Flexy Coils and Mathematical Theory for Review

[AutoCraft Aus]

The FJ is actually harder to design a coil for than the 80, due to the space, height, and dia available to fit the coil into.

We go 30mm higher on Slinky for them, like 80, 100 and 200, because we use a 40mm bump spacer to fit the extended length shock we run in there, compressed.

So we end up with a 3"" lift, instead of 2".

We are also using a straight rate coil in the FJ, rather than a dual rate, because we can get them to stay captive, and in 5 different rates, because we are actually using coils that are made for another application, that works.

Beats the time and effort, and $ that go into prototyping when you can.

The FJ flexes on the standard arms nicely too, roll steers less, maybe due to weight transfer with less overhang, and weight to an 80.

Unloaded ride height on 35's.

Us aussies generally like to carry more of a load, for remote travel than you guys, too.

 

[Delancy]

Here's the one question I have and it can be the proverbial debate ender.

Guess I answered this myself....sadly.

G'day Chris,

All sorted. Spoke with Elliot, he is going to send me the invoice for 1 FLEXTR555 coil.

I'll electronically pay him, this afternoon, then he will send down the coil to me. and I'll get it over to you ...

Easy Peasy ...

At least I can get this bit sorted....

Cheers Baz

Have to say this.

With a phone call level of communication established this became a whole lot easier, plus Elliot at SS was super quick to respond and believe he had a greater understanding of the importance to treat email like text and go real time, considering the time difference.

Now, I've got to find something really cool to send Baz for his troubles. Already sent the mundane, need something very cool, and not a concubine.

Anyhow, the plans to swap the PS 570 to DS and put the 555 on PS.

By the numbers, there'll be a 5mm difference front to rear. We'll see.

If this doesn't level, then will get one more 555 for the rear (it must be the shortest) and two 575 for the front and start spacing in 15mm intervals, since I believe the rear 555 is shortest, as is front 575.

I'll be waiting on the US Slinkies to be announced in the meantime.

car now needs bigger rear sway bar for rear weight, which makes a huge difference.

What % or rate increase or stiffness increase are you anticipating the final to be?

Whiteline is 15%, right? I'm thinking that a 25-30% stiffer rate may be in order. What say you?

To stop the rear lift, and help transfer torque to the ground, making the lower rear arms 250mm longer and raise the upper mountings at the diff really helps.

That may require more sheet metal work than possible, if you're talking on the axle end.

250mm=10" longer?

Moving front mounts forward?

Mine are ~12.75mm longer lowers, now, which should correct pinion and re-center wheel in well.

Oddly, even with 6" there's no measurable difference in diff/TC output flanges with the Chinese angle checker I bought, that Mark suggested.

 

[Delancy]

The FJ is actually harder to design a coil for than the 80, due to the space, height, and dia available to fit the coil into.

Beats the time and effort, and $ that go into prototyping when you can.

I've learned quite a bit during this round of chit, but if that holds true, then the ROI to develop must be too high, even though it was said to be $1-1.5k.

I know that the only way that a certain coil producer in the US is willing to take this on is if the actual OE coils with measurements are sent to them for testing.

maybe due to weight transfer with less overhang, and weight to an 80.

There's very little weight difference in US spec'd 80s and FJCs, in OE form.

Mine feels more stable and predictable than the 80 off road but don't have near the seat time in the 80 and with my 1.5" of down travel, she's doesn't conform well.

In fairness, the SA has allowed for taking runs that only one FJC I've ever wheeled with will even try, and that's partially due to a lot of modifications, but mostly because he's friggin' crazy.



Only shot I have from Clayton, but I'd put money on Hornfan's Atlas'd, SC'd, RCVd, locked FJC to show, just about any day, on anything a street driven rig can run.

Here's mine.





See that funny metal thing?

Game changer on road and off when I went to the long travel coils.


Even further OT.

I may be building a Pig pen tomorrow.



Know in about 14 hours. I hate eBay. Hahaha.

 

[AutoCraft Aus]

bottom arms mover bottom mounts forward 250mm, no sheet metal required.

Mocing upper arm diff mounts up may.

Ideally, you want the intersecting lines of the upper and lower arms to be as far out in front, and close to the ground as possible, for rear handling, squat, etc.

Making the lowers longer and rear of upper up, helps this.

Lifting the truck makes it worse.

As for sway bar, we go 120% or 180% depending on vehicle. I have run the 180% on a stock 80 with plastic bumper, and though it did restrict flex, it smoothed out the pitch ion the rear substantially.

I think the problem you have, is your rear coils are to high

 

[Delancy]

bottom arms mover bottom mounts forward 250mm, no sheet metal required.

