I am running the typical OTS GC/Koni yellow combo. the rates are 550lbs rear, and 430lbs front.

It just isnt stiff enough. i dont need the car to ride like a skateboard, but i just rocks back and forth during accel and decel. i need to bump it up a little bit.




what can the Koni yellows handle? the reason i ask, is because i have a set of mugen springs in front of me. they are 18k and 20k. more than stiff enough, but are they too stiff for the koni yellows OTS? and, you guys reckon these will slide onto the GC collars?

 

If the Mugen springs are the same 2.5" ID that the ERS included with GC sleeves are, they'll fit.

To convert lbs/in into kg/mm, I use Google.
http://www.google.com/search?q=550+lbs%2Fin+in+kg%2Fmm
550 lbs/in ~= 9.8 kg/mm
430 lbs/in ~= 7.7 kg/mm

18k and 20k would be insane. At 550 lbs/in, you're already at about the limit of what a Koni Sport can handle (if not already past it, according to some people).

At this point, you sure you aren't just feeling bushing slop and tire sidewall flex as squat / dive? Those are already very stiff rates for a street car. Of course, if its a track car, revalved shocks and those 1,000 lbs/in and 1,100 lbs/in springs (18 and 20 kg/mm) would be a decent start...

 

typo. they are 20k and 24k

no, the car is just wishy washy. i even considered throwing the 550s up front and buying a pair of 600 for the rear.

im getting ready to drop a K24/k20 frank (~300whp NA) which is going to weight the front down a little more and going to cause serious squat issues out back.

i race gymkana with the thing. but its registered and gets driven there and back.

there are a set of spirit N1 spec full coils (high end ones with pillow *****) layin around that i have, one of them is blown. i might just have them rebuilt. love the konis, but its def. not a heavy duty set up. good to send your daughter off to college with though.

 

any spring with a springrate of over 550 lbs will have to get the struts re valved.

 

i looked around the net on some of the miata site (where dumpted ride heightz and loffsetz yo! isnt the main focus) and have yet to find a single person who blew their yellows with too high a rate.

not saying it wont happen. we know it will. but, how can anyone put an exact poundage on when it will let go? unless of course it is internet here-say.

 

I wouldn't worry about blowing the Konis. In fact, people have reported here on HT that 700 lbs/in springs haven't blown theirs.

What I would worry about is the ability of the shock to adequately damp the spring's motion. Give the choice between correctly damped (or close to it) and softer rates vs. stiffer rates and an under damped suspension, I'd go with the former (easier to drive, better ride quality, less likely to have a sudden traction issues over uneven pavement).

Besides, if you ever do blow them from running too stiff of a rate, then you can always get them revalved.

 

you know what, youre right. they might not blow, but it'd be bouncy.

 

We have had several race cars run the normal yellows with a ton of spring. It isn't the best thing, but the world wont end. These cars ended up being faster then they were with there previous setups (the high end Tein remote resivior road race shocks).

Before you go switch around springs though i'd try turning the rebond (the adjustment ****) all the way up in front, and then in back.

This should help with what you are feeling.

 

i did the rebound first. car just feels sooooo wishy washy. ive got the bias between F/R spring rates about right, i just need to go up on both ends.

 

Dang I don't see how you could possibly feel any body roll/squat/dive with rates that high. Damn, do you have a ton of weight in your car or something?

I had 380/450 f/r and it was stiff as fack! Almost zero dive and squat, handled bad@$$ to be sure, but I just couldn't handle it on my 100-mile daily commute.

24k = 1350 lb/in = oh.... my... coccyx