Torque bias front-to-rear w/ open cen...

Log Out | Topics | Search Moderators | Register | Edit Profile

Thread Last Poster Posts Pages Last Post   Closed: New threads not accepted on this page

Author Message   Joe M. (Little_Joe) Posted on Thursday, December 26, 2002 - 09:24 am:    What is the torque bias front-to-rear in high traction driving with the center diff open on a Discovery I? What are the limits of biasing to each end when slipping is encountered? or does the bias remain static? Thanks. joe   Struan Posted on Thursday, December 26, 2002 - 09:28 am:    Torque biase is 60% rear 40% front when CDL is off and 50/50 when on. Dont know the answers to the other questions. Struan   Joe M. (Little_Joe) Posted on Friday, December 27, 2002 - 09:22 am:    Thanks Struan. I am curious now if there is any additional biasing f-to-r with the open center diff in low-traction. Anyone? joe   Al Oliveira (Offroaddisco) Posted on Friday, December 27, 2002 - 10:23 am:    Am I the only one that is lost here? The diff is open... under low traction it will put 100% torque to the wheel with least resistance. What am I missing?   Joe M. (Little_Joe) Posted on Friday, December 27, 2002 - 10:31 am:    Al, I am talking about the center diff. Struan says it's a 40/60 split f-to-r in normal high traction situations. If left open and say the fronts are on ice and slipping, will the t-case/center diff bias 100% to the rear? If not, what would the max to either end be? I am not talking about the axle differentials. Many of the AWD "SUV's" and cars have varying maximum amounts of torque bias f-to-r in their center diffs, some up to 100% to one end either in normal driving (normally resulting in a FWD) or up to 100% if one end is flailing. joe   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 10:37 am:    Disco 1 with CDL open will transfer all power to the wheel that is slipping. With an open center diff you only have one wheel actually driving the truck at any given time. If that wheel starts to slip then you are stuck. All power will go to the slipping wheel. If you lock CDL then you will have one drive wheel in the rear and one drive wheel in the front.. If both of those slip then you are stuck. If you have front a rear lockers and CDL and all are locked then you have all four wheels driving the truck. Now I don't know about the traction control on the D2 but, I am assuming that it senses wheel spin and applies the brakes to cause some resistence on the slipping wheel to transfer power to a different one. Still only a one wheel drive truck with out a CDL and with out lockers.   Al Oliveira (Offroaddisco) Posted on Friday, December 27, 2002 - 11:42 am:    Eric is correct. The Disco's 1 and 2 don't have a VC or other LSD in the center. Therefore it's all or nothing when the diff is open. ETC has litle to do with the CD and everything to do with the brakes and ABS so the setup in the D1 and D2 are the same (more or less) as far as the CD goes. It's just that some D2's can't lock the CD and is 100% dependant on the ETC.   Rob Davison (Pokerob) Posted on Friday, December 27, 2002 - 11:55 am:    LOL guys,, you are mising the point. this is in HIGH TRACTION situations, like on the dry pavement at 60 mph. traveling in a straight line the car will split the power to the front wheels and the back wheels. ALL 4 WHEELS CAN HAVE POWER AT THE SAME TIME WHILE UNLOCKED. the question is, is there a bias from front to rear? i don't know but i wonder myself. rd   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 11:59 am:    I disagree with that Rob, I think that you only have one wheel actually driving the car in "High Traction" situations at 60mph.. You just don't know which on it is at any given time. Some cars and trucks will do that but, I do not believe that the Disco will. I think it is a drag and pull set up.   Ken Dunnington (Ihwillys) Posted on Friday, December 27, 2002 - 11:59 am:    An open diff, 100% of the time, distributes TORQUE equally to both sides. It is POWER that gets distributed unevenly when one side gear is rotating faster than the other(ie spinning tire, turning corner). Do not mistake torque for power or vice-versa. Take the simplest scenario of a 2WD open diff vehicle. When driving straight, the diff is splitting the torque evenly(as it ALWAYS does) and, because the rpm of the tires is the same, the power is being split evenly. Go around a corner, the torque still remains the same(again, as it ALWAYS does), but the power output is now not evenly distributed because the outside tire is rotating faster than the inside tire. Accelerating away from a stop you spin one tire, the torque to each axle is the SAME, but the power to the spinning tire is greater, etc. So for the D1 center diff unlocked, 50% of the TORQUE always goes to the front, 50% always goes to the rear, regardless of spinning tires. Furthermore, each tire is then receiving 25% of the torque output from the transmission, assuming all three diffs are in open state. A locking diff allows for a non-equal split of torque. Ken   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 12:02 pm:    Ok, I got ya now..   