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Discussion Starter #104
Hey Guys, Sorry for the delay.. Updates on the buggy are all in software.. I have been working on the chassis, and integrating all the drivetrain components in CAD first, rather than chopping up a solid axle chassis and trying to make things fit.. I have been making alot of progress behind the scenes.. But sadly not much drivetrain goodies to add yet. I have also been working on the rig that will haul the buggy!!

Took delivery of this guy recently.. Will be a Flat-Bed Crawler Hauler!

And yes, those are 46's :smokin:

Let me know what you think!!





 

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Sweet truck man! I would throw another set of the front springs under the back and go 4x4 on it VS 6x6 just to reduce tires on ground and free up some weight and hp\tq loss. My only warnings if you never had a military truck like this before would be prepare to either do a gear swap or trim for the 14.00r20-16.00r20's if you want to drive on interstate for any amount of time and leave yourself about extra hour to get anywhere since you will be spending time talking to be people at fuel stops lol.
 

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Discussion Starter #110 (Edited)
Sweet truck man! I would throw another set of the front springs under the back and go 4x4 on it VS 6x6 just to reduce tires on ground and free up some weight and hp\tq loss. My only warnings if you never had a military truck like this before would be prepare to either do a gear swap or trim for the 14.00r20-16.00r20's if you want to drive on interstate for any amount of time and leave yourself about extra hour to get anywhere since you will be spending time talking to be people at fuel stops lol.

Yeah there are guys out there that convert to 4x4.. but then its basically an M1078.. I bought this rig because it was a 6x6 and plan to keep it that way.. It tracks way better on the highway, and the fuel milage difference is not noticeable.. They get 8 MPG no matter what.. Also, more tires actually helps in the mud, snow, and sand, especially when I have the buggy on the back.. it has the CTIS system that airs down the tires for Sand, Mud, etc. to increase surface area of the tires.. It works really well..

I have looked into putting 53" tires on it.. There are YouTube videos of guys who have done it, but they are just too big for the truck. The front tires rub while articulating/steering, and the rears get way too close to each other while off road as well. I may go with some Michelin XL 49" tires however.. This size is the largest you can go without problems..

Currently the governor limits the top speed to ~57 MPH.. Not too bad for road trips, but there is a third member swap you can do, which pulls diffs out of another large/heavy hauler in the military called an MRAP, which lowers the diff from 3.90:1 to 3.07:1.. This allows you to cruise at 65-70 MPH while keeping the RPM happy.. Got these diffs scheduled to be changed out this summer.. Going to start building the tilt-bed/flat-bed in the coming weeks.. :smokin:
 

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Getting the brakes figured out is a little tricky. Going with too large of a rotor does create a concern with ground clearance. Using a rotor too small won't allow the caliper to mount properly without interfering with the diff housing. Hmmmm :confused:
Trying to learn here... if ground clearance is a concern, why not mount the brake at the other end of the driveshaft?
 

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Discussion Starter #112 (Edited)
Trying to learn here... if ground clearance is a concern, why not mount the brake at the other end of the driveshaft?
Yes this is an option as well.. And it is an option some guys go with on rock bouncers. The problem with that is fitment gets even tighter in the transfer case area when you have rotors and calipers up there.. My plan is to use this area for a small parking brake rather than main brakes.. Will help save the U-Joints a little as well.. I don't think my diffs will be that much lower than my t-case, but we will see.. :confused:

T. Cameron did something similar to what you mentioned..

 

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Heres some pics of the rear suspension..







Weld retainers on those dog bones. The bushings dry out and you loose them.

Big washers work.
 

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NERD
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Just found this thread and can't believe I've never seen it.

Definitely a huge fan of the work you've done so far :smokin: I run Eaton H072 centers front and rear on my TJ and a 14B IFS center is right up my alley of "cool as fuck". Nice job!
 

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Just found this thread and can't believe I've never seen it.

Definitely a huge fan of the work you've done so far :smokin: I run Eaton H072 centers front and rear on my TJ and a 14B IFS center is right up my alley of "cool as fuck". Nice job!
So you have an independent with a HO72 center? Or just the center section? Got a post to look at??
 

