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Posted: Thu Sep 06, 2007 10:26 pm
by Gwagensteve
Sorry Booflux, those I understand what you are trying to say but the photos don't help illustrate the point.
A hilux has high rear roll stiffness.
A 4 Runner has low rear roll stiffnes.
That would more than account for the difference In that case.
The rear question is has anyone other than Mock owned a car with a totally open rear diff (no LSD) and a front locker.
Everyone agrees both locks are the way to go, and that yes a front lock adds lots of capability, but in doing so, a lot of drivability is lost.
I drove Mocks car "Doof" (the car in question) a fair bit offroad and I can tell you yes it was capable but it also was a complete PITA to drive, and hard on CV's. I broke one in really slippery mud - shouldn't have been possible.
It would pinball, the front end would start to bounce and skip, and you would still have to hit things hard once you got the front up to try and bounce the back up. It's a hack way to drive.
front only is great when it's not really steep (so long as you don't need to steer), but then you don't really need lockers at all.
Steve.
Posted: Thu Sep 06, 2007 10:47 pm
by cloughy
Gwagensteve wrote:Sorry Booflux, those I understand what you are trying to say but the photos don't help illustrate the point.
A hilux has high rear roll stiffness.
A 4 Runner has low rear roll stiffnes.
That would more than account for the difference In that case.
The rear question is has anyone other than Mock owned a car with a totally open rear diff (no LSD) and a front locker.
Everyone agrees both locks are the way to go, and that yes a front lock adds lots of capability, but in doing so, a lot of drivability is lost.
I drove Mocks car "Doof" (the car in question) a fair bit offroad and I can tell you yes it was capable but it also was a complete PITA to drive, and hard on CV's. I broke one in really slippery mud - shouldn't have been possible.
It would pinball, the front end would start to bounce and skip, and you would still have to hit things hard once you got the front up to try and bounce the back up. It's a hack way to drive.
front only is great when it's not really steep (so long as you don't need to steer), but then you don't really need lockers at all.
Steve.
I've got front and rear, individually selectable diff locks and have experimented, does that qualify??
You CAN steer with a front locker in, just its reduced
Posted: Thu Sep 06, 2007 10:54 pm
by Gwagensteve
Me too (Gwagen) and have, so I do know the effect. In the G I almost never ran rear only, always went straight to both, but that wasn't the original question.
Still say more value and less breakage (and better car behaviour) with rear only.
If the owner is prepared to weld, then weld rear airlocker front.
Steve.
Posted: Thu Sep 06, 2007 11:33 pm
by Dozoor
Gwagensteve wrote:Sorry Booflux, those I understand what you are trying to say but the photos don't help illustrate the point.
A hilux has high rear roll stiffness.
A 4 Runner has low rear roll stiffnes.
That would more than account for the difference In that case.
The rear question is has anyone other than Mock owned a car with a totally open rear diff (no LSD) and a front locker.
Everyone agrees both locks are the way to go, and that yes a front lock adds lots of capability, but in doing so, a lot of drivability is lost.
I drove Mocks car "Doof" (the car in question) a fair bit offroad and I can tell you yes it was capable but it also was a complete PITA to drive, and hard on CV's. I broke one in really slippery mud - shouldn't have been possible.
It would pinball, the front end would start to bounce and skip, and you would still have to hit things hard once you got the front up to try and bounce the back up. It's a hack way to drive.
front only is great when it's not really steep (so long as you don't need to steer), but then you don't really need lockers at all.
Steve.
Yes we spooled the fronts only open rear diffs 35s ,
I like to drive with the front end , poverty
Just a warning 35s 3psi be sure to have some sustegen for brekky
even done tt with only the front.
Posted: Fri Sep 07, 2007 12:18 am
by StarkRavingSimmo
Nelso wrote:I was talked into doing the rear of the mav first by the local ARB 'expert' and it made the car scary to drive up hills as it pulled wheelstands like you wouldn't believe. I've also watched many other rear locked cars such as 80 series etc torque up the front left the same way mine did. If I was to do it again I would go the front first. If you are so worried about breaking parts why not bite the bullet and put some hilux or MQ patrol diffs under it before you spend the money on lockers.