Ho Chung (Ho) Posted on Friday, December 27, 2002 - 12:27 pm:    LOL   discondixie Posted on Friday, December 27, 2002 - 03:46 pm:    Here is a helpful link: http://www.howstuffworks.com/four-wheel-drive1.htm   Rob Davison (Pokerob) Posted on Friday, December 27, 2002 - 04:01 pm:    ken , yes.. except the majic question is , is it 50/50 split or 60/40 like the rally cars & straun suggests up above. i tend to think it's 50/50 but what the hell do i know rd   Kyle Posted on Friday, December 27, 2002 - 05:04 pm:    Ho lured me into this damn thread and you are all actually wrong. If you are talking about torque and spinning wheels then you dont have 100% , 50% 75% , or what ever... Its not a constant number that can be measured that easy. If the one wheel is spiining it still has resistance , that resistance is pushing torque to other wheels.. How much ???? Who fucking knows.... But 100$ of it isnt leaking out that one spinning tire..... Measuring it statically you might come up with some kinda number thats pretty much irrelivant unless you are doing the marketing campaighn for a certain vehicle. Aside fomr that Rob has it right.. Eric ? Stop smoking that shit... Kyle   Ho Chung (Ho) Posted on Friday, December 27, 2002 - 05:09 pm:    me? lil ol me? what i do?   Kyle Posted on Friday, December 27, 2002 - 05:12 pm:    Um , you brought that shit up again , I looked earlier and then faught the urge to speak. Being pulled down the road by one god damn wheel...... Kyle   Ho Chung (Ho) Posted on Friday, December 27, 2002 - 05:13 pm:    well, ok i did, but you didnt' have to mention my name here!   Kyle Posted on Friday, December 27, 2002 - 05:16 pm:    Man I was just sitting here talking about my Disco , admiring its curb appeal sitting over in the other driveway with its 40/40 split , and then you talking about torque biasing shit making my blood pressure rise again and breaking my serenity... Yeah , I had to bring your name in... Kyle   Ho Chung (Ho) Posted on Friday, December 27, 2002 - 05:18 pm:    fuck, 40/40 split? what the fuck is 40/40 split?   Kyle Posted on Friday, December 27, 2002 - 05:20 pm:    I dont know , I dont need to. It sounds good though dont it? Wait a minute , the wind just blew , I think it went 40/30 for a moment.. Kyle   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 05:26 pm:    serenity... hahahahahaha why do you think that I smoke that shit in the first place? And curb appeal? you ramping a curb or some thing?   Kyle Posted on Friday, December 27, 2002 - 05:29 pm:    No No , its just sitting there in the driveway torque biasing....Should I make up a pretty ad about it and tell how its parking abilities are superior because of its "Parked torque biasing abilities" ?? Kyle   Ho Chung (Ho) Posted on Friday, December 27, 2002 - 05:31 pm:    ad? LOL but damn, 40/40... how the hell do you know it's 40/40? and not 40/45?   Kyle Posted on Friday, December 27, 2002 - 05:34 pm:    40/40 , 40/50 , what the hell does it matter ? It all sounds good dont it ?? Thats why advertising firms use it . AS a result we get some torque biasing going on here... Kyle   Ho Chung (Ho) Posted on Friday, December 27, 2002 - 05:36 pm:    so i guess marketing hype is the cause for stupidity? then tell me something... if you got 40/40 split, where's the remaining 20?   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 05:37 pm:    what no torque biasing meter in the garage?   Kyle Posted on Friday, December 27, 2002 - 05:39 pm:    Man , I dont know , I think the Amigo has the 20,,,yeah , its just a 20/0.... Its advertising flyer that came with the truck somewhere. Do I have to scan it now ?????????? kyle   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 05:42 pm:    scan away...   Ho Chung (Ho) Posted on Friday, December 27, 2002 - 05:44 pm:    shit man, if you ain't using the 20 there, send it to eric, he got the 50/50 and still on one wheel drive.   Kyle Posted on Friday, December 27, 2002 - 05:45 pm:    STOP!!!! Kyle   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 05:47 pm:    no, I'll have three wheel drive after tomorrow But, ya, an extra 20% torque would be sweet.. send it over.   