Dana 30 Build: Sleeve, Truss etc.... for 35's

[nosigma]

Sessy. Will it force a lot of heat up through the floor though once your belly is bolted on?

Yes it will. I am very concerned about this. I will be putting some really good insulation on this (space shuttle like stuff from a pile of left over turbine exhaust tiles). Once I put the rear seat in I will see if I can fab up a "heat riser" tube that will exit the side of the XJ just behind the front pax door (2 door) with either header wrap or more of the high tech stuff.

xriide,
We shall see how it performs. 4.56's, Gizzly auto locker, RCV's. I have no doubt it will work just fine here on the east coast. 35's dont seem to break built D30's back here like they did out west. Family wants me take another 3yr detailing to San Diego (cant wait to go back) and that will be the real test. Grippy, not slick rocks, big rocks and lots of possibilities to get bound up.

John

 

[cal]

Y Family wants me take another 3yr detailing to San Diego (cant wait to go back) and that will be the real test. Grippy, not slick rocks, big rocks and lots of possibilities to get bound up.

John

DO IT

 

[Gary Briggs]

Seems like the consensus problem is the ring/pinion strength. I recently picked up a spare 30 that I'm going to truss and gusset and then install some 4:10 gears.

I'm going to pair that with a disc brake 8.8 out back and run 33" or 35" tires. As opposed to deeper gears that are weaker I'm either going to install and Atlas T case or a doubler.

I'm hoping I'll get a desirable crawl ratio without having to install those weaker R&P gears?

Anybody see any flaws in my logic.

 

[yossarian19]

Well, your highway drivability is still going to suffer. For crawling, that'll be fine.

 

[Gary Briggs]

Well, your highway drivability is still going to suffer. For crawling, that'll be fine.

How so? Right now I'm on an AX15 with 3:07s and 31"s and I get around just fine on pavement. Even in the Sierras I don't have a problem, I simply down shift. At 65 mph on the freeway I'm turning 2050 rpm's and getting 19-20 mpg. I see people running 4:88 and 5:13 on 33's and and spinning well over 3k rpm's to hit 65mph, seems crazy to me.

I figured I'd see similar characteristics with 4:10 and 33's

Edit: I'm probably not giving enough consideration to the weight difference when you step up out of the 31's

 

[yossarian19]

Shrug. With an auto I thought 31s and 3.55 brought the suck

 

[1990JEEPXJ]

With a manual you can get away with that a little easier. With an auto I thought 33's and 4.88's was perfect. Still got 16-17mpg hwy. Now that I'm on 35's it sucks on the highway and I get worse mileage.

 

[Gary Briggs]

I suppose there is only one way to find out, I got the 4:10 gears for both the 8.8 and the 30 for 80$, I'm not out much of I'm wrong.

 

[jdjohnson]

So after reading all 10 pages i have come to the conclusion that if you buy a built axle and or spend a crap ton of money on it your a d bag and if you build your own your an idiot because it wont be strong enough. Or maybe its the other way around.

So now comes the big question. do i want to be a D bag or an idiot when i build my axle

 

[rockclimber]

I chose the D-bag route. more fun. YOLO

 

[GordoSmasho]

I used to commute hauling about 700lbs of tools with those 4.10s and 35s gary. With my ax15 it was deffinately doable. If you go with a doubler it would be awesome in the rocks. Grab a hand throttle. Ill be back to a stick soon with a doubler and d300. However ill be running 4.88s and 35. Then 5.13s and 37s.

 

[VAhasnoWAVES]

i with the manual everything is subjective.

im on 4.56s with the AX15 and 35s... no where near low enough. doable on the street, but still not ideal. time for a doubler for offroad.

 

[Gary Briggs]

I used to commute hauling about 700lbs of tools with those 4.10s and 35s gary. With my ax15 it was deffinately doable. If you go with a doubler it would be awesome in the rocks. Grab a hand throttle. Ill be back to a stick soon with a doubler and d300. However ill be running 4.88s and 35. Then 5.13s and 37s.

