Chevy 5.3 LS vs Hemi 5.7 vvt.
#31
JK Enthusiast
Join Date: Apr 2012
Location: Pennsylvania
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Something big to consider that was just brought to my attention by an inspection mechanic. Here in PA we only do a visual check to ensure the smog components are there and that it looks factory and untampered with, so if you were to put a Chevy motor in a Chrysler vehicle it would fail an inspection because obviously they did not put Chevy motors in jeeps and it would not look factory. Something to consider. It is could even fail with the hemi in it. I would research this further before I made my choice. Just my .02 but I would hate to see you spend 15,000k on it only to have to redo it with another engine.
#32
JK Enthusiast
Thread Starter
Something big to consider that was just brought to my attention by an inspection mechanic. Here in PA we only do a visual check to ensure the smog components are there and that it looks factory and untampered with, so if you were to put a Chevy motor in a Chrysler vehicle it would fail an inspection because obviously they did not put Chevy motors in jeeps and it would not look factory. Something to consider. It is could even fail with the hemi in it. I would research this further before I made my choice. Just my .02 but I would hate to see you spend 15,000k on it only to have to redo it with another engine.
1. as long as he can plug into the vehicle, and it shows no codes, then it passes.
2. i said doesn't it have to pass a 'sniff' test? - he said thats the old test, and some cars still have to go that route.
Another set of points ive discovered:
1. Insurance - i'm actually covered driving off road with my rig, as long as i'm not racing for money, im cool..
2. When i do the engine, the insurance company will not recognize the value. in the event of it being totaled, the appraiser will adjust if he/she feels appropriate....
#36
? - not sure, Motech keeps the 4 cylinder mode in their software.
[/INDENT]
I'm expecting to keep the Jeep for a long time after i do this. I had my Jeep pretty close to the way i wanted it when the 3.8 began to consume oil @ 39k miles. Jeep is a 2nd vehicle, I wheel 6-8x a year, use for some towing, plan to use on long distance vacations with family; expect to put 12k miles on a year.
I'm really stuck with my decision, i'm hoping the community can help guide me along in the choice. Plan to get this started next month.
Cheers and Ride lots!
Attachment 388826Attachment 388827[/QUOTE]
Motech keeps the 4 cylinder mode and they bypass the Chrysler computer for engine control so you if your jeep computer dies you can still drive out
[/INDENT]
I'm expecting to keep the Jeep for a long time after i do this. I had my Jeep pretty close to the way i wanted it when the 3.8 began to consume oil @ 39k miles. Jeep is a 2nd vehicle, I wheel 6-8x a year, use for some towing, plan to use on long distance vacations with family; expect to put 12k miles on a year.
I'm really stuck with my decision, i'm hoping the community can help guide me along in the choice. Plan to get this started next month.
Cheers and Ride lots!
Attachment 388826Attachment 388827[/QUOTE]
Motech keeps the 4 cylinder mode and they bypass the Chrysler computer for engine control so you if your jeep computer dies you can still drive out
#37
If you are considering the swap, let me tell you, i had same doubts a couple of years back, when i was considering mine.
I too had a great deal at first on a Hemi engine and trans, but then i did some more research on them, and it turns out that most hemi conversion have or had overheating issues, 11-14 mpg´s, and a lousy tranny. It weighs 100 lbs more than a iron block chevy, 200+ over an LS.
Then i went the right way, and found myself a LQ9 engine with a supercharger. ( iron block 6.0L )
I know for a fact that Motech´s kit is CARB certified and emissions legal in California!!, (which has toughest emissions law around) .
With a 5.3 Ls engine you´ll be in the 20 mpg´s ball park (20-24) and still have enough ponny´s to have fun. and no overheating issues ever!
But the real deal closer is the 6L80e Transmission, whether you go with a 5.3 or a 6.2 Ls engine, the tranny is what seals the deal. It is always in the right gear, not having to wait while the trans ¨think¨ (like chrysler´s) is awesome!, 6 speed allows for more mpg´s, and the ability to upshift/downshift with the touch of a button is amazing!
You´ll keep factory cruise control, no warning lights on the dash, gauges fully functional, a/c ... the list goes on ...
If you still have any doubts about Motech, call them and schedule a test drive on one of their LS Wranglers, and see for yourself.
Btw, Robbie is a stand up guy, and he knows what he´s doing. He has even had customers take out their hemi´s to put in the LS.
I too had a great deal at first on a Hemi engine and trans, but then i did some more research on them, and it turns out that most hemi conversion have or had overheating issues, 11-14 mpg´s, and a lousy tranny. It weighs 100 lbs more than a iron block chevy, 200+ over an LS.
