Why CVT and not 6 speed auto?

[jungleboogie]

I was just wondering, while sitting here at work, why Nissan opted to mate the altima with a cvt as opposed to a 6 speed auto (aside from the gas saving issues). i mean other sister vehicles of the nissan altima, such as the g35 sedan comes with a 6 speed auto, but why did the altima end up with the cvt?

also, when compared to the automatic, i assume, with the whole belt system, that a cvt is far more "fragile" than an auto with gears and synchros?

anyone care to shed some light on this issue?

[CPS]

The whole point of multiple-gear transmissions is to keep the RPM's within the powerband. With a CVT, the engine can maintain RPM's yet the vehicle gains speed, so you are always in your powerband. On flat ground you can also accelerate with no increase in RPM's. The lower that needle stays on the RPM gauge, the better fuel economy you will get. You have to think of the CVT as an infinite-speed transmission.

[jungleboogie]

hmm... but i have also heard, and this only applied to the nissan murano, that the cvt transmission must be replaced after around 100K miles while a transmission with gears, with proper maintenance, would last much longer. If the cvt is doing so much work at all times to maintain this range of powerband and fuel efficiency, would there not be far more internal wear and tear going on? mechanically, wouldn't the cvt be more prone to it?

i enjoy the cvt's not "gear-shock" shifting, yes. but i guess i'm just trying to see aside from the infinite gear possibilities and the fuel efficiency, what other mechanical benefits are there to a cvt?

[adidas2go]

Were, not sure yet, but Im about to prove to disprove the theory that the CVT is weak. Putting 400 horses into it should be a good test

[CPS]

Every problem I've seen with a CVT has been fluid-related. We are actually discussing this under the Murano forum on this site. The CVT fluid acts as a barrier to prevent excessive wear, but people always balk at the price it takes to drain and fill the CVT fluid. $200 now or $5000-6000 down the road?

[adidas2go]

I was talking to a service manager about this. Apparently you have to use a drill like tool to suck out the oil, there actually is not drain point. BMW does the same technique for oil changes.

[jungleboogie]

Were, not sure yet, but Im about to prove to disprove the theory that the CVT is weak. Putting 400 horses into it should be a good test

!!!! low pressure single turbo? i mean with that kind of power, maybe there can even be a way to reinforce the cvt. stronger chain/belt?

is this project in progress as we speak?

also, this transmission fluid... how often does it have to be flushed? intervals? when to start? and will this prolong the need to purchase a new transmission lin the long run?

[Forrest80]

the question here is durablity verse functionality.

If a product is more durable but not as good do you really want it?If the product is better but requires more maintence do you really want it?

I think im ok with the more maintence.

[adidas2go]

Yes sir. Its almost done right now. See if you can find a thread called, SFR Turbo System. Thats my build

[marlin29311]

Every problem I've seen with a CVT has been fluid-related. We are actually discussing this under the Murano forum on this site. The CVT fluid acts as a barrier to prevent excessive wear, but people always balk at the price it takes to drain and fill the CVT fluid. $200 now or $5000-6000 down the road?

my dad works for a company helps build the fluid and worked with nissan hand in hand to create this - CVT's are built for the long haul and aren't meant to die at the 100,000 mark like some auto transmission's do. CPS is right in the fact that a CVT flush is much more expensive than a normal auto transmission flush but well worth it in the end. (on a small side note the CVT fluid [N-2] is actually meant to withstand up to 75,000 miles, so if you miss by a scheduled maintenece by a few miles, you're fine).

[Robs_altima]

The difference down the 1/4 mile will be minimal if any, I doubt you'd notice any pull at any given point if racing down a straight line. Somehow most performance magazines have been favoring the 6spd over the CVT in the 1/4 mile testing. If there is any truth to it, the CVT has more moving parts in it (not as simple as 2 pulleys) and doesn't transmit as much power to the wheels as a 6spd. But that's just me going off past dynos of others cars and certain engineering calculations in the industry. Yes, both engines are rated for the same power but that all changes through the drivetrain. As more improvements are made there's no doubt that a CVT will be the way to go as power band and the reduction power lost due to heat (moving parts) is made more efficiently.

Simply put, get what you like to drive.

[adidas2go]

Wow, great info guys! Reassures me a bit about the CVT

[maxentropy]

my dad works for a company helps build the fluid and worked with nissan hand in hand to create this - CVT's are built for the long haul and aren't meant to die at the 100,000 mark like some auto transmission's do. CPS is right in the fact that a CVT flush is much more expensive than a normal auto transmission flush but well worth it in the end. (on a small side note the CVT fluid [N-2] is actually meant to withstand up to 75,000 miles, so if you miss by a scheduled maintenece by a few miles, you're fine).

Good info! Thanks!