Diff ratios
- Harry
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I asked Paul and Ian if they would change my diff ratio from 4:88 to 4:56 which they did for me and thank you to you both for fitting me in your time schedule and for the very good job you both did
With the 4:88 I would cruise on 90 to 95 km per hour doing 2100 RPM
And now with the 4:56
I am doing 95 km per hour at 1970 RPM and it is hard not to sit on the speed of 100 or more as with the the 4;56 ratio doing the 2100 rpm I would be doing 110 km per hour
The fuel I get now doing 95 km per hour is bang on 16 liters per hundred and if I was doing 85 to 89 km per hour I would and have been getting mid 15 liters per 100 km I am happy as
Oh that is with 19.5 X 305 Hankook tyres
The cost for my diff ratio change over is ......... well that is not so important but if you want to put a dollar on it may I suggest you give Paul and Ian a call
I went with the 4:56 ratio
And Deano has gone with the 4:10 ratio
And I am sure that he will let you all know his RPM and km also fuel usage as the trip goes by
Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Harry
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Chris from Kunnanara
Has also fitted 4:10 like Deano except that Chris has a 6 cylinder Perkins in his Oka
So there are a lot to compare with
Well now I have done some km
I use to get 620 km from my 105 liter fuel tank that is with the 4:88 diffs
AND NOW
With the 4:56 diffs I get 680 km from my 105 liter fuel tank
I ran them both bone dry for the test
I must say the cummins does NOT like running out of fuel
The fuel test was done both times on the same road from Tennant creek via Mataranka springs in and out 2 times and then onto Katherine total 680 km I ran out of fuel as I approached the United service station in Katherine
Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Peter and Sandra OKA 374
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OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.
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- Outback Jack
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I have done same run from Tennant to Katherine on one tank in OKA with 6bt. I did not go into Mataranka though. This is with standard spicer and 19.5 tyres that where 265`s. Sitting mostly around 90kph.
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- Harry
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My weight is front axle is 2630 kg
Rear axle is 2900 kg
Fully loaded with a spare 19.5 tyres and rim on the roof
And enough food water wine beer for 45 days
I also fitted an aluminum bull-bar on the front
Fuel that I carry is in 2 fuel tanks one 105 lt and the other 165 lt and 100 lt water 32 liters under the bull-bar and 68 lt in the belly of the Oka
Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Harry
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Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Greg Boyle
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is that a painted finish, or annodised.
cheers Greg
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- Harry
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Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Peter Davis
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Are the XT and LT bullbars the same?
Cheers
Peter
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- Harry
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I think the steel one weighs around the 80 to 85 kg
Yes Chris from Kununurra makes them for both XT and LT
Deano is getting one for his LT tomorrow
You will have to ask Chris for pricing if you are going that way he will be away until the end of July
Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Peter and Sandra OKA 374
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- Posts: 1321
OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.
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- Harry
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I am beginning to lose weight as we started off with
44 liters of red wine Jenny loves her wine and one can not buy cask wine up here
60 cans of beer which I had to replenish already feel the difference in heat up here
12 liters of scotch ( thanks Greg brewery)
Should of brang more ...... yer you got it Jenny loves the scotch as well
You know what they say happy wife happy life
176 liters upright evakool fridge / freezer
Now that is a great fridge just bought it before the trip
Had a Waeco before but evakool has more insulation and less running cost or amps I should say
We have only one draw back our Oka is wider and seems to have a lot more room so Jenny does and has filled every nook and cranny with something......... I am sure we will need it along the way
Well Jenny thinks we will
Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Harry
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But I have upgraded my XT with twin shocks in the front ,wow what a difference it does make . Thank you to Dean ( Oka parts in WA ) for supplying the parts and the fast service that you provided
A very big thank you to Ian Jones for making time for me to get them fitted what a good job you have done Ian .
Any one that has an XT and does not or has not done this upgrade I think you should do it . I highly recommend it ...
a bit firmer on the black stuff ,very very good on corros and the dirt road
Oka 045 the WIDE Motorhome 6bt cummins 500 watt solar diesel heating gas cooking up grade LSD front and rear diffs to 4:56 from 4:88 . 320 lt fuel 153 lt fresh water in 3 separate tanks 3 house batteries 1 start battery 176 lt upright fridge/freezer Black dog security
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- Peter and Sandra OKA 374
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- Posts: 1321
OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.
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- Holmz
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Harry wrote: This has nothing to do with diff ratio
But I have upgraded my XT with twin shocks in the front ,wow what a difference it does make . Thank you to Dean ( Oka parts in WA ) for supplying the parts and the fast service that you provided
A very big thank you to Ian Jones for making time for me to get them fitted what a good job you have done Ian .
Any one that has an XT and does not or has not done this upgrade I think you should do it . I highly recommend it ...
a bit firmer on the black stuff ,very very good on corros and the dirt road
How does one tell if it is over damped or under damped?
I bet it is "way better" different on e bitumen.
Can you further describe the feel on the dirt and corregations? And how that translates into "highly recommended".
Note: I believe you... I'm just trying to wrap me head around justifications to have a spend up.
And it Looks like a multi-k$ upgrade...
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- Alister McBride
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- outyonda
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Alister McBride wrote: After having one on the front and changing to two and experiencing both i would say from my experience two is crap on corrugations and bumps in general but better for 'race performance' around corners! Two just makes it stiffer in my opinion. Maths and engineering would suggest the same!. I haven't taken the second one off yet but will do when i get the time...
Then why did the LT & NT have twin shocks on all 4 corners ???
& 50% of XT's have upgraded!!
OKAs 091, 093, 094, 113, 346x6 & 405
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- Alister McBride
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This has been discussed on this forum before, someone had installed double, larger diameter shocks with (i think approx) half the damping co-efficient. (The 'Powerdown shocks' installed above may be this...?) This gave larger area/volume of oil in shock, hence less heat build up (and degradation) and because of the half or so damping co-efficient, the same overall damping co-efficient as single shocks. Overall, giving good ride over bumps and longevity. You can't really have a racing car and be good over bumps... It's just not physics! Thanks for your question Brett!
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- Holmz
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Alister McBride wrote: More is better? i don't know Brett... possibly as single shocks couldn't handle all the heat build up over bumpy roads... honestly just a guess, you'd be best asking the oka engineers. Just my experience in driving the oka with both and a little bit of knowledge about vehicle dynamics. The linear force equation for a damper is F=cv... It's quite simple really, if you have the same damping co-efficient (c) shocks and you double how many there are you get double the force applied by those shocks (F) at any apparent bump velocity (v), hence better handling on-road and stiffer over bumps...
This has been discussed on this forum before, someone had installed double, larger diameter shocks with (i think approx) half the damping co-efficient. (The 'Powerdown shocks' installed above may be this...?) This gave larger area/volume of oil in shock, hence less heat build up (and degradation) and because of the half or so damping co-efficient, the same overall damping co-efficient as single shocks. Overall, giving good ride over bumps and longevity. You can't really have a racing car and be good over bumps... It's just not physics! Thanks for your question Brett!
I did a partial differential equation (PDE) course, and dampers were a huge part.
I passed it, with a 35/100... they graded on a curve and I got an A...
It is seemingly akin to black magic
Most of the damper knowledge seems equally arcane to PDEs ...
Hence it seem like dual is better for bitumen and single better for corregations, but it is an interesting think none the less.
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- outyonda
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OKAs 091, 093, 094, 113, 346x6 & 405
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