As a result of request from forum members I am posting this new thread to discuss and clarify the options you have with Koni's on B13/14/15.
First some background.
http://www.sr20forum.com/showthread.php?t=185316
Post 79 of Shawn's "most excellent suspenionsion thread" says
Quote:
Originally Posted by 98sr20ve
CSK info
CSK need to be choosen based on the type of spring you want to use. If you are using oem style spring (any spring that does not use a coilover sleeve) then you have to use the Off The Shelf (OTS) B13 Koni unit for the rear of the B13. With drop springs or coilovers you can use the OTS B13 or B15 unit up front. B13 front unit is a touch shorter then the B15 front but does not have external adjustment while on the car. B15 front unit has external adjustment and those can be adjusted with out removing the strut. If you want to use the OTS Koni Maxima front unit you need to use it with coilovers. To use that you need to use any number of oem nissan housings. Maxima, Altima all have some housings that will work. They need to be a 2 inch O.D. to work.
Spring Rates
B13 Fronts =350
B14 Fronts = 400+ (not as short as the B13, I use it as a rear with the Maxima insert on the B13 with coilovers only).
B15 Fronts 400-450 (450 is the limit, 400 is better).
Maxima Fronts= 450+
Dampening is very personal. Some people my like the B13 fronts with higher then 350 some people would not.
Adjustability
Only the B15 front is exteranlly adjustable. All Konis commonly used wtih the B cars are adjustable, you just must remove the spring to do it.
If you update this into your post please give me credit so I don't have to reanswer a bunch of PM's about this all over again when people wonder if it's what I recommend. Also, can you include this statement as well
"B14-15 have to use OTS non-shortened units in the rear of the car. They are shocks not sturts and are sold complete. They are not inserts that can be relativly easily shortened. Koni can shorten them for you."
You should really expand you thread to include some B14-15 stuff. A lot of it's pretty universal. Plus, that statement alone would put all the Koni OTS info in one place.
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http://www.sr20forum.com/showthread.php?t=170794
He reposted most of my post the the Koni section on the first page as well.
This thread tells you how to do it yourself.
http://www.sr20forum.com/showthread.php?t=26211
With all that said I will try to break it down for each chassis what options you have for using Koni's and making/buying CSK for yourself. You need to understand that the Koni's offered for the B13-15 are inserts. They are not total replacement struts. The advantage of this is that by ignoring the directions that Koni provides (at your own risk) you can lower the insert in the oem housing and effectivly shorten your own struts. Look at the pictures posted in the How To section and you will see the insert with the nub cut off the bottom. Thats the easy way but it's not as short. I will go into more detail on this in the future.
Options for each chassis.
First a little background. The B13 comes with the shortest OEM struts of any of the three cars we are going to discuss. As a result the B13 Koni insert for the B13 is the shortest of them all. Everyone assumed because of this that the AGX for the B13 was also shorter then the AGX for the B14. Eric96ser posted pictures to show that when using AGX's there is only a small amount of difference between the B13/14. Basically they are about 13.5 inch's long.
Front Options B13-14-15
Koni B13 Fronts- Shortest unit you can use in the B13 OEM housing. It's just about 12 inch's long. Its the weakest of all the options. I don't use it very much any longer. I recommend the Spec V insert instead. Nothing wrong with this option. It’s just for $20 more you get the Spec V insert which is a better buy in my opinion. Max spring rate is in the 325# range
Koni Spec V insert- Just about 1/8 longer then the B13 insert. Its about 30+% stiffer and this unit is exteranl adjustable thru the hood. You sometimes need a spacer under the top nut to get it to properly tighten down on the B13-14 tophats. This is the unit to use on a B13-14 if you are using lowering springs or want easy external adjustment. It is also great for use with Coilover Sleeves like Ground Control. Max Spring rate is in the 400# range.
92 Maxima insert- This unit when installed by me is under 11.5 long. It is also the strongest option listed. It can handle 450# springs easily. It is not externally adjustable and it requires you to buy Maxima or Altima housings. They just need to have the right lower bolt spacing and have a 2 inch O.D. You will probably need to cut most of the oem perch off and bend the remaining ears out to lower the perch. In some cases you have to weld on a new perch. You can buy a perch from Ground Control or make one out of steel with a big washer or use a plasma cutter on some scrap steel.
Rear Option B13
Standard Koni B13 rears- This is your only option for those running lowering springs (such as Hyperco and Road Magnet) on a B13. You can not use any other Koni in the back on a B13 with those lowering springs. It is 1 inch shorter then oem standard so you don’t even need to do any tricks to lower the things. Just install them as the instructions say. They work fine with lowering springs but I don’t pair them with the Maxima fronts. Max spring rate is in the 275# range. Another option for those with lowering spring is to just use AGX's in the back with Koni in the front. The front is the place that we have major travel issue, the rear is not as big of a deal. With a under 1 inch drop you are fine in the back with AGX's with Hyperco. I have no experiance with Road Magnet springs.
B14 Koni Fronts installed into OEM B13 rear housings- This is what I pair with the Maxima fronts on a B13. This unit is strong and will easily handle your 400# plus rears. It is not externally adjustable. It require a really long bolt (grade 8) a bunch of spacers and it has to be spaced up to be the right height in the back for the GC setups. It can not be used with lowering springs. I struggle with recommending this setup as you need to install these properly or you can really have some issues. Max spring rate is in the 400+ range.
Spec V fronts installed in OEM B13 rear housings- Same info as above. Just externally adjustable and not as strong as the B14 front. Max spring rate is same as front. Around 400#.
B13 Issues in the back.
If you are running the OEM rear bar you need to use the OEM rear housing to have the swaybar mount. Not all housings have the rear swaybar mount but many do. If you use the oem housing and later run the progress bar you may run into clearance issues. The bolt on the bottom of the Koni may hit the bar. You can usually adjust the bar to solve this issue. If you are using the Progress bar already just skip the OEM rear housings and run some front housings in the back. They have a lot of clearance for the swaybar and don’t require as many hops to get the Spec V and B14 inserts to run at the right length because the housing places the bottom of the insert higher from the start.
Issues with all Koni installs.
None of the Nissan housings are the same. Its annoying. I have had the L/R varience on the same car (my car) be so great that the L side was loose and the right was perfect. I have seen one side of a maxima unit slide in perfect and the other side has this weird stamp /bulge that prevents the unit from seating the last 1 inch. You just need to be a problem solver sometimes. You can always post your problem and I will help you. I don’t want it done thru a PM because then no one else learns the information.
Spring rate issues. I list my recommendations. Everyone is different. Some may find they handle a strong spring, some may think they are underdampened at my posted limit. Knock 10% off to be safer if you like.
VVL 
