CVT Modification Megathread

[TrippyPancakes]

I see so many posts asking questions about if you can mod cvts and how much is safe I figured making a large thread about it might save some time in the future for where to refer people.

Yes you can mod a CVT, yes they are more fragile transmissions than the manuals, no that doesn't mean they can't be fun

So you want to mod your CVT? Let's start with what is pretty much universally considered the best start:
- A tune (ktuner or hondata)
- An aftermarket intercooler
- sticky tires to keep traction

Most of you can probably stop reading this post right here. Those three upgrades right there will probably fit a large chunk of what people want, I would recommend springing for the tsp stage 1 tune on top of those as well but that's just me.

So a tune and intercooler aren't doing it for you huh? Well there are other popular options but these are a little more controversial in terms of bang for buck:
- performance downpipe
- cold air intake (mostly for sound not speed)
- CVT cooler (optional, can help your CVT stay healthy with the increased power if you live in a warmer climate. Not as recommended for cold climates)

For the above mods many people recommend a custom tune to get the most out of them.

Finally if you still aren't satisfied we have some of the big dogs that REQUIRE a custom tune to be truly effective or even run at all:
- W1 turbo upgrade
- ethanol conversion (E40)

These last two options are pretty huge changes and are also a little less tested in terms of long-term reliability. That's not to say they aren't reliable it's just a lot less members mod their cvts to this point so we have less data on it as of right now.

Obviously on top of all these changes we have suspension and motor mounts and all that, but those are a little more universal between the 6MT and CVT so I'll leave them off this post.

Please comment below if anyone thinks missed important info or has something to add and I'll update the post as needed

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[zspeed]

How about getting a CVT cooler as you also bump up the power?

 

[TrippyPancakes]

How about getting a CVT cooler as you also bump up the power?

Oh that's a good one that I always forget about because I live in the bitter cold lol. I'll update it

 

[lastbluesun]

By CVT cooler for you mean a FMIC? Or is that something else? Could you shoot a link?

 

[zspeed]

By CVT cooler for you mean a FMIC? Or is that something else? Could you shoot a link?

CVT Cooler

Intercooler

 

[TrippyPancakes]

By CVT cooler for you mean a FMIC? Or is that something else? Could you shoot a link?

Here's a link
https://prlmotorsports.com/prlmotorsports2016civic15tcvtcoolerkit.aspx

 

[Myx]

@TrippyPancakes

What I specifically have been looking for outside of what you have posted are two things that seems to not exist at the moment. These are software and hardware changes to the CVT.

1) Software changes to the TCU (Transmission Control Unit) programming, the same way we can get a tune on our ECU. This programming can manipulate how the CVT performs, like changing the max rpm that the CVT will rest at vs stock (Like if you installed aftermarket cams). You can't use the new max horsepower rpm that a cam would allow unless you change the CVT's TCU programming. If I remember right (Correct me if I'm wrong @KTuner), we 'Ktuner' tested this on my 2015 Honda Fit CVT while beta testing Ktuner for Honda Fits. The ECU's rpm limit could get set but the CVT was preventing the engine rpm to change to it's new set rpm point (Ex: Maxing at 7000rpm vs 6200rpm). At the time, I had just installed custom ground Detacams that were supposed to allow for some more power past the stock max rpm. These cams were considered a Deltacam Stage 2 cam (Like Honda Civics got back in the day).

**I'm still willing to take on this project with a tuner. Even signing a waiver as we experiment**. It's the only way any progress is going to be made in this department. Big $$$ for any of them if they are successful.

2) Hardware changes are changes to the physical components of the CVT itself. Upgrading the belts, changing the pulley sizes to lighter ones, changing the gearing to be more aggressive, etc (Like snowmobile CVTs). I had talk to a couple snowmobile CVT performance shops to see if they would take on this project in my Honda Fit but they were hands off. Only one said they'd consider it but not just yet. That was some 4-5yrs ago or so.

Nice post btw!

