Topic: INFO FROM BUDBUILT!

[hudlenutz]

So if an axleshaft can take 9000 ft-lb, the diff would see 18,000 ft-lb just before failure.  That's reduced by the diff to 3402 ft-lbs at the transfer case output.   

That sounds good to me.  The most torque ever coming out of the last transfer case is 3400 ft-lb...  maybe.

[blackdiamond]

equal and opposite...  the tissue or anything else, can't push back any harder than you're pushing on it, otherwise one of you will move. F=ma

In the tissue example BigMike is suggesting that the tissue fails (is moving) so I'm not 100% sure how to apply the Equal and Opposite F=MA equation.

[hudlenutz]

Ok, I get it, so the equivalent would be torque expended into a wheel that's spinning by increasing its rotational inertia, accelerating it. 

[gedean]

   I'm just a jarhead, not an engineering student or even much of a mechanic.  I'd like to think that I have a little common sense though.  There are a couple of reasons I'd have to agree with Big Mike.
   I know that for years Downey and Northwest Offroad have both sold conversion bellhousings for toyota transmissions to adapt to domestic v-6s, and v-8s. As you read the description in their catalog though they will even tell you that they dont' really recommend it as the toyota transmissions aren't up to the task of taking that much torque.  They will even tell you that they only sell them because people will buy them.  At the same time they sell adapters to put Yota t-cases behind domestic transmissions without saying a word.  Hmm, wonder if there is something to that? 
   Not to say that Marlins design isn't robust but in all honesty how often are we using them?  Yes I know a lot of you wheel your rigs hard, but how often?  How many miles are you running around in 4 wheel low and double low?  A couple hundred a year if that?  Now how far are you going in your truck on the road during the year (well none if your rig is trail only but... you know what I mean.  So perhaps normal wear and tear will have something to do with it as well as the extra loads it's getting.

[IronClad]

all i gotta say is... 2 and a 1/2 gear   everyone i knows wishes they had one !   thats what dual trannys will give you .. i like the idea of pretty much half gears.. theres time that you need a half gear because one is to low and the other is to high..

[whiteman]

Holy crap     How do you guy's com up with all of this I wish I had the motivation to learn this crap.
   I have enough trouble with algebra

[79coyotefrg]

 

[IronClad]

Holy crap     How do you guy's com up with all of this I wish I had the motivation to learn this crap.
   I have enough trouble with algebra

they are just thinking about it to hard insted of just doing it or not doing it..

[BigMike]

all i gotta say is... 2 and a 1/2 gear everyone i knows wishes they had one ! thats what dual trannys will give you .. i like the idea of pretty much half gears.. theres time that you need a half gear because one is to low and the other is to high..

Yup I completely agree with you and others, and myself, especially when I used to drive carburated 22rs around, I really wished I had inbetween ratios.

I am just about strength issues. Ideally, like what UNBREAKABLE is thinking about doing next, is running Dual R151Fs (Turbo trannys). That is definatelly the tits. But for the average person (non-turbo drivetrain) that means they've gotta come up with more then $2000 for this modification, and I would rather have an Ultimate with a Rear Disco for that price-

equal and opposite...  the tissue or anything else, can't push back any harder than you're pushing on it, otherwise one of you will move. F=ma

Yup That's my buddies 2nd law!

And also, we have proved through Lab classes that even with an object is in an accerated rate, such as the falling 100 lb object, the tissue can only push back as much as it can, but it just seems the opposite when I think about it.

blackdiamond, I do remember from my Materials class that the applied stress increases to the yield point, and then it reduces as the specimen undergoes plastic deformation. Was that what the tensile strength was? Also, can something twist while still maintaining its original diameter? Because I remember calculating "necking" by the reduction in surface area. I wonder how this would apply to something that does not reduce its surface area

I still believe that the potiential is definately there for forces greater than 9000 ft-lbs, but of course something somewhere will fail first.

hudlenutz, nice write up.

Lets assume 37s, so the torque is 1.5417ft*2500lbs=3854 ft-lbs.

I guess with our tires deflated the radius would be less than 1.5ft, which would reduce the required torque even more

BigMike

[BigMike]

Hey hudlenutz or blackdiamond, maybe you guys are better at this as I didn't do so well in my Statics class when we learned about centroids and center of mass, but I bet if we assume like a 60/40 weight distribution, and wheel bases are around 110", so maybe we could assume that this mass is distributed over like a 130" distance, then we could see how much torque would be required to wheelie the truck about its rear axle.