Rob Davison (Pokerob) Posted on Friday, December 27, 2002 - 05:55 pm:    torque here.... ice cold torque... get your torque here.. torque... torque or torque light,ice cold.... rd   Joe M. (Little_Joe) Posted on Friday, December 27, 2002 - 05:56 pm:    Glad you guys get such a kick out of this. I asked because things like this can influence how I drive, when to use the CDL, etc etc. Others may have an interest as well. It is interesting and useful, not just some marketer's wet dream. Whatever. joe   Kyle Posted on Friday, December 27, 2002 - 05:56 pm:    Stop talking and opening doors !!! Its obvious Eric that if you had it you wouldnt know what to do with it!!!! Now stop!! Kyle   Kyle Posted on Friday, December 27, 2002 - 05:57 pm:    Joe , were did you hear about "Torque Biasing" ??? Kyle   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 05:59 pm:    opening doors? You and rob smoking some better shit then me here or what? Damn, I want some of that good shit.   Rob Davison (Pokerob) Posted on Friday, December 27, 2002 - 06:05 pm:    doors of perception? i am Overdosing on salty ham. i think it is making the same effects as if i were drinking ocean water for a few days :-P rd   Kyle Posted on Friday, December 27, 2002 - 06:20 pm:    And Joe,,,,,dammit man,,,Teenage girls say "WHATEVER!".... Dont do that... Kyle   Eric N (Grnrvr) Posted on Friday, December 27, 2002 - 06:47 pm:    ok, so, when can I expect my extra torque? will that be in the form of a super charger? or a nice bottle?   Joe M. (Little_Joe) Posted on Friday, December 27, 2002 - 11:03 pm:    Maybe I was wrong to assume that since everyone and everything refers to a "center diff lock", that there is some sort of center differential. Differentials bias torque. So I wanted to know what the bias is f-to-r and if it changes under certain conditions while the CDL is unlocked. If there is no true center diff, this all seems moot. But no-one seems to know. Whatever.;) joe   Rob Davison (Pokerob) Posted on Saturday, December 28, 2002 - 09:22 am:    joe, there is a center diff without any sort of biasing, it works like the rear diff only instead of power to the right/left or both wheels it thinks, front/back or both. if there were some kind of preloaded LSD in the center diff it might work more like you are thinking. rd   Joe M. (Little_Joe) Posted on Saturday, December 28, 2002 - 10:03 am:    Thanks Rob. So there is a static distribution with the center diff unlocked, regardless of traction - and it's believed to be 40f/60r according to Struan. Hey, 42 posts later, we have a wiener! Thanks man! joe   nadim Posted on Saturday, December 28, 2002 - 10:34 am:    Ok, As I understand it, there is not such thing as a torque biasing differential when a Disco 1, RR, Def., or any other LR truck with the LT230 transfer case rolled off the production line... It is quite simple, the engine takes the route of least resistance, therefore, when the CDL is open, then the engine will transfer ALL its power to the first tire that starts to slip, whether it is a front or rear one. With the CDL locked, the engine will transfer up to 50% of its power to the rear axle, and the other 50% to the front one. now, the same above situation (with CDL open) occures at the axle diffs, and that is why we slap in lovkers/LSD/spools... I hope that was right, and simple? If I am wrong, please correct me in order for me to get this right once and forall after years! Nadim   Peter Bullock (Downunderdisco) Posted on Saturday, December 28, 2002 - 10:54 am:    I think youll find Ken had it right actually. Sure youd be hard pressed to measure exact distribution but the key to it is, with the CDL open there is no design intention for a specific distribution ratio. For high traction straight driving, torque will be roughly even thorughout while power will only be at one wheel at any one one time, whichever that may be and however often that changes (could be many times in a few seconds). Pete - donning asbestos suit   Joe M. (Little_Joe) Posted on Saturday, December 28, 2002 - 01:43 pm:    "For high traction straight driving, torque will be roughly even thorughout while power will only be at one wheel at any one one time, whichever that may be and however often that changes (could be many times in a few seconds)." This isn't how differentials work. In perfect (mythical?) high traction straight-line driving, all 4 tires would be powered. When turning, the tires travel in different arcs and the axle diffs power one wheel per axle (side/spider gears disengage on one side), assuming the transfer case is distributing power to both axle diffs via the driveshafts. The "one wheel" suggestion just can't happen if both ends are always being fed by the transfer case. One side of each axle will always remain coupled to the ring gear & carrier assembly - there is no way for the side/spiders to completely disengage both axleshafts. So there is no biasing f-to-r with the transfer case? Then each driveshaft is always being powered --> each ring gear is powered --> one or both sets of side/spiders in each diff are powered --> one or both axleshafts per axle are powered --> one or both tires per axle are driving. joe (nomex on)   Kyle Posted on Saturday, December 28, 2002 - 04:30 pm:    Get a double layer cause you just fucke that up. Spider gears DO NOT "Dissengage".... You been smoking that same shit Eric has. Kyle   Rob Davison (Pokerob) Posted on Saturday, December 28, 2002 - 06:20 pm:    yeah, joe... this is why when you lock the center diff you shouldn't drive it on dry high tracktion surfaces like the mall parking lot. turns it into an old fashion 4x4 you'll just fuck shit up rd   scott Posted on Saturday, December 28, 2002 - 06:48 pm:    Joe, open diff (center unlocked) is 50/50 bias. There isn't a special bias for the disco like say on a honda CR-V, which is 95/5 f-r. The maximum torqe is the same for all 4 wheels, regardless of the traction. The power varies across the open diff. When you lock up a diff, the power is now fixed and the torque can vary. You max torque with all your diffs open, is limited to the wheel with the least traction. So, on pavement your limiting wheel would be one on the outside during cornering (assuming no other slippage conditions) and more power would be transfered to the outside wheel(s) to make them spin faster than the inside wheels. Same rules apply in low traction conditions, but now if you have 1 wheel that has slip (say you lift one tire off the ground) the torque goes to zero and that wheel spins (all the power goes to that wheel). Since your torque is the same on all four wheels (all are zero), you don't go anywhere and are stuck. For CDL, you have 50% power going front and 50% rear, so while you may have one of your front wheels up in the air and the whole front axle is limited to zero torque, you still have half the power going to the rear axle and the rear wheels will still keep the truck moving. The ETC on the D2's breaks the wheel that is spinning to provide some torque on the spinning wheel and transfer power back to the other wheels. It's a whole other argument, I'm not going to get into on ETC vs CDL, but the bottom line is the combination of ETC and CDL is a sweet setup for those D2 owners who can lock their center diff. And if that's not enough, you get full lockers for front/rear, but everything is a trade-off and depends upon the situation. I hope that answered your question. I'll second the poster who said to go to the how-things-work link. Your center diff is just like your front/rear open diffs until you lock it up. Scott   Joe M. (Little_Joe) Posted on Saturday, December 28, 2002 - 06:51 pm:    I am well aware of using true 4WD on high traction surfaces - my Toy w/ rear locker and front LSD is a handful to turn when it has traction on the trail, 4WD is unusable onroad except in deep snow and ice. Kyle, so a side gear disengages, not a spider, to allow differentiation. Better? joe   Joe M. (Little_Joe) Posted on Saturday, December 28, 2002 - 06:58 pm:    Scott, we posted at the same time. Thanks for the explanation. What I am understanding is there is no center diff on the Disco? If there is no center diff, what is the real difference between CDL open and locked then? I have to be missing something obvious here. I've been reading implied references to the transfer case transmitting power to only one axle with the CDL open. If that's the case, that implies a true center diff. Anyone know of any online resources or diagrams etc for the LT230 t-case? Thanks. joe   Kyle Posted on Sunday, December 29, 2002 - 10:25 am:    No Joe , a side gear is just another term fo spider gear and NO!! They dont dissengage. Scott has it dead on up there... Kyle   Joe M. (Little_Joe) Posted on Sunday, December 29, 2002 - 12:27 pm:    "No Joe , a side gear is just another term fo spider gear and NO!! They dont dissengage. Scott has it dead on up there..." The gears effectively disengage to allow differentiation. What I mean by this is one set isn't powering an axle. There is still contact between the side and pinion gears, but while differentiating, one set (or 2 in a 4-pinion carrier) isn't powering that side axleshaft. Lincoln locking is welding side and pinion (not the DS input pinion) together so they can never differentiate, or never *effectively* disengage. If I'm wrong, I'd appreciate an explanation. joe   Milan Posted on Sunday, December 29, 2002 - 01:03 pm:    Well Joe, they don't really disengage. The little pinion gears just happen to run around the side gears. Power is still applied to both sides. How much to what side (or end if we're talking t-case diff) varries (i.e. we don't know cause we can't easily tell). Scott, could you explain that torque vs. power thing to me? I always thought that if you have x-amount of torque going to one wheel while y-amount is going to the other wheel you have the same relative X and Y amount of power flowing to those wheels.   