Tare weight of XT cab/chassis?

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26 Apr 2020 10:30 #21 by Paul Scherek
Paul Scherek replied the topic: Tare weight of XT cab/chassis? Light weight motorhome proposal.
Sorry Peter, put my keyboard into gear before my brain. I just checked - 4mm aluminium composite weighs in at 4.75 kgs/sq. metre - not enough saving over our fibreglass composites to justify the lack of insulation.

Your 196 has probably given a motorhome body the toughest test of any off-road tourer in Australia - silly to change material now.
Cheers, Paul

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26 Apr 2020 11:46 - 26 Apr 2020 11:50 #22 by Alister McBride
Alister McBride replied the topic: Tare weight of XT cab/chassis?
Hi Peter, a few points i thought i'd mention from my racing days:

Aluminium exhaust terminating in front of the rear wheel.

My understanding was that alluminium exhausts were a no-no as the melting point of Ally is 500 odd degrees. Definitely not for the header/turbo dump pipe anyway...

Aluminium or carbon fibre drive shafts

We designed and made our own carbon fibre shafts with alloy flanges/couplings. They were used heavily in wartime helicopters because if they get a stray bullet they disintegrate and the chopper has more ability to 'glide' down rather than a bent shaft tearing half the chopper apart. I can help with some sources of carbon tubing but would suggest against it for 4wd purposes. The filament windings are designed for the purpose of transmitting torque down the shaft rather than a bump from a rock and will probably dent in that situation which leads to instant failure on reapplication of power.
Alloy has it's own problems of not being weldable in the middle of nowhere (this may not be an issue to you). Also they are inherently weaker unless you go for some decent grades 6061 or 7075 T6 (not weldable) for example or go twice as thick which gives you minimal weight saving for the price.

Existing spring packs weigh in excess of 250kg

I'm assuming that's combined weight? What about a 4 link airbag setup? I imagine expensive but better ride and much lighter...

Alternative transmission/T.C options???

I'm sure one of the US pickup setups like the G56 to NP273 or NV4500 to NP205 behind it may be lighter than the current (and much stronger) but worth it i'm not convinced... May be worth it if you were doing an engine conversion but i imagine you're staying as is.
Last Edit: 26 Apr 2020 11:50 by Alister McBride.

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26 Apr 2020 13:18 #23 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
I think aluminium melts at 650C+/-, so maybe OK after it straightens out after the first metre or so? My biggest concern with aluminium would be fatigue, but if it joined to the steel via a flexible flange and was a simple straight section it might be OK. Then behind the wheel it might be cool enough to use silicone hose that is good for 175C for the bends?
www.industrialspec.com/shop/media/catalo...ubing_spec_sheet.PDF
Do I need a muffler???
Not a great expense to just try it and see?

I did think the drive shafts were a bit of a pipe dream, but worth asking, thanks.

"What about a 4 link airbag setup?"I have no idea what this is - more research required!
Air bags is an obvious option. I have never been a fan, but never used them either.
Don't want to stuff the OKAs best feature . :(
Long travel air bags and just the original top 2 leaves to hold the axle in place???? Plus good shocks!

Another friend suggested a GM 4L80E trans and a Patrol T/C might be lighter, but really don't have a clue what the weights are.
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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26 Apr 2020 14:05 #24 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Tare weight of XT cab/chassis?
No keep the Spicer a 4L80E and Patrol transfer might well be lighter than the manual and NP205 but by the time you add 20+ litres of ATF, a dirty big oil cooler with fan and the plumbing as well as the wiring, TCM etc to run it you would be back past what the manual weighs.
Maybe a slightly smaller but more powerful engine and drivetrain out of something else?
The little 2.8 ISF Cummins in my Foton ute puts out 160hp and 360Nm so would probably go better than the Perky. They use the same engine in their range of light trucks which are a similar size to the Oka.

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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26 Apr 2020 14:22 - 26 Apr 2020 14:27 #25 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
Yep, to the 2.8 Cummins, but I don't want to go electronic/computer controls :(
But it has to stay on the table as an option, never the less.....because I expect the weight bonus would be significant?
- EDIT - a quick google says the Cummins is 50kg lighter than the Phaser......
www.primemovermag.com.au/products/item/cummins-isf-engine
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214
Last Edit: 26 Apr 2020 14:27 by Peter_n_Margaret.

