CVT failure: Details inside

Coupe-R

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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
Honda Civic 10th gen CVT failure: Details inside Wn2eqmC

  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".
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TypeSiR

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Glad it worked out for you. Did you initially buy the car from that dealer or have your car regularly serviced there? Which state are you in? Wondering if establishing a good relationship with the dealer helps in a situation like this or just luck of the draw.
 

xjoshuax89

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Interesting information. Wonder if your tune had too much low end torque which messed up your CVT. Because I'm on the 27WON W1 turbo, FBO and E85 and done several dragstrip pulls, track days and some highway pulls with no issues *knock on wood*.
 

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Glad you got it taken care of.

Now, as someone tuned long term with a CVT I have two really important questions. You said you were "custom dyno tuned". One, I'd like to know the kind of low end torque you were producing (please post your dyno) and two, was the tune done by a pro? And then the third question... do you ever power launch?

The thing is, these CVT failures are extremely rare and I don't think I've seen any on the base/canned tunes. Also, you said it failed on your "3rd race" of the night, so clearly you went above and beyond what a typical tuned CVT owner would put their car through. Basically you torture tested it.
 
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Glad it worked out for you. Did you initially buy the car from that dealer or have your car regularly serviced there? Which state are you in? Wondering if establishing a good relationship with the dealer helps in a situation like this or just luck of the draw.
I did not buy the car from there, and I've never been to that dealership before. It was the closest I could get a tow to, so no prior relationship.
 


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Coupe-R

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Glad you got it taken care of.

Now, as someone tuned long term with a CVT I have two really important questions. You said you were "custom dyno tuned". One, I'd like to know the kind of low end torque you were producing (please post your dyno) and two, was the tune done by a pro? And then the third question and I'd appreciate an honest answer. Do you ever power launch?

The thing is, these CVT failures are extremely rare and I don't think I've seen any on the base/canned tunes. Also, you said it failed on your "3rd race" of the night, so clearly you went above and beyond what a typical tuned CVT owner would put their car through. Basically you torture tested it.
All great questions.

  1. The first one may be hard to answer. So I had 2 separate custom tunes made for me, the first one was done last year but was lost when a dealer flashed an update on my car and erased it (I have a thread on this website about that..). The original tuner would not provide me with the tune file to reflash without repaying the full original price. I have the dyno plot from that tune, here:
Honda Civic 10th gen CVT failure: Details inside GBkTDdb



  • I went to a different tuner after the original tune loss who was out of state that had far better reviews and more experience who made my current tune. That being said, he could not get his dyno to read my power and torque levels properly (he never did a CVT, and every dyno is different) and we both agreed that the readings were far lower than they actually are, because the car drove better and faster than my original custom tune. I did not bother with a printout as his dyno read my power levels within +5 of the stock Honda ratings (obviously incorrect) when the other tune +40hp over stock with the exact same bolt ons. I will DM you the tune file if you'd like to see all of the changes yourself.
  • Both tuners would be considered "professionals" with full shop setups. Both companies build engines and do full custom work along with tuning.
2. I have no reason to lie here, I already know what I did and why it happened. I can honestly say I have never, not once, power launched my car. That was one thing I was never willing to do as my understanding was that even one power launch could cause immediate CVT failure. Totally not worth even trying IMO.

3. Yes, I definitely put it through it's paces, but I think it was the turning off of the traction control that killed it in combination with the aggressive quick enables on my balls-to-the-wall map. Something felt off the moment I started off the line and I should have stopped before I got any higher in the power band.

I'd really like to keep "early spool" turned on, but am unsure if it's safe to do so at this point considering what happened now that I have a new tranny. Maybe if I set the Turbo Responsiveness and Boost Target Ramp rate in the quick adjustment section to factory in combination with early spool will be safe. I may even reduce boost under 3,000rpm in the tune and then enable early spool, make the values closer to the ones in the 21psi base ktuner map. Any opinions on that would be appreciated!​
 

gtman

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Thanks for that thorough response. Much appreciated!

In terms of the quick adjustments, JR (KTuner designer/founder) has always said they are all safe to play with so it would be nice to have him chime in here.

I currently run the TSP Stage 1 and absolutely love it. The low end feels a bit less "snappy" then my early spool enabled aggressive setting KTuner 21.5, but the top end is superior. I kind of wonder if the TSP tune maybe doesn't have early spool enabled.
 
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Thanks for that thorough response. Much appreciated!

In terms of the quick adjustments, JR (KTuner designer/founder) has always said they are all safe to play with so it would be nice to have him chime in here.

I currently run the TSP Stage 1 and absolutely love it. The low end feels a bit less "snappy" then my early spool, aggressive setting KTuner 21.5, but the top end is superior. I kind of wonder if the TSP tune maybe doesn't have early spool enabled.
That'd be awesome if they chimed in @KTuner . I don't even know what the base "Stage 2" that they include that is partially locked out uses early spool, but I can tell you that the Stage 2 map felt very different than my custom tune; Stage 2 was less torquey down low.
 

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When you day lurch what exactly does that means? I'm asking because when I floor my car I noticed my car jumps like 1 2 3 4
By lurch, imagine as if there were "bumps" on the CVT belt and it would go over them. That's the closest thing I can give as a reference.
 
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Interesting information. Wonder if your tune had too much low end torque which messed up your CVT. Because I'm on the 27WON W1 turbo, FBO and E85 and done several dragstrip pulls, track days and some highway pulls with no issues *knock on wood*.
Are you standard or CVT? I'm sure that setup would work just fine on a standard transmission, might need an upgraded clutch there but that's about it.
 
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Coupe-R

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Do you happen to know if the CVT failure was the belt or something else? Also I don't know if you've seen it but KTuner now has an Advanced VSA feature that works in conjunction with the factory VSA/Traction Control.

http://www.ktuner.com/KTunerHelp/advanced_vsa_control_strategy.htm
I was not told what specifically failed, but based on how it felt, I'm assuming it was the belt. Probably either snapped, came off the pully, or lost teeth. The feeling right before failure felt like it would've been a snap or coming off the pulley.
 
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Coupe-R

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Hmmm I ask because I noticed when flooring.....my car kinda jerk a little and go faster for example the rpm goes to 3k and then when it goes to 4k rpm its like a gear changing but it goes faster I don't know how to explain it
I see, yeah that is definitely not what I felt. That sounds like the regular simulated shifts the CVTs do.
 

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Are you standard or CVT? I'm sure that setup would work just fine on a standard transmission, might need an upgraded clutch there but that's about it.
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.
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