CVT failure: Details inside

gtman

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Cvt. Tuned at IMW by Derek Robinson and I've been using the full VSA off.

Not sure if I am reading that chart right but close to max 390 wtq?

Seems like issue of too much tq down low with waaay too much boost.
That dyno plot was from his first tune I think. Coupe-R sent me his current tune settings and everything looked kind of "conservative", considering. Early spool on with factory part throttle turbo response and factory boost ramp. 24 psi above 5000 rpm only. Final boost at 24 as well.



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xjoshuax89

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That dyno plot was from his first tune I think. Coupe-R sent me his current tune settings and everything looked kind of "conservative", considering. Early spool on with factory part throttle turbo response and factory boost ramp. 24 psi above 5000 rpm only. Final boost at 24 as well.
Question is how much boost down low. And I dont think settings will show really how much tq is being generated down low. If its 20psi in 1st and 2nd "gear" we have our answer. Too much too early.
 
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That dyno plot was from his first tune I think. Coupe-R sent me his current tune settings and everything looked kind of "conservative", considering. Early spool on with factory part throttle turbo response and factory boost ramp. 24 psi above 5000 rpm only. Final boost at 24 as well.
When I got that dyno plot, they said ignore the torque numbers as they weren’t being read right by the dyno due to being a CVT. They said at that time it was probably around 225-235lb-ft for torque.
 

gtman

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Question is how much boost down low. And I dont think settings will show really how much tq is being generated down low. If its 20psi in 1st and 2nd "gear" we have our answer. Too much too early.
His tuner set BBG to 15 psi in 1st.

Here are the boost targets I saw 2500-6500 rpm:

2500 - 16
2750 - 18
3000 - 20
3500 - 22
4000 - 22
4500 - 22
5000 - 22
5500 - 24
6000 - 24
6500 - 24
 
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Coupe-R

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Question is how much boost down low. And I dont think settings will show really how much tq is being generated down low. If its 20psi in 1st and 2nd "gear" we have our answer. Too much too early.
As @gtman said, I sent him my tune file. I don’t have a dyno plot from my second tune as his dyno said I only made 160hp and 160lb-ft, he couldn’t get it to read the CVT right so I didn’t bother getting a printout of those dismal and obviously wrong values. My 1st gear BBG caps at 15psi, the rest are 21psi for “gears” 2-5. I’ve driven cars with higher power and torque than these Civic 1.5s make, I like to think my butt dyno is pretty good. Definitely in the 200-220hp range, and torque feels somewhere in the 220-240 range.
 

xjoshuax89

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As @gtman said, I sent him my tune file. I don’t have a dyno plot from my second tune as his dyno said I only made 160hp and 160lb-ft, he couldn’t get it to read the CVT right so I didn’t bother getting a printout of those dismal and obviously wrong values. My 1st gear BBG caps at 15psi, the rest are 21psi for “gears” 2-5. I’ve driven cars with higher power and torque than these Civic 1.5s make, I like to think my butt dyno is pretty good. Definitely in the 200-220hp range, and torque feels somewhere in the 220-240 range.

Hmmm that is certainly very interesting. Thanks for sharing!
 
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dallasjhawk

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theblackdogman

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24 psi and yours blown....gtman claims

Your at 24 psi and yours blown.....#Gtman didn't you say your making 26 psi?
The TSP non-si CVT target is 25, however, it will make 26+ during simulated CVT "shifts" per @D-RobIMW. It's perfectly normal. The conclusion of saying "you blew your motor because of 24 psi" is simply not true.
 

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Just thought I'd share my experience with my recent CVT failure, what (probably) caused it, and how it was resolved thankfully under warranty. See TL;DR on the bottom if you don't want all the details (though the details shine a lot of light on what happened). Feel free to AMA if it's not already included in this post.

