wheelflip 2018 Honda Civic Si sedan

alexzhao

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Hi everybody,

This thread is to document the build process for our 2018 Honda Civic Si sedan.

The car was purchased as an exercise to explore the potential market of 10th Civic. Since we have a lot of friends and customers with the Type R models already, we chose the Si because the customer base is broader and there are fewer companies supporting this platform.

The goal is to enhance the driving experience and greatly improve lap times without major sacrifice to the elements that make this a great street car. In doing do, the purpose is not to create an all-out time attack car (of which one already sits in the garage), but instead, a reasonable street car with performance that should rival or exceed the Type R model. Perhaps my favorite thing about this car so far is that it does not attract the same attention as a Type R.

You may notice; the car has a few minor modifications left by the previous owner such as the carbon-look mirror caps, wrapped window trim, and some aftermarket springs. All of those will be removed and done correctly.

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alexzhao

alexzhao

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A few weeks have gone by and I have begun the first few modifications. First, I addressed the awful factory suspension, replacing the dampers with (temporary) Godspeed Maxx coilovers. I have experience with these on previous cars and know them to be one of the better low end coilover systems. To my knowledge, they are the only decent damper in their product lineup and are shared with other name brand suspension companies.

Initial impression of these dampers is that they ride well and handle well. If these were not a temporary setup, I would try 10kg/8kg Swift springs which are an improvement in both ride quality and handling to basically every coilover setup on the market.

In addition to the coilovers, I added Progress 22mm rear sway bar, SPC rear camber arms, and SPC front camber ball joints. The rear sway bar aids in rotation - noticeable enough that I am reconsidering whether a staggered setup is needed in the future. Further testing will occur before the jury is in on that. The front camber joints provide an extended track and therefore should help with camber gain upon compression.

The factory wheels and tires were the next thing to address. These are the easiest things to replace to improve performance all around.

OE Wheel 18x8.0: 28 lbs
OE Tire: 25 lbs
Combined: 53 lbs

Advan TC3 18x9.5: 19.50 lbs
255/35/18 Nexen N Fera SUR4G: 27 lbs
Combined: 46.50 lbs

Net savings: 26 lbs or 6.5 lbs per corner of rotational mass

These wheels and tires are certainly not the final setup, but gave me a good platform to test wheel / tire sizing and to try out whether a square setup is ideal or not.

The wheels are secured with Project Kics R26 lug nuts.

In addressing the poor response of the engine and drivetrain, the car has a Hondata Flashpro to eliminate rev hang. Combined with the aftermarket intake, front pipe, and down pipe, the original clutch was unable to cope with the added torque. To resolve this, I have installed an ACT clutch and flywheel kit. Eliminating the factory dual mass flywheel created a major improvement to the responsiveness of the drivetrain, as well as eliminating any noticeable delays in throttle input.

Next, a GReddy Type-28E intercooler kit was installed to aid in loss of power due to heat soak. The engine response was not noticeably affected.

Over the next month, we will begin looking at areas to reduce weight (again, with the ethos being to shed weight by replacing rather than removing). I have ordered coilovers from Exceed Japan and during installation of those, we will scale and corner balance the car.

P.S. The car is dirty due to many hundreds of miles of testing.

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alexzhao

alexzhao

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Today, I started looking into the next wheel setup, beginning with the front wheels.

Advan TC3 18x10.5: 21.70 lbs

In order to comfortably fit them whilst maintaining a meaningful tire stagger, I'll be looking at 265/35 front tires and 235/40 rear tires.

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alexzhao

alexzhao

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Yesterday, I did a car shakedown at Buttonwillow Raceway.

I only set 2 hot laps because the stock brake system was pretty awful. Prior to the track day, I spent a few days researching aftermarket pad options and didn't find much. I did see that Hawk offers the HPS pad, but I knew that it would not even be a worthwhile stop gap and so I didn't bother.