Appreciate the insight Gordo. Pretty much made up my mind on the Atlas T-case. Stuck a deal with my wife, she gets a new Explorer and I get to build up my XJ.

i with the manual everything is subjective.

im on 4.56s with the AX15 and 35s... no where near low enough. doable on the street, but still not ideal. time for a doubler for offroad.

That's my experience right now with the 3.07 and 31's, acceptable on the street but leaves a lot to be desired on the trail. I feel the Atlas will do the trick!

 

[cal]

the difference in strength between gear ratios is more fable then fact. you just don't find many big tire hardcore guys on 4.11's or 3.55's. the few that you do people say their breakage is clearly other reasons.


gear for the ratio that will treat you best on the highway and don't worry about it. that is to say, go deep.

 

[1990JEEPXJ]

D-bag route is where it's at

 

[IdahoEagle]

Years ago I had an 87 MJ with 30s and a 4.0 and 5 speed. It sacked on pavement in 5th gear any slower than 80mph... But I could get 22-24mpg going that fast... I used to work in BFE Wyoming at the time, so I saw a lot of freeway use going to Utah on a weekly basis. 3.55s to 4.10s would've been a much better ratio for it even if it only had stock size tires under it... It was way over geared...

 

[nosigma]

I got the lower control arm mounts all welded in today (had a shop do it, a man should know his limits) and it looked so pretty I clear coated it.





Notice that there is no mount for an upper control arm. Yep, I moved east, its going to be a radius arm build (no one from SoCal will ever talk to me again now). Ridden in a couple east coast buggies set up with radius arms (Y link on driver side only) and I was very pleased with how they did not unload. Maybe its the rocks back here, maybe its the torque pulling the chassis down. It just simply works. Rode in an XJ with dual Y links and it unloaded bad. Rode in one with a single Y link and it didnt (same trail). I originally laid this out for a 3 link build so being a scheming bastard I can always lop off the Y link and add the tower and 3rd link. If I get the job in San Diego its going to be fun to see how it performs east/west, radius/3 link.

John

 

[DeftwillP]

Aren't the physics the same regardless of one y arm or two?

 

[nosigma]

Aren't the physics the same regardless of one y arm or two?

No. First you have binding when you run a dual Y link. This is why rubber bushings are use all around on dual Y link front suspensions. Eliminating the pax side Y link eliminates the binding on articulation. More important is the axle housing reaction. Tires rotate forward, housing rotates back. The Y link on the driver side only creates a bending moment on the long arm that pulls down the driver side. This counter acts to some extend the rear axles tendancy to LIFT the front driver side into the air. Google a "drag race launch chassis twist video" and you will see what I mean, the rear tries to lift the front driver side into the air. On a 4wd the torque reaction of the driver Y link tries to counter act that. A Y link on the pax side would only make it worse. A single Y link put all the forces counteracting the axle trying to rotate back into the driver side radius arm, pulling down the drivers side of the vehicle.

By making the long arm chassis end as far aft as possible and as high as possible (above the frame rails and under the transfer case) I move the virtual center (same as physical for a radius arm) as high and as far back as possible relative to the CG. This reduces the diving on braking and lifting on acceleration as much as possible. The long arm virtual (physical center) is never going to be as high or as far aft as a 3 link but its not bad. This is where my experience riding in the XJ's and 500hp buggy come in.

The dual Y link XJ's lifted a lot on a climb. The single Y link rigs were had no significant tendency to lift the front from the pax seat. The buggy was absolutely FLAT on a steep climb, no lifting at all. Super stable. I would not have believed it if I hadnt ridden and later driven it but thats how it was.

Lets be clear. Granite, mud an moss reduce traction and reduce the tendency for the front end to unload. A radius arm will never have virtual centers as high or as far back as a 3 link. Here on the east coast where we don't have volcanic rock or sand stone it seems work really really well. If I get back to San Diego this spring I will be able to eliminate that variable.

Hedging my bets though. I can still add the driver side 3 link tower to the cross member and go 3 link if I find unloading to be a problem. I like experiments.

John

 

[Demonoid369]

Just curious as to how to picture this, a double Y radius is like the serious offroad long arm and the single Y radius is like the IRO long arm right?