  1. Background info
    • 2018 Civic EX-T 1.5 with around 33,500 miles at time of failure
    • Performance bolt ons are as follows:
      • PRL 3" catted downpipe & frontpipe
      • AFE Takeda intake
      • 3" straight through (no mufflers or resonators) shop made catback exhaust
      • KTuner custom dyno tune targeting 24psi on the top end
    • My driving style: On weekends, for car events/meets, or just during awesome weather; sporty and aggressive. For the Monday-Friday 30 mile each way commute to work - very conservative on Eco mode.
  2. KTuner specific details
    • Early spool enabled, Improved spool II and Improved Throttle Responsiveness II.
    • On the fly maps:
    • Tune 1 is factory turbo responsiveness and factory Boost Target Ramp Rate. This tune is capped at 21psi (Eco mode is 17psi). This is what I use for the M-F commute and regular easy driving.
    • Tune 2 is Improved Turbo Responsiveness II, Boost Target Ramp Rate is Aggressive Ramp Rate II, and targets 24psi. This is what I use when I just want to feel the power, street race, etc. I use this map less than 15% of the time.
  3. So what happened? I pushed the limits (that I knew well about, thanks to this forum) on my CVT and paid the price.
    • Background: I was at a late night meet with at least 200 other cars in this industrial area of a city in my state (little to no risk of police shutting us down here). Everybody was having a great time, especially with the shenanigans. People 2 stepping, burnouts, street racing, you know how it goes. I decided to participate in a couple straight line street races against other cars in the Civic's class.
    • The first 2 races went just fine, I actually won both to my own surprise. The third one is where "it" happened.
    • I had traction control disabled (have good summer tires that don't lose traction even if floored from a dead stop), had map 2 on (the one targeting 24psi up top, aggressive ramp II, and turbo responsiveness II). Car was in "S". I flew off the line, and when I got up to around 5900rpm and the car was going to do the simulated shift point, I felt it lurch twice, then nothing. The pedal was to the floor, engine screaming, but no further movement. I let momentum bring me to the side of the road. I immediately knew the tranny went and my heart dropped. No check engine lights were present.
    • Before I had the car towed to a Honda dealer that was about 6 miles away, I returned the car to the stock tune with my KTuner v2 and unlocked it from the ECU while on the side of the road. It was Saturday-Sunday night so the dealership was closed. I dropped the key in the key drop, filled out the form, and called Monday.
    • The dealership verified transmission failure, and submitted the warranty request to "TechLine". They said that either a new transmission would show up the next day meaning the request was approved, or that they would get a call from Honda Engineering and would do an investigation first. Waiting those 24 hours for an answer was nerve wracking. I got a call the next morning, and low and behold a new transmission for me was delivered. No investigation was performed. I got my car back 3 days ago and it drives perfectly. See the below picture of the invoice I received after the service was done
Wn2eqmC.jpg

  1. Car now and going forward
    • I made the decision that though those functions in the tune are fun, I am going to pull back a good amount. I reduced the max PSI to 21, turned off early spool, and set Turbo Responsiveness and Boost Target Ramp Rate to "factory". This is a much more conservative tune and my hope is that the new CVT will last a lot longer than the original one. I feel the difference in the transmission driving with these new parameters. Before, the simulated shifts were very pronounced, especially when in the higher RPM band. It would even clunk when getting off the throttle up top. It doesn't do that anymore, and power delivery is much smoother and more "linear" feeling.

TL;DR

Was well aware of the CVT limits, pushed them anyway, then paid the price. Was doing some late night straight line street races at a meet. On the 3rd race, CVT failed. Custom dyno tune with KTuner, 24psi, early spool enabled, Turbo Responsiveness II and Aggressive Ramp Rate II. Honda dealer replaced the transmission under warranty. Moving forward I made my tune significantly more conservative. Reduced the max PSI to 21, turned off early spool, and set Turbo Responsiveness and Boost Target Ramp Rate to "factory".
I'm just curious. What was your TQ and HP?
 

a c i d.f l y

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Didn't someone take a CVT on the track, and around 225ft/lb torque would causing scoring on the belt and dome inside the CVT? But at 200ft/lb it could be run hard all day long, and showed zero signs of scoring? Wish I could find that post.
 

dallasjhawk

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Didn't someone take a CVT on the track, and around 225ft/lb torque would causing scoring on the belt and dome inside the CVT? But at 200ft/lb it could be run hard all day long, and showed zero signs of scoring? Wish I could find that post.
both @Myx and @xjoshuax89 run more than that, have been to the track and haven't ruined their cvts. The Video thats been floated about the max tq a cvt can take has no factual information with it and was just a cvt the happened to break while tuning it. could have been faulty from the factory because that happens more than tunes breaking them
 








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