I want to build a set of coilovers with Koni Yellows. Would it be possible to run 2.5" springs and perches in the rear stock lockation? It looks like every OEM style kit uses a 5 or 5.5" spring, which is harder + more expensive to get perches for.

 

Yea. Early bc kits came with standard 2.5 dia springs 7 in in length. I had that kit paired with swifts. I believe they still have that option if you upgrade to swift springs as thats swifts standard 60-70mm dia in variable lengths
Just call BC tell them you want to upgrade your standard kit to swift and you need the rear conversion which consist of the gold rear lower hat and the top black hat which has the adjustments on it for ride height. They should sell it to you.

Keep us posted

 

Did you have any noise issues with that kit? Once I piece everything together I will definitely make a thread.

 

I did not.

 

No need to ask- they sell them:

https://store.bcracing-na.com/linear...ter-p5720.aspx

They also sell the collars (at least that's what I think these are):

https://store.bcracing-na.com/rear-h...37x-p4916.aspx

We're in business! So just to price this all out:

Koni Yellows - $1000 (+/-100)
Set of 500/450lb 8Lx2.5"ID springs - $220
Front Koni sleeve kit- $70
Rear BC-Racing 2.5"ID sleeve kit- ~$150

$1440 altogether.... a little rough as Konis for my Hondas were half the price, but it is what it is.

 

Fortune auto also has a swift upgrade
Maybe price out their rear setup.

 

Just thinking about it i have an extra pair on 7 inch springs 2.5 dia
12k though.
Lmk ill let em go cheap!

 

Doesn't look like FA sells the upgrade parts separately. I'm looking to go 9K all around or 9K/8K

 

So the rears are easy. What are you doing for the fronts?

 

For the fronts, all 30 series Koni shocks can use a threaded sleeve kit with a special circlip:

Koni 30-0000-0005: Threaded Spring Perch Sleeve For 50mm and 30 Series | JEGS

So the fronts are even easier.

 

Interested seeing how this ends up, hopefully you can source everything without too much guesswork, definitely a worthwhile project!

 

Covers the bottom spring perch. What about the top?

 

Stock top hats. Standard practice for lower end coilovers.
Only real guesswork will be the spring rates; but I think 9K/8K is a pretty safe bet for a mildly lowered street G. I'm at 27.75/27.5 F/R now, and I'm going to run tires that are 26.6" tall all around. I'd like to tuck a little bit so hopefully I'll be at ~1.25-1.5" lower than stock, which combined with the Koni's shortened shafts should make everything line up perfectly. Hopefully I won't even need a camber kit....

 

Found a pic of your exact plan on a 350z:




Super interested in this setup myself...

 

Oooo.... link? Any pics of the rear?