Thread: B13 CSK Research Thread - OE diameter springs

If you still want those B15 inserts, I'm interested in a trade as well. Some NEW rear KYB AGX's would do. Last time I checked I could find a pair for $228. But I bet you can find some cheaper. The inserts alone cost me 232 euros ($310)) XD

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Returned your PM.

So, are you still gonna try the yellows in the rear?

Maybe I should just man up, try to install them, see if I like them, and if not, switch to AGXs.

I am in the same boat, and need to finish this project before the convention. What should I do? what did you guys end up doing?

I want the b15 koni yellows in the back but if they are too stiff I will settle for an AGX setup. Is there no way to use the b15 koni yellow REAR inserts in the rear of the b13? What if I cut and re-weld the spring perch in the correct location?

Will, some are telling me to try the B15 struts in the rear, others have made it very clear that they believe they are too stiff for Hyperco or RM springs.

this has led to my delay in getting this done. i'm going to shorten my struts in the rear, just not as much as Overkill did, i think they shortened 52mm iirc, and we only need to shorten 1 inch.

i'm also going to go with B13 koni red rear inserts for now. i think i have the last two in existance (that were never used anyway)

you can have the b15 inserts revalved to something not quite so stiff.. bit that costs cash... about $200 per strut iirc.

i'm about to start this back up, getting really tired of my broken rear struts.. but hey, work is only 1.3 miles away...

I have been researching this extensively and come to the conclusion that there is a TON of bad info in this and many other threads.

here is some info comparing the b13 NX, b13 SE-R, and B15 spec-v:

NX2000

curb weight = 2,509

Weight dist, f/r, %....63/37

rear weight = 928.33

front weight 1580.67


B13 SE-R

curb weight = 2414

weight distribution 62/38

front weight = 1496.68

rear weight = 917.32


B15 sentra SE-R spec-v

Curb Weight:2,710 lbs

Weight Distribution F/R :62/38

stock spring rates = 154F/247R 2002+ Spec V

front weight = 1680.2

rear weight = 1029.8


Hypercoil springs

300lb front / 200lb rear
1" to 1 1/2" drop




So, there is little or no reason to be concerned with the damping of the rear struts in the NX2000, and the rear damping in the b13 SE-R may be a little high, but the rear weight difference is only about 200lbs. I feel the danger of over damping with the b15 inserts may be overstated.


Another thing, I keep finding that the f/r rates for the spec-v are 154F/247R, which makes no sense when every other b chassis car I find has much higher front than rear spring rates. Spring rate impacts the required expansion damping and if these rates are correct (which I suspect they are not, even though they are all over the net), then we should not be using the b15 struts in the front or rear at all...

I don't think spring rates of the B13 were nearly as stiff as the spring rates of the B15. Though I don't have the info of the B15 spring rates, and the numbers you found do seem pretty low.

anyway, here's some correct data on rebound & compression of the inserts that I got directly from a Koni sales rep:

so i finally got off my ass and worked on my car a little today.

i ended up going with Koni recommended "reds" for the rear. i don't think they have anymore in stock.

old, suspected blown strut




new



side by side comparison:

my strut housings are getting and blasted and painted at a local body shop

They will be ready for pick up on Friday, I will post some pics..

Hey Will, could you point out the TON of bad info in this thread that hasn't already been corrected?

I too have done extensive research on this...