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Unread 04-23-2010, 03:40 PM   #1
zjdamien
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3.5 F>R swap now rear sag

did the F>R spring swap now ive got a little sag in the rear and if i put anything in the back it sags alot more would some front springs from a V8 zj help or do i just need to by some new rear 3.5 springs

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Unread 04-23-2010, 03:42 PM   #2
kwellzz
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I have same issue
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Unread 04-23-2010, 04:03 PM   #3
MurdaJs
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My v8 springs sit over 4" in the rear
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Unread 04-23-2010, 04:03 PM   #4
ZJJay
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That sounds weird that your ZJ was basically level (I presume), then by swapping the springs the rear is now lower. I've weighed my 4.0 ZJ at work and with a full tank of gas plus 100# in the rear, the front came in at 2,220 pounds, the rear was 2,050, and total weight was 4,360. (I know the totals don't add up.) I would expect that springs designed for the front would be stiffer to handle the constant extra weight. But then, maybe since the front weight is relatively constant, maybe the rears are a little stiffer to handle the occasional extra loads. I don't know.

Is your front end higher after the spring swap? Or does it ride stiffer?

I don't remember how much lift the ZJ V8 front springs would give the rear, but I'm sure it wasn't 3.5 inches. I think it was somewhere between 1.5" and 2". Why don't you just reinstall your springs in the original locations?

Jay
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Unread 04-23-2010, 04:06 PM   #5
MurdaJs
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Quote:
Originally Posted by ZJJay View Post
I don't remember how much lift the ZJ V8 front springs would give the rear, but I'm sure it wasn't 3.5 inches. I think it was somewhere between 1.5" and 2".
Jay
the IRO Front to Rear swap is based on the front springs giving 3.5 inches of lift in the rear, v8 springs net more
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Unread 04-23-2010, 04:11 PM   #6
spife7980
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yes his rear is higher, they are sagged from the 3.5" he was trying to get but i6 coils will net you around 3". and the fact that they are 17 years old doesnt help too much either.

and yes, v8 coils will give you 3.5", im on my 3.5" coils as we speak. go to a junkyard and grab a set of the v8, maybe even the upcountry v8 if you can find a pair. theres a reason that youre supposed to use the v8 in the first place. sure some have success with their i6 but most need a v8 coil.
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Unread 04-23-2010, 04:13 PM   #7
BlackbeastZJ
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I believe that it was intended to use the springs from a V8 ZJ. And from what I see most often from those with the I6, thats what they use, however mine sits perfect with the stock I6 springs, and thats with 100 pounds in the back. I think it just varies some from vehicle to vehicle.

But to the original poster, if yours is sagging with the stock springs, I'd recommend upgrading to the V8 ones, it'll be quite a bit cheaper than getting the 3.5 springs from IRO.

Quote:
Originally Posted by MurdaJ
My v8 springs sit over 4" in the rear
Did yours happen to come with the UpCountry package?
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Unread 04-23-2010, 04:16 PM   #8
MurdaJs
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Quote:
Originally Posted by BlackbeastZJ View Post
Did yours happen to come with the UpCountry package?
Not that I know of, no decals or special shocks. I never measured it stock, but I was able to fit 31" GY A/ts with minimal rubbing.
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Unread 04-23-2010, 04:28 PM   #9
jfabian
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did a Rough Country F>R lift and mine sits level. like spife said, old *** springs can sag, and from what i have read all over the place, no two jeeps are the same. my .02
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Unread 04-23-2010, 07:39 PM   #10
rooster51
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Quote:
Originally Posted by ZJJay View Post
I don't remember how much lift the ZJ V8 front springs would give the rear, but I'm sure it wasn't 3.5 inches. I think it was somewhere between 1.5" and 2".
Negative. I just installed v8 front springs in the rear last weekend. I got 3 3/4" pass.side, & 3 1/2" dr. side. With a large wooden cargo toolbox and a good amount of gear.
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Unread 04-23-2010, 09:03 PM   #11
tbick
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I got an extra set of BDS 2 in rear springs that gave closer to 3 or 4 in St louis. $65 for the pair plus shipping(actual). Will have 4in RC rears that will go for $65 plus shipping in a couple of weeks. And a set of V8 springs that would go for $20 plus shipping. Already got my 7in springs, just waiting to pass state inspection before I make the change. IRO Group buy is providing me with the Long CA for the front. Just PM me. If you are close Id meet you to save shipping. All springs are ZJ
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Unread 04-23-2010, 10:35 PM   #12
JrMechanic
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Does anyone have the spring rates for the V8 and I6 front springs? I'd be interested to know how much of a difference there is between the two, considering there's a very small difference in weight between the I6 and V8.
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Unread 04-24-2010, 08:36 AM   #13
zjdamien
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I've also got s home brew roof rack with a hi lift jack on it mounted on the rear both the rack and jack might be a extra 100-130 lbs. I found some springs that moog makes for the front of a v8 zj they are stock height but are progressive rate wonder what those would do??
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Unread 04-24-2010, 01:00 PM   #14
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well i will put my in here, I have a V8 did a F<R Swap with rusty's 3" springs, My back is 1/2" lower than the front, there is some stuff in the back, but not much, the springs could just be getting soft. I got nearly 200K on the back springs and only 30 on the front.
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Unread 04-24-2010, 01:34 PM   #15
zjdamien
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Well I went to the gunk yard today to get some spring and ended up finding a 242 trans case instead didn't have the $$$ for both figured the t case was harder to find so I got it
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