THSCC Forums

So I installed some Koni inserts awhile back. Stock spring rate is around 150 lb/in front & rear, and I'm going to be doubling that. Only rebound is adjustable, and can reportedly handle up to 400 lb/in springs, so that should be okay. But will the stock compression damping work well with double the spring rate, or will the Konis need to be altered? The way I see it is that the stiffer spring will compress less easily, and shouldn't need as much compression damping. But when it does compress, it'll be pushing back twice as hard, so that's why the extra rebound damping is needed. How far off am I?

And somebody please answer the following question... if the Konis only adjust rebound, why is it harder to compress the suspension when they're stiffened up? Seems like the suspension would compress normally, then stay there longer.

I thought the Koni Sport (yellow) shocks "single" adjustment altered both compression and rebound, wheras the "double adjustment" shocks allow one to adjust compression and rebound separately.

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Marvin McBride
Spec Miata #62

Kevin,

In regard to damping with stiffer springs. I bought some racing Konis valved by Koni for specific spring rates. Then I decided to double the spring rates. Work great with approximately the same rebound and bump settings used with the design spring rates. Chances are that you will not be "underdamped" and with the stiffer springs you won't need the shocks to control body roll, etc. as much as you did with softer springs.

Edit to add: When I first installed the double rate springs I backed the bump settings to zero. Didn't work (wheel hop over a series of bumps) so I went back to the previous mid-range bump settings.

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Dick Rasmussen

FS 50 2018 Mustang GT

FYI

Per my Koni catalog: SA Koni shocks, including Yellows, adjust rebound. Compression is not adjustable.

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Dick Rasmussen

FS 50 2018 Mustang GT

Yellows have more agressive dampening than comparable reds; the only adjustment in the SAs are for rebound.

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Has no responsibility whatsoever.

While we are talking springs and shocks/dampers....

When I first purchased my springs and shocks (Koni SA) from ground control I was having a hard time getting suggestions on what spring rates to use. GC suggested 400f/300r. That is what I have. However I have had a number of people say that I should have installed them the other way around with the higher rates in the rear.

I can...

* Swap them.
* Leave as is in front, but get higher rates in rear from GC (450 or 500)

This is my street car that I drive daily and I would be OK personally with higher spring rates. But I also had someone say that with the higher rates it would wear out the Koni SA faster.

I have had the Koni on the car for about two years now. My questions are...

* How will I know when they need to be rebuilt?
* Could they be worn out now and I not know it?
* Should I swap and use overall lower spring rates (extend life of shocks) or get the stiffer rear and rebuild as needed.

Right now I am heavily leaning toward swapping them (plus realignment) to see how it feels before I start buying stuff and bumping up the rates.

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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

Richard, I would do what you are planning on doing and swap them out for feel. If you can do this yourself, the cost is only an alignment. As for the Koni's, when you pull them, unless they are leaking (fluid around seals) or the adjustment no longer works, they should be ok. I will probably freshen mine about every year, just because I'm running high rates, it's not too expensive to do, and the car isn't my daily driver, so a 6 - 8 week down time isn't a problem - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Kevin, post this on Honda-tech in the roadracing/autox forum. Lee Grimes from Koni will respond with the answers to all your questions