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NERD
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So you have an independent with a HO72 center? Or just the center section? Got a post to look at??
Not independent, although I have been designing an IFS TJ project for a few years now. It's been stalled while I'm waiting for technologies involved in such a project to become a little more economical. Mainly the CVs and center sections since most Ultra4 style IFS fronts are using Series 30 CVs which are $$$ compared to a typical D60 style front.

My rear axle is an Eaton H072 with just a disc brake conversion. Still uses 17 spline axles and factory locker. The front H072 has Dodge Unit Bearing outers which are a 33 spline stub and have held up well. The Ford unit bearings seem to be a decent way to go but I prefer the drive flange style UB like Chevy and Dodge.

My build is here (kinda long): https://www.pirate4x4.com/forum/jeep-hardcore-tech/1017927-project-piss-off-my-neighbors-set-my-condo-fire-47.html

I designed and built a IFS/IRS buggy for RC Baja comps when I was in undergrad. It placed 3rd on its first outing even with terrible rear suspension geometry. I learned quite a bit from that car and never got around to implementing the 10 degree front kickup you mentioned. I also built around 40-50 RC cars, trucks, and buggies since I was a kid and that's where I learned the most about independent suspensions. I also designed a few 3 bar and 4 bar suspension systems and learned quite a bit from there and it all kinda blends together on a IFS Ultra4 type build. If you ever want some help on the geometry or design, I'd be happy to help. I design everything in Solidworks and can compare to some of the notes I've taken over the years. I'm sure there's others that can help as well if you want it.

I'm excited to see yours take shape and to see how you accomplish all of it. If you look in Gen4x4 there's the Last Starfigher IFS build which is using 42" MTRs and 935 CVs with success in front of a healthy LS3. With a front engine vehicle, a high pinion diff in front would be the best bet but it sounds like the CVs are holding up well. He seems to have more issues with the unit bearings (Ford style) but welding the rear retaining nut has helped quite a bit. You may also want to look at Maui Matt's IFS Bronco build. He did a great job putting that together and it's still one of my favorite builds to date!

The IFS Bronco build here: https://www.pirate4x4.com/forum/general-4x4-discussion/891512-hallstyle-ifs-early-bronco-skinned-buggy-build.html
 

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Not independent, although I have been designing an IFS TJ project for a few years now. It's been stalled while I'm waiting for technologies involved in such a project to become a little more economical. Mainly the CVs and center sections since most Ultra4 style IFS fronts are using Series 30 CVs which are $$$ compared to a typical D60 style front.
Andrew McLaughlin ran the 4400 class for several years with both 935 CV's. He had no issues with the inside CV and minimal issues with the outside. They were fully maintained after every race though. Others have done it also and generally broke everything else around them. The key is to minimize the travel and/or turning to keep them alive.

It is entirely possible to get 17" of travel and 34* of steering with an outside 935CV. A 30 series can net you 20+ and 38* turning. Keeping boots to live at the compound angle of 45* can be a challenge!!

Andrew's experience convinced me to use the 935 inboard and the series 30 outboard. Reducing the travel to 18" should make maintenance life easier...as a recreational rig. Another key to longevity is making sure the stub shaft exactly fit the CV outer diameters. Diameter centric , not bolt centric. Outside boots can be a PITA!

If you can live with the travel and steering, the 934 series will allow the bottom arm to mount closer to the hub center, gaining some ground clearance. Boots are easier also, and something everyone forgets about in their first go-round. An adventure.......
 

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What are the plans for the hubs? I ask because I just made a set of outer stubs in 4340 and will be doing inners soon.. 35 spline for 934 CVS... Hub is a standard 05+ Unit bearing, custom brake hat etc, custom knuckle... My center will be a D60, very similar to what you're up to... I suppose if you're not using a CV then you may be able to get away with a factory option.. but from my limited experience (of 6 mos designing) the knuckle can be tricky esp if youre trying to minimize/maximize certain parameters..
 
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