Assuming nothing fails, if I bolted the rear axles down to the ground, and then put the truck in 1st gear at 1,047:1 and just let it idle in gear, I wonder how much torque would be acting on the rear axle by the time the front of the truck is at a 45 degree angle off the ground.

If I was back at home I could just pull out my Statics book and flip to that section, and I am helpless over here

[IronClad]

i'll letcha know how things work out.. im gonna stick a 4speed behind my w56 .. we'll see what breaks first !

[blackdiamond]

   I know that for years Downey and Northwest Offroad have both sold conversion bellhousings for toyota transmissions to adapt to domestic v-6s, and v-8s. As you read the description in their catalog though they will even tell you that they dont' really recommend it as the toyota transmissions aren't up to the task of taking that much torque.  They will even tell you that they only sell them because people will buy them.  At the same time they sell adapters to put Yota t-cases behind domestic transmissions without saying a word.  Hmm, wonder if there is something to that? 
   

I have no doubt that transmission are not as strong as transfer cases, and I suspect that both will be durable enough for normal use.  I am interested to see how it works out.  I would expect that shifter linkage would be an interesting problem to solve.

A V8 has more available torque and horsepower, but it doesn't really mean that it is transferring anymore into the drivetrain.  If the tires slip or something breaks the stress in the drivetrain is the same.  If the traction exists to increase stress levels to the breaking point, a V8 will break things much sooner.  Also, V8s generally provide more acceleration with allows for more wheel hop that results in impact loads that can lead to failure (A 100-lb hammer will cause more damage than simply sitting a 100-lb weight because the motion increases the effective load).

I have enough trouble with algebra

If you can handle algebra you have nothing to worry about!

Hey hudlenutz or blackdiamond, maybe you guys are better at this as I didn't do so well in my Statics class when we learned about centroids and center of mass, but I bet if we assume like a 60/40 weight distribution, and wheel bases are around 110", so maybe we could assume that this mass is distributed over like a 130" distance, then we could see how much torque would be required to wheelie the truck about its rear axle.

Assuming nothing fails, if I bolted the rear axles down to the ground, and then put the truck in 1st gear at 1,047:1 and just let it idle in gear, I wonder how much torque would be acting on the rear axle by the time the front of the truck is at a 45 degree angle off the ground.

If I was back at home I could just pull out my Statics book and flip to that section, and I am helpless over here

My books are all at work, I think, but I have the opportunity to sit at work for 8 hours tomorrow with zip to do so I might be able to use this to keep my mind occupied.

I vote that Marlin and Bobby Long team up and break some transmissions and transfer cases and see how much it actually takes!

[blackdiamond]

Maybe I am making this way too simple...

To be conservative, I assumed a truck weight of 5,000-lb, a wheelbase of 110 inches and a 70/30 weight distribution.

If 70% of the weight is on the front axle then it would have 5000 x .70 = 3500-lb

The moment arm would be 110 inches or 9.167 ft

The torque required at the rear wheels to lift the front axle would be:

3500-lb x 9.167 ft = 32,083 ft-lb

or

16,041 ft-lb per rear axle (equally split)

6,064 ft-lb at the rear drive shaft & 3rd T-case output shaft (assume 5.29 R&P)

1,290 ft-lb at the 2nd T-case output shaft (4.70 3rd case)

274 ft-lb at the 1st T-case output shaft (4.70 2nd case)

120 ft-lb at the transmission output shaft (2.28 1st case)

30 ft-lb at the engine (3.93 1st gear)

[BigMike]

Wow, that is pretty cool. I did learn about moments but I thought it would involve some trig and the center of mass, since the torque would be highest at 45 degrees and zero at 90 degrees...

None the less, thats pretty cool. So even with 100% traction the axles may only see about 16k ft-lbs of torque dispite that the engine is only putting out about 1/5th its potential

[blackdiamond]

Wow, that is pretty cool. I did learn about moments but I thought it would involve some trig and the center of mass, since the torque would be highest at 45 degrees and zero at 90 degrees...

