Jonathanlackey
Registered Member
I originally had an np203 in my jimmy and bought a np205 and planned on just rebuilding the np205 but can anyone explain to me what the advantage of a doubler is
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
Doubler
- Thread starter Jonathanlackey
- Start date
Thats a rabbit hole for most people . . . Save the 203 for later when you need one . But for now just do the 205 . And twin stick it .
Its my street legal farm tractor . . .
yup....unless you're doing very technical, low-speed rock crawling you won't need a doubler. Put the 203 on a shelf somewhere and run the 205.
A doubler gives you the ability to go from low range to really low range by connecting the range box portion of the 203 to the front of the 205. In the end you'll get close to a 4:1 low range which is a lot slower than the stock 205's 2.72:1 range. You have to either make an adapter to go in between the cases or you can buy one from a few different 4x4 custom shops.
A doubler gives you the ability to go from low range to really low range by connecting the range box portion of the 203 to the front of the 205. In the end you'll get close to a 4:1 low range which is a lot slower than the stock 205's 2.72:1 range. You have to either make an adapter to go in between the cases or you can buy one from a few different 4x4 custom shops.
High-range gearing is 1:1, and the NP205 has a low-range ratio of 1.96:1
I was going to add that I wasn't sure of the exact numbers.
I thought 2:72 was right, but that may have been the NP231 in my Jeep.And the 241I was going to add that I wasn't sure of the exact numbers.
- Joined
- Mar 3, 2000
- Posts
- 9,121
- Reaction score
- 7,073
I use my doubler when crawling and deep snow thumping, Yep 1 to 1, 2 to 1, and 4 to 1 or very close. I have a 400 turbo trans so 3 forward gears. Zero horsepower, stock 350 TBI so the gearing helps. In low low you don't want to go faster than about 15 mph and that is in 3rd gear/Drive on the trans, low on the 205 high on the 203, 25 to maybe 30 mph in 3rd, in high on the 205 and 203 you can go as fast as my 37 horsepower will take you. This is with 4.10 gearing in the axles. Looking forward to more HP and better gearing in the axles!
And hence the want of a 8.1 w/supercharger?
I have 4:1 in my Jeep, which is why I don’t have it in my k20….here for my east coast wheeling 4:1 is usually too low. When I was in Moab there were a few times I could have used a little more gearing but I got through.
Personally I think the 205 low range is a little paltry especially with an auto…the 205 is a tough case but I prefer a 208 or 241 as the low range is better (2.62 or 2.72 respectively) without getting into a doubler. I swapped my 203 for a 208 and wouldn’t go back.
Personally I think the 205 low range is a little paltry especially with an auto…the 205 is a tough case but I prefer a 208 or 241 as the low range is better (2.62 or 2.72 respectively) without getting into a doubler. I swapped my 203 for a 208 and wouldn’t go back.
Yeah, typical use case for the doubler is big tires but stock-ish differentials, like 4.10 and using a TH-400 (2.48 1st gear). So it's very durable, quite heavy, but the tall axle gears still let you run on the highway. That's a total ratio of about 79, but not very deep gearing for launch on the street. Now take a rig with newer, lighter duty parts: 700-R4 (or 4L60), NP-241 and 4.88 gears (no doubler), which has a total ratio of 82, but will still have lower RPM at highway speed.
Now take the same 2 setups, but run the doubler rig in single low, for a ratio of about 40, while the lighter duty setup in high range is about 30.
It's about your planned use, engine powerband, etc.
Now take the same 2 setups, but run the doubler rig in single low, for a ratio of about 40, while the lighter duty setup in high range is about 30.
It's about your planned use, engine powerband, etc.