Kyle Posted on Sunday, December 29, 2002 - 01:33 pm:    You are thinking of it backwards Milan. Torque builds against resistance. No resistance , no torque.... Its that simple... Joe , yeah , you are still wrong.. Milan has a good enough explanation there for you... No matter what you do the diff gears DO NOT "Dissengage" they still have power flowing though all of them at all times... If you spin with one wheel while the other is on high traction then the movement may shift but there is certainly no dissengaging.. The power just bleeds off like water following the least resistancve.. Kyle   Milan (Milan) Posted on Sunday, December 29, 2002 - 02:12 pm:    Aha! So power builds torque if there's resistance? I was looking at it as wheels have some traction (resistance) so engine power/torque is applied. Don't matter which.   Axel Haakonsen (Axel) Posted on Sunday, December 29, 2002 - 04:27 pm:    Yeah, the formula is actually: Horsepower = (Torque x rpm)/5252 So, given that the force is equal, the rpm's would increase and the torque would decrease as resistance decreases, which is exactly what you see with a spinning wheel. And the only disengaging differential I am aware of is a Detroit locker and it's equivalents.... http://vettenet.org/torquehp.html   Milan (Milan) Posted on Sunday, December 29, 2002 - 06:13 pm:    OK. I was referring to this: "...if you have 1 wheel that has slip (say you lift one tire off the ground) the torque goes to zero and that wheel spins (all the power goes to that wheel). Since your torque is the same on all four wheels (all are zero), you don't go anywhere and are stuck." So, if the power is going to the spinning wheel, isn't the torque going there too? It's just not doing anything but spinning the wheel. If the wheel were to grab, then given I would not loose traction, I could apply up to the maximum torque to that wheel. Now with an open diff that would not happen as the torque/power would get distributed to the other wheel. At the risk of beating a dead thread, are not power and torque interchnageable in this particular case?   Ron Posted on Sunday, December 29, 2002 - 07:01 pm:    1. There is a center diff. It is completely open, no LSD, no viscous, just open with a diff lock. So you either get open or locked. 2. There is no "bias" without an LSD or viscous there is no way to split the power or torque so that front or rear gets artifically more in normal driving. 3. Please raise your hand if you have seen the inside of an LT230, ok now those who have not disassembled the differential in it, put your hands down . . . thats what I thought Ron   Milan (Milan) Posted on Sunday, December 29, 2002 - 08:12 pm:    Ron, I think when people mention split they mean you have x amount of torque coming out of the transmission and now it has to go to front and back. So when it's locked it's 50/50 split. It's really 100% going front and back, but I think people view it as 100 eaten up by 2 axles = 100/2 = each axle gets only 50. When open you get the same under full traction but when things start slipping, most of the power goes out the slipping side/end. But that's only how I'm interpretting what people say. I still struggle with that power vs. torque thing.   Curtis N (Curtis) Posted on Monday, December 30, 2002 - 01:49 am:    After three days of debate on the topic, I hate to go back to the original questions, but I think it is necessary: "What is the torque bias front-to-rear in high traction driving with the center diff open on a Discovery I? And What are the limits of biasing to each end when slipping is encountered? or does the bias remain static?" The answer to the first question is: in a three open diff situation, the bias always goes to the wheel that is rotating the most in dynamic circumstanes. This explanation is the simplest, and to try to quantify it with a percentage would require that you take into consideration too many factors to make an end result. The second question: Static situations with open diffs ar never achieved in reality. They change based on the traction of each wheel. Because static situations are not realized, the only true "bias" goes to the wheel with the greatest rotation. This takes us back to question #1. The reality is that of you have to ask such a question, you need to get in a situation where one wheel is raised to the point of no traction. This will emiliminate the power (Or torque) of the other wheels. The term "bias" will have a whole new meaning then. Once at this situation, you may consider locking your CDL. If you then lift one wheel on each axle, consider a locker in rear and maybe an LSD up front. Do the latter first and the former second. Happy Holiday Wheeling, Curtis   charles pastrano (Charles) Posted on Monday, December 30, 2002 - 02:46 am:    weel put.   charles pastrano (Charles) Posted on Monday, December 30, 2002 - 03:38 am:    oops well put.   