Cvt in a GA...? [Archive] - GrandAmGT.com Forum

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oldschoolguy
11-14-2009, 07:57 PM
Has anyone with access to money ever tried to swap in a CVT? Nissan seems to be pretty successful with them. They are the best for performance, and also for fuel economy. You'd get the best of both worlds

[ChaosweaveR]
11-14-2009, 08:07 PM
Why? There really is no gain to mating one of these up to the GA. You're better off doing a five speed 282 Getrag trans swap.

oldschoolguy
11-14-2009, 08:58 PM
Read up on the williams renault f1. They developed a race car with the variable transmission, but it was so fast that the FIA banned it.
How much time does your tranny waste while shifting? How much faster would your 1/4 mile times be if you could keep your engine running at the RPM which produces the most power. That way you could adjust all your mods to concentrate your power at one point, instead of spreading it out over the whole RPM range.
Just food for thought

Never mind the fact that it would probably cost a fortune

[ChaosweaveR]
11-14-2009, 09:13 PM
Never mind the fact that it would probably cost a fortune

This is pretty much the only thing that matters in what you said. Want a CVT? Go buy a Nissan.

/thread

cardude007617
11-14-2009, 09:16 PM
have you ever driven a vehicle with a cvt in it? theyre annoying.

and besides, GM doesnt make any CVTs so its not as though you'd have anything to use to bolt up like the murano trans might fit the 350z as they both ave the same 3.5 i believe.
or the new subaru's that have cvts should be able to be swapped with the older outbacks that have the same motors, just automatics.

[ChaosweaveR]
11-14-2009, 10:54 PM
have you ever driven a vehicle with a cvt in it? theyre annoying.

Damn right they are. My friend hs an 08 Nissan Sentra SE-R, and they're just...strange. Luckily there's a six speed manual mode via paddle shifters. I'd be driving in manual mode all day. lol

oldschoolguy
11-15-2009, 12:14 AM
I've heard that they make a vehicle sound really gutless, because the sound of the engine is always the same note, but hey, it was just an idea. Some people only look at numbers.

AaronGTR
11-15-2009, 07:51 AM
They also are only meant for fuel economy. They are meant to keep the engine in one range where it is most efficient with the transmission accelerating up and down instead of the engine rpm going up and down. Problem is, the engine designed to work with the CVT trans is usually modified to increase it's efficiency at that point, unlike most engines that are designed to have an overall balance of power and torque throughout a given rpm range but not be optimized for any one point. Point being our engines wouldn't work as well with a CVT transmission. Also CVT's are not made for any powerful engines so they aren't very strong and would break easily if put behind an engine with any power. ;)

Malaclypse
11-15-2009, 07:23 PM
have you ever driven a vehicle with a cvt in it? theyre annoying.

and besides, GM doesnt make any CVTs....

GM actually did make a CVT transmission for use in the Saturn Vue for a few years. The problem is that the transmissions failed so often that it never made it out of that model in a two year span. Then was killed off.

So as Aaron says, the power handling capabilities of CVTs are extremely limited. That and the engine has to be tuned/cammed in such a way that the transmission can make the best use of it.

Having spent a week in a Nissan Sentra with the CVT... I'd never ever want to drive a car with one again.

notsoaveragej0e
11-16-2009, 09:43 AM
^^Yeah, Saturn put them in the Vue at first, but everyone hated them, so they got nuked.

oldschoolguy
11-16-2009, 10:17 AM
A friend of mine lives on a dairy farm, and they use all fendt tractors. 350hp with 1000 pound feet of torque. All of these tractors use the CVT. Thats why I thought the power wouldn't be a limiting factor.

Malaclypse
11-16-2009, 04:48 PM
A friend of mine lives on a dairy farm, and they use all fendt tractors. 350hp with 1000 pound feet of torque. All of these tractors use the CVT. Thats why I thought the power wouldn't be a limiting factor.

The big difference there is that they're using a tractor and not a car. I'm sure packaging and size would be quite different between the two.

oldschoolguy
11-16-2009, 05:13 PM
The big difference there is that they're using a tractor and not a car. I'm sure packaging and size would be quite different between the two.

Yeah, they are big lol

AaronGTR
11-16-2009, 05:33 PM
Yeah, the trans has to be designed to handle that kind of power and torque and that will make a difference in the size and weight of the trans. I'm sure they could design a cvt trans for cars that would handle more power. It would probably be more expensive though, and all the current ones are designed for cheap low power engines.

Personally though I just think it's unnatural to not hear the sound of the engine going through it's rev range and the changing of gears. Mathematically and from an engineering standpoint there may be advantages to a cvt... but you lose the "soul" of the car.

Malaclypse
11-16-2009, 05:55 PM
Speaking of sound... its completely unnatural for an engine to just hold high revs during acceleration...

It becomes incredibly annoying when you consider the buzzy 4 cylinder factor. Sounds like a damn weedeater gone mad.

GA2000GTSpeed
11-16-2009, 07:54 PM
not to mention how expensive the trans fluid is. and in class we were going over the cvt in the ford five hundred and that the metal band used is extremly exspensive as well and that ford got theres from volvo. they are defiantly are not meant for power

oldschoolguy
11-16-2009, 08:15 PM
Not to defend the idea any farther, but belt driven isn't the only kind of cvt. You can also have it oil driven, where the motor drives an oil pump, and your speed and power is based on the amount of oil let through. this will also allow for an AWD setup. where there's no room for a driveshaft, there is room for a few lil oil lines.

GA2000GTSpeed
11-16-2009, 09:28 PM
hmmm thats interesting... but after looking it up its really only been used on zero turn lawn mowers. (the hydrostatic style that your talking about). so would they be able to stand up to alot of low end torque?

AaronGTR
11-16-2009, 10:12 PM
Probably not, and you'd have huge amounts of friction heat and power loss, just like in a regular automatic with a torque convertor.

rocketfast123
11-16-2009, 10:29 PM
Speaking of sound... its completely unnatural for an engine to just hold high revs during acceleration...

It becomes incredibly annoying when you consider the buzzy 4 cylinder factor. Sounds like a damn weedeater gone mad.

http://www.youtube.com/watch?v=LlWYTnaDnK0

I can understand how it can keep the car in the power band.

oldschoolguy
11-16-2009, 10:57 PM
http://www.allbusiness.com/manufacturing/machinery-manufacturing/594491-1.html
all right. I wasn't completely right. The Fendt Vario uses a combination of mechanical and oil drive. this makes for awesome low end power, with an efficient high end.

Edit: I now see that the article is 13 years old, but the technology is the same. It still runs on the same principles

IanGT99
11-21-2009, 09:07 PM
I've actually been seriously considering a new Maxima for my next vehicle. I'm more than likely going with a pickup, but if I do go for a car again, the Maxima is in the running. However, I've never driven a car with a CVT. The looks, features, and spec'd power are appealing. I'm curious to see exactly how this "four-door sports car" performs. Personally, I think the FWD platform doesn't make sense for a "sports car." 290 hp and 261 lbs/tq looks great on paper, but I'd be interested to hear from someone who's actually driven one.