Quote:
Originally Posted by Bayareabrz
Thanks tcoat. I was basically trying to make sure what I purchased were from a brz and not an frs. Since they are complete with tophats and springs I was hoping to just do a full swap. My worry is i'll end up with frs springs where I prefer to keep brz rates. I was hoping it might be documented somewhere which color dots on on which springs just so I'd be sure.
Hopefully its all good!
|
FYI, you can mix and match springs. But you need to know what you are getting at the end.
Here is a spring rate table.
2013 brz F2.7k R3.5k
2013 FRs F2.3k R 3.8k
Both have 18mm front sway and 14mm rear
The 2017 model have unpublished OE spring rates. But based on the comparison we can estimate the ball park range.
TRD F3.5k R 5.8K 15mm drop
STI F ~2.9K R ~3.7k 15mm drop progresssive springs
RCE Y F 4.5k R4.5K .8” drop
RS-R soft F2.8K R 4.5K .5” drop
2017 also had a swaybar change to 18mm front and 15mm rear.
One thing you may notice is that STI spring rate is very close to the 10-15% spring rate reduction as observed from most published article. I.e FRS rear is 3.8k, take 10% is around 3.4~3.5k, very similar to initial BRZ rate.
With this being said,
If you switch from pre 2016 BRZ suspension springs to 2017 suspension springs only, the handeling would change by being slightly more oversteer when throttling out of a corner. However the rear will feel more sloppy compared to current 2017 due to smaller rear swaybar. Once you increase the rear swaybar from 14mm solid to 15mm solid, the rear end of car should feel a bit tighter/stiffer and more compliant.
PS for a better analysis of front and rear spring balance. We have to account for motion ratio.
I.e front is 1:1, rear is 1:0.5625
Thus if you are looking at total spring rate
0mm drop Stock height
13 BRZ 9.34k
13 FRS 8.88K
17 ~. 9.3~10k
10mm + drop
STI. 9.96k
TRD. 13.52k
RCE Y. 14.06K
RS-R d. 10.66k