Rob Davison (Pokerob) Posted on Monday, December 30, 2002 - 10:04 am:    i dont think you can even really use the term bias for even your first circumstance. it seems to imply to me, that there was an engineered favoritsm toward a certain wheel while in a situation. when in fact, it is simply designed to work withought bias. rd   Eric N (Grnrvr) Posted on Monday, December 30, 2002 - 10:14 am:    um, who really cares?   Kyle Posted on Monday, December 30, 2002 - 10:59 am:    Exactly Eric... Kyle   Rob Davison (Pokerob) Posted on Monday, December 30, 2002 - 11:11 am:    i don't but i am stuck at work... rd   Eric N (Grnrvr) Posted on Monday, December 30, 2002 - 11:18 am:    As long as I put my foot on the gas and the truck moves either forward or reverse and stops when I put my foot on the brake, I'm happy.   Rob Davison (Pokerob) Posted on Monday, December 30, 2002 - 11:25 am:    foot on brake, stops? must mot be ABS rd   Eric N (Grnrvr) Posted on Monday, December 30, 2002 - 11:32 am:    My brakes work pretty good.. Squeak like crap but, they stop pretty well. ABS hasn't come on very often unless I slam my foot down while I'm on snow, ice, or wet leaves. For the most part it's only really come on when I'm trying to make it turn on. Like when you get some snow and you want to see just how slippery it is so you give the truck some gas and then slam your foot on the brake to see if you slide.   Dean Brown (Deanbrown3d) Posted on Monday, December 30, 2002 - 11:40 am:    Well eric, my brakes suck. I must have the same version as Rob. On ice, I can accelerate (with the traction control kicking in) at least twice as fast as I can stop, and that's not an exaggeration either.   Eric N (Grnrvr) Posted on Monday, December 30, 2002 - 11:44 am:    Maybe the traction control is messing up the stopping. I don't have traction control.   Kim S (Roverine) Posted on Monday, December 30, 2002 - 09:50 pm:    Hey, I finally gained acsess to the computer (and computer is actually working!) Just (trying, hahaha) to catch up a little (why oh why God, do I always go to these type of technical threads first??? LOL ... some of you know .. anything to do with T case and CDL ...) As usual, I become confused; Then I see: "this is why when you lock the center diff you shouldn't drive it on dry high tracktion surfaces like the mall parking lot. turns it into an old fashion 4x4 you'll just fuck shit up" (Mary Tyler Moore) "Oh Rob" ... Ah, but all is not lost ... I keep reading, and see: "As long as I put my foot on the gas and the truck moves either forward or reverse and stops when I put my foot on the brake, I'm happy." (Thanks Eric keep smoking your stuff ) I am a happy, happy girl again. Happy 2003 everyone! Kim Heading "for the hills" again in a couple of weeks   Brian (Rover_Wannabe) Posted on Tuesday, December 31, 2002 - 10:07 am:    Just to make things interesting I'll throw this out. I am now assuming that because the Disco I's have ABS, if a wheel slips, using the foot brake and gas isn't going to get you any more traction, because the ABS will keep the spinning wheel from locking therefore not increasing the torque sent to that wheel, OR will it intermittantly lockup, thus intermittantly allowing torque build up, internittantly giving torque to the wheel with true traction? (I now want to go back to Tillamook State Forest and try this) Brian   scott Posted on Tuesday, December 31, 2002 - 02:11 pm:    Brian- I believe the 2-footed driving technique is a simple play on how ETC works. When you have a locked CDL on a D1 and you get cross-axled and have wheel spin, by applying the brakes at the same time as giving it some gas, you are artificially creating a torque situation on the spinning wheels (by applying the brakes you supply some "traction" to the spinning wheel) - this allows the other wheel on the same axle to also have the same torque (open diff means equal torque across the diff), therefore you can move forward again. ETC on the D2's does the same thing, but breaks each spinning wheel independently. I'm catching up since my last post. Torque is not the same as power. See prior post with the equation... Open diff: equal torque on both sides. Locked diff: equal power on both sides. Disco's have 3 open diffs. On some D2's and all D1's you can lock the center diff. Hope we answered the original question clearly by now??? Scott   Kim S (Roverine) Posted on Tuesday, December 31, 2002 - 02:23 pm:    All I know is it is much easier to get up & over certain areas/obstacles when I have both center diff locked and ETC (D2). Makes me feel better. (Helps to make up just a little for the extra width and big ole back end on the family wagon) Kim   Brian (Rover_Wannabe) Posted on Tuesday, December 31, 2002 - 03:18 pm:    Won't the ABS kick in when 2 footed driving, thus not allowing the spinning wheel to not spin?   