1 Lucky Texan Posted August 12, 2013 Share Posted August 12, 2013 (edited) 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 September 14, 2013 by 1 Lucky Texan Link to comment Share on other sites More sharing options...
ivans imports Posted August 12, 2013 Share Posted August 12, 2013 still has a crown / pinion they are not meant to run backwards powerd Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 12, 2013 Author Share Posted August 12, 2013 no question the engineering is for forward, dunno how much running backwards would tear-up the internals. Would it cut the unit's lifespan down to days? in half? 10%? Link to comment Share on other sites More sharing options...
presslab Posted August 12, 2013 Share Posted August 12, 2013 (edited) 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. 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 August 12, 2013 by presslab Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 12, 2013 Author Share Posted August 12, 2013 interesting - looks like that planetary reduction could be 'locked' with some kind of drop in? Link to comment Share on other sites More sharing options...
Uberoo Posted September 5, 2013 Share Posted September 5, 2013 thats just a regular 4EAT not the CVT. A CVT doesn't have the tradional sun/planet gears a normal automatic has. Link to comment Share on other sites More sharing options...
ivans imports Posted September 5, 2013 Share Posted September 5, 2013 I most defanatly smoked the backside of crown / pinion and only did a 150 backwards pass mind you 300+ hp with nos and 31 paddle tires. It dident break just melted smeared and striped. I a'm still not a beliver of backwards runing diff Link to comment Share on other sites More sharing options...
presslab Posted September 7, 2013 Share Posted September 7, 2013 thats just a regular 4EAT not the CVT. A CVT doesn't have the tradional sun/planet gears a normal automatic has. You're sure about that? Must be, otherwise you wouldn't have posted it... Link to comment Share on other sites More sharing options...
Gloyale Posted September 14, 2013 Share Posted September 14, 2013 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 More sharing options...
Uberoo Posted September 21, 2013 Share Posted September 21, 2013 My bad I was under normal automatics had the planetary gears,I suppose its not that far of a stretch for a CVT to have a planetary gear for reversing duties.Normal automatics use them like that that. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now