Here's something I came up with using the equation from the previous two links.
rpm = (mph x final gear ratio x 336*) / tire diameter

Hopefully I did it right.

Not sure on the double OD so I just multiplied .77 * .77 cause I think thats probably a likely overdrive ratio.

Cheers,
Devin

 

That loos very good. I just made one that calculates rpm for a 5 speed main with up to 4 aux gears and a hi/lo transfer case. It also accepts metric and imperial size tires. You can change any fundamental value and it recalculates. It doesn't have any nice colors though.

If anyone wants to take a look, feel free to ask. I'll post it on a file sharing site tonight or later.

 

post it up here, picture is fine, that's what I did, cause I'm lazy.

Devin

 

http://www.filedropper.com/gearratiotiresizerpmchart_1

Here's a link to the file for anyone to use. A picture wouldn't be large enough. You can change the rear end ratio, tire size, the 5 gear ratios, the 4 aux ratios, and the transfer case ratios. Don't change anything in the large table unless I made an error. I made a small table underneath as a sample so you don't have to search through the big table. 1 sheet is metric tires and the other is imperial.

If anyone has a preferred file sharing site, just let me know and I'll re-host.

 

So had a pretty productive weekend.

Wired in the fuel filter heater on a relay and fuse, no switch yet. It has a quick connect underneath it and its own shut off at 70 degrees. So I will probably unplug it in the summer and think about adding a switch later on.

Anyway finally got to one of the projects I've been pretty excited about. Finally mounted my 19 gallon air tank to the frame for my on board air project.

Hopefully i will get to plumb it in tomorrow.

Cheers,
Devin



Making the bracket




Fastening with 1/2 bolts




Test fit, used ratchet straps previously to test fit.




Mounted with 2 1/2 bolts on top








Pulled it back off after I tacked it with the welder




Not a bad weld




All mounted




All cleaned up and back in her parking spot

 

So just got off the phone with a guy that has a diesel 2wd zf5 about an hour from me. I am seriously considering going down to pick it up this weekend as part of my drivetrain project. I do feel alittle uneasy though because I have not finished my research. As of now my thought is a 2wd zf5 linked via a u-joint to the brownie and a u-joint connected from the brownie to a divorced transfer case, maybe a np205, I don't know a lot about transfer cases yet. The part that really hangs me up is how am I going to make all the shift linkage work? People must be doing it somehow.

Thoughts?
Devin

 

Personally I think that set up sounds over complicated with too many joints, long janky shift linkages, and a whopper of a mile long front drive shaft. If it were me, I would hold out for a 4x4 ZF-5. That would give you hi and lo range gears in 4 wheel drive up to .77 overdrive. Then if you want a double overdrive, mount your brownie behind the transfer case and use it in 2wd ONLY. That is how the GearVendor unit functions. The controller prevents it from engaging in 4wd. With a transfer case and a ZF you already have low gears all over the place. Lots of them and close together. The only thing you are really missing is a cruising highway gear (i.e., double overdrive). You don't really have any business driving that speed in 4wd anyway, so no real loss in running it behind your transfer case as long as you don't ever engage it in 4x4. I'm not saying your combo couldn't be made to work, but it sounds like a U joint/shift linkage/cross member/driveshaft nightmare from hell.

 

Yeah I will need to think this through, because my thought was if I did the brownie I would have the low speed too which would be cool for double low with the transfer case, but if I go to a np205 the low is only 1.96, which if I would be sacrificing the 2.74 low from my bw1345, so if I ended up with say a 1.26 low in the brownie, it really wouldn't make any sense at all because I wouldn't even end up with a better low range setup. So maybe there is some food for thought in a overdrive behind the tcase.

Devin

 

Ok here's another angle. I'm not gonna be doing any rock crawling, what else can I do with double low? Would it be good for pulling things, downed trees, rocks, stumps? I get how it slows you down, but I don't get how you get more torq

Devin

 

it's nice to have .. the low low

it winds up real loud in 'monster truck mode'

and it drives cool .. everythings' split in half essentially so 1st is really slow but pure torque .. can pull 2 houses down at once instead of just on e ..

