zaphod

Hey All Knowing Scooby Wizards,

After 116,000 miles of abuse my stock springs and struts have had it. I just replaced them with KYB struts and Eibach springs.

I compressed the front springs and installed the top hardware. Decompressed and installed into the car. No probs. Looks good, camber was adjustable to the correct tolerances, rides good, etc.

For the rear I found that the spring didn't need compressed in order to install the top hardware. I continued on and installed them. The rear looks good, and after a few clunks when initially driving, they seem to have quieted down and it rides good.

Thinking back on my many hours of work, my question is this: could I have accidentally swapped the front and rear springs?

1. The front struts are longer than the rear struts, and this led me logically to believe that,

2. The tallest pair of springs should be placed on the longer struts (i.e. front).

Is this correct? Or did I goof?

scottzg

the springs can be swapped front to rear, unfortunately, i dont know if the rear strut is longer when fully extended.

zaphod

Well I'm sure the front struts are longer/taller than the rear struts.

However, the springs are different heights, and I'm assuming that the higher spring goes on the higher strut... ?

lovesmysuby04

iTrader: (4)

no that's not true. I just put the prodrive springs on my wrx and the short fat springs went up front and the the taller ones with more coils were for the rear. Prodrive springs are made by eibach so they should be similar. Mine said front and rear on them anyways. The springs shouldn't be swapped because of difference in drop and spring rate.

zaphod

Oh man that really really sucks. What a PITA. Now I have to remove them and swap the springs. GRRRRR!

Anyone else want to confirm?

MO REX

iTrader: (2)

Thats how my SPT's (Eibach) were, here's some info to prove he's right.

2002-2003 WRX Sedan Performance Spring Set


Q. What is the "Free-Length"?
A. Front: 253 mm, Rear: 308 mm

Q. Who manufactures them for Subaru?
A. Eibach

Info taken from here http://www.spt.subaru.com/microsites...trim=WRX+SEDAN.

Do the wheel gaps look way off?

zaphod

Oh, this does not make my day. The rear wheel-well gap looks right.

Today at 4 AM on my way driving the car to the airport I got to thinking again.

* The front struts are longer than the rear struts
* One pair of springs is taller than the other pair

Keeping this in mind, if the short springs had no tension (actually a decent gap) on the short struts, then the short springs would have even a LARGER gap on the long struts (front).

Now, I realize the front of the car is probably at least twice as heavy as the rear, so the shocks will never be fully extended, BUT, this still leaves me uneasy. In *MY* logic I'm thinking that *SINCE* the front is so much heavier that I would *WANT* the tall springs (hence more potential energy) on the longer struts in the front...

I was just originally worried that by having the tall springs installed on the front that I was putting undue extra compression on them which would cause premature failure. HOWEVER, since the rear struts are SHORTER than the front, by placing these tall springs on the shorter struts, the constance compression would also be present (and I would have no tension and quite a large free gap on the front struts by installing the short springs). Of course the rear of the car is lighter, so the constant compression force would not be nearly as great as the front, but it was quite a lot of compression I had to use to get the tall springs installed on the front/long struts in the first place and by compressing them even more to get them on the rear/short struts might even be hazardous to my health!

Is this current configuration, with the tall springs on the long struts, a safety hazard in any way? I do not see how it could be, because of my stated facts above, but I am driving to Ontario this weekend for a family renunion and would hate to have to tow my car back to Ohio...

Someone please explain the flaw in my logic...

MO REX

iTrader: (2)

I’m starting to think you have them on correctly if the rear wheel gap looks good. Are you sure you installed the taller springs in the front? Here are some links to some pic’s of my 02 with SPT springs https://www.i-club.com/forums/attach...chmentid=22404 https://www.i-club.com/forums/attach...chmentid=22406 https://www.i-club.com/forums/attach...chmentid=22405 . You’re drop should look similar.

I’m almost positive the front struts and springs are the shorter than the rear struts and springs. I have some Koni inserts and gutted oe strut housings in my garage right now and unless I'm mistaken the fronts are shorter than the rear.


One thing to remember is that the lengths you are talking about are what is called the free length (length before compression) which will be compressed x amount depending on the rate of the spring and the amount of weight that is put on it. A WRX weighs around 3085 lbs. and it has a weight distribution of 60/40 (front is 20% heavier) so that means the front weighs around 1851 lbs. and the rear weighs around 1234 lbs.

zaphod

Thanks for the reply! I'm virtually positive the front shocks should be higher than the rear shocks. But I will call TireRack and ask them since that's where I bought the struts and springs.

I say the car does look okay on the wheel-well gap, but since the stock springs were compressed nearly 2" already I'm not sure that I am qualified to say it looks right now. haha. The new "shorter" shocks/springs actually "raised" the car 1".

I get home from this business trip late tonight, and will take a good look at the car in the morning and see if the gap in the front is roughly equal to the gap in the rear. I'll post back with my results, as well as the info from TireRack.

thanks again!

Jacob

MO REX

iTrader: (2)

The front strut/spring is on the left and the rear is on the right.

scottzg

hey mo, do scoobs have the same motion ratios front and rear? Do you happen to know what they are?

If they don't, your example doesn't hold water.

Sweetness!

MO REX

iTrader: (2)

I’m no expert on the subject but AFAIK the motion ratio of an Impreza is 1:1 so I don’t think that would change anything but I just remembered that the Pro kit uses progressive rates and the ERS springs I was using are linear (different % front to rear from the 1st rate of the pro kit) so disregard the static rest figures I wrote (time to edit/erase) .

Pro kit progressive rates (not sure if these are accurate but it was all I could find)
Front - 1st Rate= 171 #/inch
2nd Rate= 193
Rear - 1st Rate= 94
2nd Rate= 161

BTW, if you have some info on the motion ratio of an Impreza that contradicts my #’s or how it will change static rest #’s please speak up.

scottzg

I dont have any info, my car (which is actually an old legacy) is in a very lightly tuned and im satisfied with it.

1:1 really makes it easy to calculate rates though, that's cool.

Progressive springs suck. You don't know how the rate increases and matching struts to them never works out quite right.

zaphod

Okay so after arriving home from the airport I can definitely see that the front of my car is up ever-so-slightly higher than the rear. Furthermore, upon inspecting my stock struts (thankfully my wife did not throw them away while I was out of town), to my utmost surprise I found that the REAR struts were LONGER than the FRONT!

So now this totally makes sense in my head why the TALLER springs should be on the REAR... cuz the TALLER STRUT should be on the REAR!

I'm just happy that I won't have to remove the springs from the struts! All I need to do is swap the front and rear assemblies. W00t!

Thanks for all the info everyone. I'll post pics before & after soon so you can see the diff.

J

zaphod

So after sleeping and probably dreaming about this all night, I now realize that if indeed the rear struts are longer than the front struts:

* Why do the rear struts (taller) have the 4-position damper adjustment on the top where I could only get to it by removing the back seat?

* And that would make the front struts (shorter) have the lower side-mounted 8-position damper adjustment.

It makes more sense that TireRack swapped the two struts. Seems to me I should have the top-adjustment type on the front (shorter) and the side-adjustment type on the rear (longer), but indeed they're swapped.

Upon inspection I notice that the longer strut has the welded flanges for the brake-line and the ABS sensor, whereas the shorter strut has only the flange for the brake-line. This flange configuration, along with the top-mounted dial v. the side-mounted dial, is what led me to believe the longer struts belong on the front.

I've placed a call to the sales rep at TireRack that fulfilled my order. Hopefully he'll be able to tell me that they sent me the wrong configuration... What do you think the chances are they'll let me return all four struts to be swapped with the proper configuration?