Ideally, you want the intersecting lines of the upper and lower arms to be as far out in front, and close to the ground as possible, for rear handling, squat, etc.

Gotcha.

What I assumed, but assume starts with ass.

If going to that trouble, think consideration to a 3 link or 4 link with gas tank mods might be in order, but not headed there, myself.

If the shocks and better brake proportioning don't help the hop, not sure what I'll do, but can guarantee that'll be a big problem I'll address in another thread.....someday. Hahaha.

 

[AutoCraft Aus]

You cant stop now....



Moving the arm mounts is a day job including making the arms.

I would be using a brake bias valve, rather than try and change the LSPV.


Im sure your next thread will be "IFS 80 front, and a frame rear, easiest way in a weekend?"

 

[Delancy]

You cant stop now....

You have nothing to worry about on that front.

Moving the arm mounts is a day job including making the arms.

It took me a year to feel comfortable ordering the shocks......

I would be using a brake bias valve, rather than try and change the LSPV.

I manually engaged the LSPV 100% and it changed very little.

I haven't researched fully, but I believe the valve throws ABS into a fit.

Im sure your next thread will be "IFS 80 front, and a frame rear, easiest way in a weekend?"

Bahahahaha.

No, I'll go to classifieds and buy a 100.....then feet and stew over how to put an SA under.....bahahahaha.

Honestly, next for me is the sway bar, but there's so many detractors, thread would be purposeless, except for those whose viewing pleasure is my meltdowns.

This one ain't done yet, by the way.

Still have a coil to swap.

 

[sleeoffroad]

G

Anyhow, the plans to swap the PS 570 to DS and put the 555 on PS.

By the numbers, there'll be a 5mm difference front to rear. We'll see.

How exactly is this going to work? Confused. You have 25mm difference front to rear now, but you are going to swap springs side to side and it is going to lower it? Or are you moving current short spring to other side and installing new short spring?

 

[AutoCraft Aus]

ABS ... pull the fuse.


A year on shocks, glad you can get so much of a journey from the details of modifying the car.

The easier you can mod stuff, the faster they get built, the less it gets about the journey, and the harder goals you end up setting for yourself.....

So just keep freakin out bout the little stuff, its better in the long run.

 

[Delancy]

Just a fleeting comment from the peanut gallery, because none of our trail trucks, including the 80, will be anything like what's discussed here.

It's really not that far off the wall, as it may seem.

Can spend countless thousands (I disposed of the spreadsheet tracking this "build" last year, hence countless. Ignorance is bliss) and still not exponentially increase the capability of the 80.

My intent was to drive to and from, comfortably, give it as much as I could, then drive home, maximizing all possible along the way, without the need of a tow rig.

Well, come to think of it, my Blazer can bounce like Mr. D's 80 in that video any day, without even trying very hard ...

Here's what's funny. That was last year and I said then I was ordering the shocks the next day, and when the conversation started with Glenn.

but that's because I'm to cheap to spring for the $400 per corner on shocks that it would take ...

I wish.

I'm watching because once our 80 needs to be higher than the current OME 2", I want to know my options...

Unless LT or Christo venture into the long travel coils, which doesn't sound like either have any intention, the only option I see will be whatever Icon comes up with. Think it's Todd that recently bought an 80 with intent to develop products for, and they've experience not only with shocks but full suspension systems, including arms, links, bumps, coils, all designed addressing all aspects.

But if $400 a shock is daunting, then I'd suggest sticking with a given off the shelf offering from a proven vendor.

Here's my deal.

Before getting into taking Toyota's off road, was a duner (yes, we have dunes in OK) and learned that suspension is the difference between riding for an hour or two, or riding all damn weekend.

To me, it's the second most important aspect of a "build", second only to reliability/durability.

I find the reference to "rock crawlers" problematic....,.,,,,,So, the "rock crawler" terminology might not be so useful for a truck that'll see street use.... Just sayin'

You're right and think "rock station wagon" is more fitting.

It is what it is.

I've an affinity for Cruisers since my buddies dad bought one new in '83 at the tender age of 8. Don't think any other vehicle that I have actually laid eyes on and ridden in ever had the same impact, but my families simple, so haven't been in much more than domestic POS my whole life.

That said, if the ONLY goal was a rock crawler, of he money ahead to buy a Heep or buggy, but it's not and never has been, but want a capable, rock capable Cruiser (I know. I was confused Pos app.

...the FJC.

More or less, my goal has always been to take the OE and maximize it for all it's worth.

Stupid, expensive, but it makes me happy.with the

 

[sleeoffroad]

Just a fleeting comment from the peanut gallery.

