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Spring rate recommendations for coil overs and Koni shock ?'s on an FC.

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Old 04-16-02, 11:06 PM
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Spring rate recommendations for coil overs and Koni shock ?'s on an FC.

1987 RX-7:

I am going for a 70% street car and 30% track car. Still yet to purchase coilovers and shocks..... but I'm leaning towards K2RD.com coilover kit and caster/camber plate setup and then buy Koni's from Ground Control.

What spring rates are you guys running up front/rear?
I hear 400lb up front and 275lb rear is the norm. I want the car to handle like a ****.

What Koni shocks would you guys recommend with the coil over kit?

Is a strut tower brace worth the cost and how much stiffer does the car feel?

-GNX7
Old 04-18-02, 05:01 AM
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400 up in front to a little to harsh for 70% street use try like mid low 300's
Old 04-18-02, 10:56 AM
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I have 450/375 koni yellow with GC kit... on 18's.
Ofcourse this is FD...

I didn't find it overly harsh for the street..I do have a high tolerance
Old 04-18-02, 11:02 AM
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The k2rd kit comes with 350Front and 225 rear, I believe. I'm very happy with the kit, Paul at k2rd is great to talk to on the phone and his products are nicely made. The camber plate is a much better and the GC unit, IMO... k2rd's kit puts all the shock bound load on metal plates in compression. The GC kit puts the bound load on four bolts (in tension!) tsk tsk, ground control.
Old 04-18-02, 02:32 PM
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Anyone else running coil overs on their FC?

I need some other comparison numbers. I think I'm leaning towards 375lb front and 250lb rear running the K2RD coil over kit and AGX's.

-GNX7
Old 04-18-02, 02:53 PM
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You got a number on how much that GN engine weighs?
I'm running the "old" GC set-up at 400 front/275 rear...



-Ted
Old 04-18-02, 11:02 PM
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Ted,

With those spring rates how do you feel the car is as far as stiffness? If you were to do it over again would you get less aggressive front springs?

I imagine my car will weigh 2730-2750lbs in street trim with spare tire etc.

What is the corner weighting of a stock FC?

GNX7

I am looking at getting either 400/375 fronts and 275/250 rear.... I spoke with Jay at Ground Control and he said they rarely go over 400lb springs in the front even on V8 Z car conversions.

Someone has had to have corner weighed their FC before.
Old 04-18-02, 11:45 PM
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the k2rd camber plates won't fit on konis. different shock sizes. if you want a koni/ coil over kit check out the ITS kit at www.mazdamotorsports.com

I have the k2rd kit with 350/225 and it seems good for street. I don't think I'd want to use the agx's on the track though. I hear they don't hold up.
Old 04-19-02, 08:42 AM
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Don't hold up? I heard of a guy on here who was testing prototype camber plates for k2rd and whacked a curb so hard that he BENT the camber plate, but didn't blow the shock. Besides, even if you did blow the shock, you can buy 3 agx's for the price of on koni... well, two anyway
Old 04-19-02, 08:07 PM
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it's cause they are gas. I think they just get too hot and wear out really fast with track abuse. where as I think konis are oil
Old 04-19-02, 08:48 PM
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Originally posted by gnx7
With those spring rates how do you feel the car is as far as stiffness? If you were to do it over again would you get less aggressive front springs?
Right now, they are about "perfect" with the Tokico Illuminas I run.&nbsp You need to keep in mind that the springs need to work with the dampers you run.&nbsp An overly high spring rate is just going to over-oscillate the dampers, and you end up with a very unstable vehicle!&nbsp It really depends on what kinda dampers you're going to run.&nbsp If you're going with any of the stock replacements (KYB AGX or Tokico Illuminas), 400/275 is about as stiff as you can go without over-oscillating the dampers.&nbsp If you're going with Koni's (which can go slightly stiffer), you can move up to 450 or even 500 up front.


I imagine my car will weigh 2730-2750lbs in street trim with spare tire etc.
That doesn't tell me much... I need to know front to back weight ratios...&nbsp The good thing is that this is very close to a stock 13B weight, so the 400/275 should work fine.&nbsp If you need to change the springs, it's only $100-$150 per pair - not too bad.


What is the corner weighting of a stock FC?
I see you asking this question, but you have no idea what you're trying to accomplish with corner weighting?&nbsp I'm not insulting you or anything, so please don't take this the wrong way.&nbsp When you corner weight the car, you're looking for *identical* diagonal weights.&nbsp So add LF/RR should equal to RF/LR - this has nothing to do with absolute numbers per corner, per se.&nbsp If you can get the diagonals to match each other, that's your target!



-Ted
Old 04-23-02, 07:47 PM
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Ted-

400/275 it is. I'm going with the AGX's as I have a tight budget. Should be good enuf for me considering I've never owned a car with modified suspension.

Thanks for everyone's input.

GNX7
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