3rd in low with lockers on is a blast .. it's louder and more torque and slow .. when it's loose and i'm just going for fun or off roading i put it in low ..

it really is the 'monster truck gear'

and people are amazed at the sound it makes it winds way up and pulls really hard for the speed .. it's great keeping under 30 mph in the loose stuff ..

i would a agree though .. get a 4x4 mated tranny and box and put a overdrive behind that .. and the lockers are great too but just use when really hairry like super mud or ice ..

 

Basic gears dude. Reduction is speed loss and torque increase overdrive is speed increase torque reduction. So if it was 2:1 reduction and the input was 500 rpm and 200 ft lb of torque with a 2:1 ratio it would make it 250 rpm output and 400 ft lb of torque. So with an underdrive box lets say set up is s-42 460 5 speed with a 1356 transfer case with a 205 and 4.10's, it works out 5.72 x 2.69 x 1.96 x 4.10 works out to a total reduction of 123.648. So for one revolution of the drive tires is 123.648 engine input. So what ever the reduction is the input torque is multiplied by that so like a stock n/a 7.3 making 338 ft lbs of torque so 123.648 x 338 would make a whooping 41793 ft lbs of torque of the tire, not accounting for any driveline loss with this math but you can see low low can make a whooping amount of torque if setup right.

 

4 Lo is already pretty crazy. At that point traction is by far more of a problem than having enough torque. If you want ultra lo range, then get a wide ratio ZF-5 that has the granny low 1st gear. Diesel F450's have it or just drill the bellhousing from a 460 gas ZF to fit the diesel. In 4 lo and 4.10 axle gears your final drive ratio is like 64:1.... About three times lower than most granny crawl gears. 460 ZF's are easier to find, and Justin put 400+ hp 900+tq through his with a drilled case without issues.

 

hey now thats' good to know ..

a 460 ZF is a much more realistic JY find then a diesel tranny ..

if one does happen across such a beast should the flywheel and clutch pack also be yanked .. will it setup or will need a matching luk kit anyways?

is there any difference to how the flyweel would balance on a 6.9 and would the 1345 bolt to the back ?? driveshaft length stays the same or grab the ZF shaft?

sorry Devin ^^ for somalli pirate >> but inquiring minds want to know

 

460 and diesel use the same input shafts so any zf5 clutch will work just dont use a dual mass clutch on a single mass flywheel bad things will happen they dont have centre hub dampeners. As far as drive shafts 5 speed is longer than 4 speed but shorter than E4OD. 460 driveshafts may or may not work ethier. But with your trucks set up with 3.55's and 35's a 460 5 speed would work pretty good I would think, first is 5.72 instead of 4.14, and your transfer case off the back of your 4 speed would bolt right up to the zf5. Worst case scenario lengthen front shorten rear shafts.

My own personal set up on the gray f250 is going to diesel transmission with 1356-1345 doubler with 4.10s and 40's, theirs only 35s on it right now. I need the doubler to pull out the black f250 when its broke and stuck bad as its a heavy sob 460 5 speed 205 transfer case 1 ton's with 44 and miller and lincoln lockers so when its stuck its stuck bad.

 

The 460 flywheel won't work. You need the Luk kit for the IDI. The 4x4 ZF length is close enough that it will swap directly with a T-19 or C6 with no modification to either drive shaft. Do get the ZF cross member if you can, as it will bolt directly to the existing frame holes. A T-19 cross member works but you have to move it slightly and drill new holes which is easier said than done with the cab on the way. The best way to re drill the 460 bellhousing is to enlarge the top two holes first (IDI uses bigger bolts) then remove the adapter plate from the back of the engine and bolt it on as a template. The starter bolt holes are the same. The wide gear ratio may or may not be the greatest depending on your tires and axle ratios, but for my set up I will prefer it over the close ratio gear set.