Crazy assed idea: Full Time Active AWD
 

So,

Anyone here know how ABS systems work?

I've decided that I'm going to try to make the AWD in the power wagon active AWD.

The NP203 is full time 4WD... Its NOT AWD. There's the problem. The 203 has a center differential that is open to allow front rear differentiation. However, when one end of the truck looses grip, I lose the ability to drive the wheels with grip, as all the power goes to the end with the least grip. I'm already planning on putting a lockright locker in teh rear, and a detroit torsen in the front, so, it will drive both wheels on whatever end it send power to, but...

Here's my idea:

Get the yokes on the T case outputs custom machined to accept a splined hub. slip the hub on, and bolt a brake disc to the hub. Now, there is a disc on the front and rear outputs of the transfer case. Put a caliper over each rotor, and hook it up to an ABS pump.

Put ABS sensor rings and sensors on the front and rear driveshafts, and have an Data Aquisition or a simple input/output ECU monitor the driveshaft speed. If it varies by more then X percent (TBD, I need to do the math and see what the difference in shaft speeds front/rear is at full turning radius, but I estimate it at around 8%), the ECU applies the ABS pump to the shaft that is spinning faster. This will make the power go to the slower moving shaft, and Voila, Active AWD.

Now, I know that ABS pumps should have no issue suppling the pressure and such, and, the sensor rings are no problem, the issue is writing the software and finding an ECU. I'd like to hear thoughts on wether you think I'd be better off trying to "hack" some sort of stock ABS controller, or, trying to write my own using an input/output controller?

Re: Crazy assed idea: Full Time Active AWD
 

cool concept. Im thinking if you know how to write the software to do it, that will be your best bet..
But i dont know... Looking forward to seein some pics of this..

Re: Crazy assed idea: Full Time Active AWD
 

you realize that 80hp overpowers stock brakes right?

solid concept, but you need to think about your braking setup a little more. drums would be a good idea, like 1ton and up service vehicles use (the parking brake on the driveshaft)

i have a d20 t-case (2.03:1 low, single stick) you can have for scrap price if you wanna ditch the center diff

Re: Crazy assed idea: Full Time Active AWD
 

thanks, but, It currently has a 205 in it right now, but, the 203 is the only case other then the Military hummer case that can be run in 4x4 on dry pavement and not eat itself. Teh Mil spec hummer case is teh 242 HD AMG. ITs hard to find, expensive, and, the drop is on the wrong side of the truck. I could flip it over, but, its got an oil pump in it because of the temperatures AWD generates. If I flip it over, the pump obviously wont work.

As far as overpowering stock brakes, what brakes do you mean? I was going to run like 4 piston RX7 caliper on a 10" rotor on each shaft. ABS pumps can put out like 2000 PSI. I also dont want to stop the driveshaft, just drastically increase its drag to make the power find the least resistance path, which, would then be the other drive.

Re: Crazy assed idea: Full Time Active AWD
 

another sick german :6

Re: Crazy assed idea: Full Time Active AWD
 

More work, but here's what I'd do. Weld up the open diff that splits torque to the front and rear axles. Now, you install a clutch pack betweeen the front diff so you can turn it on and off, and vary the % torque transfer to it by the hydraulic pressure on the clutch packs. That's how OEM's do it anyways. Might be just as simple as what you are proposing. Problem with your method is you're gonna loose a lot of energy to the brakes. If you loose traction in the rear and need to put 100 HP to the front tires, you have to eat 100 HP through the brake thingy to send an equal amont to the front. So you loose 1/2 of your power....

Re: Crazy assed idea: Full Time Active AWD
 

twin turbo, twincharged 360 V8... she aint gonna be short on power. I could just stick a Jeep Grand Cheroke Quadra Trac case in it (has your aformentioned Clutch pack type AWD), but, those are only rated to 3K ft-lb input. after the multiplication through the trans, the T case will see north of that by alot.

Re: Crazy assed idea: Full Time Active AWD
 

full time active awd is, get a non-diffed t-case.

/thread

seems like alot of extra work for a high hp high torque application that can be solved by simpler means

Re: Crazy assed idea: Full Time Active AWD
 

and then I'll have fatigue breaked to add to my standard power driven parts breakage. Not to mention the crummy tire wear.

Id love to put a NV242HD AMG out of an H1 hummer in it, but, they are expensive, and, the drop is on the wrong side. Its a shame, they can take like 8K ft-lb input, and have a 60/40 torsen in them.

Re: Crazy assed idea: Full Time Active AWD
 

Gonna waste a lot of power if you do the brake idea, and if you have a -----ton of power, you'll overload the brake fast and then it will fail anyway. Beef up something and make it work. :)

Re: Crazy assed idea: Full Time Active AWD
 

here i fixed it for you O0

Re: Crazy assed idea: Full Time Active AWD
 

You're cool.

Re: Crazy assed idea: Full Time Active AWD
 

yeah i hear that from time to time.....btw i was routing for you on that one till you let me down. :'( :'(

Re: Crazy assed idea: Full Time Active AWD
 

Power is wasted anyways if all it does is spin two tires because of an open center diff.

O0 :6

Re: Crazy assed idea: Full Time Active AWD
 

OMG you're a genious!


Welcome to 1985.

Re: Crazy assed idea: Full Time Active AWD
 

OMG, getting an active AWD system to stand up to a twincharged V8 is harder thenmy dick when you're moms around!

:6

lol!

