Civic X Acceleration issue

[ranajazib]

Hi,
I was wondering if anyone has experienced a sudden leap in Civic X when you release throttle after flooring it. This is while driving in D.
I've driven 3 1.5's and experienced the same thing in all of them.
Also can anyone confirm if this happens in 1.8 too?

This is something worrisome I think because this takes away a couple of meters in braking distance and a fraction of a second in time as well, which is very critical in emergencies.

[usman1texh]

Hi,
I was wondering if anyone has experienced a sudden leap in Civic X when you release throttle after flooring it. This is while driving in D.
I've driven 3 1.5's and experienced the same thing in all of them.
Also can anyone confirm if this happens in 1.8 too?

This is something worrisome I think because this takes away a couple of meters in braking distance and a fraction of a second in time as well, which is very critical in emergencies.

This issue isn't present in my 1.5T. However it is definitely there in my brother's 1.5T. When you release the throttle after flooring it, the car does seem to sort of jump/leap before cutting power.

[butwhy]

That's the CVT kick...

What it does is that turns all of that kinetic energy stored in the fast running engine and sends it to the wheels and rpm falls suddenly, while the car seems to suddenly speed up. On a normal car, lifting off the accelerator(on auto) or pressing clutch simply disconnects the power from engine to the wheels. And if you are at a higher than idle rpm, the kinetic energy of the engine masses moving/spinning is wasted to friction. A CVT puts all of that down to the wheels instead of wasting. Basically, the energy you need to get rid of to slow down the engine is not wasted. Think of it as reverse transmission braking. When you put your car in a lower gear at high speed medium rpm, the engine rpm rises and the car slows down, the car's kinetic energy is transferred to the engine. Here, the exact opposite happens. The same can be done on a manual/auto as well obviously, but it's not so efficient I guess.

You won't experience this in the standard auto/manual (with gears) civic.

[butwhy]

This issue isn't present in my 1.5T. However it is definitely there in my brother's 1.5T. When you release the throttle after flooring it, the car does seem to sort of jump/leap before cutting power.

That is because you drive your own civic very very very carefully and slowly. And drive your brother's civic like crazy (apni jo nai)...

[usman1texh]

That is because you drive your own civic very very very carefully and slowly. And drive your brother's civic like crazy (apni jo nai)...

Oh yeah. Most accurate statement in all of human history. [emoji2]

[salik990]

This issue isn't present in my 1.5T. However it is definitely there in my brother's 1.5T. When you release the throttle after flooring it, the car does seem to sort of jump/leap before cutting power.

I have not experienced this in my civic 1.5T, i ve floored many times. maybe its coz of first batch civic 1.5T is having this issue.

[usman1texh]

I have not experienced this in my civic 1.5T, i ve floored many times. maybe its coz of first batch civic 1.5T is having this issue.

Yup same here. No such issues in my car. I've floored it many times too. But yes, this could be an issue with early production cars.

[Khurram26]

That's the CVT kick...

What it does is that turns all of that kinetic energy stored in the fast running engine and sends it to the wheels and rpm falls suddenly, while the car seems to suddenly speed up. On a normal car, lifting off the accelerator(on auto) or pressing clutch simply disconnects the power from engine to the wheels. And if you are at a higher than idle rpm, the kinetic energy of the engine masses moving/spinning is wasted to friction. A CVT puts all of that down to the wheels instead of wasting. Basically, the energy you need to get rid of to slow down the engine is not wasted. Think of it as reverse transmission braking. When you put your car in a lower gear at high speed medium rpm, the engine rpm rises and the car slows down, the car's kinetic energy is transferred to the engine. Here, the exact opposite happens. The same can be done on a manual/auto as well obviously, but it's not so efficient I guess.

You won't experience this in the standard auto/manual (with gears) civic.

I think it is Honda specific rather than being a characteristic of CVT. There's no such thing in any Toyota CVT. I've kept Axio, Premio, Prius and now Grande, all with CVT but none had this issue under any driving circumstances.

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[butwhy]

I think it is Honda specific rather than being a characteristic of CVT. There's no such thing in any Toyota CVT. I've kept Axio, Premio, Prius and now Grande, all with CVT but none had this issue under any driving circumstances.

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I've experienced it in all CVTs I've ever driven...And this is not an "issue".

You notice this the most when the car is at high rpm with full throttle. And then suddenly releasing the throttle.

[Khurram26]

I've experienced it in all CVTs I've ever driven...And this is not an "issue".

You notice this the most when the car is at high rpm with full throttle. And then suddenly releasing the throttle.

What Super CVTi in Toyota does is, if you floor the accelerator and then suddenly release it, the ECU identifies it as a driving situation where either sudden acceleration would again be required, or hard braking would be applied. The transmission in both cases will support control best if it maintains the same gear ratio in which accelerator input was abruptly removed... so if you floor the pedal and engine speed builds up, say at 5000 rpm, when you suddenly take your foot off the pedal, the gear ratio is maintained by the CVT, and consequently a higher ratio gear immediately slows the car due to engine braking. Now you tell me, how in this situation can the car continue to accelerate with zero throttle input?
The technology and programming of Honda CVT is different. It probably does not maintain its gear ratio in this situation thus drivers experience the momentary surge despite taking their foot off the pedal.
I am not at all saying which programming is better, just highlighting the probable difference.

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[butwhy]

What Super CVTi in Toyota does is, if you floor the accelerator and then suddenly release it, the ECU identifies it as a driving situation where either sudden acceleration would again be required, or hard braking would be applied. The transmission in both cases will support control best if it maintains the same gear ratio in which accelerator input was abruptly removed... so if you floor the pedal and engine speed builds up, say at 5000 rpm, when you suddenly take your foot off the pedal, the gear ratio is maintained by the CVT, and consequently a higher ratio gear immediately slows the car due to engine braking. Now you tell me, how in this situation can the car continue to accelerate with zero throttle input?
The technology and programming of Honda CVT is different. It probably does not maintain its gear ratio in this situation thus drivers experience the momentary surge despite taking their foot off the pedal.
I am not at all saying which programming is better, just highlighting the probable difference.

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I've noticed this surge in Toyota CVTs as well.

Bold part does not happen. If the transmission maintains constant ratio at 5k rpm, the rpm would not drop without the car slowing down or clutch disengaging. If the rpm drops and the clutch is not disengaged(if it's equipped with clutch which I don't know about), the energy taken out from the engine (which slows it down) needs to go somewhere and it goes to the wheels and you get the surge in speed.

[usman1texh]

I think it is Honda specific rather than being a characteristic of CVT. There's no such thing in any Toyota CVT. I've kept Axio, Premio, Prius and now Grande, all with CVT but none had this issue under any driving circumstances.

Sent from my SM-N900 using PW Forums mobile app

Not even Honda specific, only certain cars from Honda. Like salik mentioned in his post he hasn't faced this issue, and neither have I. But I've certainly noticed this in other 1.5Ts

[butwhy]

Not even Honda specific, only certain cars from Honda. Like salik mentioned in his post he hasn't faced this issue, and neither have I. But I've certainly noticed this in other 1.5Ts

I've experienced this in Toyota cars.

[khuram2703]

explained the Senario perfectly