2025 Si 1st to 2nd shift car cuts power

[SuperDave]

Hey Civic lovers. When launching my 2025 Si, say to hit 0-60 quickly, about half the time the car cuts a ton of power as soon as I shift into 2nd gear. I have sticky summer tires so I know it's not a traction issue. Sometimes it hits 2nd perfect and keeps accelerating as normal. Anyone have a fix for this?

Also it did this before and after tuning the car. So it's not tune related. Cheers!

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[cryptolime]

Hey Civic lovers. When launching my 2025 Si, say to hit 0-60 quickly, about half the time the car cuts a ton of power as soon as I shift into 2nd gear. I have sticky summer tires so I know it's not a traction issue. Sometimes it hits 2nd perfect and keeps accelerating as normal. Anyone have a fix for this?

Also it did this before and after tuning the car. So it's not tune related. Cheers!

do you have a video? could be your technique. it can be hard to get a perfect 1-2 shift.

 

[pwp25si]

Its tricky to shift perfectly with clutch delay valve and damper. Replace the clutch line with ss braided line while you're at it. It feels so smooth.

Its crazy how late clutch engages with the delay valve. You have to time it early.

 

[2025-Si]

Does it feel jerky, and if so, do you have a stock RMM? I don't recall having this issue on mine. If you had a video that would help

 

[SuperDave]

Does it feel jerky, and if so, do you have a stock RMM? I don't recall having this issue on mine. If you had a video that would help

I need to find a way to film it.

PRL RMM. Doesn't feel jerky, but definitely feel the drivetrain shock the car between 1-2 shift. Maybe I'm shifting too fast/hard?

The car is catching 2nd gear just fine. As soon as I let the clutch out I can feel the power reduced drastically. Almost as if traction control is limiting it. I need to run some tests with TC off to verify if that helps.

Have been driving manuals my whole life. And I had a 2017 Si before this one. Don't remember having this issue in that car. Used to drag race it at the track often.

 

[2025-Si]

I don't know about the 17 Si but other older cars I had, I could do fast shifts between 1-2 without issue. For the 25 Si, I've needed to always wait 0.5 seconds for the 1-2 shift if I wanted it smooth.

 

[SuperDave]

I don't know about the 17 Si but other older cars I had, I could do fast shifts between 1-2 without issue. For the 25 Si, I've needed to always wait 0.5 seconds for the 1-2 shift if I wanted it smooth.

The more I research the more I see this car and 1-2 shift is not easy to master ha. I definitely need to play with different techniques like slipping the clutch more or adding more gas pedal to the equation.

 

[Chilly613]

I had an 11th Gen Sport Touring 6MT and now an FL5. Didn't have a problem with power loss, but it would be a little rough going from 1st to 2nd. I've changed out the transmission fluid after break in and its helped with shifting.

The clutch delay valve is why you cant shift fast in this car. They made it so its "easier" to drive this car with less shock to the clutch. Some people have taken the plunger of the delay valve out and its helped.

I will say, that when I do see posts like this everyone is always like "I've always driven manuals over the years and I had XYZ car and it doesn't drive like that". Well of course its not gonna drive like XYZ car, its a different year and generation/model. Just drive it like you're brand new to the platform and figure out the nuances with this car, forget all the shit about the other cars you've driven. Every car is gonna be different and have their quirks. Once you have this car figured out, you'll be fine and probably won't have the issues you're having.

 

[2025-Si]

Yeah every car is different. I even managed to master heel toe downshifts in this car without any sort of pedal adjustment, but it took a while.

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