Rob Davison (Pokerob) Posted on Tuesday, December 31, 2002 - 04:32 pm:    when you are situation where shit is spinning madly and you want to go forward, folks tap the brake in hopes that it will work, sometimes it can give that little bit you need. ABS coming on could happen or might not. sometimes you stop mash the brakes and start ramping up the RPM and then ease off and it will go.   Brian (Rover_Wannabe) Posted on Tuesday, December 31, 2002 - 04:41 pm:    I hope I remember that the next time I go out (2nd time out 4-wheelin). Thanx for the info.   Milan (Milan) Posted on Tuesday, December 31, 2002 - 07:51 pm:    Aaaaah. This thing still going? Scott, "Torque is not the same as power." I knew that and I know the formula, but... "Open diff: equal torque on both sides. Locked diff: equal power on both sides." These are the things that confuse me. If you have torque going to any one side or both, you have power going there. If you have power going there, you have torque there. Simple as that. Unless you take the view that Kyle eluded to that unless there's resistance, there's no torque. I'm not really arguing anything, I'm just wondering if people understand what I'm saying and if it makes sense. Let's see if my post can kill this thread as it usually does.   Kim S (Roverine) Posted on Tuesday, December 31, 2002 - 08:29 pm:    Dont worry Milan, it's usually me - I can be the queen killer of threads Kim Still a bit confused - Tomorrow I think I'll ask Greg to talk v e r y s l o w l y to me about this subject, and take out a toy truck to demonstrate with   Keith Kreutzer (Revor) Posted on Tuesday, December 31, 2002 - 08:46 pm:    Wow! I think i'll just weld the spiders in my LT230 and put hubs in the front...:0 !!!!!   Ron Posted on Wednesday, January 01, 2003 - 03:25 am:    Keith, its been done. Generally you put a bush or bearing on the front output. bcb offroad has a kit. Ron   Keith Kreutzer (Revor) Posted on Wednesday, January 01, 2003 - 11:06 am:    Actually I've done it in my 109 with an LT230 (and other "special stuff") I put an Ampco bushing up fron to support the cut off front output shaft... I've spent many hours on the Phone with Timm talking Rovers and just stuff... He is why i have all that "special stuff" in my Series   scott Posted on Wednesday, January 01, 2003 - 01:46 pm:    Milan, I'll look up the torque equations in my physics book tomorrow, when I'm back at work. That may help explain. I read thru the www.howstuffworks.com web site on differentials and 4x4 so I could better understand what was going on. It was there that I read about the open vs. locked diffs and how torque vs power is varied for open and locked. Kyle is correct, if there is no resistance then the torque applied by that wheel is zero. Scott   Milan (Milan) Posted on Wednesday, January 01, 2003 - 03:08 pm:    Right. But I'm talking about power to the wheel not to the ground. I know how the diff works. My main point is, power/torque is coming from engine through transmission, t-case, driveshafts, diff and axleshafts to the wheels. One or all, doesn't matter. Maybe you guys are thinking about power/torque to the ground. Maybe you see only power coming and no torque - that's what's odd to me as I view it as still being there just not measurable until resistance comes to play. But it's not important as this could turn into a physics class and while I love physics, I have been out of school for, oh shal we say, quite some time. Just trying to get on the same page. Kim, Don't worry about this too much. Like someone said, it really doesn't matter as long as the vehicle can move. And the thread killing, what can I say? I just have a knack for it. At least I'm pretty good at something.   Ron Posted on Thursday, January 02, 2003 - 01:08 am:    Sounds cool keith. I toyed with the idea but it took too long for it to become axailable so I put the t-case togther open. I started to "specialize" my 88 so my 110 direction changed to something more stock (for a 110 not a 64 109) so part-time was not needed, it has a disco II driveshaft so any vibes from the lift should be eliminated. You have special axles too? I really like special axles. Ron   scott Posted on Thursday, January 02, 2003 - 06:24 pm:    Milan, Yes, the output torque from the engine doesn't change, and you will have a torque on the wheel that spins, so I guess you are correct. I guess it's a case of what torque you are talking about. The diff must cause equal torque to be applied to the ground to overcome friction. If one wheel spins, no torque is applied to the ground and therefore the wheel with good traction also can not apply any torque to the ground, thus it doesn't rotate. anyway, after digging thru my physics text, I'll agree that it's not nearly as simple as one might want to make it sound and would involve more physics that I feel like working