Stock 19' Si Sedan: High Speed Stability

Hey folks.

I wanted to know what yall have done to keep the car stable at higher hwy speeds.

Not to say the car feels dangerous, its not, this is more of improving on whats already a decently handling car.

@ 80/90mph+ ... she feels floaty, vague, no "planted". (All in regular mode, not sport.. havent tested it yet)

I want more of a secure feeling drive. The is agile but wonders around a little to much for my liking.... as if its reaching its max if that makes any seens.

Anyways, lets here it. Noob to fwd "rice" but not to "cars" and "car forums" ... flame suit is always at the ready.

all three of the x civics iv'e had were beautiful at speeds at least to 113, that was in a 2.0 lx sedan, my hatch and now the si, i don't think iv'e gone above 90. it was not the speed that stopped me it was ticket fear. my si is the best of the bunch.
maybe the road surface didn't go well with your tires.

xcivicx said:

all three of the x civics iv'e had were beautiful at speeds at least to 113, that was in a 2.0 lx sedan, my hatch and now the si, i don't think iv'e gone above 90. it was not the speed that stopped me it was ticket fear. my si is the best of the bunch.
maybe the road surface didn't go well with your tires.

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Perhaps... but you mentioned something i was just reading on here: stock tires.

Perhaps im spoiled by cars with a wider contact patch or a true summer tire, not an all season. I hate throwing parts at something without understanding it but im thinking a wider wheel/tire change and lowering springs might help.

Obzidian said:

Perhaps... but you mentioned something i was just reading on here: stock tires.

Perhaps im spoiled by cars with a wider contact patch or a true summer tire, not an all season. I hate throwing parts at something without understanding it but im thinking a wider wheel/tire change and lowering springs might help.

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I run 255/40/18 Pilot Sport 4S all around on 9.5 wide wheels and have no complaints about high speed stability. FWIW; My car is on Skunk2 springs and I also have a BMSpec spoiler extension.

ONEPNT5.Si said:

I run 255/40/18 Pilot Sport 4S all around on 9.5 wide wheels and have no complaints about high speed stability. FWIW; My car is on Skunk2 springs and I also have a BMSpec spoiler extension.

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Can you compare to how it rode to stock?

Obzidian said:

Can you compare to how it rode to stock?

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I couldn't tell you exactly how it rode stock because it's been a while, but I distinctly remember feeling that the car started to feel "floaty" at higher speeds, and I don't feel that anymore.

ONEPNT5.Si said:

I couldn't tell you exactly how it rode stock because it's been a while, but I distinctly remember feeling that the car started to feel "floaty" at higher speeds, and I don't feel that anymore.

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Interesting, thanks

Thats kinda the feeling im getting on my end too. Floaty and a little vague in normal mode. Maybe in sport mode itll change a little, well see

Obzidian said:

Interesting, thanks

Thats kinda the feeling im getting on my end too. Floaty and a little vague in normal mode. Maybe in sport mode itll change a little, well see

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Stay safe out in the storm.

swah_fk7 said:

Stay safe out in the storm.

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Thank you my bro!!

Too u as well

Given your location (South Florida) make sure the highway/road is not "rutted" - Worn roadways (think NJ & PA) have visible (wagon wheel) groves that will pull the vehicle back and forth if you don't stay centered. Rain-grooved or milled roads will do the same.

I just switched to K-Tuned Coilovers, along with other suspension upgrades helped reduce the floatiness I had on high speed turns on backroads and track events. It's a light sedan with not a lot of aero so it takes a bit of work to get them to feel like the high speed stability I feel/felt in European cars.

Something that would also help high speed stability are the rear trailing arm bushings.The regular Civics all use fluid filled rta bushings.Only the Si and Type-R use solid rubber bushings.I Remember from the old Civic hatches when you upgraded the rta bushings it would feel much more planted on high speed.

First things first, I’d recommend switching to sport mode and see how that feels. That’ll put the dampers in their stiffer setting and should take away the “floaty” feeling you describe.

Next and relatively inexpensive is check your alignment. Toe settings go a long way towards steering feel and reaction. Make sure they are in spec, more toe out front or toe in rear will help with stability.

Next, if it still feels like it’s wandering, I’d suggest a set of stiffer swaybars. This will allow the chassis to respond quicker to changes in trajectory and give youbthat secure feel.

While stickier tires will give you traction and response right at input, ifvthe chassis and suspension settings are still on the “soft” side, there’ll be a slight delay between input and body roll, which is what wandering feels like. Like your constantly behind the tire movements.

These SIs feel great on the interstate, try a yaris going 90. Now that is a skittish feeling car on the interstate.
I have no complaints of the SI other than road noise.

I think if your lower the car will help with this