Springs for Koni Yellow shocks?
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From: Netherlands
Springs for Koni Yellow shocks?
Hey guys,
I took the plunge and ordered a set of Koni Yellow Sport shocks and Whiteline Sway Bars for my 2003 Track with unrevised suspension.
Now I'm debating whether to go with the OEM Springs or get some aftermarket ones.
I can't drop more than maybe 0.6 inch because of speedbumps in my street so my choices are very limited. A little drop would be nice but I'm more interested in performance.
Which of the following springs will be the best choice from a performance perspective?
Stock (will probably do the springmountmod in the rear if I go with stock)
Spring rates in LBS 314/342
RSR 350Z linear springs .6”/.6”
Spring rates in LBS 345/417
Hotchkis 350Z Linear springs .6”/.8”
Spring rates in lbs 340/330
Tein H-tech 350z linear springs .3”/.2”
Spring rates in LBS 358/375
Thnx in advance.
I took the plunge and ordered a set of Koni Yellow Sport shocks and Whiteline Sway Bars for my 2003 Track with unrevised suspension.
Now I'm debating whether to go with the OEM Springs or get some aftermarket ones.
I can't drop more than maybe 0.6 inch because of speedbumps in my street so my choices are very limited. A little drop would be nice but I'm more interested in performance.
Which of the following springs will be the best choice from a performance perspective?
Stock (will probably do the springmountmod in the rear if I go with stock)
Spring rates in LBS 314/342
RSR 350Z linear springs .6”/.6”
Spring rates in LBS 345/417
Hotchkis 350Z Linear springs .6”/.8”
Spring rates in lbs 340/330
Tein H-tech 350z linear springs .3”/.2”
Spring rates in LBS 358/375
Thnx in advance.
Thread Starter
Registered User
Joined: Jun 2008
Posts: 252
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From: Netherlands
thnx for the info.
i read somewhere that the koni shocks were specifically designed for the unrevised oem springrates. the rsr rear springs are quite a lot stiffer than the oem rear springs. won't this be a problem with the valving of the rear koni shocks?
i read somewhere that the koni shocks were specifically designed for the unrevised oem springrates. the rsr rear springs are quite a lot stiffer than the oem rear springs. won't this be a problem with the valving of the rear koni shocks?
I wonder how hard these are to get... they seem to be something along the lines your looking for, Linear, aggressively sprung, plenty of ground clearence and streetable.
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
From the "other site's" spring wiki.
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
From the "other site's" spring wiki.
Or...
It's also possible that the damping of the shocks have been considerably stiffer than the unrevised stock shocks from day 1. Stock Z's have understeer and using shocks to stiffen the back was probably the original intent. (rear sway bars are not allowed in stock classes, so a stiffer spring that doesn't change ride hight, or stiffer damper are the only options.)
Last edited by Z1NONLY; Jul 11, 2010 at 10:20 AM.
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I wonder how hard these are to get... they seem to be something along the lines your looking for, Linear, aggressively sprung, plenty of ground clearence and streetable.
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
I wonder how hard these are to get... they seem to be something along the lines your looking for, Linear, aggressively sprung, plenty of ground clearence and streetable.
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
From the "other site's" spring wiki.
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
From the "other site's" spring wiki.
I tested them with Koni shocks (and a whole lot of other springs) they were poor combination for whatever reason. I pulled them and sold the springs. Owner comments with the D-spec shock and spring kit have been really good. But when matched with Koni's, the spring should be avoided. BTW, the measured drop from Tokico springs is 1"/1.5"
Last edited by Gsedan35; Jul 13, 2010 at 08:51 AM.
I wonder how hard these are to get... they seem to be something along the lines your looking for, Linear, aggressively sprung, plenty of ground clearence and streetable.
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
From the "other site's" spring wiki.
Espelir GT Springs
List Price: $280
Found Price: $225
Design: appears to be linear
F Drop: 10mm (.4in)
R Drop: 10mm (.4in)
F Stiffness: 6.9 (385)
R Stiffness: 9.2 (514)
Manufacturer: Espelir
From the "other site's" spring wiki.
http://g35driver.com/forums/brakes-s...w-updates.html
Last edited by Gsedan35; Jul 13, 2010 at 09:00 AM.
375/375 (Tokico D-spec springs, avoid as mentioned above)
358/375 (Tein h-tech)
358/427 (Tein H-tech fronts, oem revised rear)
448/342 (Tein tapered front, unrevised oem rear on cut down upper seat)
448/427 (Tein taperd front, revised oem rear on cut down upper seat, this is the setup I liked most of all, shocks were resold with this setup to a member that uses them for autocross)
560/427 (Koni coilover conversion, Bc Racing pillowball upper mount, revised oem rear on cut down upper spring seat)
560/500 (Koni coilover conversion, TomsMotorsport coilover spring/adjustable seat)
The 560lbs front spring, worked, but wasn't the best choice. in the rear the 500lbs spring worked, but also wasn't the best choice. Based on experience, I do not recommend beyond 448lbs in the front and beyond 450lbs in the rear without revalving the shocks.
This platforms anti dive and anti squat geometry is why a lot of setups do not use high rear rate bias. Which my own testing does support.
Koni's R&D concentrated on getting the most out of the car. The 350EVO Grand Am team that was assisting them, did make public comments about what Koni thought was wrong with the 03 shocks as did my on converstion with Jason and Grant Lee inside Koni. With less compression damping and adjustble rebound, the shocks have the range to cover the RS-R spring rates. I have shock dyno's for both shocks, though at this time I cannot locate my 03 oem front dyno's. That and my own testing is where I'm comming from.
I tested them with Koni shocks (and a whole lot of other springs) they were poor combination for whatever reason. I pulled them and sold the springs. Owner comments with the D-spec shock and spring kit have been really good. But when matched with Koni's, the spring should be avoided. BTW, the measured drop from Tokico springs is 1"/1.5"
Thread Starter
Registered User
Joined: Jun 2008
Posts: 252
Likes: 0
From: Netherlands
just got a very nice reply from lee grimes at koni north america about what year springs (unrevised/revised) work best with koni shocks:
Thank you for your interest in KONI Sport shocks for your 350Z. Although Nissan did make the running change on the spring rate, either of those springs or really any reasonably streetable performance aftermarket lowering springs will be just fine with the KONI Sports. As you increase the spring rate on a car, you typically need to increase the amount of rebound damping however the KONI Sport shocks are adjustable for rebound damping. Since the KONI damper has a very wide range of adjustment (twice as firm at the max setting as it is at the min setting), there is an extremely wide range of spring rates that these dampers will be compatible with.
So whichever of these two springs that you decide to use, you can easily adjust the shocks to suit their needs. It would not surprise me if the later, higher rate springs might need a bit higher rebound adjustment than the lower one. This is something that you as the driver can decide what feels best for your preferences on the roads that you drive and however you use the car. Although this change in rate might be a bit more of a challenge for a non-adjustable shock, the adjustable KONI Sport shock will let you easily tune to get your preference regardless of which spring that you go with.
So whichever of these two springs that you decide to use, you can easily adjust the shocks to suit their needs. It would not surprise me if the later, higher rate springs might need a bit higher rebound adjustment than the lower one. This is something that you as the driver can decide what feels best for your preferences on the roads that you drive and however you use the car. Although this change in rate might be a bit more of a challenge for a non-adjustable shock, the adjustable KONI Sport shock will let you easily tune to get your preference regardless of which spring that you go with.
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