through. It's been about 10+years since taking the class for me. Scott   Peter Matusov (Pmatusov) Posted on Thursday, January 02, 2003 - 06:44 pm:    Ken and Scott have the flag. the open diff splits torque 50-50. now, why would anyone care is a different question. I ask myself why do i care to ever post on any thread related to this matter - anyone who does care could do a little bit of thinking and come up with a clean concept (and explanation why this or that axle broke). By the way, howstuffworks.com managed to fuck up the write-up about differentials, and so far i haven't come across a single website that has its physics consistent. there are only two basic statements about differentials - - an open diff splits torque 50/50. - a locked diff (spool) forces the driveshafts (or axleshafts) to spin at the same rate of rotation. all other things come from these two. a limited slip will try to cause the driveshafts to spin at the rates as close to each other as possible, and, as a consequence, to bias torque towards the wheel or axle that has the least traction. You were right, Kyle, when you said there's only so much torque as traction would take. But it doesn't change the fact that open diff will send exactly as much torque to the spinning wheel as it will to the stalled one. peter   Keith Kreutzer (Revor) Posted on Thursday, January 02, 2003 - 11:54 pm:    Ron likes "special axles" Me too!!!!! Roverzilla has a Salisbury with a "twist" out back.. First reason was to run BIG brakes the other was to fit 35 spline axles.. To do this I put a Dana 60 spool in it, next i had to make a custom stub axle (spindle to fit teh spindles from a GM 14 bolt.. Doing this i was able to use GM 1 ton backing plates and 13" GM rotors in conjunction with regular old GM 2.825 Calipers.. If that's not special enough the front is a whopper! I'm not a big fan of the GM 10 bolt but i had a complete one from a heavy 3/4 ton available to me cheap.. But the pinion is puny and the diff is the same as a Dana 30 so i used the center section from a Ford 8.8" Which also had the right gears! The 8.8 is really a decent axle with big bearings all around...Plus it was free! Grafting the GM outer bits on to my 8.8 gave me the same big brakes as the rear (but with 3.125 pistons) the same bolt pattern and a decent third member.. It shold be a bit better than a Dana 44. Using alloy halfshafts i should be pretty strong! I only lament loosing the 5X6.5" bolt pattern to an 8X6.5" But not it matches my Jeep so i can swap tires around. The other "special parts include a EFI 302 from a 96 F150.. A T18 from somthing (?) Ford PB booster and MC Scout II steering and 42" front springs.. You had to ask   Curtis N (Curtis) Posted on Friday, January 03, 2003 - 01:01 am:    Wow Keith! That sounds pretty solid. Who cares if the front is what...75% of the back? It sounds like it is still a solid setup and much more capable than...OK...almost anything I have heard about. I am not familiar with Roverzilla. I almost hate to be a pain, but do you have pics of the rig? Curtis   Peter Matusov (Pmatusov) Posted on Friday, January 03, 2003 - 11:58 am:    Keith, what have you left of your Rover? one Q here - why to build an axle that's a bit better than a 44 when you could get a 44 with a correct width and offset, stuff it with Moser axles, and only weld on the trailing arm mounts? (not that I am a big fan of D44s anymore) peter   Milan (Milan) Posted on Friday, January 03, 2003 - 02:51 pm:    Thanks Scott.   Keith Kreutzer (Revor) Posted on Saturday, January 04, 2003 - 04:31 pm:    Hey Peter/Ron/Curtis....Roverzilla is a 109 five door. I plan to keep the leaf springs do to the fact that they always work, up front i've added longer springs from another vehicle so they actually flex... To answer Peter's question..Whats left.. Well the Body, a superior chassis and that's about it.. But It's being made for silly wheeling.. I wish I could say I was a big fan of the 44... I do have one in the front of a CJ7 with an ARB, 37" tire's and 300 hp.. I've only broke it a few times (axles what else) while wheeling hard.. A 60 would be cool but they're expensive.... Other options in the front are again expensive... The stuff I used to build this front anomolly was about $75 in addition to that i got all the goodies to put on these huge brakes. While i like adventure i don't like puny brakes, Since i'll be running 37"+ tires on this truck I want to stop. ... I'll add Moser axles and a locking diff of some type and I'll have about $1000 into it... Far less than an over the counter D44 from Currie or the likes and I will actually be better... Plus I like building this stuff.. As for pics.... I'm working on it but the Disco is using up the garage and Roverzilla is Stuck off in the corner.. I will post pics of my toys on this site soon for all to see...