View Poll Results: Which engine for my Durango swap?
LM7 NA 5.3
1
12.50%
LM4 5.3
1
12.50%
LQ4 6.0
0
0%
LQ9 6.0
4
50.00%
LM7 turbo 5.3
2
25.00%
Voters: 8. You may not vote on this poll
Gen 3 engine selection advice
Gen 3 engine selection advice This is my first foray into truck swap territory, and my first automatic trans swap as well. As my sig and username indicate, I've done some prior swaps into imported cars (Supra, 2x RX-7s, a 280Z, and a BMW wagon).
I'm replacing the engine, trans, and transfer case in my 1998 Durango 4x4 SUV. Here are the specs:
Curb weight:5,100 pounds.
Gear ratio: 3.92 open (option was 3.55), my truck has the larger 9.25" diff since it had the 5.9 engine. Stock R/T tires 275/60-17.
Engine: Was a 5.9 Magnum. Replacing with ???. Bay has been wired for a Gen 3 engine.
Trans: Was a 46RE. Now a 1997 4L80 core being rebuilt and converted to 4WD. Will use a stock stall converter.
Transfer case: Was a NP231, converting to a 242 out of a WJ Grand Cherokee.
Planned use: The Durango will be my daily driver for a 60 mile round trip to work. I rarely tow with it, but will occasionally haul a car or bike. I'd like an engine that gives a performance improvement over OEM, but that is not in the Dodge Magnum 14 MPG range.
OEM HP and TQ for the 5.9 were 245 HP @ 4,000 RPM and 335 TQ @ 3200 RPM.
I am not considering the LS1 or 5.3L L33 truck motor since they remain made out of gold based upon prices- which is a shame since I have used 2x L33s on my prior swaps. I'm likewise not considering a Gen 4 motor since I have already wired the truck for a Gen 3.
Engines I'm considering:
5.3L
LM7
Pro: Low cost ($250-500)
Con: Weight w/o the added 6.0 power
Specs I found were 295 HP and 335 TQ
LM4 (Trailblazer/Rainier/Envoy/Ascender 2003-2004)
Pro: Light weight, low cost ($650-750)
Con: Availability & funky oil pan- pan is a non-issue since I have picked up a Hummer H3 setup.
Specs I found were 300 HP and 335 TQ
LH6 (Trailblazer et al 2005-06 since they used a 24x wheel)
Pro: Light weight, 799 heads
Con: Availability & cost. Displacement on Demand, but that can be handled via a new cam & lifters- and I'm planning a cam swap in nearly all of these. The only way one of these would work would be to buy a wrecked truck & part it out, which is more work than I want right now.
Specs I found were 315 HP and 330 TQ
6.0L
LQ4
Pro: More displacement, good path for upgrade later using L92 heads.
Con: Cost- over $1,000. Can buy a core for around $500, but making that a reliable motor may exceed the 5.3 engines above.
Specs I found for a 2005 van engine were 300HP @ 4400 and 360TQ @ 4000
LQ9
Pro: Same as LQ4, relatively cheap in the 02-03 model years, around $800 for a running long block.
Con: Availability
Specs I found for a 2005 Escalade were 345HP @ 5200 and 380TQ @ 4000
I wrote up a spreadsheet and calculated the cost to rebuild & mod a core or to mod a running motor.
The lowest cost (about $1,000) was to mod a semi-local LM7 with a cam. All builds had the same costs for accessories and exhaust (except turbos).
The highest cost (at least $1700) was to overhaul a van LM7 using the Hooker turbo manifolds and making up my own crossover and remaining hot side.
There are a lot of options here, such as a local LQ9 and some semi-local 243 heads, but the increased CR would likely require more expensive fuel (93 octane). The estimated cost difference between the LM4 and LQ9 is under $200.
Since fuel mileage is a concern, I'm leaning towards the LM4's lower weight, and out of the box it makes more power than my Dodge 5.9. My planned mods include a 212/218 cam and some mid-length headers- long tubes are a problem since the truck is 4WD. Apparently the driver side outlet and front driveshaft want to occupy the same space. I may go with a low lift cam since the truck won't see much high RPM use and that saves buying and installing springs. I have HP Tuners and can mod a tune as needed for best overall use. I have a cold air intake leftover from the 5.9 I can reuse.
One idea I kicked around was going with the LM7 and adding a single turbo (possible best of both worlds), but I'm not sure there will be enough room in the engine bay. Having tried a rear mount on my TA, I'd rather not do that again- too complex.
