3rd gen Explorer Coilovers

[Hbrichman]

This sound awesome, I might end up doing this after I see how it turns out. Like Ronin said, please post pics as you go along!

 

[rangermidtn]

Will do, just got to find time to get started. Holidays always put me behind what I want to do.

 

[Ronin8002]

This will be a really good mod for the 4th Gen suspension. The OEM type struts only have about 2.5" of travel which is pretty much the limit when you install Truxxx spacers even with BTF uppers. With the aftermarket coilovers it should be pretty easy to get a 5" travel shock in there and end up with the same lift as stock struts plus Truxxx spacers, but with double the travel. Even more travel and lift than the Rancho Quicklift struts which have about 4.5" of travel for the 4th Gen model.

Might even be possible to get a 6.5" travel coilover installed.

All of this talk finally gave me an excuse to pull the trigger on a plasma cutter, so that will make it a lot easier to make up all my own brackets out of steel plate, and I can make a good custom skidplate later with it too.

 

[spoolin]

Im interested in this. With worn out suspension and no strut lift this may be more economical. I also have two bad uca ball joints and one bad lca ball joint. I would like an improved uca balljoint to get with this. Maybe modify some junkyard arms with a uniball taller ball joint to handle the height without breaking apart. Not ready,to throw money at parts so i will sit on the sidelines now and let you guys figure it out.

 

[rangermidtn]

This will be a really good mod for the 4th Gen suspension. The OEM type struts only have about 2.5" of travel which is pretty much the limit when you install Truxxx spacers even with BTF uppers. With the aftermarket coilovers it should be pretty easy to get a 5" travel shock in there and end up with the same lift as stock struts plus Truxxx spacers, but with double the travel. Even more travel and lift than the Rancho Quicklift struts which have about 4.5" of travel for the 4th Gen model.

Might even be possible to get a 6.5" travel coilover installed.

All of this talk finally gave me an excuse to pull the trigger on a plasma cutter, so that will make it a lot easier to make up all my own brackets out of steel plate, and I can make a good custom skidplate later with it too.

I am jealous, wish I could get a plasma cutter. I just have to stick to my buddies band saw to cut my brackets. The 6.5 is what most of the people have talked to say we need to match the Extended and collapsed of our struts. The hardest part I am haveing is finding the right coil rate.

 

[Ronin8002]

I am jealous, wish I could get a plasma cutter. I just have to stick to my buddies band saw to cut my brackets. The 6.5 is what most of the people have talked to say we need to match the Extended and collapsed of our struts. The hardest part I am haveing is finding the right coil rate.

I had to shop around quite a bit to find one that would be affordable but still meet my needs, but finally settled on an Everlast model. They've got a few that are in the 400-500 range you might want to check out. I don't have room for anything but a portable bandsaw, and my abrasive chopsaw is only good for straight cuts or basic angles so I figured a plasma would be a great thing to have.

As far as spring rate, did you get confirmation that 550# springs are going to work well? Some of the 2nd Gen guys I see are getting 700-800 lb springs for their coilovers, but then again they are running heavy bumpers and/or winches up front.

 

[rangermidtn]

After talking with few, it's beginning to look like we will need a 600-650lbs. I am probably going to go heavier, because my next project is a custom front bumper.

 

[Ronin8002]

After talking with few, it's beginning to look like we will need a 600-650lbs. I am probably going to go heavier, because my next project is a custom front bumper.

I think the tricky thing is I want a spring that will compress enough with the truck's weight so I have 50% travel up or down from ride height with no preloading of the spring. That way I can crank up the spring seat a bit to get some more lift if needed and set up the suspension so it's maybe 60% downtravel and 40% uptravel out of the total shock travel.

 

[Ronin8002]

Mike, I ran across this link that might help us:

http://www.f-o-a.com/calculator.html#

Look at the "how to use" tab and get the measurements from figure 1 to get the numbers to plug in.

 

[HiImBrian]

After talking with few, it's beginning to look like we will need a 600-650lbs. I am probably going to go heavier, because my next project is a custom front bumper.

Hey! Something I kinda know about!

My buddy has 500lb springs on his sandrail. They are enough for that, but it's still a pretty bumpy ride. With the weight of my explorer we figured out I would need at least a 600lb spring.

But then he started in on this "2 different weight springs" thing. Apparently you can combine a lower weight spring with a heavier spring in a single coil. I guess it's supposed to make both the street ride and offroad ride nice and smooth. Maybe look into that?

 

[Ronin8002]

Hey! Something I kinda know about!

My buddy has 500lb springs on his sandrail. They are enough for that, but it's still a pretty bumpy ride. With the weight of my explorer we figured out I would need at least a 600lb spring.

But then he started in on this "2 different weight springs" thing. Apparently you can combine a lower weight spring with a heavier spring in a single coil. I guess it's supposed to make both the street ride and offroad ride nice and smooth. Maybe look into that?

Oh you mean one of those tender spring setups. Yeah I've seen that, I guess the small spring provides a softer rate for the first part of the spring travel and the bigger one takes care of bigger jolts. Basically like the progressive rate coils that are come stock on on the rear suspension of our trucks, but you can mix and match to achieve whatever combo you want.

