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The Organizer
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Discussion Starter #1 (Edited)
So here is a picture of it from the JATCO site:



And here is what they say:

Belt CVT for medium vehicles JF011E * Light and compact design
* Wider gear ratio range for both acceleration performance and fuel consumption * High efficiency and fuel economy at the top of its class * Applicable up to 2.5-liter class * Main vehicles equipped with this CVT:
NISSAN LAFESTA, SERENA,
BLUEBIRD SYLPHY
MITSUBISHI OUTLANDER, DELICA D:5
SUZUKI LANDY
DAIMLERCHRYSLER DODGE CALIBER,
JEEP COMPASS, JEEP PATRIOT

According to what I've read, from a few sources, the CVT's computer communicates with the engine's computer. So what do they talk about? It seems that if the CVT doesn't like all the torque it's getting from the engine, it tells the engine to back off. Then the CVT goes to a lower ratio. All this to prevent the belt from slipping.

As you can see from above, this CVT is good for up to a 2.5 liter engine. I suspect most 2.5 liter engines have a certain maximum horsepower and torque. This leads me to believe that to much hp is going to be counter productive.
 

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Z ADDICT
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That image look great om my 19 inch screen. I tried to find information on the maxium horsepower and torque the cvt could handle but had no luck.
 

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Discussion Starter #3
The JATCO site shows several CVTs. Each one is for a specific application. The next bigger (the biggest) one is for the Maxima and the Murano. I'm still researching the hp and torque question. The closest I came so far is a patent for the control technology that limits the engine torque applied to the CVT. This tells me there is a limit for hp and torque people can bump their Caliber up to before the CVT overrides it. I'll keep searching.
 

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Discussion Starter #4
More research results. I read an abstract of an engineering paper on the CVT. The CVT has to be mated to a specific ranged hp and torque rated engine. I've read in another paper that a modification of anything over 20 hp will result in belt slippage and premature failure of the belt. The transmission fluid used in the CVT has rubber particles mixed in to give the metal belt traction.

Here is a good article: http://www.lasercannon.com/cvt.htm
 

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So, the additional Hp supposedly offered by Mopar thru their CatBack exhause, headers and HAI will be sustainable by the CVT. That's good. But the "chippers" better watch their settings...



Joe
 

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Discussion Starter #6
So, the additional Hp supposedly offered by Mopar thru their CatBack exhause, headers and HAI will be sustainable by the CVT. That's good. But the "chippers" better watch their settings...



Joe
I'd say that is a good assessment. And those that want to put a turbo on had better only do it on the manual Calibers.
 

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So extra power is not to be added to the CVT. That falls right in line with the rpms being limited at low speed so the CVT doesn't ever get a lot of low speed torque. Dodge & Jatco, in no uncertain terms, are telling people to treat the CVT with gentle care to preserve reliability. The final limiting step is one's own personal choice to seldom use lots of power. Such a step is also the only way to good CVT gas mileage.
 

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So if the transmission does communicate with the engine, and limits the power from the engine, the only true performance upgrade would be something on the line of a new module of some type for the cvt so it would not limit the power output of the engine. Any modifications done without this change will still result in the the module limiting the power from the engine to the transmission. (or am I just missing something? )
 

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Discussion Starter #9
So if the transmission does communicate with the engine, and limits the power from the engine, the only true performance upgrade would be something on the line of a new module of some type for the cvt so it would not limit the power output of the engine. Any modifications done without this change will still result in the the module limiting the power from the engine to the transmission. (or am I just missing something? )

Yeah, you're missing the reason for the CVT over riding the engine's torque. It's to prevent the belt from slipping, which will cause premature wear of both the belt and the pulleys. We're talking big $$$ for the repairs.
 

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Yeah, you're missing the reason for the CVT over riding the engine's torque. It's to prevent the belt from slipping, which will cause premature wear of both the belt and the pulleys. We're talking big $$$ for the repairs.
That's is not what I was getting at! Yes I understand it is doing it for the premature wear reason. But, if you spend alot of money trying to make your econo into a screamer, won't the CVT still override the engines torque? If it already has a preset limit built into it, increasing horsepower or torque will have no effect on this factory preset limit. It will still continue to limit it at the same amount, (or am I still missing something?)
 

