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-   -   997 Spring Rate roundup!! (https://rennlist.com/forums/997-forum/932618-997-spring-rate-roundup.html)

Tj40 05-04-2016 11:07 PM

997 Spring Rate roundup!!
 
1 Attachment(s)
Hi all,


Fairly new to 997 ownership (2009 Carrera), I drove it home the week before the snow and so spent the winter lurking on the forums. As I've upgraded the suspension on various other cars before I collated all the spring rate data I could find for the 997's.


My disclaimer is this rate data is primarily surveyed off the forums, it's just presented here in one place.


The eibach rates I found over on 6Speed were quoted as,
F
19/34 nm
168/300 in/lbs

R
52 /90 nm
460/796 in/lbs


Which does not compute as the conversion rates are wrong. I've used the n/mm values.


Of note both the eibach and Pss9 progressive rates start lower than stock - this is not necessarily true when installed on the car as static sag will 'take up' some of this lower rate travel. Given that most people who install these springs saw they find ride to me more compliant than stock over smaller bumps this might reflect the initial lower rate. Of course this will quickly rise as the suspension moves.


The table attached gives the rates plus a comparison % to the stock C2 Carrera rates so you can see how much stiffer the springs are than stock. Plus a front/rear comparison that shows how much stiffer the rears are to the front.


You care about this as stiffer rear/softer front will tend to dial out understeer, so you would expect that the KW V3's at over 400% stiffer at the rear would give less understeer than even a GT3 stock setup.


Anyway - enjoy!!

floatingkiwi 05-11-2016 04:46 PM

Hey that's awesome! Keep it updated if you can with more sway bar numbers.

Hilltopper 05-11-2016 06:32 PM


Originally Posted by Tj40 (Post 13259270)
Hi all,


Fairly new to 997 ownership (2009 Carrera), I drove it home the week before the snow and so spent the winter lurking on the forums. As I've upgraded the suspension on various other cars before I collated all the spring rate data I could find for the 997's.


My disclaimer is this rate data is primarily surveyed off the forums, it's just presented here in one place.


The eibach rates I found over on 6Speed were quoted as,
F
19/34 nm
168/300 in/lbs

R
52 /90 nm
460/796 in/lbs


Which does not compute as the conversion rates are wrong. I've used the n/mm values.


Of note both the eibach and Pss9 progressive rates start lower than stock - this is not necessarily true when installed on the car as static sag will 'take up' some of this lower rate travel. Given that most people who install these springs saw they find ride to me more compliant than stock over smaller bumps this might reflect the initial lower rate. Of course this will quickly rise as the suspension moves.


The table attached gives the rates plus a comparison % to the stock C2 Carrera rates so you can see how much stiffer the springs are than stock. Plus a front/rear comparison that shows how much stiffer the rears are to the front.


You care about this as stiffer rear/softer front will tend to dial out understeer, so you would expect that the KW V3's at over 400% stiffer at the rear would give less understeer than even a GT3 stock setup.


Anyway - enjoy!!

I am a retired mechanical engineer and had a lot of experience with spring rates including ski safety bindings. Please remember that the Eibach Sport are progressive spring rate and I have used them from 1983 URQUATTRO to my 997.1. IMO-still the best!


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