Hemi conversion
07-20-2013, 05:16 AM
#21
JK Enthusiast
I'm not so sure they have all the bugs worked out on the LS conversions yet. I just went through the process of choosing a V8 for a conversion, and chose the 6.4 Hemi. Part of the reason I chose the 6.4 was because a friend had just done an LS swap in his JK. In the first two months that he has had it, he has taken it back to the conversion shop three times to have electronic glitches fixed. The 6.4 may not be perfect either, and I have heard complaints about inadequate engine cooling. But I picked mine up in Las Vegas when it was 111 F outside, and no cooling problems on the way home. The temp gauge stayed right in the middle the whole way. And no electronic glitches either.
The $6100 the OP saw for a 6.4 Hemi conversion was just for the conversion kit. It includes the motor mounts, new radiator, air intake, wiring harness, coolant overflow bottle, and I believe the exhaust. Look up the price of a 6.4 crate motor in Jegs catalog, I believe it is something like $18,000, ... although I could be wrong on that. I had been looking up a lot of different engine prices back then.
The $6100 the OP saw for a 6.4 Hemi conversion was just for the conversion kit. It includes the motor mounts, new radiator, air intake, wiring harness, coolant overflow bottle, and I believe the exhaust. Look up the price of a 6.4 crate motor in Jegs catalog, I believe it is something like $18,000, ... although I could be wrong on that. I had been looking up a lot of different engine prices back then.
07-20-2013, 07:38 AM
#23
JK Enthusiast
Join Date: Aug 2012
Location: Carson Nv
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
No issues with Motec's kit, cruse works tap shift etc..5.3 won't overheat using the std JK radiator period. better MPG's and performance than the 5.7. 6l80e Trans superior to Dodges. Only adds aprox 65lbs to a JK unlike the Hemi.
Why do you think guys are yanking out Hemi's and putting in the small block...cause the Hemi conversions are problem prone. Same reason Hemi conversions are all over the forums for sale, disappointed owners.
Why do you think guys are yanking out Hemi's and putting in the small block...cause the Hemi conversions are problem prone. Same reason Hemi conversions are all over the forums for sale, disappointed owners.
07-20-2013, 04:13 PM
#24
JK Enthusiast
Join Date: Sep 2011
Location: Quitman, Texas
Posts: 243
Likes: 0
Received 0 Likes
on
0 Posts
No issues with Motec's kit, cruse works tap shift etc..5.3 won't overheat using the std JK radiator period. better MPG's and performance than the 5.7. 6l80e Trans superior to Dodges. Only adds aprox 65lbs to a JK unlike the Hemi.
Why do you think guys are yanking out Hemi's and putting in the small block...cause the Hemi conversions are problem prone. Same reason Hemi conversions are all over the forums for sale, disappointed owners.
Why do you think guys are yanking out Hemi's and putting in the small block...cause the Hemi conversions are problem prone. Same reason Hemi conversions are all over the forums for sale, disappointed owners.
07-20-2013, 07:37 PM
#25
Here is what a week in the life of a Hemi is like, for my JK...
Spent the week driving to work and back, and giving friends rides in my new Jeep. Invariably, every person I give a ride ask me to get on the gas a little, so they can see what it is like. So, lots of short acceleration runs that week. Today the wife and I drove up the mountain to get out of the heat. It was 101 F when we left home to take the 20 mile trip up the mountain where the summit is 10,500 feet elevation. On the way up the mountain we get to the one and only place where passing is possible, and I decide to pass a newer Chevy pickup truck that is only going 40 mph. Then, somehow we're both going 80 mph up the 10% slope, and we're running out of room to make the pass. Time to give the 6.4 full throttle, which quickly completes the pass. (why do these clowns always try to drag race on the one and only place to pass them?) Once on top of the mountain we spend the afternoon driving two lane paved roads, and some dirt roads, and take the time to soak are feet in Mammoth Creek for a few minutes. Then we drive back to town, go to dinner, and take in a movie (The Conjuring), and then drive home for the night.
So the 6.4 makes a good daily driver. It runs great, drives great, and has no problems with overheating. My temp gauge has never moved from its normal position, whether it is in the 111 F heat of Las Vegas, the 101 F heat of home, or drag racing clowns up mountain roads at high elevation. Overall hand calculated fuel mileage for this week was 14.5 mpg. Not too bad if you ask me.
Spent the week driving to work and back, and giving friends rides in my new Jeep. Invariably, every person I give a ride ask me to get on the gas a little, so they can see what it is like. So, lots of short acceleration runs that week. Today the wife and I drove up the mountain to get out of the heat. It was 101 F when we left home to take the 20 mile trip up the mountain where the summit is 10,500 feet elevation. On the way up the mountain we get to the one and only place where passing is possible, and I decide to pass a newer Chevy pickup truck that is only going 40 mph. Then, somehow we're both going 80 mph up the 10% slope, and we're running out of room to make the pass. Time to give the 6.4 full throttle, which quickly completes the pass. (why do these clowns always try to drag race on the one and only place to pass them?) Once on top of the mountain we spend the afternoon driving two lane paved roads, and some dirt roads, and take the time to soak are feet in Mammoth Creek for a few minutes. Then we drive back to town, go to dinner, and take in a movie (The Conjuring), and then drive home for the night.