Actually, the idea of the MQ diffs is half tempting, they're strung under, so theres a bit less work to do, but I couldn't do the work myself anyway, and i'm trying to save the bucks :-S
Is MQ diff conversion difficult? I imagine you'd need custom driveline?
Posted: Fri Sep 07, 2007 12:23 am
by Dozoor
StarkRavingSimmo wrote:Nelso wrote:I was talked into doing the rear of the mav first by the local ARB 'expert' and it made the car scary to drive up hills as it pulled wheelstands like you wouldn't believe. I've also watched many other rear locked cars such as 80 series etc torque up the front left the same way mine did. If I was to do it again I would go the front first. If you are so worried about breaking parts why not bite the bullet and put some hilux or MQ patrol diffs under it before you spend the money on lockers.
Actually, the idea of the MQ diffs is half tempting, they're strung under, so theres a bit less work to do, but I couldn't do the work myself anyway, and i'm trying to save the bucks :-S
Is MQ diff conversion difficult? I imagine you'd need custom driveline?
Search in the zook section its been covered heaps .
Posted: Fri Sep 07, 2007 12:24 am
by StarkRavingSimmo
Gwagensteve wrote:Me too (Gwagen) and have, so I do know the effect. In the G I almost never ran rear only, always went straight to both, but that wasn't the original question.
Still say more value and less breakage (and better car behaviour) with rear only.
If the owner is prepared to weld, then weld rear airlocker front.
Steve.
I'm not that keen at all for welding the rear, the sierra's aren't well known for being totally bullet proof.
Posted: Fri Sep 07, 2007 7:39 am
by Gwagensteve
Your information is not totally correct. With 31's a welded diff will live for years and years if you weld it well. Even the axles should be fine unless you are a superabusive driver. In vic I have seen a couple of rear axles go but only with over 35" tyres.
Ultimately, a sierra with an airlocker is no stronger than a sierra with a welded diff.
Steve.
Posted: Fri Sep 07, 2007 7:45 am
by ROGQ
me3@neuralfibre.com wrote:midi73 wrote:blkmav wrote:me3@neuralfibre.com wrote:Q. When one front wheel is in the air spinning freely, and the other is getting no power, how much weight is on the opposite rear that is supposed to push you forward and have traction?
A. Next to none. If one front is in the air, the opposite rear has next to no weight on it.
This is why you need it in the front
No, this is why you need it in the back. All the weight of the car is transfered over the back wheels, therefore giving far better traction, than being in the front trying to drag the back up with one wheel still spining. If it is in the back, it doesnt matter if the front wheel still spins.
Not true. With open diffs, then across an axle, the maximum torque delivered to the wheel with the most traction is the same as can be delivered to the wheel with the least traction.
eg. If the car weighs 3000kg and is climbing a steep rutted hill the rear has one wheel with weight (1900KG) and one wheel just touching (100KG) then there is a maximum equivalent of 200KG (2x100KG) traction avaialble at the rear wheels. With a locker this increases to 2000KG (1900 + 100). (count the zero's)
As there is only 1000KG weight on the front wheels due to the hill, with one in the air, this is split to 1000KG one side and 0KG the other giving a maximum equivalent of 0KG traction (0+0=0) with open diffs. With a front locker this increases to 1000KG.
2000KG beats 1000KG in terms of putting power down.
Remember, across an open diff, the BEST you get is 2x the WORST wheel's traction.
Please note, the weight numbers used here are for comparitive purposes. I haven't tried to convert them to real forces with coefficient of friction, interference bahaviours, torque splits etc. It is simply comparitive between wheels, but the effect is equivalent.
There is traction on ONE rear wheel. The trick is getting enough torque there to do something useful. This is what a locker does. They don't aid traction, they allow a diff to deliver more torque to one wheel.