I'm open to some ideas as to what my best option is. I don't want to go too small on displacement since I have a GMC Acadia that is an example of doing that (3.6L V6 in a heavy vehicle), but I don't want to go overboard on it either.
I'm replacing the engine, trans, and transfer case in my 1998 Durango 4x4 SUV. Here are the specs:
Curb weight:5,100 pounds.
Gear ratio: 3.92 open (option was 3.55), my truck has the larger 9.25" diff since it had the 5.9 engine. Stock R/T tires 275/60-17.
Engine: Was a 5.9 Magnum. Replacing with ???. Bay has been wired for a Gen 3 engine.
Trans: Was a 46RE. Now a 1997 4L80 core being rebuilt and converted to 4WD. Will use a stock stall converter.
Transfer case: Was a NP231, converting to a 242 out of a WJ Grand Cherokee.
Planned use: The Durango will be my daily driver for a 60 mile round trip to work. I rarely tow with it, but will occasionally haul a car or bike. I'd like an engine that gives a performance improvement over OEM, but that is not in the Dodge Magnum 14 MPG range.
OEM HP and TQ for the 5.9 were 245 HP @ 4,000 RPM and 335 TQ @ 3200 RPM.
I am not considering the LS1 or 5.3L L33 truck motor since they remain made out of gold based upon prices- which is a shame since I have used 2x L33s on my prior swaps. I'm likewise not considering a Gen 4 motor since I have already wired the truck for a Gen 3.
Engines I'm considering:
5.3L
LM7
Pro: Low cost ($250-500)
Con: Weight w/o the added 6.0 power
Specs I found were 295 HP and 335 TQ
LM4 (Trailblazer/Rainier/Envoy/Ascender 2003-2004)
Pro: Light weight, low cost ($650-750)
Con: Availability & funky oil pan- pan is a non-issue since I have picked up a Hummer H3 setup.
Specs I found were 300 HP and 335 TQ
LH6 (Trailblazer et al 2005-06 since they used a 24x wheel)
Pro: Light weight, 799 heads
Con: Availability & cost. Displacement on Demand, but that can be handled via a new cam & lifters- and I'm planning a cam swap in nearly all of these. The only way one of these would work would be to buy a wrecked truck & part it out, which is more work than I want right now.
Specs I found were 315 HP and 330 TQ
6.0L
LQ4
Pro: More displacement, good path for upgrade later using L92 heads.
Con: Cost- over $1,000. Can buy a core for around $500, but making that a reliable motor may exceed the 5.3 engines above.
Specs I found for a 2005 van engine were 300HP @ 4400 and 360TQ @ 4000
LQ9
Pro: Same as LQ4, relatively cheap in the 02-03 model years, around $800 for a running long block.
Con: Availability
Specs I found for a 2005 Escalade were 345HP @ 5200 and 380TQ @ 4000
I wrote up a spreadsheet and calculated the cost to rebuild & mod a core or to mod a running motor.
The lowest cost (about $1,000) was to mod a semi-local LM7 with a cam. All builds had the same costs for accessories and exhaust (except turbos).
The highest cost (at least $1700) was to overhaul a van LM7 using the Hooker turbo manifolds and making up my own crossover and remaining hot side.
There are a lot of options here, such as a local LQ9 and some semi-local 243 heads, but the increased CR would likely require more expensive fuel (93 octane). The estimated cost difference between the LM4 and LQ9 is under $200.
Since fuel mileage is a concern, I'm leaning towards the LM4's lower weight, and out of the box it makes more power than my Dodge 5.9. My planned mods include a 212/218 cam and some mid-length headers- long tubes are a problem since the truck is 4WD. Apparently the driver side outlet and front driveshaft want to occupy the same space. I may go with a low lift cam since the truck won't see much high RPM use and that saves buying and installing springs. I have HP Tuners and can mod a tune as needed for best overall use. I have a cold air intake leftover from the 5.9 I can reuse.
One idea I kicked around was going with the LM7 and adding a single turbo (possible best of both worlds), but I'm not sure there will be enough room in the engine bay. Having tried a rear mount on my TA, I'd rather not do that again- too complex.
I'm open to some ideas as to what my best option is. I don't want to go too small on displacement since I have a GMC Acadia that is an example of doing that (3.6L V6 in a heavy vehicle), but I don't want to go overboard on it either.
Thanks for the votes. I scored a semi-local 130K mile JY LM4 for $535 out the door complete w/ harness, intake, TB, coils, and accessory bracket, so that is the plan now. I can sell the harness and recoup some $. May even be able to sell the funky oil pan. 
