The 08 STI Front Springs wasn't the problem, it was the Rear Springs that were the problem. That's why I left the 08 STI Fronts on there.

 

...

 

Thanks to JRocko for the springs, I can't wait to install them now!

 

^^^ NO problem....Good Luck with the Install

 

wooooo more work!

 

yup, thursday night. install/bbq your house!

 

It sounds like you bought 2008 STI springs and 2010 WRX springs. If this is correct, how did you conclude that the 2008 STI had horrible rates causing them to increase the spring rate in 2009-2010? It is impossible to come to this conclusion with a picture of 08 STI and 10 WRX springs side by side.

 

First of all I am talking about Rear Springs. And yes you can tell by just a Picture.

The 2008STI Springs had alot more Space in between the Spring Coils. Therefore the spring Rate is not as good as the 2010.

If you are bored one day you can Buy some 2010 WRX and 2008 STI Spring and compare them.

 

Front or rear, my understanding was that there were no spring changes for the STI from 2008 to 2009.

I really don't care if the 2010 WRX and the 2008 STI have the same or different springs. I only care about changes for the STI. When you said the 08 STI rear spring rate was increased in 09-10 (STI, not WRX), I wanted to know how you came to this conclusion. I still don't know how you can say that the 09-10 STI and 08 STI rear spring rate is different by comparing 08 STI and 10 WRX springs.

Also, your conclusion about spring rate based on space between coils is incorrect. All other relevant parameters being the same (material, spring wire diameter, overall spring diameter), the spring with fewer coils per unit length (i.e., more space between coils) will have a higher spring rate. So based on your observations the STI spring should be stiffer. I don't disagree with you that the 10 WRX has stiffer rear springs, but you can not tell spring stiffness from a picture, especially if the wire diameter of the spring is not measured and material properties are unknown.

 

I think you took what I said the wrong way.
I am talking about installing these Springs on my Forester.
I am not talking about STI Springs on a STI, itʻs on a 2009-2010 Forester.
So, yes the 2008 STI spring rate on a Forester sucks, but I didnʻt mean in General.
I know stiffen the 2009 Wrx and 2010 Wrx suspension.

Which is exactly what I mean, the 2008 STI springs and not as Stiff as the 2010 WRX springs. One thing you have to consider is 2008-2010 are all Hatchʻs. 2008-2010 WRX are sedanʻs. which have a little more weight in the back.

 

I'm confused now. My research indicates the following:

08-10 STI
Front: 38 N/mm (217 lbs/in)
Rear: 34 N/mm (194 lb/in)

08 WRX
Front: 26.5 N/mm (151 lbs/in)
Rear: 24 N/mm (137 lbs/in)

09-10 WRX (same as 08-10 STI)
Front: 38 N/mm (217 lbs/in)
Rear: 34 N/mm (194 lb/in)

So how is it that the rear 08 STI springs have less coils than the 10 WRX rear springs even though they list the same spring rate?

The only explanation I can think of (assuming the the same wire diameter and coil diameter) is that the 08 STI rear springs are longer (i.e. wider spacing between coils) than the 09-10 WRX but actually they both have an equal amount of coils. In other words, the distance between coils doesn't affect spring rate but the amount of coils does.

 

Ok, maybe they have the same spring rate but the Wrx are stiffer. If my memory is correct the WRX had more coils to make the
Ride a little more stiff.

But the the springs are the same length

 

I was Bored this Morning....

2008 STI OEM Springs


2009-2010 WRX Springs


Let me know if you see a difference?

 

I need to add too that if you put these on an FXT you need to change the front upper spring purges because the coil diameter is smaller than the FXT ones

 

^^^THis is correct. For the Front Springs only.
Dylan did you call servco this morning?