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Old 03-09-2012, 01:48 PM   #1
Scooby Specialist
Member#: 91212
Join Date: Jul 2005
Chapter/Region: MAIC
Location: Martinsburg, WV
2011 WRX 5DR
Satin White Pearl

Default How To: Install Koni inserts in a GR (2008+)

After putting 28K on my 2011 WRX 5DR, I decided that it was time to do more upgrades to the suspension. To date, my only modifications were Kartboy endlinks and Eibach swaybars F&R. This did a lot to help with body roll, but I could not help but to think that some better dampers and springs (more on that later) would help with ride and handling.

Winter wheels are the OEM WRX wheels with 235/45/17 Continental ExtremeContact DWS. Summer setup (yet to be bolted on the car) is a set of 17x8 et48 OZ Ultraleggera wearing 235/45/17 Hankook Ventus V12 Evo K110.

Braking mods are a GrimmSpeed MCB (done) and Technafit lines and Performance Friction Z-Rated pads (yet to be installed).

I plan to autoX the car a few times a year and to possibly do hyperdrive events, and maybe an HPDE is in my future.

So why Konis?

Two reasons- First, I have liked them in every car that I have driven that had them installed, including my 2003 Sentra SE-R SpecV, which had them paired with the Nismo springs (the only known setup of its kind in the country at the time). Second- Price. I got my Konis (NEW) for $550 shipped using a discount code for the "Shock Value" sale. This made them a lot cheaper than Bilsteins, which were my other main consideration. I was not sure how much (if at all) I wanted to drop the WRX, so I was not sure whether I wanted to put $1350 into the Bilsteins and RCE yellows. Even factoring in a spare set of 2009 WRX front strut housings I am still under $600 for the full set of Konis.

My standard disclaimer: I drive approximately 100 miles every weekday on my commute. It consists of 4-lane divided highways, 2-lane secondary roads, and about 15 miles of twisting mountaintop roads with serious curves, elevation changes, and lots of other fun features. I have 2 children, so the car has to be able to have them comfortable in the back seat, so no killer-stiff suspension will work for me. I also don’t want suspension that will require a lot of tweaking, frequent rebuilds, or a huge up-front investment.


During the planning phase, I found this thread informative about the general process, but not about drawing/pushing the insert into the OEM housing:

I also found this thread (mostly important to 2011-2012 owners) regarding using 2008-2010 struts as donor struts. This was not the intent of the thread, but nothing in the thread (which was geared toward RCE/GTWorx Bilsteins on a 2011+ WRX) is different as far as fit.

Here is the important part:

Originally Posted by RaceComp Engineering
The holes in the front clevis tabs are spaced 10mm further out than on the GH struts. I did not take additional measurements, but I assume that the front control arms are 10mm wider as well. What this means is that when using 08-10 struts on the 2011, you gain a ton of front negative camber. With the car on the alignment rack, it maxed out at -2.8 with OEM strut top mounts It can also be dialed back as far as -1.2 for a more conservative alignment.

With all of these mods done and the camber dialed in to max negative, the car feels absolutely amazing. [Y]ou might gain a large advantage (in competition)with the additional camber capability.
I also posted a new thread, just to be sure that I was understanding/interpreting the information correctly:

Before you begin:

First off, I HIGHLY recommend having a set of donor struts. They can be from a WRX or “regular” Impreza, so they are not too terribly hard to find. I got mine complete with all F&R mounting hardware for $85. That was for 2009 WRX front struts (with 31K), F&R top mounts, bearings, bumpstops, dustboots, etc. Once installed with my spare springs, I will not have to disassemble my OEM parts to swap from OEM to upgraded.

I did NOT gather the parts for a full swap-out suspension setup so that I can do a summer/winter swap. My reason was to make it simple to do the install in an afternoon without rushing, and so that I can revert back to stock in an hour or so if I really need to do so. Also, if I ever need the Konis rebuilt or re-valved, I don’t have to do much disassembly.

  • Torque wrench (3/8” and ” in my case)
  • Metric sockets (I have “go-thru” sockets from harbor Freight as well as regular metric sockets)
  • Socket wrenches
  • Allen head sockets- specifically 6mm and 8mm
  • Bench vice
  • Tape measure (one with metric markings helps)
  • Hacksaw
  • Drill with assorted bits (1/8” 3/8” and ” in my case)
  • Assorted screwdrivers
  • Rags
  • Catch basin/bucket
  • Punch (or a really hard, sharp screw or nail)
  • Hammer
  • Sharpie
  • Masking tape
  • Threadlocker (Red)

Not really a “tool” but really helpful for my install (more on that later):
  • M12-1.50 bolts in 30mm, 40mm, and 45mm lengths
  • Washer with a ” opening


Koni 8610 1453Sport (2)
Koni 8010 1055Sport (2)

2011 WRX STi front springs (rate approximately 250 lb./in) w/ 15K
2008 WRX STi rear springs (rate approximately 197 lb./in) w/18K

Complete tophats, mounts, housings, bushings, bearings, bumpstops, dustboots, etc. from a 2009 WRX w/ 31K.