In speaking with Project Mu, they do not have the unique pad shape of the Civic Si - as you know, this car is not sold in Japan. I'm in talks with Winmax at the moment to hopefully bring a W5/W6 compound to market for this car.

During the first session, I experienced pedal-to-floor brake fade for the Sunset turn (for those familiar with Buttonwillow) on the first lap. Because of this, and a bit of traffic, I was only able to set a 2:06 time.

After the first session, we bled the brakes and swapped to Castrol SRF. I let my friend, who is far more experienced with driving FWD cars, take the car out for this session. I wanted to collect more data for myself to look at on the AIM Solo 2 lap timer. He was able to set 2 consecutive 2:07 laps and did not report brake fade until towards the end of lap 2. The fluid definitely helped, but nonetheless, the conclusion is the same.

With noon approaching and desert temperatures exceeding 100°, I decided to call it a day. I had learned what I came to find, which was the following:

1. The GReddy intercooler, along with flex fuel (E36 today) did a great job in keeping the engine cool. While my friend with the Civic Type R was having trouble with overheating all day, the Civic Si coped well.

2. With the square setup, Progress rear sway bar, and fairly aggressive alignment (-3.4° F, -2.0° R camber settings), the car rotated fairly well. Some front toe out and new staggered setup will improve rotation.

3. The 5kg progressive rear spring on the Godspeed Maxx coilovers is too low and should be swapped out to a linear 8kg Swift spring. I will not be doing this because I have Exceed dampers coming, but just a recommendation for anybody else running them.

Power-wise, I am pretty happy. Since the last post, I added a Remark exhaust system which shaved weight, sounds much better than stock, and most importantly, it smoothed out the torque bomb that I had at ~3500 rpm and moved some of the power higher in the rpm range.

Before the next track day, I will install the Recaro RS-GK bucket seats, swap the radiator for a Koyorad unit, swap to the staggered wheel/tire setup, and figure out a brake solution.

I do have some GoPro footage, but the driving was not to the best of my ability so I'm on the fence about posting it. The car with better weather conditions and said changes I will be making should be sub 2:00.

PS: Car is ugly, a bit undecided if anything on the market makes it look better.

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alexzhao

alexzhao

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Here is the video of my 2 hot laps. Refer to previous post regarding the stock brakes. My driving is rusty and this first session was meant to just get a feel for the car. I believe I can shave 3 seconds with driving optimization alone. Small tweaks to the setup, including upgrading the brakes will bring the car to sub 2:00 territory with current power level.

I am by no means a top tier driver, but I have done a 1:53 here in my S2000. I'm still adapting to FWD driving style so I will try to get more seat time in the near future.

 
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alexzhao

alexzhao

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In speaking with Winmax, they have the front pad shape (Honda Vezel / HR-V), but they do not have the return springs. In my experience, this means the pads will move around up and down / side to side making a ton of noise.
 
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alexzhao

alexzhao

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Yesterday, I added the Zoom Engineering rear view mirror that we are now selling in our store.

It is a carbon fiber piece that would make a fine addition to any interior, and a simple 5 minute installation.

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alexzhao

alexzhao

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First Name
Alex
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Today, I went ahead and test fit the front wheels to the new wheel setup.

They are sized 18x10.5 +25 and are paired with 18x9.0 +25 rears (not shown). I used 265/35 Yokohama A052 tires that were sitting around, but the ideal size would be 285/30. This gave me a good baseline to test for fender clearance and for potential interference under suspension compression. While this size clears as is, I believe that it will require an additional half degree or more of negative camber in order to clear the 285's.

I do have a set of 18x10 +30 Volk Racing TE37SL wheels as well that perhaps may be better suited to this car, but until I can find an appropriate match for the rear, they won't make it onto the car. My guess as to the final setup that I settle on, will be 18x10 with 285/30 front and 18x9 with 235/40 rear.

This week, I will be installing the bucket seats. While a new front lip may be in development, I am tempted by the offerings from Mugen and Blitz. As I tend to do, aesthetics will be the focus only when I am satisfied with how the car feels and performs.

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