Paul
im not trying to hijack.... but would you agree with this theory on a trayback that has lsd rear? cauz they got bugger all weight in the rear...
Posted: Fri Sep 07, 2007 9:47 am
by cloughy
Gwagensteve wrote:Me too (Gwagen) and have, so I do know the effect. In the G I almost never ran rear only, always went straight to both, but that wasn't the original question.
Still say more value and less breakage (and better car behaviour) with rear only.
If the owner is prepared to weld, then weld rear airlocker front.
Steve.
More value, really depends on the situation, but yes for the general guy
Less breakage, You're halving your front wheel speed, from 1 turning flat out and hitting the ground, to 2 turning at the same speed, you just need to know when to turn it off
Posted: Fri Sep 07, 2007 9:50 am
by cloughy
Gwagensteve wrote:Your information is not totally correct. With 31's a welded diff will live for years and years if you weld it well. Even the axles should be fine unless you are a superabusive driver. In vic I have seen a couple of rear axles go but only with over 35" tyres.
Ultimately, a sierra with an airlocker is no stronger than a sierra with a welded diff.
Steve.
Welded diff's live forever, just dont be scared to weld fark out of them
Was my mates, with 35"claws for a year or so, road driven and retired to my joint with 34" tractor tyres, only ever broke 1 axle
Posted: Fri Sep 07, 2007 10:34 am
by largesuzy
cloughy wrote:RUFF wrote:I theory its totaly impossible for a bumble bee to fly.
How so??
wing span to body size ratio is totally wrong
Posted: Fri Sep 07, 2007 12:26 pm
by StarkRavingSimmo
Gwagensteve wrote:Your information is not totally correct. With 31's a welded diff will live for years and years if you weld it well. Even the axles should be fine unless you are a superabusive driver. In vic I have seen a couple of rear axles go but only with over 35" tyres.
Ultimately, a sierra with an airlocker is no stronger than a sierra with a welded diff.
Steve.
A Sierra with an air locker is different to a welded diff tho. The air lockers only straining it when its turned on, the welded diff is straining all the time
Posted: Fri Sep 07, 2007 1:09 pm
by Gwagensteve
The maximum amount of "strain" is only equal to the amount of traction you have, so when you are giving it hell on a ledge, the amount of load on he axles is exactly the same welded or airlocker.
The axles don't break on road.... they break when you get on it offroad, which is when you would also break an axle with an airlocker.
The strain on road is much lower than offroad, especially with aggressive tyres. My Swampers don't squeal at all in carparks etc with the welded diff.
Steve.
Posted: Fri Sep 07, 2007 1:15 pm
by booflux
Gwagensteve wrote:Sorry Booflux, those I understand what you are trying to say but the photos don't help illustrate the point.
A hilux has high rear roll stiffness.
A 4 Runner has low rear roll stiffnes.
That would more than account for the difference In that case.
The rear question is has anyone other than Mock owned a car with a totally open rear diff (no LSD) and a front locker.
Everyone agrees both locks are the way to go, and that yes a front lock adds lots of capability, but in doing so, a lot of drivability is lost.
I drove Mocks car "Doof" (the car in question) a fair bit offroad and I can tell you yes it was capable but it also was a complete PITA to drive, and hard on CV's. I broke one in really slippery mud - shouldn't have been possible.
It would pinball, the front end would start to bounce and skip, and you would still have to hit things hard once you got the front up to try and bounce the back up. It's a hack way to drive.
front only is great when it's not really steep (so long as you don't need to steer), but then you don't really need lockers at all.
Steve.
When my rear airlocker is off, and I am in 4wd with the front auto locker yes I do and I find that I very rarely use the rear.
Half the time I only turn it on as I paid for it so I want to use it
Posted: Fri Sep 07, 2007 1:44 pm
by RUFF
cloughy wrote:RUFF wrote:I theory its totaly impossible for a bumble bee to fly.
How so??
Im sure if you PM
me3@neuralfibre.com he will be able to give all the theory as to why they can not fly.