So the 6.4 makes a good daily driver. It runs great, drives great, and has no problems with overheating. My temp gauge has never moved from its normal position, whether it is in the 111 F heat of Las Vegas, the 101 F heat of home, or drag racing clowns up mountain roads at high elevation. Overall hand calculated fuel mileage for this week was 14.5 mpg. Not too bad if you ask me.
07-21-2013, 05:33 AM
#26
JK Enthusiast
Here is what a week in the life of a Hemi is like, for my JK...
Spent the week driving to work and back, and giving friends rides in my new Jeep. Invariably, every person I give a ride ask me to get on the gas a little, so they can see what it is like. So, lots of short acceleration runs that week. Today the wife and I drove up the mountain to get out of the heat. It was 101 F when we left home to take the 20 mile trip up the mountain where the summit is 10,500 feet elevation. On the way up the mountain we get to the one and only place where passing is possible, and I decide to pass a newer Chevy pickup truck that is only going 40 mph. Then, somehow we're both going 80 mph up the 10% slope, and we're running out of room to make the pass. Time to give the 6.4 full throttle, which quickly completes the pass. (why do these clowns always try to drag race on the one and only place to pass them?) Once on top of the mountain we spend the afternoon driving two lane paved roads, and some dirt roads, and take the time to soak are feet in Mammoth Creek for a few minutes. Then we drive back to town, go to dinner, and take in a movie (The Conjuring), and then drive home for the night.
So the 6.4 makes a good daily driver. It runs great, drives great, and has no problems with overheating. My temp gauge has never moved from its normal position, whether it is in the 111 F heat of Las Vegas, the 101 F heat of home, or drag racing clowns up mountain roads at high elevation. Overall hand calculated fuel mileage for this week was 14.5 mpg. Not too bad if you ask me.
Spent the week driving to work and back, and giving friends rides in my new Jeep. Invariably, every person I give a ride ask me to get on the gas a little, so they can see what it is like. So, lots of short acceleration runs that week. Today the wife and I drove up the mountain to get out of the heat. It was 101 F when we left home to take the 20 mile trip up the mountain where the summit is 10,500 feet elevation. On the way up the mountain we get to the one and only place where passing is possible, and I decide to pass a newer Chevy pickup truck that is only going 40 mph. Then, somehow we're both going 80 mph up the 10% slope, and we're running out of room to make the pass. Time to give the 6.4 full throttle, which quickly completes the pass. (why do these clowns always try to drag race on the one and only place to pass them?) Once on top of the mountain we spend the afternoon driving two lane paved roads, and some dirt roads, and take the time to soak are feet in Mammoth Creek for a few minutes. Then we drive back to town, go to dinner, and take in a movie (The Conjuring), and then drive home for the night.
So the 6.4 makes a good daily driver. It runs great, drives great, and has no problems with overheating. My temp gauge has never moved from its normal position, whether it is in the 111 F heat of Las Vegas, the 101 F heat of home, or drag racing clowns up mountain roads at high elevation. Overall hand calculated fuel mileage for this week was 14.5 mpg. Not too bad if you ask me.
07-21-2013, 10:00 AM
#27
JK Newbie
Join Date: Oct 2007
Location: Albuquerque
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
So the 6.4 makes a good daily driver. It runs great, drives great, and has no problems with overheating. My temp gauge has never moved from its normal position, whether it is in the 111 F heat of Las Vegas, the 101 F heat of home, or drag racing clowns up mountain roads at high elevation. Overall hand calculated fuel mileage for this week was 14.5 mpg. Not too bad if you ask me.
The real culprit in engine temps for the hemi is underhood temps.
Other than that I agree with everything you said. I've got a 5.7 vvt/6 spd and I drive it like I stole it 100% of the time.
Also agree with a previous post here talking about the poor performing mopar transmissions. But disagree with the performance advantage of a 5.3 vs 5.7. I'm available with my 40's clad heavy JK with a stock 5.7 if anyone wants to race
.
07-21-2013, 01:29 PM
#28
JK Enthusiast
Join Date: Mar 2010
Location: LAS VEGAS, NV
Posts: 112
Likes: 0
Received 0 Likes
on
0 Posts
The LS JK swap is nearly as rationalized as the Hemi swap, we have been doing them for 5 years.
Any engine swap is a very involved process and is only as good as the quality of components and install labor. Even with the best kit improper installation will cause problems. We work on 3.8 installs that were done poorly and have issues.
Both the Hemi and LS make the JK fun to drive, is no longer a burden on the open road.
