auszookers.com :: View topic - Transfer Case Durability

jdk81 wrote:

Power (W) = torque (Nm) x angular velocity (rad/s)
rad/s = rpm x 2 x 3.14 /60

It isn't the power which opens the transfer cases, its the torque.

at 200 kW at say 7000 rpm
1st gear (ratio for example will be sierra 1st gear 3.652).
Torque on the gear box output shaft will be
Torque = Power / Angular Velocity
Torque = 200 000/ (7000 x 2 x 3.14/60)
Torque = 273 Nm.

Now say you are in first gear...
Ratio is
Torque on gearbox output shaft is approx 273 Nm x 3.652
This torque is almost 1kN.
As we saw the other day, a torque of 1kN through the box is enough to make it go pop.

Further example using a stock 1.3L in first gear
High range output = 1 kNm x 1.409 = 1.4 kNm
Low range output =1 kNm x 2.268 = 2.3 kNm
High range is 1.4kN x 5.12 diff ratio = 7.2 kN.

You're correct that it is torque that gearcases are rated for, not power. At the rev range that an engine produces max Power, it may not be producing it's max Torque (in fact, definately won't be). It's the max torque figure you have watch.

But to get your figure of 1kN torque on the gearbox, why have you multiplied it by 3.652 twice?

It should be flywheel torque x gear ratio=output shaft torque, so a stock 1.3 is: 100Nmx3.652=365.2Nm going in to the case and x2.268 gives 828.2Nm in lowrange.

A G16B EFi has a max torque figure of 132.4Nm, so in a Sierra with 6.5s, we're looking at 132.4Nmx3.652(1st)x6.5(lo)=3142.9Nm load on the T case housing, a massive increase of 279% of what the case was designed to cope with.

Author:	Zook_Fan [ Sat Sep 11, 2010 9:41 am ]
Post subject:	Transfer Case Durability
How much power would you be able to run through a sierra transfer case without expecting an explosion? It would be standard gears, most likely 1L, as most of the gearing for the vehicle will be done by the diffs. Looking at running an auto with it as well so it isn't as harsh on the transfer and driveline. Would a theoretical 200kw be pushing it?

Author:	want33s [ Sat Sep 11, 2010 9:56 am ]
Post subject:	Re: Transfer Case Durability
I would think 100Kw would be pushing the friensdship. 200 is asking for trouble.

Author:	steak_knife [ Sat Sep 11, 2010 9:59 am ]
Post subject:	Re: Transfer Case Durability
http://cgi.ebay.com.au/Suzuki-Sierra-V8 ... 946wt_1137 This thing has a 253 & a 1.3 transfer for"lower gearing" The 20v 4age's with Haltec's push 100kw & thay don't seam to smash case's to often..(Bruskibilt boy's)

Author:	lump_a_charcoal [ Sat Sep 11, 2010 10:37 am ]
Post subject:	Re: Transfer Case Durability
It is more driving style than brute HP. Also depends on whether the Tcase is stock or not, and if it is braced or not.

Author:	oozuk [ Sat Sep 11, 2010 11:27 am ]
Post subject:	Re: Transfer Case Durability
I split one with 140hp atw. No big launches I was just taking off from the lights and buried the foot in first gear once I was moving, boost came in and transfer split in two ...... Bugger Now the new one is fitted with a mighty kong and a rocktoy ring, all good now

auszookers.com https://auszookers.com/forum/

Transfer Case Durability https://auszookers.com/forum/viewtopic.php?f=5&t=15029	Page 1 of 1

Author:	Zook_Fan [ Sat Sep 11, 2010 11:54 am ]
Post subject:	Re: Transfer Case Durability
have you given it a good go with the new reinforcement? like in similar circumstances of what broke the old case? the plan in my head is to run a 13b rotor, using the auto box and sierra transfer. just want to see if it is plausible or if i would need to utilise a toyota gearbox/transfer combo

Author:	jdk81 [ Sat Sep 11, 2010 1:09 pm ]
Post subject:	Re: Transfer Case Durability
Zook_Fan wrote: How much power would you be able to run through a sierra transfer case without expecting an explosion? Would a theoretical 200kw be pushing it? EDIT: Cleaned up post Power (W) = torque (Nm) x angular velocity (rad/s) rad/s = rpm x 2 x 3.14 /60 It isn't the power which opens the transfer cases, its the torque. at 200 kW at say 7000 rpm Torque at the flywheel will be Torque = Power / Angular Velocity Torque = 200 000/ (7000 x 2 x 3.14/60) Torque = 273 Nm. Now say you are in first gear (ratio for example will be sierra 1st gear 3.652). Torque on gearbox output shaft is approx 273 Nm x 3.652 This torque is almost 1kN. As we saw the other day http://auszookers.com/index.php?name=Fo ... ic&t=14850 a torque of 1kN through the box is enough to make it go pop. IMO his case opened up like paris hilton due to the torque generated at the gearing interfaces. 6.5s in high range or not, the load the case can handle is the same. Further example using a stock 1.3L in first gear High range output = 1 kNm x 1.409 = 1.4 kNm Low range output =1 kNm x 2.268 = 2.3 kNm Gearing interface loads high range 44 to 41 = 1k Nm x 0.93 = 0.93 kNm 41 to 62 = 0.93 kNm x 1.512 = 1.4 kNm Remember sierra cases are designed for 47kW, which would normally generate 1/4 of the torque you are looking at. The 47kW motor can still bust the transfer case. It would probably be wise to scrap the sierra xfer case idea and use one designed for more power. EDIT: even with diff gears, the load will still be too much. You could consider hilux cases coupled with diff gears. spending big on reinforcement is fairly silly, engineer it properly the first time. Select the diff ratios and transfer case which is suited to the loads you will be applying. I'm not even certain the cvs and axles will hold. High range is 1.4kN x 5.12 diff ratio = 7.2 kN.