Posted: Fri Sep 07, 2007 5:40 pm
by Dozoor
RUFF wrote:cloughy wrote:RUFF wrote:I theory its totaly impossible for a bumble bee to fly.
How so??
Im sure if you PM
me3@neuralfibre.com he will be able to give all the theory as to why they can not fly.
So enos all about em
Posted: Fri Sep 07, 2007 6:05 pm
by me3@neuralfibre.com
RUFF wrote:cloughy wrote:RUFF wrote:I theory its totaly impossible for a bumble bee to fly.
How so??
Im sure if you PM
me3@neuralfibre.com he will be able to give all the theory as to why they can not fly.
Bumblebees are the same as 4wd's. Anything can be done with enough power :onfire:
Posted: Fri Sep 07, 2007 6:11 pm
by me3@neuralfibre.com
ROGQ wrote:me3@neuralfibre.com wrote:midi73 wrote:blkmav wrote:me3@neuralfibre.com wrote:Q. When one front wheel is in the air spinning freely, and the other is getting no power, how much weight is on the opposite rear that is supposed to push you forward and have traction?
A. Next to none. If one front is in the air, the opposite rear has next to no weight on it.
This is why you need it in the front
No, this is why you need it in the back. All the weight of the car is transfered over the back wheels, therefore giving far better traction, than being in the front trying to drag the back up with one wheel still spining. If it is in the back, it doesnt matter if the front wheel still spins.
Not true. With open diffs, then across an axle, the maximum torque delivered to the wheel with the most traction is the same as can be delivered to the wheel with the least traction.
eg. If the car weighs 3000kg and is climbing a steep rutted hill the rear has one wheel with weight (1900KG) and one wheel just touching (100KG) then there is a maximum equivalent of 200KG (2x100KG) traction avaialble at the rear wheels. With a locker this increases to 2000KG (1900 + 100). (count the zero's)
As there is only 1000KG weight on the front wheels due to the hill, with one in the air, this is split to 1000KG one side and 0KG the other giving a maximum equivalent of 0KG traction (0+0=0) with open diffs. With a front locker this increases to 1000KG.
2000KG beats 1000KG in terms of putting power down.
Remember, across an open diff, the BEST you get is 2x the WORST wheel's traction.
Please note, the weight numbers used here are for comparitive purposes. I haven't tried to convert them to real forces with coefficient of friction, interference bahaviours, torque splits etc. It is simply comparitive between wheels, but the effect is equivalent.
There is traction on ONE rear wheel. The trick is getting enough torque there to do something useful. This is what a locker does. They don't aid traction, they allow a diff to deliver more torque to one wheel.
Paul
im not trying to hijack.... but would you agree with this theory on a trayback that has lsd rear? cauz they got bugger all weight in the rear...
Dunno on that one. Would be interesting to test. I know the toyota LSD design is pretty poor. Fixed resistance through clutches and springs. The patrol design varies the resistance based on load applied. More load = more lockup, so park brake may be your friend (although I remember some Patrols have the park brake on the transfer, in which case it won't help)
Paul
Posted: Fri Sep 07, 2007 7:06 pm
by cloughy
RUFF wrote:cloughy wrote:RUFF wrote:I theory its totaly impossible for a bumble bee to fly.
How so??
Im sure if you PM
me3@neuralfibre.com he will be able to give all the theory as to why they can not fly.
Posted: Fri Sep 07, 2007 11:34 pm
by Tapage
IMOP ( and my taste ) weld rear diff in a DD vehicle .. but off road it's a diferent story and it deppends ( again IMOP ) the terrain and off road type you do ..
In a slippery descent hill rear locker can cause you go off camber and get a side slide of your rear end ... the same situation with both locker engaged ( that it's the same scenario as both 3rd members welded ) can cause your complete vehicle go side slide ..
When I found one situation as is .. ( slippery descent hill ) I desactivate both lockers and allow the diff do it work .. and get better control handling and steering of your rig ..