None the less, thats pretty cool. So even with 100% traction the axles may only see about 16k ft-lbs of torque dispite that the engine is only putting out about 1/5th its potential

The required torque should be the highest when the truck is horizontal because the center of gravity is at the maximum distance from the point of rotation.  As the truck gets closer to vertical the torque approaches zero.  The center of mass is involved; however, it doesn't matter if you use the center of gravity or the weight on the front axle becasue the change in weight is offset by the reduction in the moment arm.

It would seem that the only reason for more power (i.e V6 or V8) would be so that a higher gear could be used offroad and for onroad performance.

What are you doing up so early on a Sunday morning?  I am stuck at work with nothing to do, except pay for the Aussie Locker/Longfield install from Friday, so I can't really complain.  It is way more efficient for me to sit at work for 8 hours than to do the work myself.

[BigMike]

Ah dang, you got me on that one. Yup, it would be the greatest at the horizontial.

Well it is just past 1am Monday morning here. I think learning so much about Japan and trying to catch up to everyone's language has caused me to loose some of my mechanical touch. I have been killing myself lately

[blackdiamond]

Ah dang, you got me on that one. Yup, it would be the greatest at the horizontial.

Well it is just past 1am Monday morning here. I think learning so much about Japan and trying to catch up to everyone's language has caused me to loose some of my mechanical touch. I have been killing myself lately

Maybe you should try cooking your food?  It might be having adverse effects.   

I have learned to enjoy seared fish, but sushi isn't quite right for me.

[UNBREAKABLE [OP]]

Hey all. I just wanted to let EVERYONE KNOW THAT THE TRANSMISSIONS ARE STILL BEING WHEELED>>>AND HARD

[blackdiamond]

Hey all. I just wanted to let EVERYONE KNOW THAT THE TRANSMISSIONS ARE STILL BEING WHEELED>>>AND HARD

    

[toynizzy]

call me silly if ya want but i am from the school of Keep.It.Simple.Stupid.i learned this in the air force and it works for me.im sticking with duals and some 4.7 gears in my crawl box.i think its cool that people are out there trying new things but i like simple and proven just my    but good luck with that set up  

[IronClad]

if you think about it  dual trannys is alot simpler.. all you have to do is make the adapter ( 2 pieces of plate and a tube) and bolt the 2 trannys together..  now with dual cases you have to tear down a case   modify shift rods and all kinds of other stuff..  the only reason  dual trannys doesnt look as simple to some  is because  its not a normal thing.

[blackdiamond]

if you think about it  dual trannys is alot simpler.. all you have to do is make the adapter ( 2 pieces of plate and a tube) and bolt the 2 trannys together..  now with dual cases you have to tear down a case   modify shift rods and all kinds of other stuff..  the only reason  dual trannys doesnt look as simple to some  is because  its not a normal thing.

Having dual transmission is sort of like having two complete transfer cases, a bit redundant. 

Reverse + Reverse = Forward 

That is why it should be Transmission, Crawl Box and transfer case.

[BigMike]

Well as you know reverse is lower than 1st gear (4.09 vs 3.95) so you could have a 15.6:1 First Gear Ratio (1st + 1st) or a 16.7:1 First Gear Ratio (reverse + reverse). But the sad thing is that, besides 5th gear (I hope UNBREAKBLE keeps his second transmission out of 5th gear or he should change his screen name), the #1 weakest gear in a transmission is Reverse, and the #2 weakest gear in a transmission is 1st Having one of these weak links is enough for me, let alone having twice the weak links.

BTW 1st gear + 4.70:1 t/case = 18.6:1 (and 50 times stronger then reverse + reverse!! ). Well you all know my opinion on this, but for the space Dual Trans would take up, I would rather have triple t/cases ANYDAY.

[UNBREAKABLE [OP]]

OH. BTW I am ordering 23 sp 4.7's I don't know what I am going to put them in though.

[BigMike]

Sweet!! BTW, Cheers on the Dual Tranny setup! I betcha love all of those inbetween ratios!

[UNBREAKABLE [OP]]

If I put the dual cases and 4.7's in I'd be over 695:1 with 4.10's in 1/1/L/L

[BigMike]

If I put the dual cases and 4.7's in I'd be over 695:1 with 4.10's in 1/1/L/L

I would hate to see the rear drive line on that setup, if it would even fit that is

[UNBREAKABLE [OP]]

HA my rear d-shaft would STILL BE LONGER THAN A TJ!