Re: Crazy assed idea: Full Time Active AWD
 

Just put a locker or limited slip for the center diff. Problem solved.


Brake based traction control will never work effectively for your application. A hydraulic system would work way better for loading.

Like attaching a through shaft hydraulic pump to both sides of the center diff and control the loading with two valves.


This is how some active diffs work. Transferring energy around through fluid and pressure.

Re: Crazy assed idea: Full Time Active AWD
 

Can't do that. The center diff isnt your standard differential... Id like to replace it with a torsen, but, Im not sure how you'd do it, it would be a completely custom unit.

http://www.coloradok5.com/milemarker/74mm5.jpg

see, the drive shaft from the trans drives that splined hub in the center. That drives the 4 spiders and outer ring, and then the side gear you cans ee drives the front, and the one you cant see drives the rear, so, neither end of the truck is actually 100% coupled to the engine at any point in time. It can swap drive front to rear all it wants.

I dont see why braking wouldnt work.... Is it as efficient as a torsen, definately not. However, as far as bang for my buck, Its pretty dang good.

Re: Crazy assed idea: Full Time Active AWD
 

just get a spool machined for it or get an adapter machined to replace the diff gears

Re: Crazy assed idea: Full Time Active AWD
 

you guys are missing the point.

I have a 205 in it... arguably the toughest T case ever built and put in a pickup.

I want the 203 for the full time 4x4.

If I put a spool in it, I loose the full time 4x4....

Re: Crazy assed idea: Full Time Active AWD
 

Seriously I think the braking idea would be fail big time. It might work, but it's a piss poor way to do it. You try to dump 100HP through that brake for just a few seconds and you will overheat it. It won't spin fast enough to dissipate any heat. Build it, but I bet it will suck, wast 1/2 your power (how you can write this off, I dunno), and ultimately fail when it overheats. What's cooler, putting 1K HP to the front wheels or putting 500 and smelling some big brake rotor burning about to melt the pads off.

Re: Crazy assed idea: Full Time Active AWD
 

how the ---- is a diff-free t-case not full time 4wd? throw the tcase in 4wd, and you're in 4wd.

i seriously don't see how you think splitting the power via a diff and brake rotors makes it 'full time'


on the other hand, spend the money and just get a t-case that comes with a torsen or a center differential that can be user controlled (like sti's) you can split torque more to the rear, front, or lock the diff all together. much more logical than another foot of downward hanging ---- from the t-case that is prone to warpage and broken rotors from trail debris

Re: Crazy assed idea: Full Time Active AWD
 

Once again... I want to run in 4WD ALL THE TIME. EVEN ON DRY PAVEMENT. I cant do that with a T case that doesnt differentiate front to rear. And for those who say "---- ti, run it in 4wd all teh time, it doesnt matter" if that was the case, no cars would have center diffs. Audi, Subaru, Mazda, Mitsubishi, BMW, M-B, Dodge, Ford, Porsche, etc wouldnt bother with a center diff.

I'd love to put a torsen in the center. however, the only torsen that stands a remote chance of holding the power is an Audi center diff. Good luck finding one of those wouthout buying the whole tranny.

The only AWD case that is worth a crap with a torsen is the 242HD AMG. Used in the military Humvee. It has its own issues, like, overheating. And, it drops on the drivers side, I need it to drop on the passengers side. I'd love to flip it over, but, because of the overheating issues, it has a shaft driven oil pump that pumps the lubricating oil through a cooler, and into jets that spray it onto the bearings and gears and torsen differential. Flip it over, that aint gonna work right.

Only other T case that will take the power and still have fill time differentiated 4wd is the NP203, like I want to use, but, I'd like it to split torque front rear, which, it won't do if I loose traction on one end or the other.

The truck weighs 6K lbs. Of that, 3600 is on the front, and 2400 is on the rear. Coeeficient of friction for pavement to rubber for average tires is around .85 .85X3600 is around 3K lbs of grip. Ice on rubber is .06 give or take a bit. .06X2400 lbs is around 150 lbs of tractive effort. SO: If I have the rear on ice, and the front on pavement, it being full time differentiated 4wd wont do ---- for me without some way to force the power to go to the end I want it to.

Also, the 203 has a 50/50 split setting. All you gotta do is pull the little shifter lever, and it slides a collar over the differential in teh middle and locks it, to force a 50/50 split, but, then you loose the differentiation that allows you to run on dry pavement without damaging anything.

Finally, I'm sure you're saying "woopty do, why do you need AWD on dry pavement..." Well, remember, the front gets 3K lbs of tractive grip. Even on dry pavement the rear only gets 2K lbs of tractive effort. So, If I could get something like, say, the Audi diff that sents 60% to the front, and 40% to the rear, I'd have near perfect power distribution for the tractive effort of the truck based on its weight.

Make sense now?

Re: Crazy assed idea: Full Time Active AWD
 

i wasn't aware that you were looking to make a daily driven road warrior out of this, and i can't see where you stated such in this thread. why not get a 1-way bearing setup that allows the rear driveshaft to backpedal the bearing when turning, giving you better turnability? differentials that have 1-way bearings make ---- for engine braking, but installing one on the rear driveshaft output might be a little closer to what you're looking for in terms of drivetrain bind and ---- blowing up when your tires dont wanna break traction

Re: Crazy assed idea: Full Time Active AWD
 

Why don't you make a t case out of an irs rear end? Use a supra rear end sideways or something and then mate the axles to the front and back like that.