CoolGuy094

I was trying for quite some time to find the instruction manual for these coilovers in English to see what the factory settings were. I finally found the information in the depths of the interwebs after flushing through some Japaneese.

Info on AP1: http://www.hks-power.co.jp/en/produc...ermax/db/13018
Info on AP2: http://www.hks-power.co.jp/en/produc...ermax/db/13017

I am also uploading in PDF form in case they take these links down.

I have seen several other threads with people looking for this information. Hopefully this can be helpful to future searchers.

CoolGuy094

So using the above manual, I attempted to set a newly purchased set of Hipermax III Sports to the factory recommended settings. I disassembled each coilover, wire-brushed the threaded surfaces, and cleaned everything up before reassembling. Then, using the values from the chart labeled "Setting Data" in the manual, I used a scale and caliper to accurately set the "Spring Set Length" and "Length to Ride Height Adjuster" as shown in the image below:



Note that the "Spring Set Length" was measured from the bottom of the rubber gasket to the top of the first aluminum adjustment knob. This includes the length of the spring, the helper spring, and the aluminum seat between the two. The "Length to Ride Height Adjuster" was measured with calipers between the bottom of the second aluminum adjustment knob to the top of the third aluminum adjustment knob.

After snugging down all the locking rings and double-checking my measurement values, I put everything back on the car. With the front and rear suspension pre-loaded, I torqued the strut tower nuts, a-arm bolts, and lower coilover bolt to spec (while also adjusting my end links for my Saner bar to remove any pre-load from them).

With that done and the wheels back on the car I took it for a short spin around the neighborhood to settle everything in, then came back to take some measurements.

From hub center to metal fender edge:
Front Right: 12-3/8" (314 mm)
Front Left: 12-3/8" (314 mm)
Rear Right: 13-3/8" (340 mm)
Rear Left: 13-3/8" (340 mm)

This is the most common measurement taken when comparing ride height to other cars, as it doesn't take into account what size tires you are running. However, HKS used a "from road surface" measurement in their test data, so I recorded this as well to see how I compared to their setup vehicle. Note I am on 4x rear AP2V1's with square 255 RS3's.

From road surface to metal fender edge:
Front Right: 24-5/16" (618 mm)
Front Left: 24-5/16" (618 mm)
Rear Right: 25-5/16" (643 mm)
Rear Left: 25-5/16" (643 mm)

So, comparing to HKS' test vehicle, my front is at 618 mm while theirs was at 636 mm. Rears compare much closer with mine at 643 mm versus theirs at 650 mm. My tires are also about 10 mm taller in the front and 8 mm taller in the rear than their test vehicle's tires, so really the difference is greater than what it seems.

None of this really bothers me, as I can easily attribute the differences to my 12 year old bushings, the used condition of the coilovers, and so-forth. But the 1" difference from front to rear has to go; so I plan on raising the front by about a half-inch. This will result in a 1/2" lower bias in the front, which is about what HKS had on their test vehicle.

Overall, I am very happy with the results of taking the time to properly measure out the preload and height adjustments. The greatest thing is that the car is perfect side-to-side. Hopefully this will further help anyone looking to return their set to factory specs.

rip_ej1

thanks for the useful info!

gen2gsr

I followed this guide for a used set I just bought. My set had collars in all different spacings, so I'm glad this guide gave me a reputable baseline. A few buyers guide notes:
One of my dust boots was significantly torn. Make sure you are happy with the dust boots you're getting on your set. Super torn dust boots could be a sign of hi miles. You could probably use OEM dust boots as substitute. Also, peek under the dust boots to gauge the level of "gunkiness." If one shock has significantly more gunk, it could be a sign it is blown.
Bring a coilover collar wrench with you and try out the collars to ensure they aren't frozen. These dampers are stainless so they shouldn't rust, but you never know.

The HKS guidelines call for a spring set length of 20cm. This primarily compresses the helper spring till it has less than 1cm compression left. When changing springs you'll have to choose between springs of 7" length and keeping those helpers, or 8" springs and losing the helpers. It makes the math all wonky if you mix n match the 2 options. Luckily, with following this guide I didn't find the ride nearly as harsh as others have alluded to. I'd happily commute daily on these.

The guide calls for front ride height 1cm lower than the rear. The OP noted his car was more like 1.5cm lower in the front. My 13kg HKS springs, although stiffer, were saggy (16.85cm unsprung length) compared to the 11kg springs (17.0cm). The front shocks "length to ride height adjuster" specs 6.2cm, but because of the saggy springs & the OP's initial measurements I opted for 7.0cm here.

CoolGuy094

Glad this info is helping people out!

-=Zeqs=-

Ya, your thread was very helpful. I never posted, but when I picked up my used set from my friend, your thread was helpful in fine tuning things.