Re-gearing
04-01-2015, 04:35 PM
#11
JK Enthusiast
Join Date: Feb 2012
Location: Charlottesville, VA
Posts: 145
Likes: 0
Received 0 Likes
on
0 Posts
there is nothing like being geared properly. it changes everything. i don't know about the hemi but i know a few RIPP guys (roughly same HP to the wheels) with the 3.6L love 4.56 with 37s.
my guess is go with 4.11 if you spend 10% or less on the trails, and 4.56 if you spend more on the trails or want to tow or deal with hills a lot.
my guess is go with 4.11 if you spend 10% or less on the trails, and 4.56 if you spend more on the trails or want to tow or deal with hills a lot.
04-02-2015, 08:49 AM
#12
JK Enthusiast
Thread Starter
Join Date: Jul 2011
Location: Green Brook, NJ
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Well from what it seems, regearing is the vote & with 4.56's.
I do my fair share of towing- trailer & boat- also live around steep hills. Cruising at 55 brings RPM roughly to 1200...not much at all! I was surprised by the minor sluggishness of it when first installed, I assumed it was just what it was supposed to feel like but guess not. Mpg is on avg 12/13...as long as it's not less, I'll be content.
I'd say 15-20% is on the trails but not heavy wheeling.
I used to have a '00 TJ, 3.5" on 33's, 5spd 6cyl and geared with 4.56's.....the thing had power! I'd like to get a portion of that back. Considering my JK is automatic, I'd like to do whatever I can to get as much power as I can by minimal but necessary effort.
I do my fair share of towing- trailer & boat- also live around steep hills. Cruising at 55 brings RPM roughly to 1200...not much at all! I was surprised by the minor sluggishness of it when first installed, I assumed it was just what it was supposed to feel like but guess not. Mpg is on avg 12/13...as long as it's not less, I'll be content.
I'd say 15-20% is on the trails but not heavy wheeling.
I used to have a '00 TJ, 3.5" on 33's, 5spd 6cyl and geared with 4.56's.....the thing had power! I'd like to get a portion of that back. Considering my JK is automatic, I'd like to do whatever I can to get as much power as I can by minimal but necessary effort.
04-02-2015, 08:53 AM
#13
JK Enthusiast
Thread Starter
Join Date: Jul 2011
Location: Green Brook, NJ
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
So u have been driving it with this combo for a year and a half already?
When going 55 in oveddrive, what is ur rpm average?
How does it feel. Luggy, slow to respond? Weak. Constantly shifting out of lockup or overdrive on the slightest incline?
If not then leave it alone. If yes then gears may be good option. For the amount of difference between them, it will improve power feel at all speeds, shift sooner and at lower speeds, and have a slightly reduced top speed, not that it matters. Will most like negatively affect mpg.
The more powerful it feels, the less impressive the mpg. Its a balancing act.
When going 55 in oveddrive, what is ur rpm average?
How does it feel. Luggy, slow to respond? Weak. Constantly shifting out of lockup or overdrive on the slightest incline?
If not then leave it alone. If yes then gears may be good option. For the amount of difference between them, it will improve power feel at all speeds, shift sooner and at lower speeds, and have a slightly reduced top speed, not that it matters. Will most like negatively affect mpg.
The more powerful it feels, the less impressive the mpg. Its a balancing act.
The first thing I do when I get in is shut the OD off, it's always been too sluggish but wasn't sure if it was my expectations.
04-02-2015, 08:57 AM
#14
Well that should be your first hint that a regear is in order.
Gearing is everything. Regardless if you have a hemi.
04-02-2015, 09:35 AM
#15
When I make a gear selection the only impact the engine has is what RPM range I am targeting. Since almost all of today's engines are tuned for more top end than grunt, I would make the same choice for a V8 as I would a V6.
35s and mostly road 4.56, 35s and mostly trail 4.88, 35s and all trail 5.13
37 and mostly road 4.88, 37s and mostly trail 5.13, 37s and all trail 5.38.
(Obviously the axle type needs to be considered. I would never suggest 5.13s in a D30 or 5.38s in a D44)