Mitsu article - CVT Drivetrain Vibration Analysis and ACS Design (2005)

[evo_soul]

http://www.mitsubishi-motors.com/cor...005/17e_03.pdf

For those looking to Turbo a CVT, it maybe wise to consult with mitsu's white paper on their CVT applications. Althou this article is from 2005, their core efforts havent change much on a hardware/technical level.

I will comment more, when I get further time,

Cheers

[MasterAK]

Good find. I glanced through some of the paragraphs and it deals with vibrations of the CVT drivetrain caused mainly by sudden application of torque.
It also mentions that the belt might slip if the cramp pressure on the pulley is weak.
My understanding is that the cramp pressure decreases when the CVT continuously changes the gear ratio. So your comment (if I remember correctly) about the japanese tuners who had turbocharged the CVT equiped lancer, that they had to run the car only with the fixed ratios (using only the paddle shifters) makes sense. So if you use only the fixed ratios, the transmission will maintain fixed ratios which means that it will also have a higher pressure(force) to grab the belt and to prevent belt slipping.

On CVT, power is transmitted via a belt. If the cramp
pressure on the secondary pulley to grab the belt is too
weak, the belt and pulley will slip and the input torque
cannot be transmitted any further.

So it seems that the cvt has limitations about the torque it can handle.

So the cvt tends to try and contlol the engine torque.

Torque control by means of ignition timing can only
achieve a reduction of approximately 40 % due to combustion
stability requirements. Needless to say, it cannot
increase the torque more than the throttle valve
does. However, the method offers great possibility for
shock reduction if used properly. Fig. 16 shows torque
control by means of ignition timing that has been
applied to vibration reduction.

Anyway this is how I understand the article and what it means regarding turbocharging the CVT based on a quick glance.

[evo_soul]

it tooks me about my second and third read of it to full understand the document enough to understand its effects on boost applications.

Second this may or may not explain why the CVT transmission consistantly receives lower output numbers on the dyno. It would appear that there is an Anti vibration algorithm in the programing or in the very design of the CVT controller.

[Bladed]

Good read, took me like 3 read throughs to understand it, but it gave me a better understanding on the CVT system. I was reading through the Evo X forum when someone mentioned cryo systems as an alternative to nos. I looked at the website and I was thinking that instead of spraying the intercooler or air intake with liquid c02, could you spray some component in the CVT (not the belt or pulleys themselves for fear of freezing and breaking) to reduce the heat and get more power? Or spray the intercooler, intake, and CVT.

If I'm able to find a totaled car with a good CVT transmission, I wouldn't mind doing a few test with this setup just to see how much power the CVT can take with and without cooling.

Here's the site the other member posted. http://www.designengineering.com/pro...asp?m=sc&cid=1

[RC2099]

May also consider a trans fluid cooler, like on large trucks with high towing capacity! This would help too.

Scott

[evo_soul]

monitoring and actively attempting to cool the transmission is vital for the long term health of a boosted CVT

[prophecy11]

I know this is an old thread but that is good stuff..

I don't really know much about cars but I had just bought a 2009 Lancer ES sport CVT as my DD getting the CVT because of my long traffic filled ride to work and back each day.

I was recently contemplating turbocharging it, at least looking into it. But from what I'm reading, I don't know that I would want to do that on a DD.

[evo_soul]

contrary to what you maybe hearing, there is nothing wrong turbocharging the CVT. Not many have a firm grasp of the CVT and how it operates, but even the manufacturer beleives that they are much more reliable then even Automatic transmissions. There are fewer moving parts and the operation is pretty simple. Now alot of work goes into making it as good as it is. but this technology has seen many revisions over the 15 years.

Your only objective is to minimize heat stresses and you should be fine. that said I dont think you should expect to turn this in to a 500 WHP freak car lol thats a no no. but it should handle 250whp fine

[Hydrolikz]

^What's the deal with fuel management and tuning with the Turbo? There is a guy on here with a custom-turbo'd CVT and he's having issues getting it tuned, and when I looked into it they said fuel management and tuning would be the biggest things to get it done correctly.

[evo_soul]

dont know, fuel should be independant of the transmission. so if he is having trouble, so would someone with a manual.

Maybe injectors? hehe maybe we need a bigger squirt gun

[eg6motion]

this certainly explains the low dyno #'s and poor power-braking results. Its too bad they used a belt-CVT vs chain. Chain would have taken so much more abuse and power. But, even though it was slow, I thought my lancer CVT was still fun and very different to drive. People that rode with me were always baffled at the CVT tranny and wondered why it never shifted.