Spring Rate Choices
 

Planing to purchase a set of OEM style coils w/ swift springs upgrade. Was told swifts ride slightly softer. Rears are set to 11kg. Fronts have the option of 13k/12k. Any opinions? Mostly street car w/ occasional/rare track. Attempted to look around but not many threads talk about the difference between front 13k/12k front spring rates. Any input would be appreciated.

Stiffer is better for the front. A lot of track and autox guys will actually run 1000 lb/in or more in the front. I personally run 1100 lb/in springs in the front. If the shocks are valved correctly for the spring rate, a stiff spring isn't really that bad on the street.

Would 13kg fronts create oversteer as compared to 12kg fronts w/ 11kg rears? Thanks.

Stiffer front springs will tend more towards understeer.

I went with BC's newer DR series with custom valving and 18/14k swift springs. It's not nearly as bad as I thought it would be but it's definitely stiff. I can't see 13/11 being all too bad.

I just got 12k/10k combo I think that's a perfect setup not too stiff I was told but not too soft either

I am running Fortune Auto 500's 13k front and 10k rear. The ride is a little on the stiff side but no where near harsh. I love the setup!

Also considering 13k or 12k swift fronts / 11k switch rears OEM style coils. Subbed

Popular choice is 12k/11k. Though since you are totally changing your setup, 1k difference in the front isnt that much. But in the end it all depends on driving style. Some people get a bigger sway bar in the rear to match up with the overly stiff front springs. Just depends if you want more or less understeer.

BC Racing BR or DR. Fortune Autos new 500s all are great choices with a set of Swift Coilover springs. I can get you great pricing on all of those if interested.

I just got this setup, with 14k/10k and it seems stiff as hell, almost feels static and the only absorption i'm getting is from tires, is it possible that installer set preload to tight? Changing stiffness setting on them only changes how much bouncy they are, which is better then 100% stiff i guess. If fronts are too stiff then i'd imagine that rear would feel ok at 10 but even rear is very stiff

What is the setting on your shocks? Compression, Rebound?

I am at 14k front and 12k rear and my rebound is 12 clicks up front and 8 clicks in the back for street. If you go to FA website (https://fortune-auto.com/service/) they have instructions on how to set the preload as you stated your installer may have adjust the preload too much. If you decide that your spring rates are to much let me know as I have Swift spring in 12k that I am willing to let go.

The main thing to consider when choosing spring rates is the tire you will be running and the surface that you drive on most regularly. The springs job is to make sure the tires stay in contact with the road. A lot of the times, a more compliant suspension will be faster than one that is overly stiff. Just food for thought. I would stay away from getting into the 2.3+ hz range unless I was running r compounds on a well groomed track, especially if The car is dual purpose.

is there a way to set this? to me it seems that there is no/very little compression. The only way for me to adjust is the clicks on top, which i have set at 5 clicks from soft, which makes it pretty bouncy but the only way for me to drive, any more stiff and i'm hitting the roof with my head when i hit a bump, i'm not even joking, my butt is doing the compression.

Ok i read the FA install guide doc and preload seems to be very important for compression, so i will watch him redo it to make sure its right. Thanks fam

Sounds like you have only on adjustment on you dampers meaning you have single adjustable dampers. On most all single adjust dampers, that one adjustment is almost always rebound.

A few things you need to keep in mind.

1. Your spring rate is what determines the force it takes to compress the damper a given amount. The damper adjustment has no affect on this.

2. On linear spring rate springs the force to compress the spring from 0-1 inch and 1-2 inches is the same force.

3. Most spring manufactures have a optimal spring operating range that provides the listed spring rate most accurately. I.E. between 1-2.5 inches of compression, a 1000 lb/in spring is +/-10 lb/in while outside that range it may be +/-50 lb/in.

4. The rebound (and compression that yours don't have) control the speed at which the damper moves in compression and expansion based on the spring forces being applied.

Also if you think your 14k springs are stiff you should feel what my car is like with 24k springs in the front.

Thats why i'm thinking something is not right...worst case i'll get new springs or assist springs

How did you like it on the Dragon and around Fontana?

It was a blast and a great time. Met a bunch of forum brothers and sisters. Took a few for a ride up Hell Bender and the Dragon. I love them both with Hell Bender being my favorite. I drove my car from Nashville to Fontana Village with the setup I stated earlier and the cars ride was very compliant. On the Dragon she was even more settled so at speed. I'm not sure why some Zs seem to be unruly on coil overs.

I am on 12k/10k swift springs with Aragosta coilovers. 12k fronts are OK. I have wished they were 13k's fronts and 11k rear. I am a little more than half way on the dampers to get the bounce/rebound out of the car at speed. If I do any aero improvements an upgrade will be mandatory. Another thing I have noticed is when it is hot outside, I had to increase the damper rebound a click or two front and rear.

my friend grew up in Knoxville and came up to zdayz while we were there and we were talking we both tend to like hellbender a bit better. it feels more like a track where the dragon feels more like an autocross.

:iagree::iagree::iagree:

I may or may not have scared a Yokohama engineer on the drive up HB and the dragon... lol