Junkski

Hello I have a 2015 si coupe and I was wondering if anyone knows the best measurement for the sway bars, the car stock comes with 21/20 and so far I can only find eibach with 24/19. Is this ok or just I just keep looking around?? Thank you.

orb

What do you mean by "the best measurement"? Are you asking what sway bar setup is best? If so, best for what exactly? "Best" is very subjective and can also depend on how your particular car is setup. Perhaps you are trying to actually measure them? Hard to tell what you're asking, exactly... I'm sure someone can help you if you specify what you mean. You'll have to pardon me if I'm missing something here; I just finished a 12 hour night shift.

Junkski

I guess I can see where I went wrong with my wording. Lol I guess what I mean what would be a good size increase I'm going to add a turbo but before I want to have my suspension set up ready

Voodoo7

a turbo has no bearing on your sway bar setup, what he is saying on being more clear is, what do you plan to do with the car?

Track days? autocross? drag race? or just normal street driving. Suspension setup can be very complex based on a lot of things, the spring/shock package you plan on running, the tire setup you plan on running, camber setups etc.... SO first we would need to know the plans of use of the car so that we can inform you to be more aggressive with a sway bar, street and track driving sway bar, or if upgrading the sway bar is even necessary for what you plan to do.

junkyard racer

Check out my thread on my 2014 Civic Si (linked in my sig), which is the same chassis as the 15. I have the Eibach rear sway bar and the difference is significant. I also put different tires on the car and together, it is a dramatic improvement over factory. The car feels much more planted when cornering and delivers a great deal of confidence.

Size wise, the sway bar is the same, I believe. The difference is in the strength of the bar, and for $165, the improvement is well worth it. I think it is something like 200% stiffer than factory, but don't quote me on that.

By the way, my car is set up for auto-x use, in H Street, SCCA. (I also do some HPDE when available). In this class, I can modify 1 sway bar and I decided on the rear bar to induce some oversteer. So far, its never happened, lol. I would imagine that with both front and rear sway bars that Eibach offers installed on the Si, the car would feel super solid. Unless you are going with a top shelf coilover package, I wouldn't put too much emphasis on what to get and how to set up your car.

My guess is, since you are asking this question, an off the shelf sway bar will be just fine. I would also urge you to put more focus on brakes and tires well. Those two items will do more to the car than anything else, if you are driving in a sprinted manner and many people overlook it.