Motor difference question

X

XJOwner95

NAXJA Forum User

Location

Hemet,CA

• Jan 15, 2011

• #1

i and my mom/her bf both have seperate jeep cherokees and my moms bf once had a jeep wrangler with a 4.0L 6cyl. but it was an HO(high output)
does anyone know the difference between the HO's in the wranglers and the standard 4.0L's in the XJ's??

 

B

Ben824

NAXJA Forum User

Location

Woodstock, GA

• Jan 15, 2011

• #2

if the cherokee is a 90 and older model year then it is a renix engine but 91 and newer are also H.O. until either 99 or 00 then they are the PowerTech engines. Basically they are all about the same just with the major difference being in electronics, fuel delivery, and cylinder heads.

 

D

DieselSJ

NAXJA Forum User

Location

QC AZ

• Jan 15, 2011

• #3

HO engine (91-later in the XJ) is the same between the XJ and Wrangler. The non-HO (Renix) in the XJ was never in the Wrangler.

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Jan 15, 2011

• #4

For the XJs:

87-90 4.0s are Renix engine management with EGR systems.

The 91-95 are HO--high output--OBDI engine management without EGR systems and higher engine output in HP.

The 96+ are HO--high output--OBDII engine management.

IIRC there was a final change in 99+ for additional HP trying to make up for losses due to more stringent emissions.

 

X

XJOwner95

NAXJA Forum User

Location

Hemet,CA

• Jan 16, 2011

• #5

so the only difference is electronics?

 

B

Ben824

NAXJA Forum User

Location

Woodstock, GA

• Jan 16, 2011

• #6

in the change from 90 to 91 H.O. models there were some notable changes in the cylinder heads but for the most part they mostly just changed the electronics over the years. basically they just kept tweaking the motor trying to make it just a little bit better from the year before

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Jan 17, 2011

• #7

4.0L I6 EFI "Power Tech" - 177 hp @ 4750 rpm, 220 ft lb @ 4000 rpm - used 87-90

4.0L I6 MPI "Power Tech HO" (High Output) - 190 hp @ 4750 rpm, 220 ft lb @ 4,000 rpm - used in 91-95 and updated in 96-01 to 225 ft lb torque @ 3000 rpm (00-01 models use a distributor-less ignition system)

Differences in 4.0 heads:

http://www.enginebuildermag.com/Art...again_the_facts_about_40l_cylinder_heads.aspx