coilover question

vipergtrdj

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May 7, 2016
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in the process of doing a coil over conversion on my 04 LLY. Torsion bars are junk (cranked up and wheel sits inside fender well), and I need to replace everything in the front end. So figured now is a good time to throw coil overs on. I have always done SAS with coils, never messed with coil overs before.

Threw in some QA1 DS501, and 10" 850lb springs (Qa1 springs, linear). The highest rating Summit had for 10" springs. Got the coils on and fender height is at 38.5" but it seems like the spring coils are fairly close together, I had to put about an inch or so of preload on them to get it there, otherwise it sank to the ground. I have some 900lb 12" springs, but they won't fit due to mount spacing for the DS501s. I can't get a spring compressor in place either due to everything in the way.

What do I do so it doesn't want to squat so much when there's no preload on the springs ? short but stiffer springs, I found 6" 1800lb springs and 8" 1000lb springs ? I saw a kit for a 2500HD Diesel that had 750lb springs so I figured 850lb would work.

I haven't taken it for a drive yet to see how it rides, still need to replace tie rod, sway bar links, and cv axles.
 

ZeroGravity58

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vipergtrdj

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Thanks. My mounts are similar, just much shorter. Maybe I should redo them so can fit a longer spring? From what I have been reading the spring rate should be fine, but my ride height is a problem if the preload isn't cranked up.
 

ZeroGravity58

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I saved that post along time ago, i still kick the idea around of converting to coilovers. I'm sure James will post in here and give you some input.
 

vipergtrdj

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I saved that post along time ago, i still kick the idea around of converting to coilovers. I'm sure James will post in here and give you some input.

that would be great, I’m always open for ideas and such. I’ve always done solid axle swaps so coil overs are new to me. I did the solid axle on my 03 gas I used coil springs that were rated for 1800lbs, I’m not sure why coilover springs are rated less.
 

Chevy1925

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that would be great, I’m always open for ideas and such. I’ve always done solid axle swaps so coil overs are new to me. I did the solid axle on my 03 gas I used coil springs that were rated for 1800lbs, I’m not sure why coilover springs are rated less.

It’s called “motion ratio”. Hence why a solid axle can run less spring rate on a coilover than on an a-arm vehicle
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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Phoenix Az
in the process of doing a coil over conversion on my 04 LLY. Torsion bars are junk (cranked up and wheel sits inside fender well), and I need to replace everything in the front end. So figured now is a good time to throw coil overs on. I have always done SAS with coils, never messed with coil overs before.

Threw in some QA1 DS501, and 10" 850lb springs (Qa1 springs, linear). The highest rating Summit had for 10" springs. Got the coils on and fender height is at 38.5" but it seems like the spring coils are fairly close together, I had to put about an inch or so of preload on them to get it there, otherwise it sank to the ground. I have some 900lb 12" springs, but they won't fit due to mount spacing for the DS501s. I can't get a spring compressor in place either due to everything in the way.

What do I do so it doesn't want to squat so much when there's no preload on the springs ? short but stiffer springs, I found 6" 1800lb springs and 8" 1000lb springs ? I saw a kit for a 2500HD Diesel that had 750lb springs so I figured 850lb would work.

I haven't taken it for a drive yet to see how it rides, still need to replace tie rod, sway bar links, and cv axles.

Your gunna hit coilbind in a hurry. That means your spring will be fully collapsed and stop shock compression before you fully compress the shock.

Also, those shocks won’t hold up and will blow out either the spherical bearings or spring retainers (specially if you have coilbind).

To make coilovers work on a stock truck, you need to ditch the stock frame mount and put a different one in with a better shock. Much more is needed beyond that but a lot of that has been posted on this site. Gotta research it.

This isn’t a simple deal due to motion ratio and weight
 

vipergtrdj

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May 7, 2016
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Your gunna hit coilbind in a hurry. That means your spring will be fully collapsed and stop shock compression before you fully compress the shock.

Also, those shocks won’t hold up and will blow out either the spherical bearings or spring retainers (specially if you have coilbind).

To make coilovers work on a stock truck, you need to ditch the stock frame mount and put a different one in with a better shock. Much more is needed beyond that but a lot of that has been posted on this site. Gotta research it.

This isn’t a simple deal due to motion ratio and weight

Ive read a few threads on here. I noticed a few people run the qa1, and some other Vikings ? What’s a good shock to use? I am going to redo the frame mounts this weekend.

Also to remedy the coil bind I am assuming a heavier coil spring so it won’t collapse the spring completely ?
 

Chevy1925

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Ive read a few threads on here. I noticed a few people run the qa1, and some other Vikings ? What’s a good shock to use? I am going to redo the frame mounts this weekend.

Also to remedy the coil bind I am assuming a heavier coil spring so it won’t collapse the spring completely ?

pure race trucks that see min street time can get away with vikings or qa1's, specially cause they are lighter. you need a 2.5" body shock at min and then the uca wont fit correctly if you are using a stock one.

no, heavier is not better.
 

vipergtrdj

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May 7, 2016
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pure race trucks that see min street time can get away with vikings or qa1's, specially cause they are lighter. you need a 2.5" body shock at min and then the uca wont fit correctly if you are using a stock one.

no, heavier is not better.

thanks. I will look into it more. I know nothing when it comes to coil overs, now I can do a solid axle swap with coils and 3 or 4 link no problem. So what I have gathered so far is, a 2.5" shock, and try to get it as long as possible for the spring. At what point does spring rate come into play ? I know these are heavy trucks and just want to make sure I calculate everything correctly.

My plan is to mock up new mounts, measure for shock then once shock is in place, measure for spring ?
 

Chevy1925

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@Chevy1925 do you have a parts list for coilovers, stock height (or minimal lift) with stock shock mounts? I love that setup and am looking to do some custom work without much welding (I don't weld).

negative. GMT800 chassis just wont make it happen without a custom shock/spring. the spring mfg's i worked with made me lots of promises and then gave me the cold shoulder.
 

moparkxracer

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I wound up having to do 4 shocks on the front end to be able to keep springs from coil binding. We cut the factory shock mount out and made new ones, the cv shaft runs between the two shocks.
 

moparkxracer

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Per your request.
 

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moparkxracer

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The sway bar was not on in those pictures, you’ll need to find someone that can weld. In my opinion you’re asking a lot from the tack welds that are there from the factory for coil over mounts. The truck is lowered abt 5 inch.
 
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Chevy1925

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The sway bar was not on in those pictures, you’ll need to find someone that can weld. In my opinion you’re asking a lot from the tack welds that are there from the factory for coil over mounts. The truck is lowered abt 5 inch.

The steel in the center where the shock would mount to bends up before any welds give out. i tested these stock shock mounts very thoroughly lol