive noticed that it appears to be pushing forward while in one of the synchro modes. but as andy said, its pressurising the atessa system.

snow mode limits boost, thats why youre seeing less fuel usage. but please note that every atessa mode on an M35 has full range of the gearbox!!

[Angus Smart]

snow mode from what i can work out, doesn't use first gear, so it stops any wheel spin.

so if you are stuck in snow, you can pull out with easy.

jumping forward i wouldn't know. but would driving around on snow mode be good for the car ? some whiz will be here shortly to clear that up

snow mode doesnt help you get unstuck haha

but yer driving up the mountian with snow mode on i find it hard so slip.. with it off. i am all over the place when i push the pedal a little bit.

[pixel8r]

my nav unit already as the fuel economy on the screen

Just wondering if anyone knows what snow mode does and weather its ok to drive around using it

short answer: NO.

Snow mode means ATTESA is driving the front wheels a lot. The ATTESA system is not designed as a full-time 4WD system if that makes sense. Basically if you leave it in 4WD mode all the time eventually the clutch packs will burn out and I'm told they are very expensive to replace.

ATTESA is designed to give traction where its needed, but drive in RWD where the extra traction is unnecessary.

The system most likely wont break if you use synchro or snow mode 1 day a week or something like that...but i wouldn't recommend leaving it on permanently. Just puts more pressure and wear on the clutch packs.

This is all stuff I've gleaned from this forum so someone correct me if I'm wrong.

[KiwiRS4T]

I can only speak authoritatively about the C34 although I believe its the same for the M35:

Snow mode cuts out first gear. I have used it for a while to try to get better economy but got bored with it!

Whatever you do to lock the Atessa has no effect once you get some speed up (I am not sure exctly it may be as low as 30 km/hr) and then the Atessa computer takes over again so I don't see any harm can come from leaving it in snow mode (and I am not even sure that it affects the atessa anyway).

[zei20l]

as stated above AND in another thread. Snow mode has use of all 5 gears.

[jpave]

The only reason i thought it might be good is that when im on the highway and hit the snow switch is my boost drops right back and i thought that would cause me to save fuel

[iamhe77]

The only reason i thought it might be good is that when im on the highway and hit the snow switch is my boost drops right back and i thought that would cause me to save fuel

You are using boost while cruising on a highway? What speed do you cruise at???

You should be able to get around 11km/L (or better) from a stock M35 cruising at 100kph.

[pixel8r]

The only reason i thought it might be good is that when im on the highway and hit the snow switch is my boost drops right back and i thought that would cause me to save fuel

As iamhe77 mentioned, you generally wouldn't be on boost while cruising on the highway. Boost is determined by engine load, not rpm. Unless you're accelerating, the boost guage would likely be showing either 0 or -ve pressure (vacuum).

At 100km/h the revs should be almost exactly 2000rpm when the torque converter is locked (and in 5th gear). To keep it like that, put the gear lever into tiptronic and bump it forward to 5th gear (it will default to 4th when you first move it over from drive but if you move it fowards quick enough the gearbox will stay in 5th). Keeping it in 5th this way will still allow it to change back to 4th at full throttle, but makes the throttle less sensitive so that you wont keep hitting boost etc. You'll find it much easier to keep the revs on 2000rpm this way than when the lever is in drive.

[LordMidol]

Who cruises @ 100kph?

I sit on 110kph, or sometimes accidentally drift up to 118-120.

Our speed limit is 110 though.

[iamhe77]

Who cruises @ 100kph?

I sit on 110kph, or sometimes accidentally drift up to 118-120.

Our speed limit is 110 though.

I think you missed the point. Even at 110kph, you should be getting around 11km/L as all the hard work is accelerating up to that speed, not maintaining it (unless uphill/ headwind etc)

try taking it to 120kph, then backing off and gently applying a light foot to maintain 110kph. You will be amazed how different your economy is (especially if you can control your right foot after holding your desired speed) when compared to accelerating up to a certain speed and holding it.

[pixel8r]

I think you missed the point. Even at 110kph, you should be getting around 11km/L as all the hard work is accelerating up to that speed, not maintaining it (unless uphill/ headwind etc)

try taking it to 120kph, then backing off and gently applying a light foot to maintain 110kph. You will be amazed how different your economy is (especially if you can control your right foot after holding your desired speed) when compared to accelerating up to a certain speed and holding it.

I believe you are referring to the torque converter lockup which will occur if you do this. Often it wont lock until you lift the throttle just slightly. You can tell its locked because the revs will drop by about 500-600rpm.

Putting it in 5th using tiptronic helps because otherwise I find it keeps boosting which causes the torque converter to unlock again...

At 110 (118 on my speedo - 110 measured by my portable satnav) my revs are normally around 2300.

A satnav will give you a more accurate speed readout than your speedo provided it has a good signal and you stay at a constant speed.

Interestingly the torque converter on our 5sp auto will lock up in either 4th or 5th gear, when travelling over 80km/h.

[LordMidol]

I think you missed the point. Even at 110kph, you should be getting around 11km/L as all the hard work is accelerating up to that speed, not maintaining it (unless uphill/ headwind etc)

try taking it to 120kph, then backing off and gently applying a light foot to maintain 110kph. You will be amazed how different your economy is (especially if you can control your right foot after holding your desired speed) when compared to accelerating up to a certain speed and holding it.

I tend to miss the point alot

Yeah, i get great fuel consumption on highways. I pretty much average 550km a tank now and I have developed a bit of a lead foot. I would get more if I didn't live on a mountain range.

[mxfly]

As iamhe77 mentioned, you generally wouldn't be on boost while cruising on the highway. Boost is determined by engine load, not rpm. Unless you're accelerating, the boost guage would likely be showing either 0 or -ve pressure (vacuum).

At 100km/h the revs should be almost exactly 2000rpm when the torque converter is locked (and in 5th gear). To keep it like that, put the gear lever into tiptronic and bump it forward to 5th gear (it will default to 4th when you first move it over from drive but if you move it fowards quick enough the gearbox will stay in 5th). Keeping it in 5th this way will still allow it to change back to 4th at full throttle, but makes the throttle less sensitive so that you wont keep hitting boost etc. You'll find it much easier to keep the revs on 2000rpm this way than when the lever is in drive.

That's a very good point and I will try it out next time on the freeway. Last weekend I drove down to Goulburn and did notice the moment you gas it a little, it would gear down to 4th from 5th and hit boost. While it's great to overtake quickly, it will use more fuel on boost for sure. Nevertheless, I can get about 700kms on a single tank when run entirely on the freeway.