CVT swap? (Into 2005 Civic, replacing 4-spd auto)

[19bonestock88]

It took that car until almost 100kph to reach 6000RPM India lowest gear. Meaning if you punch it at 40mph (~65-70kph) it wont jump to 6K. Having driven all three mentioned types of transmission, I definitely prefer manual. Want response? Downshift. The manual can be geared to take advantage of whatever traits you want

[Fat Charlie]

As an added bonus, the manual doesn't shift based on load, it shifts when you tell it to. So it's already in the right gear when you do stomp on it.

[19bonestock88]

Right! No waiting for the PCM to say, “alright throttle is down, we want second gear” and the trans to go “what, are you sure?”

[EcoCivic]

Originally Posted by 19bonestock88

It took that car until almost 100kph to reach 6000RPM India lowest gear. Meaning if you punch it at 40mph (~65-70kph) it wont jump to 6K. Having driven all three mentioned types of transmission, I definitely prefer manual. Want response? Downshift. The manual can be geared to take advantage of whatever traits you want

I think the computer's programming is poor since the transmission is mechanically capable of redlining the engine at any speed of 36 MPH or more since its lowest ratio is 2.49 with a final drive of 5.81. I don't know why its programmed to start upshifting before the engine reaches its power peak with the throttle wide open, seems stupid to me. I wonder what it would do if put in L while driving at speed? Or floored from a stop in L?

[EcoCivic]

Originally Posted by 19bonestock88

Right! No waiting for the PCM to say, “alright throttle is down, we want second gear” and the trans to go “what, are you sure?”

That is true, some autos have a very noticeable lag when flooring it. Compared to most of the automatic cars I have driven mine actually downshifts pretty quick when mashing it. I wonder how much time it takes the CVT to downshift

[Fat Charlie]

Originally Posted by 19bonestock88

Right! No waiting for the PCM to say, “alright throttle is down, we want second gear” and the trans to go “what, are you sure?”

And that's after the PCM and its friends finally agreed that third was worth a try.

[cRiPpLe_rOoStEr]

Originally Posted by EcoCivic

I think the computer's programming is poor since the transmission is mechanically capable of redlining the engine at any speed of 36 MPH or more since its lowest ratio is 2.49 with a final drive of 5.81. I don't know why its programmed to start upshifting before the engine reaches its power peak with the throttle wide open, seems stupid to me.

It might depend on terrain conditions and driver's behavior, just like any other automatic transmission with fuzzy-logic electronic controls.

I wonder what it would do if put in L while driving at speed?

It might be just like downshifting in a manual or in an automatic with sequential mode. Depending on the difference between the low ratio and the regular, you might experience the engine increasing the RPM in order to keep the speed, or it may slow down with a less noticeable impact on RPM.

Or floored from a stop in L?

Then it might be more likely to retain lower ratios for longer, and become more rev-happy.

[EcoCivic]

Originally Posted by cRiPpLe_rOoStEr

It might depend on terrain conditions and driver's behavior, just like any other automatic transmission with fuzzy-logic electronic controls.




It might be just like downshifting in a manual or in an automatic with sequential mode. Depending on the difference between the low ratio and the regular, you might experience the engine increasing the RPM in order to keep the speed, or it may slow down with a less noticeable impact on RPM.




Then it might be more likely to retain lower ratios for longer, and become more rev-happy.

Surely the shifting logic would depend on terrain conditions and driver behavior. However, with the throttle wide open, maximum acceleration is clearly desired above all else, therefore the ECU should adjust gearing to hold the engine's RPM at the power peak, 6300 RPM in the case of the vehicle in the video I posted. This means not upshifting until 6300 RPM or close to it is reached regardless of the mode the transmission is in.

I can't imagine that the engineers who designed these transmissions didn't know that, I think they designed it this way so it feels more like a traditional auto instead of just holding one specific RPM. Sort of like the stupid "simulated shifting" they do with CVTs these days where they shift it in steps, which defeats the entire purpose of having a CVT to begin with.

I asked the guy who made that video what happens if he floors it from a stop in L but he said he never tried it and he sold the car since making the video so he can't retest it.

[cRiPpLe_rOoStEr]

I'm not so familiar with the CVT behavior in a Honda, but anyway, now with all that emissions and fuel-efficiency concerns this may be the reason for the cars with a CVT being tuned the way they are. Even in a certification test won't reflect real-world usage, there is no way to overcome it without the risk for the automaker to be under a scrutiny similar to what nearly led Volkswagen to bankruptcy due to the Dieselgate.

[EcoCivic]

Originally Posted by cRiPpLe_rOoStEr

I'm not so familiar with the CVT behavior in a Honda, but anyway, now with all that emissions and fuel-efficiency concerns this may be the reason for the cars with a CVT being tuned the way they are. Even in a certification test won't reflect real-world usage, there is no way to overcome it without the risk for the automaker to be under a scrutiny similar to what nearly led Volkswagen to bankruptcy due to the Dieselgate.

You are probably right. I wonder if certification tests include any full throttle operation? I wouldn't think they would since no one floors it because they want good mileage, but we're talking about the government here so we can't expect their "logic" to make any sense.