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26 Apr 2020 15:54 - 26 Apr 2020 15:55 #26 by Alister McBride
Alister McBride replied the topic: Tare weight of XT cab/chassis?
"4 link suspension" (google it) is what all the yanks put under their pickups as soon as they buy them. It really is a better suspension system but probably going to be expensive for the oka... although at 4.5T you could probably just buy a set designed for a RAM or whatever, adapt it and get an engineer to sign it off, probably possible.

aluminium exhaust is from my experience a taboo as far as exhausts go, but i suppose so is silicone so i'm happy for you to try it and let me know... ;)

How does a 4bt compare for weight? it's also much more tuneable than the perky...
Last Edit: 26 Apr 2020 15:55 by Alister McBride.

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26 Apr 2020 16:52 #27 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
Why taboo???
4BT is heavier than a Perkins by a big margin, I think.
Will check out the suspension, ta.

What is the larger after market air cleaner people are using? I think it is plastic not steel???
Do I need a muffler?
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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27 Apr 2020 05:13 #28 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Tare weight of XT cab/chassis?
Fleetguard Optiair 1100 aircleaner, model AH19334, yes its plastic, you need to open the hole in the body a little bit so that removes more metal ;-))
No muffler is fine but it can get very crackly and drone at certain revs which becomes annoying. The little one that is straight through on 374 only weighs a few kilo's, way less than the standard one.

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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27 Apr 2020 07:02 #29 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
The air cleaner sounds like the way to go and I reckon I might trial the exhaust on #196. Ta.

The complexity of the 4 link suspension seems to be the rods to keep the axle in position. The 2 existing top leaves would do that. Then I could add simply coils or air bags to support the weight? Air bags would be lighter I expect?
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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27 Apr 2020 18:59 #30 by OKAPETE
OKAPETE replied the topic: Tare weight of XT cab/chassis?

Chaplain. Won x One Chaplaincy.
AM SAE-A. AAFRB.

Oka 383. In process.... Cummins 6bt. Allison 2500 6spd. NP205. Dana 80 F & R.
Attachments:

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27 Apr 2020 19:05 #31 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
Thanks Pete, much obliged.
Any idea what they included in that weight eg spare wheel would be expected, nominal fuel, no accessories....
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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27 Apr 2020 19:14 #32 by OKAPETE
OKAPETE replied the topic: Tare weight of XT cab/chassis?
Pretty sure it was basic order....single tank. No bull on bar :) Single battery. No sunvisor.etc.
Pete.

Chaplain. Won x One Chaplaincy.
AM SAE-A. AAFRB.

Oka 383. In process.... Cummins 6bt. Allison 2500 6spd. NP205. Dana 80 F & R.

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27 Apr 2020 20:17 #33 by Alister McBride
Alister McBride replied the topic: Tare weight of XT cab/chassis?
When i say taboo i just meant 'thrown out pretty quickly' as the melting point was a dealbreaker. If you run a graduated setup with steel to ally to silicon what happens if your egt's rise by accident for a small trip...? You would at least be lighter at the end of it! ;)

You're right but two leaves would still be heavier i reckon. You could run a panhard rod setup. Really, i just want someone to do it but you're right, two leaves with helpers is probably the best solution if you're going down that path...

OKA Pete those figures would be for the LT wouldn't they?

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29 Apr 2020 11:10 - 29 Apr 2020 11:11 #34 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
I reckon this will crank the Perkins. www.evworks.com.au/winston-lp12v40ah-lifepo4-battery-12v-40ah especially the geared starter motor (which is also much lighter than the OEM).
And if it goes flat, I will be able to switch in the house batteries as I do now.
A saving of 28kg.
I will also shift it to a light weight plastic box behind the passenger seat to keep it dry and then eliminate the standard battery tray which would be another 10kg, at a guess?
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214
Last Edit: 29 Apr 2020 11:11 by Peter_n_Margaret.

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29 Apr 2020 12:57 #35 by Dean and Kaye Howells
Dean and Kaye Howells replied the topic: Tare weight of XT cab/chassis?