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Discussion Starter #11
That's is not what I was getting at! Yes I understand it is doing it for the premature wear reason. But, if you spend alot of money trying to make your econo into a screamer, won't the CVT still override the engines torque? If it already has a preset limit built into it, increasing horsepower or torque will have no effect on this factory preset limit. It will still continue to limit it at the same amount, (or am I still missing something?)

Yeah you got that part. But when you mentioned changing the CVT's computer to allow the increased torque to get to the CVT, it sounded like you missed the point.
 

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Discussion Starter #12
Ok you CVT owners. Here is something I discovered by accident. Try this and confirm it. I've found that you can accelerate faster by doing the following.

From a dead stop, start to accelerate for a split second, let up for a split second, then hit the gas again. It's almost like the CVT gears way down and it feels like the car accelerates twice as fast.

Maybe I'm imagining this, but it sure feels like it's accelerating faster.
 

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Ok you CVT owners. Here is something I discovered by accident. Try this and confirm it. I've found that you can accelerate faster by doing the following.
Think I noticed this before when I was playing with the trottle and reving it. I'll keep it in mind on my run tomorrow
 

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I'll have to try that. I think I've done it by accident and noticed something similar. I still end up using the Autostick though. :)
 

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Your right Prop1,I tried this am and indeed there is something going on in that
sequence,althought can simulate the situation by accelerating in "L" to 25mph and
shifting to drive,feels about the same on my Caliber.
 

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I gave your throttle a test run and tried to test the true acceleration, I personally didn't find much of a difference except for the sound. (Stomping the throttle vs the hit-up-hit throttle) I will still test it further since I didn't exactly have the situation to wind it completely out.
 

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Do any Dodge/Chrysler engineers view these posts ?

I hope so. I'm wondering why gas mileage improves with mileage and am wondering if the CVT has to breakin. As the friction of the system reduces then the gas mileage would go up. Is this one of the reasons ?

Regards
Jib01
:i_rolleyes: :i_rolleyes: :i_rolleyes:
 

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CVT's

Really an interesting article in the current Car and Driver, about CVT's. In Pat Bedars's column, I think he's the author, talks about getting two Nissan Versas from Nissan head honcho, Carlos Ghosen. One was powered by a CVT, the other used a four speed conventional auto tranny. The CVT in acceleration tests blew away the four speed, but in the fuel consumption test the four speed won by a couple of MPG's . Bedard attributes this to the amount of hydraulic pressure necessary to squeeze the two sides of the pulleys together which creates a power drain on the engine. Then the article goes on to mention some snotty remarks about CVT's by the engineering department of BMW. Bottom line for me? CVT's are cheaper to build and keep prices down...but, a five speed Caliber with a 2.0 liter engine, if it were available, would blow the doors off an RT Caliber, with it's torque reducing program and also get better mpg. But the CVT may be cheaper to build which in turn make it easier for you and me to buy one!
 

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Supposedly the CVT should be a little more efficient than 4 speed automatic transmissions. However, the CVT loses lots of MPG when driven hard. Even moderate driving loses too many MPG. Only real careful featherfooting gets the superior MPG to the 4 speed autos. & we know that Car & Driver ain't featherfooting any vehicle.

P.S....Hey, Jib01...Good to see you here! You got a lot of readin' to catch up on.
 

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CVT's

Supposedly the CVT should be a little more efficient than 4 speed automatic transmissions. However, the CVT loses lots of MPG when driven hard. Even moderate driving loses too many MPG. Only real careful featherfooting gets the superior MPG to the 4 speed autos. & we know that Car & Driver ain't featherfooting any vehicle.

P.S....Hey, Jib01...Good to see you here! You got a lot of readin' to catch up on.
I think you;re correct. Less torque produced by the engine with a feather foot means less hydraulic pressure required to squeeze the sides of the pulleys together so less drain on the engine and better mgp...The Caliber, Jatco, CVT uses the Van Dorn principal which goes all the way back to the fifties..so the cliche, "nothing new under the sun!" sounds reasonable. I thought it was interesting that the CVT out accellerated the four speed...
 
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