 

[CAPTS]

i don't think a cvt cooler will bump up the power

 

[TrippyPancakes]

i don't think a cvt cooler will bump up the power

Correct, but it is believed adding a cooler to the CVT will helps it's longevity under the increased stress of more than stock power

 

[zspeed]

i don't think a cvt cooler will bump up the power

A CVT cooler is helpful if you are increasing the power from the engine and if you’ll be running it with lots of abuse in order for the CVT to not have a premature breakdown and to be able to keep up with the additional demands and stress. It’s like adding a differential cooler and an oil cooler for a manual transmission engine to ensure reliability and longevity with more power.

 

[Myx]

A CVT cooler is helpful if you are increasing the power from the engine and if you’ll be running it with lots of abuse in order for the CVT to not have a premature breakdown and to be able to keep up with the additional demands and stress. It’s like adding a differential cooler and an oil cooler for a manual transmission engine to ensure reliability and longevity with more power.

Are we sure about this? Keeping the CVT fluid cool helps the CVT transmission from failing. Two questions to ask ourselves is: 1) How does the CVT transmission fail and 2) How can we prevent this failure from happening.

So....how does keeping the CVT fluid cool keep the CVT transmission from failing? How do CVTs fail anyway? What exactly is the purpose of the CVT fluid itself?


I'm posing these questions for a reason. Bare with me......

 

[zspeed]

Are we sure about this? Keeping the CVT fluid cool helps the CVT transmission from failing. Two questions to ask ourselves is: 1) How does the CVT transmission fail and 2) How can we prevent this failure from happening.

So....how does keeping the CVT fluid cool keep the CVT transmission from failing? How do CVTs fail anyway? What exactly is the purpose of the CVT fluid itself?


I'm posing these questions for a reason. Bare with me......

This is in regards if you’re running it on the track and spirited driving.

A friend of mine had a tuned WRX STi CVT with FBO. Without the CVT cooler, his transmission fluid was reaching critical level when he does aggressive and spirited driving. Installing a CVT cooler helped to keep the transmission fluid from reaching critical level.

 

[arnoldo]

CVT or ATF cooler might be only useful in the following conditions:

1. Towing
2. Traffic at inclined roads (flyover, hills, etc.).

 

[Myx]

This is in regards if you’re running it on the track and spirited driving.

A friend of mine had a tuned WRX STi CVT with FBO. Without the CVT cooler, his transmission fluid was reaching critical level when he does aggressive and spirited driving. Installing a CVT cooler helped to keep the transmission fluid from reaching critical level.

Thanks for responding so quickly. So the CVT fluid heats up and hits a 'critical' level. So what happens after that? The fluid must be cooling something to prevent something from happening.

I ask because I was trying to find an answer to this and read that the purpose of the CVT fluid is to help keep the friction of the belt on the pulleys. That was it. If friction is lost (Due to too much power being put on the CVT belt or the fluid not helping the belt keep friction), then the belt would slip and eventually break from the heat generated from the slipping.

So I am not understanding how a CVT cooler cooling a slipping belt is going to keep the CVT belt from breaking. It's either going to heat up and break from slipping or break from too much torque being applied to the belt, despite its friction.

Maybe I am overthinking this and got it all wrong here.

Edit: I guess I should've included at least one link to state what I am talking about.
The Effect of Belt-Drive CVT Fluid on the Friction Coefficient Between Metal Components or
Lubricants for Metal Belt Continuously Variable

In these links, especially the 2nd one, it only talks about the CVT fluid increasing the belts friction to be able to deal with more torque. Nothing about cooling the fluid to prevent heat.

**I have attached the .pdf from the 2nd link below, in the event the site goes down and this information is lost.**

 

[TrippyPancakes]

2 more points on the CVT cooler that I might be worth considering.

1. From the factory I think the CVTs ship with a form of heater on the transmission (please correct me if I am wrong). So for whatever reason Honda was concerned about the fluid getting too cold. Maybe the fluid has a bad freezing temps for cold weather areas?

2. The CVT cooler is made by PRL and they are quite well respected and trusted in the community so they obviously understood some benefit to it

Just some food for thought on it

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