 

[HiImBrian]

Oh you mean one of those tender spring setups. Yeah I've seen that, I guess the small spring provides a softer rate for the first part of the spring travel and the bigger one takes care of bigger jolts. Basically like the progressive rate coils that are come stock on on the rear suspension of our trucks, but you can mix and match to achieve whatever combo you want.

Yeah that. A friend of mine is really getting into custom fab work, hence why I haven't gone with BTF spacers or uppers yet....

 

[Wills05xlt4x4]

Yeah my btf spacers have been sitting almost a year... Why? Coilovers!
I'm glad to see your beating me to it lol... I really like where this is headed, my only thing would be do you really need to add to those lca's? Theyre pretty solid as is and need to be able to clean out after stuff so you definately need to let it breathe... Also for the lower coilover mount why not use the oe bolt setup? Unlike most trucks we have struts and that point is already designed to carry all the weight of the truck now...
makes me want to stop by my local off road shop for some reccomendations...

 

[Ronin8002]

I think I am going to hold off on installing my truxxx spacers and BTF arms, doesn't make sense to install the truxxx on my worn out struts only to uninstall them again soon for a front coilover setup. Besides, it will be easier to make the upper mounts for my coilovers if I have the truxxx spacers handy.

 

[rangermidtn]

Yeah my btf spacers have been sitting almost a year... Why? Coilovers!
I'm glad to see your beating me to it lol... I really like where this is headed, my only thing would be do you really need to add to those lca's? Theyre pretty solid as is and need to be able to clean out after stuff so you definately need to let it breathe... Also for the lower coilover mount why not use the oe bolt setup? Unlike most trucks we have struts and that point is already designed to carry all the weight of the truck now...
makes me want to stop by my local off road shop for some reccomendations...

If you used the lower mount, I do not know if you could clear the CV axle, plus you wouldn't you need the offset bushing like the ones in the strut?

 

[Ronin8002]

If you used the lower mount, I do not know if you could clear the CV axle, plus you wouldn't you need the offset bushing like the ones in the strut?

I think he is saying (and what I was thinking of too) is design a flat plate type bracket that will sit over the hole that the lower strut mount fits into. You would have 2 tabs coming down off that with holes drilled in them that will fit down in where the lower strut mount eye goes, and run the original strut bolt through that to hold it in place. Basically make something like the coilover lower mount bracket you posted pics of earlier and weld tabs to the underside of that. I think he was also saying you shouldn't need to box in the lower control arm since it already is strong enough to stand up to the stress of being the mounting point for the OEM struts.

 

[rangermidtn]

I think he is saying (and what I was thinking of too) is design a flat plate type bracket that will sit over the hole that the lower strut mount fits into. You would have 2 tabs coming down off that with holes drilled in them that will fit down in where the lower strut mount eye goes, and run the original strut bolt through that to hold it in place. Basically take the lower mount bracket you posted pics of and weld tabs to the underside of that. I think he was also saying you shouldn't need to box in the lower control arm since it already is strong enough to stand up to the stress of being the mounting point for the OEM struts.

I got you.

 

[rangermidtn]

Mike, I ran across this link that might help us:

http://www.f-o-a.com/calculator.html#

Look at the "how to use" tab and get the measurements from figure 1 to get the numbers to plug in.

Ronin, have you tried using this? Everytime I get Infinity as my spring rate. Not sure what is going on with this.

 

[Ronin8002]

Ronin, have you tried using this? Everytime I get Infinity as my spring rate. Not sure what is going on with this.

Not yet. I'll give it a try tonight.

 

[Ronin8002]

Ronin, have you tried using this? Everytime I get Infinity as my spring rate. Not sure what is going on with this.

Ok Mike, I made some quick measurements.

Total wheel travel: that's how much total movement the wheel hub makes from full droop to full compression if there was no strut assembly installed. No idea what that would be. but seeing as I'm going to use 5" travel shocks and i expect to use all of it, that's a starting point. But 5" of shock travel isn't 5" of wheel travel. Due to the suspension geometry in the IFS, the wheel travel on our trucks ends up being about 1.5 x the shock travel. So 5" of shock travel should give about 7.5" of total wheel travel.

Corner sprung weight: the curb weight of my truck is listed at 4750 lbs, with a weight distribution of 54% on the front and 46% on the rear. So 54% of 4750 is 2565. Divide that by 2 to get the corner weight and I'm coming up with about 1282. Now sprung weight is everything basically from the lower strut mount up, so subtract the weight of the wheel, tire, brake rotor, knuckle, lower control arm, etc. Guess thats prob in the 200lb range so corner sprung weight should be about 1082 which we'll just round up to 1100.

D1: on my truck, measurement d1 looked to be about 10"

D2: Measurement d2 looked to be about 14.5"

Droop %: I'm hoping to have half of my available travel up and half down when the truck is sitting on the flat ground, so I used 50% for this

spring angle from vertical: looked to be about 15 degrees tilt on my struts from vertical when truck is sitting on flat ground

so I entered all that in and came up with 660 lbs for my spring rate.I could have been off a bit on any of those figures, found when I adjusted the numbers slightly it could put me as low as 630 or as high as about 700. so I think a 650 would work for me. might just go for a 700lb though.