 |
|
01-25-2011, 02:55 PM
|
#1
|
|
Registered User
Join Date: Jun 2009
Location: Milton, Fl
Posts: 326
|
I have a 98 5.9 Limited that is in phenominal shape and I love it, but I would like to ge a little better mileage. Has anyone put a newer 5spd auto that the hemi uses in their older jeep. Would I get any benefit out of it and is it possible???
__________________
[]||||||[]
|
|
|
|
01-25-2011, 03:30 PM
|
#2
|
|
Captain Awesome
Join Date: Aug 2009
Location: Oregon
Posts: 1,870
|
The benefits would not outweigh the amount of money it would take to fit it in and make it work. Most likely.
The only benefit I could see is that it would be less parasitic loss. I don't think the overdrive is geared much better than the 46re in your 5.9.
__________________
93 red ZJ 189k 4.0. Spent more money than I should have ...
Isn't red the only color a vehicle should be?
If at first you don't succeed, use more speed.
|
|
|
|
|
01-25-2011, 03:55 PM
|
#3
|
|
Registered User
Join Date: Oct 2008
Location: Calgary
Posts: 1,408
|
good lord, this forum needs a thread stickied on gas mileage, and how bad it is in ZJs.......
__________________
95' ZJ ~ trail rig
92' YJ ~ just another reason for the wife to yell at me
11' JKU ~ minvan power!
05' GMC Sierra ~ daily
|
|
|
|
|
01-25-2011, 07:29 PM
|
#4
|
|
Registered User
Join Date: Mar 2010
Location: Farmington, CT, Connecticut
Posts: 480
|
Quote:
Originally Posted by JohnnyZJ
good lord, this forum needs a thread stickied on gas mileage, and how bad it is in ZJs.......
|
agree 
__________________
1998 ZJ 5.NINER Limited
"JEEPING... Because football, baseball, basketball, and soccer only require one ball."
[B][_]I II II II I[_][/B]
Brass Balls Offroad
[COLOR="Black"][CENTER][SIZE="4"][FONT="Showcard Gothic"][COLOR="Black"][URL="http://groups.jeepforum.com/built-not-bought/"][COLOR="Black"]Built Not Bought #560[/COLOR][/URL][/FONT][/SIZE][/COLOR][/CENTER][/COLOR]
|
|
|
|
|
01-25-2011, 11:14 PM
|
#5
|
|
Living dead mod
Join Date: Dec 2006
Location: , Pennsylvania
Posts: 19,811
|
It is possible to put a 545rfe in, you would need to do some custom wiring, custom mounts, shifter, and must likely a custom torque converter.
a manual trans would be a much bigger improvement in economy. I jumped 4mpg in city driving.
__________________
'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.
|
|
|
|
|
01-26-2011, 02:23 AM
|
#6
|
|
Registered User
Join Date: Nov 2010
Location: 74, France
Posts: 33
|
Have a set of tires with a bigger diameter. The result will be the same as a longer gear ratio.
__________________
1995 ZJ 5.2 Limited (Export)
1998 ZJ 5.9 (LX Export)
|
|
|
|
|
01-26-2011, 02:34 AM
|
#7
|
|
Living dead mod
Join Date: Dec 2006
Location: , Pennsylvania
Posts: 19,811
|
Except for the weight penalty offsetting any gains from lower rpms.
Cruising at anything less than 1800 in an auto zj will have you below the converter stall speed and out of the power band.
__________________
'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.
|
|
|
|
|
01-26-2011, 03:02 AM
|
#8
|
|
Registered User
Join Date: Nov 2010
Location: 74, France
Posts: 33
|
Larger diameter tires, but same width, meaning also street and not AT tires. i.e.there is not a sensible weight difference between a 225/70 to a 225/75 tire height ratio IMHO.
The ZJ as most modern vehicles has a TC lock up above 50 mph, so the TC will not release at low rpm; engine to wheel transmission is 100%. Hence at cruising speed the TC will not rob power. City driving below 50 mph affects mpg quite a lot in facts.
__________________
1995 ZJ 5.2 Limited (Export)
1998 ZJ 5.9 (LX Export)
|
|
|
|
|
01-26-2011, 06:40 AM
|
#9
|
|
Living dead mod
Join Date: Dec 2006
Location: , Pennsylvania
Posts: 19,811
|
Quote:
Originally Posted by Goumoun
Larger diameter tires, but same width, meaning also street and not AT tires. i.e.there is not a sensible weight difference between a 225/70 to a 225/75 tire height ratio IMHO.
The ZJ as most modern vehicles has a TC lock up above 50 mph, so the TC will not release at low rpm; engine to wheel transmission is 100%. Hence at cruising speed the TC will not rob power. City driving below 50 mph affects mpg quite a lot in facts.
|
Thanks for the lesson...but it locks at 45mph unless od is off actually.
Engine to wheel power transmission is never 100%, parasitic losses will always be present.
225/70 vs 225/75 is such a miniscule size difference it won't even register at the speedo. And 10lbs of rotating mass is equivalent to an extra 100lbs of sprung weight.
__________________
'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.
|
|
|
|
|
01-26-2011, 07:51 AM
|
#10
|
|
Registered User
Join Date: Nov 2010
Location: 74, France
Posts: 33
|
Sorry, there was no intention for a lesson, just discussing bolts and nuts issues.
__________________
1995 ZJ 5.2 Limited (Export)
1998 ZJ 5.9 (LX Export)
|
|
|
|
|
|
>
Curious?!?!?!