Each have their advantages, the Hemi is powerful and integrates well with the JK. Electronics. The Hemi is large, heavy, burdened by poor transmissions(auto), and runs patched calibrations. Being large and heavy affects vehicle dynamics and cooling.
The LS is light, compact, powerful and has excellent automatic transmissions. The LS is supported by the aftermarket like no other engine since the SBC, some Hemi parts are rare as hen's teeth.
The 5.3 is a great engine, inexpensive, durable, lightweight, efficient and should run longer than any factory JK engine, may even outlast your JK.
The 5.3 is a workhouse and powers millions of GM ½ ton trucks. It can run on regular gas, operate in extreme temperatures and even tolerate abuse.
The 5.3 runs truck heads and is not a hot rod; although many are built to 400+ HP. The 5.3 will reliably power a JK for years. The first swap we did in 2009 was a 2008 JKU using a 2009 5.3 LH6 engine. It now has 112,000 miles on it and runs like a top and gets 20+mpg on the highway with 3:21 gears. My wife drives it every day with our baby. Temperature here has been close to 120* and it runs 195-215*, and that's running the stock JK radiator. My wife would not drive a 3.8 auto JK. The above post is correct, the JK temperature gauge is a suggestion, you could be at 235* at ½ gauge. Usually the needle will jump to overheat quickly, especially with a V8, get a real scan gauge.
A few weeks ago I drove a 5.3 JK back to Vegas from Hurricane, it was 123* through the Valley of Fire and it ran cool. When I got back to the shop there were two Hemi JK's waiting for me, one melted down a PCM and the other a TIPM. Underhood temperature exceeded 300* and plastic in the engine compartment was soft and melting.
This is extreme conditions and lots of vehicles broke down.
Comparing a 400 HP Hemi to a 300 HP LS is pointless, the Hemi is more powerful; however, the 5.3 will outperform the Hemi in many other ways.
Either way a Hemi or LS will wake up your JK and make it a blast to drive.
Sent from my M886 using Tapatalk 2
Any engine swap is a very involved process and is only as good as the quality of components and install labor. Even with the best kit improper installation will cause problems. We work on 3.8 installs that were done poorly and have issues.
Both the Hemi and LS make the JK fun to drive, is no longer a burden on the open road.
Each have their advantages, the Hemi is powerful and integrates well with the JK. Electronics. The Hemi is large, heavy, burdened by poor transmissions(auto), and runs patched calibrations. Being large and heavy affects vehicle dynamics and cooling.
The LS is light, compact, powerful and has excellent automatic transmissions. The LS is supported by the aftermarket like no other engine since the SBC, some Hemi parts are rare as hen's teeth.
The 5.3 is a great engine, inexpensive, durable, lightweight, efficient and should run longer than any factory JK engine, may even outlast your JK.
The 5.3 is a workhouse and powers millions of GM ½ ton trucks. It can run on regular gas, operate in extreme temperatures and even tolerate abuse.
The 5.3 runs truck heads and is not a hot rod; although many are built to 400+ HP. The 5.3 will reliably power a JK for years. The first swap we did in 2009 was a 2008 JKU using a 2009 5.3 LH6 engine. It now has 112,000 miles on it and runs like a top and gets 20+mpg on the highway with 3:21 gears. My wife drives it every day with our baby. Temperature here has been close to 120* and it runs 195-215*, and that's running the stock JK radiator. My wife would not drive a 3.8 auto JK. The above post is correct, the JK temperature gauge is a suggestion, you could be at 235* at ½ gauge. Usually the needle will jump to overheat quickly, especially with a V8, get a real scan gauge.
A few weeks ago I drove a 5.3 JK back to Vegas from Hurricane, it was 123* through the Valley of Fire and it ran cool. When I got back to the shop there were two Hemi JK's waiting for me, one melted down a PCM and the other a TIPM. Underhood temperature exceeded 300* and plastic in the engine compartment was soft and melting.
This is extreme conditions and lots of vehicles broke down.
Comparing a 400 HP Hemi to a 300 HP LS is pointless, the Hemi is more powerful; however, the 5.3 will outperform the Hemi in many other ways.
Either way a Hemi or LS will wake up your JK and make it a blast to drive.
Sent from my M886 using Tapatalk 2
Last edited by VEGASROBBI; 07-21-2013 at 01:47 PM.
07-21-2013, 01:44 PM
#29
JK Newbie
Join Date: Oct 2010
Location: Fort Collins CO
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Just my 2 cents....love the 5.7 and it never and I mean never gets above 211 before the fan engages and brings it back to 200-202.
Gas mileage is no worse, and I am now running 37in Toyo's and 5:13s vs 35in Pro-Comps and 35s.
The Bruiser diesel would not pass emissions from my understanding, so that's why the 5.7.
Gas mileage is no worse, and I am now running 37in Toyo's and 5:13s vs 35in Pro-Comps and 35s.
The Bruiser diesel would not pass emissions from my understanding, so that's why the 5.7.