It's Time to SUPERSIZE Moby - MoTech 6.2L LS Jeep Motor Swap

mudmobeeler

mudmobeeler

Caught the Bug
wayoflife said:
As far as MPG goes, before the motor swap, we were getting about 8-10 MPG at best with our 3.8L motor pushing our JK that weighs about 7000 lbs. and riding on 40's. Now, we average about 10-13 MPG and could easily get more if we drove slower so yeah, the fuel economy is much better and we get a lot more power to boot. :yup:
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Probably more smiles to gallon as well. :thumb:
 
J

JKStair

New member
Just finished this thread up last night. Incredibly informative for someone who has zero experience with engine swaps. Gives you real world expectations of what issues/concerns there could be. Thanks again!!:thumb:
 
sc_rhino

sc_rhino

Member
CarsonCindy said:
The last of the parts are in (I hope) :)


Our reprogrammed instrument cluster back from MoTech
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Hey Eddie or Cindy, and sorry if you already answered this (I'm halfway thru this build), but did you have to reprogram the cluster because it was orignially setup for a manual transmission?
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wayoflife

wayoflife

Administrator
Staff member
scrhino said:
Hey Eddie or Cindy, and sorry if you already answered this (I'm halfway thru this build), but did you have to reprogram the cluster because it was orignially setup for a manual transmission?
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Yes. If you have an auto, you should be fine.
 
jims68

jims68

New member
These motors are just so awesome you can't seem to get enough of them! I am so glad Robbi at Motech convinced me to go this route even though I didn't completely listen and went with the 5.3 instead of a 6.2 at the time. The 6.0 with the 6l80 wasn't an option at that time but would of been a better choice then the 5.3 also based on where I went with tuning. Don't get me wrong the 5.3 is the little engine that could but the potential is so much more with the bigger motors. All the benefits of the 5.3 I have tuned out, VVT, 87 octane fuel for the fun factor of these motors. The 5.3 is living on the edge with the stock low octane tune. All of the fun is tuned out with timing and over fueling in order to keep the high compression motor happy! When you tune it for premium and get the suburbanite shifting out of the 6l80 it is unreal how they come alive! Low range is worthless except for crawling which in stock form wasn't too bad. Now from a dead stop if I nail it in 15' I hit the rev limiter which is now at 6500 with 4:10 gears! Lower gears multiply the effect. There is no doubt with a 6.2 tuned like this, very aggressive, the stock drivetrain would be junk by now. I am impressed the little Dana 30 hasn't had issues yet but my feelings are the gearing has let it live to this point so far. I am a little lean on cold startup and need to spend more time on the fueling, lean cold and rich on top WOT but works great for a daily driver. Mileage average did not change much from stock form initial install to now. Mixed city highway 12 and highway at 75 mph has been 15 or better depending on terrain and wind. I've seen and heard some of the two door 6.0 pushing the 20 number!! Like Robbi told me from the begging he wouldn't like to own a non LS jeep after driving one!
 
SevenSlotSpartan

SevenSlotSpartan

New member
For real though! That's the first time I've seen that video and WOW it's incredible what a well built jk can take on and I'm so glad Mel was protected through the whole thing by the quality parts that are on Evo1!
 
sc_rhino

sc_rhino

Member
wayoflife said:
This is true. EVERYONE I know with a HEMI has over heating problems or have to run a powerful fan that sound like a jet engine and prevents you from hearing the great motor all the time to help keep it cooler. The LS we have is still running our factory fan on a Griffon radiator and everything runs cool. We did have a tach issue once and a temp sensor wire issue once that caused over heating but both were simple problems to track down and easy to fix. Haven't had an issue since.

As far as MPG goes, before the motor swap, we were getting about 8-10 MPG at best with our 3.8L motor pushing our JK that weighs about 7000 lbs. and riding on 40's. Now, we average about 10-13 MPG and could easily get more if we drove slower so yeah, the fuel economy is much better and we get a lot more power to boot. :yup:
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Hey Eddie, I hope your jeep is staying cool, but if it's not you might want to consider upgrading to the Pentastar fan which Motech is now selling. After just upgrading to an LS3 myself this is what I found to be the case. I too had a powerplant and I think it was blocking a lot of the airflow to the radiator and after upgrading to the Pentastar Fan it made a big difference and allowed me to keep my winch.
 
wayoflife

wayoflife

Administrator
Staff member
scrhino said:
Hey Eddie, I hope your jeep is staying cool, but if it's not you might want to consider upgrading to the Pentastar fan which Motech is now selling. After just upgrading to an LS3 myself this is what I found to be the case. I too had a powerplant and I think it was blocking a lot of the airflow to the radiator and after upgrading to the Pentastar Fan it made a big difference and allowed me to keep my winch.
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Thanks for the heads up. I've actually talked to Robbie about this and hope to make the switch soon.
 
sc_rhino

sc_rhino

Member
wayoflife said:
Thanks for the heads up. I've actually talked to Robbie about this and hope to make the switch soon.
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i sort of spoke too soon. The aftermarket radiator still wasn't enough, but since the Pentastar fan is slimmer we put an even bigger/thicker radiator in it's place and that seems to be working.
 
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