Spring Rate Choices

Z34VQ · 12-31-2016, 10:09 PM

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.

gomer_110 · 12-31-2016, 10:16 PM

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.

Z34VQ · 12-31-2016, 10:21 PM

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

gomer_110 · 12-31-2016, 10:36 PM

Stiffer front springs will tend more towards understeer.

PharmDZ · 01-01-2017, 11:34 AM

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.

JerryDeluxe · 01-01-2017, 12:32 PM

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

Hotrodz · 01-02-2017, 08:16 PM

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!

ColemanLee09 · 01-07-2017, 11:46 PM

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

KamiSpeed · 01-10-2017, 04:34 PM

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.

scope22 · 05-21-2018, 02:40 PM

Quote:

Originally Posted by Hotrodz

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!

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

Rusty · 05-22-2018, 01:30 AM

Quote:

Originally Posted by scope22

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?

Hotrodz · 05-22-2018, 08:57 AM

Quote:

Originally Posted by scope22

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

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.

Brendan · 05-22-2018, 10:00 AM

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.

scope22 · 05-22-2018, 10:13 AM

Quote:

Originally Posted by Rusty

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

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.

scope22 · 05-22-2018, 10:23 AM

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

12-31-2016, 10:09 PM	#1 (permalink)
Z34VQ Base Member Join Date: Jun 2016 Location: CA Posts: 12 Drives: 370z Rep Power: 9	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.

12-31-2016, 10:16 PM	#2 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	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. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

12-31-2016, 10:36 PM	#4 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	Stiffer front springs will tend more towards understeer. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

01-01-2017, 11:34 AM	#5 (permalink)
PharmDZ Track Member Join Date: Jul 2012 Location: New Jersey Posts: 997 Drives: 11 Nissan 370Z BS M6 Rep Power: 14	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. KamiSpeed likes this.

01-01-2017, 12:32 PM	#6 (permalink)
JerryDeluxe Enthusiast Member Join Date: Aug 2015 Location: San Diego, Ca Posts: 277 Drives: 16' 370z auto sport Rep Power: 10076	I just got 12k/10k combo I think that's a perfect setup not too stiff I was told but not too soft either __________________ Swift Spec R/KONI Yellow Shocks, SSR Executor CV01, GThaus, CF Lipkit, CF Hood/Fenders

12-31-2016, 10:21 PM	#3 (permalink)
Z34VQ Base Member Join Date: Jun 2016 Location: CA Posts: 12 Drives: 370z Rep Power: 9	Would 13kg fronts create oversteer as compared to 12kg fronts w/ 11kg rears? Thanks.

01-02-2017, 08:16 PM	#7 (permalink)
Hotrodz A True Z Fanatic Join Date: Aug 2012 Location: NW, AZ Posts: 9,330 Drives: 10 Nissan 370z Nismo Rep Power: 2684385	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! __________________ *Fast Intentions TT Installed and Tuned by Seb at SpecialtyZ 610whp 560tq:\|Fast Intentions 3" TT-TDX*\|SpecialtyZ/Fast Intentions 72 Row Oil Cooler\|SZ 6 Puck Clutch & Flywheel\|3GsCustoms\|Z1\|Wavetrac\|Hotchkis\|Whiteline \|Blitz\|Fortune Auto 500\|Fujimura\|SPL\|H&R\|TK\|TWM\|RPM Rollbar\|Sparco\|Next Level Performance\|TrackSpec\|AeroFlow Dynamics\|Pioneer\|

01-07-2017, 11:46 PM	#8 (permalink)
ColemanLee09 Base Member Join Date: Feb 2015 Location: NorCal Posts: 149 Drives: Z34 Rep Power: 10	Also considering 13k or 12k swift fronts / 11k switch rears OEM style coils. Subbed __________________ 09 370Z Sport 6MT Chicane Yellow Powertrix \| Swift \| SPL \| SPC \| Fast Intentions \| Berks \| Stillen \| Z1 \| Setrab \| Mocal \| H&R \| TWM \| RJM \| Sparco \| Buddy Club \| Tanabe \| GaleForce \| EVO-R \| ZSpeed \| Pioneer

01-10-2017, 04:34 PM	#9 (permalink)
KamiSpeed A True Z Fanatic Join Date: Feb 2011 Location: Orlando, FL Posts: 5,888 Drives: 09 370z Rep Power: 25	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. PharmDZ, Hotrodz and Themitchman3 like this. __________________ KAMISPEED \| SHOP 370Z PERFORMANCE PARTS & MODS \| SUPPORT@KAMISPEED.COM KAMI SPEED REVIEWS \| FINANCE YOUR PARTS WITH US \| MILITARY & FIRST RESPONDERS PRE-ORDER DEPOSIT PROGRAM \| HKS MASTER SELLER

05-22-2018, 10:00 AM	#13 (permalink)
Brendan Track Member Join Date: Apr 2013 Location: Colorado Posts: 642 Drives: Poor man's Porsche Rep Power: 542	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.

05-22-2018, 10:23 AM	#15 (permalink)
scope22 A True Z Fanatic Join Date: Apr 2012 Location: Roswell, GA Posts: 1,179 Drives: wife crazy Rep Power: 55	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 Hotrodz likes this. Last edited by scope22; 05-23-2018 at 06:59 AM.

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