NorthWestFab said:
thanks, thats the confirmation i was looking for
CK5
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doubler - 203 in low, 205 in high
- Thread starter muddybuddy
- Start date
thanks, thats the confirmation i was looking for
jays68yak
1/2 ton status
For me its easier to shift the 203 then the 205. Besides I still have yet to get my shifting down and figure out what I am in I have 3 sticks to pick a gear, not counting the tranny.
I wouldn't worry about it unless you had a monster engine with an ungodly amount of torque. A hopped up Cummins with a 3:1 np203 could prolly bust some intermediate shafts...
my puny ass near-stock 350 prolly ain't gonna break anything in the 203 or 205, so long as both are well maintained.
j
my puny ass near-stock 350 prolly ain't gonna break anything in the 203 or 205, so long as both are well maintained.
j
FWP
CRS
FWIW, I've run the the 203 in low/205 in hi (2:1) 2wd rear, with the hammer down, up dirt hills many a time. No problems, although I'm only runnin a mild SBC with around 300 horse, not a BB in the 500+ numbers.
FWP said:
sweet. im going to be running a 150hp 6.2
it may eventually get a turbo but we'll see. sounds like i shouldnt have any problems
az-k5
1/2 ton status
FWP said:
Ditto. That is how I do all of the parker climbs. I hit 203 low 205 4hi in the dunes. Haven't had a problem yet. If I had a BB I might switch up to 203 hi and 205 4lo if wheel spin was needed. I cover 70%+ of a trail in 203 low 205 2hi FWIW. Learned that from rob and marv.
blazersnburban
Registered Member
what i was saying is that the 205 input shaft sees the same torque applied to it if 203 is in low, no matter where you have the shifters downstream from it.
i can see how using the low as far down the drivetrain as possible helps keep the strain off the shafts ahead of the reduction, but the 205 input has same amount of torque applied to it when 203 is in low and 205 is in hi, as when 203 is in low and 205 is in lo.
so why would it fail more easily when the 205 is in hi? when 203 is in low it puts out x amount of torque, if everything is in low the 203 is still putting x amount of torque to the 205's input.
explain to me ,other than breaking a shaft down stream) why useing 203 in low is any worse than both 203 and 205 is in low?
i can see how using the low as far down the drivetrain as possible helps keep the strain off the shafts ahead of the reduction, but the 205 input has same amount of torque applied to it when 203 is in low and 205 is in hi, as when 203 is in low and 205 is in lo.
so why would it fail more easily when the 205 is in hi? when 203 is in low it puts out x amount of torque, if everything is in low the 203 is still putting x amount of torque to the 205's input.
explain to me ,other than breaking a shaft down stream) why useing 203 in low is any worse than both 203 and 205 is in low?
spoolnaround
1/2 ton status
blazersnburban said:
I was thinkig the same thing.
EDIT: I fixed the part I was thinking about.
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think of it this way, if hes running a auto with 3:1 first and the 203 in 2:1 thats around the same reduction a 465 would put into a 205 and many of thoese had 10 spline inputs
a high gear would be weaker then a low gear. If the tranny is in first the 203 is in low, now your doubling the torque to the 205 if the 205 is in high gear, the gear is not as strong as the low gear, so there is a small chance something can break. The 205 is now spinning twice as fast as it usually does in high. When both are in low, i thing both tc's are strong enough. ive done it a couple of times not paying attention, nothing happened.
marv_springer
1/2 ton status
blazersnburban said:
The concern is when using "single low"... W/ a 203/205 Dubbler, there are 2 ways to get there:
1) 203 in low, 205 in high
2) 203 in hi, 205 in low
The topic of this thread is based on the fact that the 32 spline input on the 205 has less torque applied in option 2).
Just trying to clear things up...
That said, I've run alot of dune miles in the 203lo/205hi position w/Big Block power.... Reason is, it's common to run around in 2wd. But if you get 75% up a climb and start to bog, then you can click in the front axle by going from 2hi -> 4hi in the 205 - and do it easily on the run...!
It's the only way to cruz the dunes!
Marv
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well if things work out 1:1, 2:1, 3:1, and 6:1 talk about gear selection
az-k5
1/2 ton status
Okay, here is the theory behind the 205 input stress.
Using fake numbers and perfect world physics as an example.
You need 400 lb/ft of torque to the driveshaft to spin the wheels or climb a ledge. The output of the 205 will always see 400 lb/ft to make the rig move.
Your engine puts a max of 250 lb/ft to the front of the 203.
Put the 203 in hi and the 205 in low. The 205 output still sees 400 lb/ft. The 205 input sees 200 lb/ft as does the 203 input.
Switch that around. Your 203 is in low and your 205 is in hi. You still need 400 lb/ft to move. The 205 ouput sees 400 lb/ft as does the 205 input. The 203 input only sees 200 lb/ft.
Now go for double low. The 203 in low and the 205 in low. The rear ouput of the 205 sees 400 lb/ft as usual. That means that the 205 input sees 200 lb/ft, and the front of the 203 only actually sees 100 lb/ft.
In double low the driveshaft would need to overcome 800 lb/ft for the 205 input to see the same 400 lb/ft as it did in 203 low and 205 hi.
This is how it can techically see more stress. In the real world I flog my input and don't worry. As said prior, with a cummins desiel or a very heathy big block I might do otherwise.
Using fake numbers and perfect world physics as an example.
You need 400 lb/ft of torque to the driveshaft to spin the wheels or climb a ledge. The output of the 205 will always see 400 lb/ft to make the rig move.
Your engine puts a max of 250 lb/ft to the front of the 203.
Put the 203 in hi and the 205 in low. The 205 output still sees 400 lb/ft. The 205 input sees 200 lb/ft as does the 203 input.
Switch that around. Your 203 is in low and your 205 is in hi. You still need 400 lb/ft to move. The 205 ouput sees 400 lb/ft as does the 205 input. The 203 input only sees 200 lb/ft.
Now go for double low. The 203 in low and the 205 in low. The rear ouput of the 205 sees 400 lb/ft as usual. That means that the 205 input sees 200 lb/ft, and the front of the 203 only actually sees 100 lb/ft.
In double low the driveshaft would need to overcome 800 lb/ft for the 205 input to see the same 400 lb/ft as it did in 203 low and 205 hi.
This is how it can techically see more stress. In the real world I flog my input and don't worry. As said prior, with a cummins desiel or a very heathy big block I might do otherwise.
That would be the ultimate in gear selection, too bad the lomax kit is expensive, otherwise i would have got it.muddybuddy said:
