build thread from the wind tunnel

[Justin]

Depending on the complexity I can probably knock it out on Saturday.

[Gunnibronco]

Oh yeah I forgot. I reread a post in my 66 parts wanted thread about t-case shifter. I'll gladly take the steering linkage. Thanks.

[Eck]

Not sure if you looked back at my pics on the ZF crossmember and I am not sure what all I posted but here are some pics that may help with coming up with a solution. As you can see, the tube is rear to the stock hole location and we welded it to a plate that was installed still using the stock holes. You can see the plate that attaches to the ZF is also forward of the tube. With already having a support crossmember on the ATLAS, I would think that you could do something very similar to what we did on mine and it would be plenty strong enough...

[Gunnibronco]

Justin,

Can you put a 130* bend in a piece with 17" on one side & 15" on the other? That would give me a little on each side to cut off & fit.

I thought about an "S" shaped mount, but I don't see why a simple "V" shape wouldn't work. If I don't like it I can improve on the design later.

[landshark]

Here's mine thanks to Justin as well.







I used 1/4 plate to reinforce the frame and added duff long arms shortly after this. No issues has held up nicely.

[Gunnibronco]

Thanks for all the pics. The 'doubler' part of the Atlas4 sets the front output back far enough that a straight crossmember is just not going to work. I'm not 100% happy with my current plan for a crossmember, but it's the only option I can see right now. I think it will work, it will just look odd.

[Justin]

Justin,

Can you put a 130* bend in a piece with 17" on one side & 15" on the other? That would give me a little on each side to cut off & fit.

I thought about an "S" shaped mount, but I don't see why a simple "V" shape wouldn't work. If I don't like it I can improve on the design later.

Yes. You want the parts on either side of the bend bent back to straight, right? 3 bends total?

[Jesus_man]

I see a napkin sketch in the works!

[Gunnibronco]

MS Paint actually.

LOL, it looks like I forgot to attach this to the message I sent Justin yesterday.

[Rox Crusher]

Gunni, what will your final low gear crawl ratio be ?

[Gunnibronco]

Right now with 3.50 gears my crawl ratio will be 54 in my 2.62 low gear, 86 with the 4.3 gear, and 224 with both engaged @ 11.2.

I may be able to regear & add an Aussie locker to the front soon, as well. If I go 4.56s it will bring my low/low crawl ratio to 292. That seems reasonable.

[Jesus_man]

4.56's on 37's seems like a good setup. I'd like to do the same someday, but I am pretty happy with my 4.10's on 35's.

224:1 is plenty reasonable! But check your math... 4.56 x 11.2 x 6.72 = 343.

[Digger]

Right now with 3.50 gears my crawl ratio will be 54 in my 2.62 low gear, 86 with the 4.3 gear, and 224 with both engaged @ 11.2.

I may be able to regear & add an Aussie locker to the front soon, as well. If I go 4.56s it will bring my low/low crawl ratio to 292. That seems reasonable.

That is low!

Remember when 100:1 was a big deal? 2x on 4.56s with 37s. I love the way mine is geared with the 351W. Even pushing 20mph headwinds in Kansas, there was no issue maintaining 75+, but holy cow the gas mileage. I was getting 8 or 9 mpg until I slowed down.

[ZOSO]

4.56's on 37's seems like a good setup. I'd like to do the same someday, but I am pretty happy with my 4.10's on 35's.

224:1 is plenty reasonable! But check your math... 4.56 x 11.2 x 6.72 = 343.

6.72 is wrong. The zf is 5.72 and the 435 is 6.69

[Jesus_man]

4.56's on 37's seems like a good setup. I'd like to do the same someday, but I am pretty happy with my 4.10's on 35's.

224:1 is plenty reasonable! But check your math... 4.56 x 11.2 x 6.72 = 343.

6.72 is wrong. The zf is 5.72 and the 435 is 6.69

Yep, been out the game too long!!!

Chad - nevermind my mindless rambling. 292 is indeed accurate. If I felt more confident I'd break it down into feet/min for you! That's when it becomes real!

[Rox Crusher]

4.56's on 37's seems like a good setup. I'd like to do the same someday, but I am pretty happy with my 4.10's on 35's.

224:1 is plenty reasonable! But check your math... 4.56 x 11.2 x 6.72 = 343.