I find the reference to "rock crawlers" problematic. Some of my rock crawler friends think nothing of e.g. starting with a nice 550lbs Dana 60 that ends up as a 1200lbs front axle after extensive trusses, and whatnot, and water in 42" stickies... Of course, that thing will droop to the max AND stick to the ground. For these guys, all the stuff above the springs appears to be a necessary evil, and they don't care where it hangs, rubs, or leans, as long as the axles are on the ground and the motor doesn't lose oil or fuel pressure. So, the "rock crawler" terminology might not be so useful for a truck that'll see street use.... Just sayin'

Peanut gallery knows some stuff Especially the last sentence, unless you are trying to make a pig into a butterfly!

Believe me, I can show you the Toyota Trails article where I wrote after the first outing in the ShortBus that I thought this was the best rock crawler eva! Still choking that one down, but I guess the rocks just grew over time and eventually I drank beers in the camp while waiting for parts!

That is why I think this is the best rock crawler now!

 

[Delancy]

I have a love/hate relationship with my iPhone.

 

[Delancy]

Or are you moving current short spring to other side and installing new short spring?

Yes.

Moving the current PS shorter spring (570) to the to the DS and replacing the PS with new shorter coil. (555)

 

[Delancy]

That is why I think this is the best rock crawler now!

TRAITOR!!

Bahahahaha.

 

[AutoCraft Aus]

Part of the reason us aussies like a different set up too.


We tend to carry everything in the car, to live out of it, everywhere we go, not base camp or trailer the vehicle there and back.

Its a whole new challenge, that keeps it interesting, especially with the amount of holidays we get

One week cannonball desert trip load.

Just need to work out how to fit a RZR in the 80....

 

[kbahus]

So the peanut gallery is wondering about the sway bar now, if you add a super stiff rear bar how does that NOT limit flex? It's basically another spring forcing the axle to be parallel to the frame to reduce body roll.

 

[Delancy]

So the peanut gallery is wondering about the sway bar now, if you add a super stiff rear bar how does that NOT limit flex? It's basically another spring forcing the axle to be parallel to the frame to reduce body roll.

It does, to some degree, but I contend the benefit to outweigh the detraction.

I'm not talking about an OE replacement bar, though, which hits the housing on mine and it's ability to control body roll is diminished drastically on a lifted 80.

In my opinion, running a stiffer bar aft the axle isn't a fix, either, since it still doesn't address the amount of force that's endured by the links.

My vote is frame mounted sway with axle mounted links.

 

[ChaseTruck]

...
But if $400 a shock is daunting, then I'd suggest sticking with a given off the shelf offering from a proven vendor...

It's not necessarily the $ number that's the deterrent. It's that the truck is a slightly tired leaf-sprung oversized box (which has served me very well over those last 17 years, I should add...). It's also that I've been to most places in my range where the Blazer will fit. Furthermore, I neither have time nor equipment nor knowledge to do shock tuning.

One of the things I've always admired in my 6+ years of trail running with 80s is the inherent stability of that vehicle. I've done a lot of spotting 80s thru obstacles in that time, and have a pretty good idea. Not that we've got one, I won't want to give up that stability.

I guess I'm becoming too old for both the soft, wobbly Blazer AND the shopping cart-like suspensionhillbilly of my wife's '40...

 

[AutoCraft Aus]

So the peanut gallery is wondering about the sway bar now, if you add a super stiff rear bar how does that NOT limit flex? It's basically another spring forcing the axle to be parallel to the frame to reduce body roll.

I think if you read what I posted, it says it did limit flex.

If you add weight, and add sway bar, the leverage is roughly the same, so if any travel limiting happens, its minimal.

Below, with heavy rear coils, 130% sway bar, empty 185 lt fuel tank, empty 60lt tank, empty 60lt fridge, no camping gear, sway bar made about 2.5" difference on the ramp to total travel.

Having said that, we have spoken with a shock company about a bypass adjustable sway bar link with lock.

One day when I have nothing to do.

 

[Delancy]

One of the things I've always admired in my 6+ years of trail running with 80s is the inherent stability of that vehicle. I've done a lot of spotting 80s thru obstacles in that time, and have a pretty good idea. Not that we've got one, I won't want to give up that stability.

I hear you, and reason why I sought to keep it 3" and admired Darren's build style on the first slinky 80 I came across long before buying.

Guess the mentality is flawed, but wanted low to keep stable, yet free up articulation to make it crawl over anything.

I'm coming from wheeling and FJC that the entire undercarriage is a solid steel skid. Used to dragging it over everything, so don't know what would be different about the 80.

One thing about the rock crawling discussion that should be cleared.

We don't have but about 200 acres of rocks like y'all have out west. Most of ours looks like this



Boulder ridden trails on steep inclines, not much smooth rock faces with huge crevasses.