Then i went the right way, and found myself a LQ9 engine with a supercharger. ( iron block 6.0L )
I know for a fact that Motech´s kit is CARB certified and emissions legal in California!!, (which has toughest emissions law around) .
With a 5.3 Ls engine you´ll be in the 20 mpg´s ball park (20-24) and still have enough ponny´s to have fun. and no overheating issues ever!
But the real deal closer is the 6L80e Transmission, whether you go with a 5.3 or a 6.2 Ls engine, the tranny is what seals the deal. It is always in the right gear, not having to wait while the trans ¨think¨ (like chrysler´s) is awesome!, 6 speed allows for more mpg´s, and the ability to upshift/downshift with the touch of a button is amazing!
You´ll keep factory cruise control, no warning lights on the dash, gauges fully functional, a/c ... the list goes on ...
If you still have any doubts about Motech, call them and schedule a test drive on one of their LS Wranglers, and see for yourself.
Btw, Robbie is a stand up guy, and he knows what he´s doing. He has even had customers take out their hemi´s to put in the LS.
#38
JK Enthusiast
Join Date: Sep 2011
Location: Quitman, Texas
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I had to make the same choice early last year, Hemi or LS. At that time thay were still working out a few issues with the LS but now they have worked through everything. Still have to wonder about support though when you are on the road since the install is in a Jeep and the programing may be different. Although the programing for the 5.7VVT that is in my Jeep has been changed also. I have not driven an LS Jeep but if it performs like everyone is saying with the fuel economy near 20 mpg then I say go for it. My Hemi is not broke in yet and I am getting 14 mpg with 4:56 gears and 35's although my foot has been in it. The install with the new programing will spin the 35's on concrete from a dead stop. plenty of low end torque. Something I did not have with a supercharger. All in all I am happy with my Hemi but it seems the LS may be the better way to go now. Just remember if you wreck the jeep you are eating that cost because I have not found any insurance that will cover hte upgrade cost and many would cancel you for it.
#39
JK Enthusiast
Thread Starter
Update
I finished this swap in mid March of 2013. Since then i've driven about 2000 miles on the 5.3 vvt with 6L80 transmission.
Initially i didnt plan to upgrade my radiator and i was going to keep the old exhaust. The local shop told me what advantages i would have to both so i ended up getting the Motech upgraded custom Radiator and my local shop did a custom exhaust and magnaflow muffler.
These unexpected costs, plus a new front drive shaft..(as stock was ripped) was ~2500 more than expected.
The setup is more powerful than i expected. MPG has been hard to estimate, since i had to get a procal to set up my tire size recently. I think i'm getting close to 15mpg in mixed driving, but the onboard computer is saying 20. a few more tanks and i'll update with correct amounts.
I should re gear to 410s as im running 4.88's and at highway speed its a bit high on rpm's 2350-2400 @ 72mph. Motech said should be at 1900-2000rpms. oh well, i just go the normal speed limit for now. towing my M101 army trialer with this thing is easy now. pulling up 8% grades in 5th gear with a load is no problem now. No wheeling yet, report after that too.
i've never drove another Jeep conversion, so its hard to compare to that.....but to the 3.8 it's unreal the improvements. Also, i test drove the 3.6 before i did this swap...and i like the low end power of the v8 more than the 3.6.
sorry for the crappy phone pics, i'll get some better shots soon.
Initially i didnt plan to upgrade my radiator and i was going to keep the old exhaust. The local shop told me what advantages i would have to both so i ended up getting the Motech upgraded custom Radiator and my local shop did a custom exhaust and magnaflow muffler.
These unexpected costs, plus a new front drive shaft..(as stock was ripped) was ~2500 more than expected.
The setup is more powerful than i expected. MPG has been hard to estimate, since i had to get a procal to set up my tire size recently. I think i'm getting close to 15mpg in mixed driving, but the onboard computer is saying 20. a few more tanks and i'll update with correct amounts.
I should re gear to 410s as im running 4.88's and at highway speed its a bit high on rpm's 2350-2400 @ 72mph. Motech said should be at 1900-2000rpms. oh well, i just go the normal speed limit for now. towing my M101 army trialer with this thing is easy now. pulling up 8% grades in 5th gear with a load is no problem now. No wheeling yet, report after that too.
i've never drove another Jeep conversion, so its hard to compare to that.....but to the 3.8 it's unreal the improvements. Also, i test drove the 3.6 before i did this swap...and i like the low end power of the v8 more than the 3.6.
sorry for the crappy phone pics, i'll get some better shots soon.
Last edited by ridelots24; 05-28-2013 at 12:59 PM.
#40