Peter_n_Margaret wrote: I reckon this will crank the Perkins. www.evworks.com.au/winston-lp12v40ah-lifepo4-battery-12v-40ah especially the geared starter motor (which is also much lighter than the OEM).
And if it goes flat, I will be able to switch in the house batteries as I do now.................

Cheers,
Peter


Hi Peter, if it goes flat it's in the bin unfortunately :( 11 volts is the minimum voltage for this battery before it's fatally damaged. It does not have a built in BMS.
Its optimal discharge current is <15 amps, it's maximum discharge current is <120 amps and its maximum peak discharge current is <400 amps (for max of 10 secs in one minute) which may not be enough for some starter motors, certainly not enough a decent electric winch if you have one.

Battery Specs

It's interesting to note that this is a LiYFePO4 battery. I don't know what the Yttrium does but it sounds special :)

Deano

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29 Apr 2020 13:13 - 29 Apr 2020 13:18 #36 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
Thanks Dean. Might need a bigger (heavier) one?
No winch in the light OKA. :(
Is there someone out there who will try one for me :)
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214
Last Edit: 29 Apr 2020 13:18 by Peter_n_Margaret.

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30 Apr 2020 18:18 - 30 Apr 2020 18:22 #37 by Holmz
Holmz replied the topic: Tare weight of XT cab/chassis?
If it is motorsports porn, that we are wanking on about, then I'll throw in my 2¥.

Almost all small airplanes use stainless 321, and almost all very high end race cars use inconel 625. Some motorcycles use titanium.
The Inconel 625 is stronger red hot than at room temp, and the thickness is usually limited by the welders skills, so 0.5-mm is about the limit... that is the same gear that the X25 rocket plane was skinned with, and the SR-71 used titanium... so it is the difference between Mach 3+ and Mach 5+

Anyhow we can all have fantasies if we want... but the reality is that saying weight on drive shafts and exhaust systems are pretty small. We start with a (God knows exactly how heavy) of a heavy engine..
One could probably replace the exhaust manifold with a tubular header style and save more than the whole rest of the exhaust being exotic.

Diffs are not light, and they are unsprung weight.
Rims are also not light, and unsprung weight... but all the alloy rims are cheap cast jobs. If there were any forged choices, I have not found them.

The other place to remove weight gets increasing "goodness" the higher it goes.
Maybe the steel tray for alloy makes sense?
And an alloy bus body would be lighter than a steel bus body.
Fibreglass would be even better as it has generally better fatigue life than alloy.
Last Edit: 30 Apr 2020 18:22 by Holmz.

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30 Apr 2020 18:32 #38 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
Thanks Holmz.
There is a quick realisation that the first bits of weight saving are easy, but the further you need to go, the harder and more expensive it gets.
To help with making sense of competing opportunities I find that it helps to put a price on a weight reduction and the price I propose to use is $50 per kg. No doubt that will get "massaged" as time goes by, but to put that in context taking 500kg out of a 3T cab chassis then gets a "value" of $25,000.
Susi & Ruedi took 1T out of NT001 a while back. I bet it cost lots more than $50,000 though.

And I like the exhaust manifold suggestion. Thanks. That goes onto my list!
Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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30 Apr 2020 18:48 #39 by Peter_n_Margaret
Peter_n_Margaret replied the topic: Tare weight of XT cab/chassis?
I have a list of the common materials I will probably be dealing with and their SGs.
There are multiple considerations - 1. Reduce the thickness, 2. Change materials, 3. Combination of 1 & 2.
Aluminium 2.6
Steel 7.8
FRP sheet 1.9
Glass 2.8
Polycarbonate 1.2
HDPE 0.95
Polypropylene 0.91

Cheers,
Peter

Cheers, Peter.
OKA196 tinyurl.com/OKA196xtMotorhome
Mob.0428171214

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01 May 2020 00:17 #40 by Dean and Kaye Howells
Dean and Kaye Howells replied the topic: Tare weight of XT cab/chassis?

