2023 Civic Si Spring Rates, Motion Ratio, Ride Frequencies, Autocross

[absolude]

Interesting feedback about the twitchiness and loss of stability. Are you using the FK8 for FL5 sway bar on your Si?

I'm using the FK8 swaybar on the 2023 Si.
Hope I didn't come across all negative about this. I was just surprised that it didn't feel the same as I experienced before.
Probably there is more good than I noticed in this mod but I was looking in the wrong place for it.
By the time I realized the changes in behaviour were not exactly what I expected I was already adapted to it and couldn't tell exactly what the difference was. One thing that stood out was that it could take sudden steering inputs better but require a quick, precise rebound.

Since on rare occasion I wish for a bit more stiffness in the front, I'll probably just go ahead and try the Type R front springs, see how it changes things...

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[absolude]

Just back to say that I have the same impressions on the type R front springs mounted on an Si as ones DYI01 shared earlier in the thread.

This is after a short drive from the shop, on not very familiar roads and hope it'll stay the same when going over rougher patches.

Si is more buttoned down and the slight extra stiffness doesn't really translate in roughness I was worrying about.
The type R springs and RSB give pretty much the same balance as stock, just a bit more tight.
The tiny trace of wobble on sudden steering inputs and very minor front heaviness under braking are now gone. Not that they bothered me before, as I didn't even know they were there, but it's just something one notice. Car is just a bit cleaner under loads.
There is definitely some extra stability or maybe solid feel.
Going at slow speeds over cracks in pavement show the rear is still stiffer than the front, which I think is how it should be.
Moving the steering wheel from dead centre ,that became slightly lighter with the addition of the RSB alone, feels now pretty much as stock again. Not a pro or con, just an observation.

All in all, probably this is not a popular mod since it doesn't lower the car.
The improvement from stock is not huge, as the Si handles very, very good for a stock FWD car, but I'm nevertheless happy to have done it.
The addition of the springs brought was I was hoping for.

 

[DYI01]

Glad you liked the FK8 front spring mod

 

[absolude]

Glad you liked the FK8 front spring mod

Thanks for sharing this mod!
My car hasn't settled yet to stock height and I wish I knew why passenger front is higher than driver's side.
Luckily I noticed before switching springs otherwise I'd be going crazy.
I measured the height just before the switch, for reference, and didn't pay any attention to the difference, thinking it's just the floor being uneven. Just wanted an average. It was a difference of 14mm.
Only after I realised the garage floor it's actually even...

Is your car even left to right front?
Are the shocks still managing?

 

[Vito.FL5]

Very informative post, with good information not just bla bla.

If you look into the swift springs for the FL5, they are a little bit stiffer than what you considered, but still, very close.

 

[fbirch]

Does anyone here know the spring rates of the Sport Touring Civic? How different is the Si setup compared to the less sporty trims?

 

[eromani]

First autocross of the season and it was during a snowstorm. Super fun, I was running everything stock except Blizzak tires. 245/40/18 front, 225/45/18 rear on stock wheels.

 

[eromani]

First autocross of the season and it was during a snowstorm. Super fun, I was running everything stock except Blizzak tires. 245/40/18 front, 225/45/18 rear on stock wheels.

And we ran 2 courses. This is the other one, which was super fast, and plenty of oversteer. I love the Honda's setup from the factory (except tires):

 

[Chilly613]

The cheap and easy option to up the front spring rate is a pair of OEM FK8 CTR front springs, which are 263 lb. springs. They really seem to balance the feel front to back and the stock shocks handle the rebound no problem. The increase in front spring rate definitely increases the roll stiffness and keeps the front tires planted better. An OEM FK8 20.5mm rear sway bar will also help to keep the balance. These are stealthy and cheap OEM+ upgrades IMO.

I'm currently using a Whiteline 22mm rear sway bar and It clunks on me occasionally and feels almost too stiff at times. I've been contemplating going to the OEM CTR rear bar to give a bit more of a compliant ride over uneven left/right bumps, it unsettles the car a bit too much. Otherwise the setup makes the car handle extremely neutral, a bit of understeer at the limit of the tires, lift off a bit to make the rear step out a little and power down to straighten it back up.

This is very interesting, never thought about getting OEM FK8 springs for the front. I wonder if this will have similar results in a Sport Touring Hatchback.

 

[absolude]

This is very interesting, never thought about getting OEM FK8 springs for the front. I wonder if this will have similar results in a Sport Touring Hatchback.

This may not be of much help, but I used Si springs on my 10th gen hatchback. Perfect fit.

 

[ValkenDnB]

Thanks for sharing this mod!
My car hasn't settled yet to stock height and I wish I knew why passenger front is higher than driver's side.
Luckily I noticed before switching springs otherwise I'd be going crazy.
I measured the height just before the switch, for reference, and didn't pay any attention to the difference, thinking it's just the floor being uneven. Just wanted an average. It was a difference of 14mm.
Only after I realised the garage floor it's actually even...

Is your car even left to right front?
Are the shocks still managing?

Any chance this works with 2023+ type r springs?

 

[ValkenDnB]

Thanks for sharing this mod!
My car hasn't settled yet to stock height and I wish I knew why passenger front is higher than driver's side.
Luckily I noticed before switching springs otherwise I'd be going crazy.
I measured the height just before the switch, for reference, and didn't pay any attention to the difference, thinking it's just the floor being uneven. Just wanted an average. It was a difference of 14mm.
Only after I realised the garage floor it's actually even...

Is your car even left to right front?
Are the shocks still managing?

Did your car ever settle correctly with the fk8 spring mod?

 

[absolude]

Did your car ever settle correctly with the fk8 spring mod?

I think it's settled ok but not sure if the ride hight is the same.
Planning to visit a dealer just to compare it to a stock car.

 

[absolude]

Any chance this works with 2023+ type r springs?

Sorry, no clue.

 

[ValkenDnB]

I think it's settled ok but not sure if the ride hight is the same.
Planning to visit a dealer just to compare it to a stock car.

Gotcha thank you

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