So why the springs that I chose?

Originally, I was going to go with all 2008 STi takeoff springs. This would have given me a slight lowering in the front (~5mm) with the same spring rates as my 2011 WRX (approximately 220F/200R, at least accoring to forum lore). I looked at the 2011 WRX rates and compared them to the STi rates and was hoping that I could take advantage of the STi reported rates of 250F/297R. I bought a set of low-mile 2011 STi take-offs, but after some hands-on research, more forum searching, and some frustrating measurements I determined that the 2011 STi rear springs were too short to work on WRX Koni struts.

I abandoned that idea and went back with the 2008 STi rear springs, which were SUPPOSEDLY the same as the 2011 WRX rear springs. With similar mileage on my 2011 stockers and the '08 STi takeoffs, I was surprised to find that the rear came up by about .25" even with the front still at stock height.

At some point, I may disassemble my OEM rears and put them on the Konis and take off the '08 STi springs, but we'll see if they settle any more.

It is important to note that the '08 STi springs are longer than the 09-12 STi springs. Only '08 STi rear springs will work for this, but they DO raise the rear very slightly.

08-12 STi fronts will work fine but the rates differ from year to year. DO YOUR RESEARCH!


Starting with the assembled strut, you have to take it apart. Obviously my application did not have springs, so you need to adjust the procedure to account for safely and properly using spring compressors to remove the tophats from the spring assembly. What I am depicting is exactly the same process except that I don’t have springs and compressors in the mix.

Using a 17mm go thru socket and a 6mm allen head socket, I removed the top nut. The allen socket basically holds the piston in place while the go-thru socket turns the top nut. Because you will be hacking the OEM strut anyway, you could use vice grips or something similar to hold the piston in place and then use a standard socket on the top nut but I prefer to do it the “right” way. Having done it both ways, the $21 for the go-thru sockets was well worth the investment.

With both sockets in place, you really just squeeze the handles together to loosen the top nut.

Everything apart:

At this point I placed the strut in a vice with the bottom facing up. Koni instructs you to mark the center of the strut, center punch the hole, and then drill a 1/8” hole in the bottom of the strut. On the GR, the bottom of the housing is not a perfect circle. The tube in the middle is a perfect circle, but the section that wraps around the main tube to allow it to bolt to the rest of the suspension makes a “c” shaped wrap that can throw off your measurements. I found that if I ignored the “c” shaped metal, the exact center was at the 1” mark on the tape.

Here it is going from both angles:

I placed my punch in the location that I thought was the center and then I verified that I was 1” in from all 4 angles. At that point, I whacked it with a hammered and made my orienting mark for the drill.

Normally I would totally ignore safey and not wear safety glasses but I decided to wear them based on the fact that the struts were pressurized. Don’t put your face over the end of the strut while drilling.

I positioned the strut vertically and drilled straight down, using a 1/8” drill bit. I let the drill do the work and did not put too much downward pressure on the drill. Metal shavings built up on the bottom of the strut and then all of the sudden the bit broke through and the metal shavings went flying. No oil escaped at that point, but once you break through you can stop drilling.


The 1” measurement from the main body sides ended up being dead center.
To drain the strut I removed it from the vice and aimed the hole into the catch basin. I then pumped the piston slowly to expel the oil from the housing. After a minute or so the oil was out and the housing was ready for the next step.
Repeat for the other side and you are good to go there.

Koni next instructs you to measure the distance from the top of the insert body to the “nubs” on the side of the insert. This distance will determine how far down the OEM body you go to cut it off to allow the insert to nest into the housing.

Let me make it easy for you: The nubs are at 46mm, equating to the need to cut 40mm off of the OEM housing.

Based on that, I measured down 40mm and used masking tape to mark a ring. I checked the measurement at multiple points- 40mm all around.

Note: If you have a pipe cutter, use it. Borrow, rent, buy…whatever. Hacksawing this (with a new blade) was a PITA. My variation around the circle was about 1mm at most, but it was just a pain. Some people use a reciprocating saw (sawz-all)- which I have- but I did not want to risk making a mistake, so I took the 10 minutes to do it by hand.

Whether by hacksaw, sawz-all, or pipecutter, you end up with this:

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Last edited by phenryiv1; 03-20-2012 at 02:57 PM.
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