Jump to content
Ultimate Subaru Message Board

Crazy idea!


1 Lucky Texan
 Share

Recommended Posts

On another forum, someone asked how fast the CVT transmission could go in reverse.

 

That made me have the crazy idea, suppose someone could 'hack' the CVT to run its full gear range in reverse! Yeah, maybe some external fluid pumping would be needed? And custom electronics (or firmware?) etc. But, it make for interesting swaps and customized vehicle!

 

has it been done? who's gonna be the first to do it?

Edited by 1 Lucky Texan
Link to comment
Share on other sites

Interesting idea.

 

Reverse is possible because of a planetary gearset aft of the chain.  Going forward this gearset is locked up and has no ratio effect.  In reverse this unlocks allowing the sun gear to spin in reverse.  What this means though is that reverse has a different gear ratio than forward.  I don't know what this ratio is (maybe 150%) but it's something to consider - basically it means there is less torque multiplication available in reverse.  Also I'm not sure if the planetary gearset is durable enough for continuous use.

 

20384d1311213130-2011-ob-cvt-reverse-pow

 

There are people running entire Audi transaxles in reverse.  While a R&P does have drive/coast directions, the Subaru transaxle already "drives" off the "coast" side so I don't believe that's the issue.  The R&P is only designed for the front drive wheels which will slip much easier than the rear wheels.  If driving in reverse (or mounting the transaxle in reverse) the peak loads it sees will be much higher.  In drag racing the front housing has been known to break on the 4EAT.  This implies that the gears are strong enough, but the housing is not.

 

That said, I think as long as the torque is kept below the point that will distort/crack the housing, it should have a long service life.

Edited by presslab
Link to comment
Share on other sites

  • 4 weeks later...

thats just a regular 4EAT not the CVT. A CVT doesn't have the tradional sun/planet gears a normal automatic has.

 

That's definately not a 4EAT.  Maybe a 5EAT, never seen one apar.t

 

The 4EAT you cannot remove or even see the plantary sets with the rear housing removed.

 

I think that may be the only set of gears in there, and they are used just for reversing like press suggested.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...