6.72 is wrong. The zf is 5.72 and the 435 is 6.69

Yep, been out the game too long!!!

Chad - nevermind my mindless rambling. 292 is indeed accurate. If I felt more confident I'd break it down into feet/min for you! That's when it becomes real!

FPM, the true measure

I saw kinder walk beside his rig once and thought that was so cool. But hey, I'm easily impressed.

[crawlercreations]

Figuring 700 RPM idle with 292 final drive on 37" tires you will travel about 23 feet per minute. Just over 1/4 mile per hour.

[Gunnibronco]

That is low!

Remember when 100:1 was a big deal? 2x on 4.56s with 37s. I love the way mine is geared with the 351W. Even pushing 20mph headwinds in Kansas, there was no issue maintaining 75+, but holy cow the gas mileage. I was getting 8 or 9 mpg until I slowed down.

I remember when I thought I was hot chit with a NP435 & 4.11s.

That's good news about the gears, I wasn't sure how the 351 would like the 37's on the highway. Thought the rpms might be a little low.

I figure I'll probably end up on 37's before I swap motors. That will probably turn my ZF into a 4 speed. In 4th, at 1:1, with 4.56s it gives me a decent cruising rpm @ 2800 (close to my 4.11's & 33s). Then I can swap in a bigger motor and start using 5th gear again.

I really bought the 4 speed because I wanted a deep gear like the 4.3, but didn't want to be so deep that I couldn't keep up on average trails, or switch back to 1:1. I like that I have a stockish low, and a deep low. I didn't think the 11.2 would be that useful, but JD & others have discussed the control it offers, and I'm looking forward to experiencing that.

[Gunnibronco]

Roughly eleventy bajillion spot welds & sheet metal screws later. Driver's side is welded in. Next, grind, grind, grind.

[Gunnibronco]

Folded the seams over in the wheel tub.

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I'll seam seal everything, and I'm thinking of adding HNR & bedliner to the insides of the wheel wells too.

Passenger side wheel well cut out.

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[Kinder]

Roughly eleventy bajillion spot welds & sheet metal screws later. Driver's side is welded in. Next, grind, grind, grind.

Looks great!

[Gunnibronco]

I haven't been slacking. Just taking so long.

Driver wheel well is 95% done. Two pieces left to patch in, but I'm going to wait till the cage is out. Moving on to resetting the gas tank & fitting the fuel neck.

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[Jesus_man]

Thank you for documenting this process. Someday I'm going to show someone qualified than me your pictures and ask them to duplicate!

[Gunnibronco]

Thank you for documenting this process. Someday I'm going to show someone qualified than me your pictures and ask them to duplicate!

No problem, I'm glad to. I thought the driver's side would go faster, after doing the passenger side. But with the recesses for the fuel filler necks, it was different enough to slow me down.

I wish I had an old (or new) rear tub to use for the stretch. It would have made it a lot easier. I wouldn't have had to work around the body line in the tub. And the 16g metal I'm using for the patch isn't easy to work with.

[Justin]

I bought one new wheelwell for mine, cut in half, then used the pieces to extend things. More expensive, but less fab time.

[Gunnibronco]

Smart.

I hadn't planned out the next steps after the leaf spring swap. I have a 4x8 sheet of 16g steel, and saw a way forward.

Gas tank brackets are tacked in, and I test fit the tank. Tomorrow I'll pick up the right hardware, and try to get it hung permanently. Then figure the fuel filler.

[Justin]

I just ran the stock filler. Should work fine, although my axle isn't as far back as yours.

[Gunnibronco]

My filler neck has already been cut up, the Silverback flares pushed the filler from the original location. I might have to move it again. I haven't positioned my flares yet.

I've also moved my tank back a couple inches.

[Gunnibronco]

Although it may seem I've been busy hustling Broncos from the poor people of Gunnison, I really have been hard at work on my 74. It just has all seemed so slow and tedious.

Gas tank hung, new lower half of rear bumper built, added license plate to gas tank holder on spare tire carrier. Some more prep work on welds & herculiner done. Added a cheap aftermarket washer bottle, because I couldn't figure a way to put my old stock tank back on. Moved my P/S cooler down in front of the radiator.

[Justin]

Nice!