Peter_n_Margaret wrote: Thanks Holmz.
There is a quick realisation that the first bits of weight saving are easy, but the further you need to go, the harder and more expensive it gets.
To help with making sense of competing opportunities I find that it helps to put a price on a weight reduction and the price I propose to use is $50 per kg. No doubt that will get "massaged" as time goes by, but to put that in context taking 500kg out of a 3T cab chassis then gets a "value" of $25,000 ................

Cheers,
Peter


It's a bit like embarking on a quest Peter. It starts off easy just to suck you in and gets progressively harder and expensive as you go :)

I'd always been weight conscious when touring with various 4WD's over the years but probably got a bit lazy with the Oka. Not only with adding extra weight but with managing what was there. Another aspect of weight management is front/rear loading.

After 10 years of continual fiddling/upgrading/modifying things #413 had transformed from a Perkins powered multi-cab to a well equipped Cummins powered full bus camper :) I put it over the weighbridge and was shocked to find 2870 Kg front and 2540 Kg rear. As it started life as a multi-cab front axle max is 2400 Kg (bus 2800 kg) so I was nearly 1/2 tonne over on the front axle so the weight loss quest began. I'm not sure if I'm a Don Qixote or Sancho Panza here but there were plenty of windmills to tilt at :)

With a mixture of weight loss and weight re-distribution these figures were soon improved ie.2390 Kg front and 2960 Kg rear. It's interesting to note that hanging a spare off the back took significant weight off the front axle with the cantilevering effect of hanging behind the rear axle. Same with the rear mount winch. Changing the spares to alloys actually increased the front axle weight because of this cantilevering effect.

The bang for buck weight re distribution was very good as there was no major costs involved and the result was a much better handling vehicle.

When considering the cost of losing weight IMO there's also 'op-ex' and 'cap-ex' to consider ie. operational expenditure and capital expenditure to get a realistic cost of the upgrade. Probably the best bang for buck upgrade can be replacing heavy tyres on steel rims with lighter tyres on alloy rims. eg. If the tyres are worn out anyway replacing them is an ongoing operational expenditure cost and not extra money that needs to be spent such as for new rims to replace perfectly good old rims which is a capital cost or 'cap-ex'. Make sense ?

With six tyres and rims weighing in at 82 Kg each and the new tyre/rim combo's at less than half that the overall weight saving was just over 250 Kg. My overall cost considering I did a bit of a tyre rim swap was around $2500 or $10/Kg.

The next big weight saving was swapping out 4 X 24 Kg 66 ah Optima house batterys for 2 X 12 Kg 100 ah Lithium batterys for a weight saving of 72 Kg and a net. cost of around $500 after selling my Optimas or about $7/Kg. But to be fair I also upgraded charging systems, switching, inverter etc at the same time and spent easily another $500 which I would have spent regardless of the battery upgrade. I moved the nearly 100 Kg of batterys from just behind the drivers seat to directly over the rear wheels which took 100 Kg off the front axle or the additional weight of the Cummins over the Perkins as a bonus.

Replacing the front steel bull bar with an alloy bar and removing the factory Warn winch/steel cable/carrier/fair-lead etc. and replacing it with a rear cradle mount electric winch and replacing the front steel visor with an aluminium one saved (guesstimate) 180 Kg and all of it off the front axle :) The net. cost of doing this was around $3200 after selling the old winch, visor and bullbar. So around $18/Kg.

Replacing the old 105 litre steel fuel tanks with 160 litre alloy tanks probably saved around 50 Kg (dry weight) but add another 50 Kg or so to the overall vehicle weight when full. So a bit hard to do a 'bang for buck' calculation here.

The next big thing will be changing out the NT HD150 transfer case (150 Kg) for a fully rebuilt and upgraded NP205 (around 75 Kg) for an overall weight saving of 75 Kg. My all up costs for this I estimate will be around $4500 which comes in at $60/Kg. I've no idea what I can sell the old TC for.

My latest weigh in gave me 2420 Kg front and 2620 Kg rear for a total of 5060 Kg. If I can get this to under 5 tonne with the TC upgrade I reckon that's about as good as I can get with a full bus body.

So there you go Peter, you've got all this or similar (and more) to look forward to :)

Are you sure it wouldn't be easier to sell your pride and joy and start anew ? Ian Jones has nearly completed a ground up rebuild on an early XT cab chassis and it looks great :)

Deano :)

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