OK... decided on the k2rd coilovers

now what spring rate do i want... the car will be setup for auto crossing. and commuting to work (a short
commute)

here are teh springs rates i was thinking of

400F/275R - which was the original Ground control recommendation, and also mazdamotorsport.com spring rates for their supsension package stage II

375F/225R - Paul Ko default spring rate... also cymfc3s yellow car setup, apparently this is what Paul runs on his race cars

350F/225R - a few forum members are using this.

So these are the options.

I originally decided on 400F/275R
talked to Seth and he uses 375F/225R

what do i want? i want to get the setup right or as close to right as possible.

Suggestions? how does a 400F/275R handle compared to 375F/225R?

Thanks

 

If you got the shock damping then go stiff! I run 600/400 on my third gen and know of others running another 300 over that with acceptable ride quality.

Great street setup might be 550/375. If you run 18" or over wheels then back off the above spring rates a bit.

 

irun 650/ 450 on a roadrace 3rd gen. still streetable

 

woah... those are some really really stiff rates you guys are posting...

How about some of teh FC guys chime in.

 

I run the default 400/275 on my road racing FC, but I'm going to move to 500/325 and see how that works. These ERS springs are cheap enough that experimenting isn't going to set me too far back.

The 400/275 works fine with my stock front, no rear, swaybar setup, just a hint of understeer at the moment, but easily steerable by throttle. I would think this would be a bit stiff for the street though (although that might be the Delrin bushings causing the harshness)

PaulC

 

I run 550/450. Very streetable.

???Why run lower rates for larger wheels??

 

I'm certainly no expert but my guess would be the tires are shorter. Taller wheels means you'll have shorter sidewall tires and they have less deflection causing your ride to be more harsh. Running slightly lower rate springs could compensate.

Make sense?

Cory

 

Just a word of advice, I'm not sure spring rates between FD and FC are comprable because the motion ratios are different.

 

You are exactly right.

 

375 fr/ 250R and it's a bitch for long trips. but IT handles.

 

i'm running the full K2RD set up: coil-overs, camber plates, rear pillow ball mounts, etc... LOVE IT! i'm also running the 375#/225# setup. i'm going to experiement a bit, just to see. driving style determines a lot. i tend to be pretty smooth, but also tend to like my cars set up a bit loose. also running no rear sway bar. doing the bushings soon. also, if you're track tends to be a bit rough or bumpy, too tight a setup while make the car stutter/bobble, especially in turns.

good luck,

mike
RCF MotorSports

 

ah... the decisions... no! don't force me to make one.

thank u to everyone who replied.
silkworm... i want more car **** vids

especially laguna seca

 

so what is the motion ratio of FC? needed for damper revalve, thanks

 

um... what is motion ratio?

 

Motion ratio is the ratio of movement between the wheel and the shock absorber, because the suspension arm acts as a lever and gives mechanical advantage. For the sake of arguement (these numbers are not exactly right) the FC front suspension is a MacPherson design, so the spring/damper is mounted nearly at the tip, so we will call it a 1.2:1 ratio, or the wheel moves 1.2 inches for every one inch on the strut/spring. On the FD, I think the damper is mounted towards the middle of the A-arm, so the motin ratio would be something like 2:1, so the extra mechanical advantage means you need a heavier spring for the same "wheel rate" which is the spring and damper value as measured at the wheel. make sense?

 

Ah, that's interesting. I'm no longer as jelous of you FD guys. Anyone have some more concrete numbers?

I'm assuming Cheers! has done his homework so I'll ask; Why wouldn't the Tein 'HA' coilovers be better? KYB AGXs are kind of limited in their damping ability, it would seem to me that a performance damper would be a better choice?