Cylinder Head compatability
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JK Enthusiast
Joined: Mar 2008
Posts: 199
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From: Kansas City
Cylinder Head compatability
Since this thing has been an offshoot from the old mini-van engines does anyone know what years of cylinder heads are compatible with the JK?
I'm wondering how well they can be made to flow - I know a good head porter and if there are significant gains to be made in airflow it might be worthwhile to get some ported.... I just want to start with the cheapest cores that I can - heck I've seen complete 99-2001 minivan 3.8's for $350-450! If there is enough to be gained in cylinder head flow it might even be worthwhile investing in having one of the shops profile the head and CNC port them...
I'm wondering how well they can be made to flow - I know a good head porter and if there are significant gains to be made in airflow it might be worthwhile to get some ported.... I just want to start with the cheapest cores that I can - heck I've seen complete 99-2001 minivan 3.8's for $350-450! If there is enough to be gained in cylinder head flow it might even be worthwhile investing in having one of the shops profile the head and CNC port them...
JK Freak
Joined: Apr 2008
Posts: 674
Likes: 1
From: Las Vegas, NV
a start...
3.8
The 3.3 was bored and stroked (3.78 in/96 mm and 3.43 in/87 mm respectively) to create a 3.8 L (230.5 CID/3778 cc) variant.[1] This EGH version is built at Trenton Engine in Trenton, MI.
The 3.8 got an increase in power of 12 hp (9 kW), for a total of 162 hp (121 kW) in 1994 via a new intake system. In 1998 the compression ratio increased for a total of 180 hp (134 kW) and 240 ft·lbf (325 N·m). In 2001, the engine got a Variable Intake System which boosted output to 215 hp (160 kW) at 5000 rpm with 245 ft·lbf (332 N·m) of torque at 4000 rpm.
Vehicles using the 3.8 include:
1991–1993 Chrysler New Yorker and Chrysler Imperial 150 hp (112 kW), 213 ft·lbf (289 N·m)
1994–present Chrysler minivans
2007–present Chrysler Pacifica
2007–present Jeep Wrangler
Originally Posted by wikipedia
3.8
The 3.3 was bored and stroked (3.78 in/96 mm and 3.43 in/87 mm respectively) to create a 3.8 L (230.5 CID/3778 cc) variant.[1] This EGH version is built at Trenton Engine in Trenton, MI.
The 3.8 got an increase in power of 12 hp (9 kW), for a total of 162 hp (121 kW) in 1994 via a new intake system. In 1998 the compression ratio increased for a total of 180 hp (134 kW) and 240 ft·lbf (325 N·m). In 2001, the engine got a Variable Intake System which boosted output to 215 hp (160 kW) at 5000 rpm with 245 ft·lbf (332 N·m) of torque at 4000 rpm.
Vehicles using the 3.8 include:
1991–1993 Chrysler New Yorker and Chrysler Imperial 150 hp (112 kW), 213 ft·lbf (289 N·m)
1994–present Chrysler minivans
2007–present Chrysler Pacifica
2007–present Jeep Wrangler
JK Freak
Joined: Aug 2009
Posts: 700
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From: Mason, Ohio
That wiki information is not quite accurate. Someone else had a great post on the different chrysler motors. This 3.8 we are dealing with is based off the old 3.3 motor that they have in some caravans, not the 3.8 that's most often encountered (and praised.)
I say this because I had the luxuary of owning 2 mini-vans at the same time, a 2002 with the 3.8 and a 2006 with the 3.3. The 2002 we still own, and it RUNS. I have always praised that motor. Now the 2006 with the 3.3 on the other hand may as well have been a 4cyl. It couldn't get out of its own way, had to down shift on up hills, and even when you stepped in it just made more noise than actual progress. Guess which one got traded in for the new JK.
I was VERY disappointed to learn our 3.8 is based off that POS motor.
I say this because I had the luxuary of owning 2 mini-vans at the same time, a 2002 with the 3.8 and a 2006 with the 3.3. The 2002 we still own, and it RUNS. I have always praised that motor. Now the 2006 with the 3.3 on the other hand may as well have been a 4cyl. It couldn't get out of its own way, had to down shift on up hills, and even when you stepped in it just made more noise than actual progress. Guess which one got traded in for the new JK.
I was VERY disappointed to learn our 3.8 is based off that POS motor.
JK Enthusiast
Joined: Sep 2007
Posts: 131
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From: El Paso, TX.
not true. if you improve the low and mid lift flow numbers you will gain power/torque under the curve. not to mention while the heads are off he can mill them to bump up the cr which will also give him more power/torque.
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Thread Starter
JK Enthusiast
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From: Kansas City
) I also wondered if the follower/rocker ratio could be increased a bit to gain a faster opening valve with a little more lift...If I can get a 10% improvement in HP that would take it from the 205 stock to at least 225-230 and maybe more with tuning and an exhaust/intake setup.
JK Newbie
Joined: Nov 2008
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From: San Juan, PR
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