You are not allowed to do that with both axles welded ..
It's more than only stress or resistance of your axxles .. much more about safety. But again it depends kind of off road and terrain.
Now .. the other side ( black one
) you can learn and live with your diff welded .. I know buddyes than do very well.
with both selectable lockers ( indepent conected ) not most of the time you will run only the rear .. and the front only for extreme situations .. more to get better andling and soft steering.
Rear
Posted: Mon Sep 10, 2007 1:55 pm
by liam hall
Rear. Seen Nissan gq break front cv's because of the front locker. Go rear first then front. All the weight is on the rear
Posted: Mon Sep 10, 2007 3:54 pm
by bazzle
midi73 wrote:j-top paj wrote:id do the front first then go from there.
i have a locker in the rear of my paj and open front and in the trol i have a limo in the rear and locker in the front.
i find the front being locked instead of the rear makes the car drive up hills so much easier.
I find the locker in the back so much easier for climbing hills. My brother has one in the front of his trol, and I dont know how many times he has slid sideways at the front, nearly rolling because it was trying to drag the car up with no drive at the back.
WHich is one reason why I said front 1st.
Bazzle
Posted: Tue Sep 11, 2007 12:42 am
by midi73
bazzle wrote:midi73 wrote:j-top paj wrote:id do the front first then go from there.
i have a locker in the rear of my paj and open front and in the trol i have a limo in the rear and locker in the front.
i find the front being locked instead of the rear makes the car drive up hills so much easier.
I find the locker in the back so much easier for climbing hills. My brother has one in the front of his trol, and I dont know how many times he has slid sideways at the front, nearly rolling because it was trying to drag the car up with no drive at the back.
WHich is one reason why I said front 1st.
Bazzle
Yeah that makes sense. Go the front first so you can roll the car. You are saying exactly opposite to what the post says.
He slid sideways at the front, because of the locker.
Posted: Tue Sep 11, 2007 1:11 am
by cloughy
midi73 wrote:bazzle wrote:midi73 wrote:j-top paj wrote:id do the front first then go from there.
i have a locker in the rear of my paj and open front and in the trol i have a limo in the rear and locker in the front.
i find the front being locked instead of the rear makes the car drive up hills so much easier.
I find the locker in the back so much easier for climbing hills. My brother has one in the front of his trol, and I dont know how many times he has slid sideways at the front, nearly rolling because it was trying to drag the car up with no drive at the back.
WHich is one reason why I said front 1st.
Bazzle
Yeah that makes sense. Go the front first so you can roll the car. You are saying exactly opposite to what the post says.
He slid sideways at the front, because of the locker.
That's what happens if you dont know when to turn it off and on at the right times
Posted: Tue Sep 11, 2007 8:30 am
by StarkRavingSimmo
Well, I'm thinking about changing my plans for my zook so i can just afford to air lock bloody both
Posted: Wed Sep 12, 2007 12:04 am
by Tapage
StarkRavingSimmo wrote:Well, I'm thinking about changing my plans for my zook so i can just afford to air lock bloody both
Your best bet ..
Posted: Wed Sep 12, 2007 12:33 am
by midi73
Tapage wrote:StarkRavingSimmo wrote:Well, I'm thinking about changing my plans for my zook so i can just afford to air lock bloody both
Your best bet ..
Nah, Cloughy is the best.
Posted: Wed Sep 12, 2007 1:44 am
by Tapage
midi73 wrote:Tapage wrote:StarkRavingSimmo wrote:Well, I'm thinking about changing my plans for my zook so i can just afford to air lock bloody both
Your best bet ..
Nah, Cloughy is the best.
Cloughy ..? ( sorry I'm miss
)
Posted: Wed Sep 12, 2007 2:10 am
by cloughy
midi73 wrote:Tapage wrote:StarkRavingSimmo wrote:Well, I'm thinking about changing my plans for my zook so i can just afford to air lock bloody both
Your best bet ..
Nah, Cloughy is the best.
Yep, just ask me