Author:	303zuke [ Sat Sep 11, 2010 2:57 pm ]
Post subject:	Re: Transfer Case Durability
jdk81 wrote: Power (W) = torque (Nm) x angular velocity (rad/s) rad/s = rpm x 2 x 3.14 /60 It isn't the power which opens the transfer cases, its the torque. at 200 kW at say 7000 rpm 1st gear (ratio for example will be sierra 1st gear 3.652). Torque on the gear box output shaft will be Torque = Power / Angular Velocity Torque = 200 000/ (7000 x 2 x 3.14/60) Torque = 273 Nm. Now say you are in first gear... Ratio is Torque on gearbox output shaft is approx 273 Nm x 3.652 This torque is almost 1kN. As we saw the other day, a torque of 1kN through the box is enough to make it go pop. Further example using a stock 1.3L in first gear High range output = 1 kNm x 1.409 = 1.4 kNm Low range output =1 kNm x 2.268 = 2.3 kNm High range is 1.4kN x 5.12 diff ratio = 7.2 kN. You're correct that it is torque that gearcases are rated for, not power. At the rev range that an engine produces max Power, it may not be producing it's max Torque (in fact, definately won't be). It's the max torque figure you have watch. But to get your figure of 1kN torque on the gearbox, why have you multiplied it by 3.652 twice? It should be flywheel torque x gear ratio=output shaft torque, so a stock 1.3 is: 100Nmx3.652=365.2Nm going in to the case and x2.268 gives 828.2Nm in lowrange. A G16B EFi has a max torque figure of 132.4Nm, so in a Sierra with 6.5s, we're looking at 132.4Nmx3.652(1st)x6.5(lo)=3142.9Nm load on the T case housing, a massive increase of 279% of what the case was designed to cope with.

Author:	jdk81 [ Sat Sep 11, 2010 3:09 pm ]
Post subject:	Re: Transfer Case Durability
303zuke wrote: jdk81 wrote: Power (W) = torque (Nm) x angular velocity (rad/s) rad/s = rpm x 2 x 3.14 /60 It isn't the power which opens the transfer cases, its the torque. at 200 kW at say 7000 rpm 1st gear (ratio for example will be sierra 1st gear 3.652). Torque on the gear box output shaft will be Torque = Power / Angular Velocity Torque = 200 000/ (7000 x 2 x 3.14/60) Torque = 273 Nm. Now say you are in first gear... Ratio is Torque on gearbox output shaft is approx 273 Nm x 3.652 This torque is almost 1kN. As we saw the other day, a torque of 1kN through the box is enough to make it go pop. Further example using a stock 1.3L in first gear High range output = 1 kNm x 1.409 = 1.4 kNm Low range output =1 kNm x 2.268 = 2.3 kNm High range is 1.4kN x 5.12 diff ratio = 7.2 kN. You're correct that it is torque that gearcases are rated for, not power. At the rev range that an engine produces max Power, it may not be producing it's max Torque (in fact, definately won't be). It's the max torque figure you have watch. But to get your figure of 1kN torque on the gearbox, why have you multiplied it by 3.652 twice? It should be flywheel torque x gear ratio=output shaft torque, so a stock 1.3 is: 100Nmx3.652=365.2Nm going in to the case and x2.268 gives 828.2Nm in lowrange. A G16B EFi has a max torque figure of 132.4Nm, so in a Sierra with 6.5s, we're looking at 132.4Nmx3.652(1st)x6.5(lo)=3142.9Nm load on the T case housing, a massive increase of 279% of what the case was designed to cope with. I didnt mulitply it twice by 3.652, only the once. I mentioned it twice, was a messy post on my behalf I appologise (lack of sleep). My OP in this thread has been edited and structured better. I was basing the calcs on power stated by OP, using sierra 1.3 1st gear as example with 1.3 stock xfer gears (as in high range these generate the lowest torque output). And from the link I posted, we know the ball park power, hence torque, hence case load in high range. It is clearly obviously in low range it will not last, let alone with other gears. EDIT: I am also aware of torque and power output characteristics, however from the OP that is unknown, so is rev range, so is gear ratio

Author:	31zook [ Sat Sep 11, 2010 10:16 pm ]
Post subject:	Re: Transfer Case Durability
are you going to make it a 4wd race car? sick bra

Author:	Zook_Fan [ Sun Sep 12, 2010 7:01 am ]
Post subject:	Re: Transfer Case Durability
looking at making it a winch challenge car. I agree with lump_a_charcoal that driving style is better than all out horsepower BUT in this event two out of ten stages, so 20%, where hill sprints where it is nothing but horsepower that will win you the race. I was also looking to the rotary because they are light, small, make awesome power, rev well and the torque isn't half bad either. I have a yota transfer and a 5 manual box but i was hoping to stick with sierra stuff if possible. Thanks for doing the physics guys, I was going to do that but the latest physics assignment is due and well i'm sick of it

Author:	steak_knife [ Sun Sep 12, 2010 7:06 am ]
Post subject:	Re: Transfer Case Durability
Zook_Fan wrote: I was also looking to the rotary because they are light, small, really??

Author:	royce [ Sun Sep 12, 2010 7:14 am ]
Post subject:	Re: Transfer Case Durability
I have heard of series 1 rockhoppers surviving with rotaries how about a miss match of mazda gearbox and transfers till something fits together?

Author:	Zook_Fan [ Wed Sep 15, 2010 10:00 am ]
Post subject:	Re: Transfer Case Durability
yeah royce I think that is how I will have to do it.

Page 1 of 1	All times are UTC + 9:30 hours
Powered by phpBB® Forum Software © phpBB Group https://www.phpbb.com/