Final Decision Point: JSS vs BOR Hemi Kit (or LS?) - JKowners.com : Jeep Wrangler JK Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 49 Old 12-26-2011, 09:06 AM Thread Starter
Rock God
 
Jeep2.0's Avatar
 
Join Date: Aug 2010
Location: Buda, TX
Age: 57
Posts: 1,303
Garage
Feedback: 3 reviews
Final Decision Point: JSS vs BOR Hemi Kit (or LS?)

I have collected my 5.7L VVT Truck Motor and my 545RFE - picked those up in the Fall. I now have the coin saved up to spring for the swap kit & begin the process of the swap. Before dropping that much coin (more than $5,000), I'm having some doubt & thought I'd come here for some reassurance.

1) Swap Kit: JSS or BOR?
The Posts from 86CJ-07Rubi helped me to decide on the truck motor. He was very helpful when going through his swap. He went with JSS, but his post-swap reports show he's not happy with his mileage. (See below). I'm wondering if the BOR kit has different programming? I know, I know: don't expect good mileage if you're putting a Hemi in a JK - let's not go there. But 3 mpg is 20%. Also it looks like BOR includes a fan shroud, which is one less thing I'd have to do later. But there's not a lot of information on their kit. JSS, while not the best at spelling, has a lot of information out on their kit and also answers questions on the phone much better than BOR did when I called them last year. Having that available as a resource is important to me.

Now for the big question (and doubts):

2) Should I scrap these plans, sell the Hemi & Go for an LS?
Why the radical thoughts? Here's the email I got from 86CJ-07Rubi after he did his swap & I told him my Hemi had just arrived:

Quote:
You poor smu. You should be installing an LS motor. I really wish I had. I am getting 9-10mpg in the city with the lightest foot possible and 10-11mpg on the interstate at 70mph (9-10 at 75 and 8-9 at 80). With the cruise on 50mph, I am pulling a whopping 15mpg and at 30mph I am getting 16mpg. I know the Jeep is a brick, but under 55mpg aerodynamics don't matter that much. I know I weigh almost 6000lbs, but so do the Dodge Rams that are getting up to 20mpg. At this rate, if I get 100k out of the swap, it will cost me $25,000 in fuel. Not to mention I need to cut a hole in my hood to get my intake temps down. These are problems the LS motors don't have. I can't imagine it has much to do with the JSS kit unless the programing is off.

If you can afford the fuel and live with the shit mpg, go for it, it is worth it for the power and prestige. If the Hemi was the only V8 out there, I would do it again, but now that the LS motors are going in without issues (at least that we know of) I would have probably went that route.

Soooo, now I'm really waffling before I jump the final step. I could sell the 2012 5.7L Hemi & 2010 Trans and break even. Shipping would be a PITA. I'm very leery about the LS swap though, because it's so new, there's just not enough data on it

I'm not wanting 20mpg. But 13-15 is what I'm getting now & what I was expecting after reading up extensively here. 86CJ-07Rubi's note above really shook my confidence to the core. I have 4.88's & 35's.

I also really like the integration of the Hemi with the JK, both using Chrysler computers & parts. I don't take my Jeep to the dealer now & don't intend to after the swap, but mating a GM engine to a Chrysler body computer is way more complicated than it was when I first got into Jeeping & EFI was still new.

From what I can tell, the LS swap is no cheaper than the Hemi swap - motors that I've found are the same, or even more than the Hemi motors. Haven't seen the swap kit cost, but I can't imagine 2 computers are cheaper than 1.

I want everything to work like stock - or as close as possible. JSS told me ESP won't work, and I was OK with that. (I heard BOR may be different??) I had planned on a heat reduction hood and have Aeroforce gauges to monitor the temps. So I know no swap is perfect & there are some things that have to be dealt with. This is my daily driver, although in a year or so I hope to get a new daily driver & keep the JK as my occasional driver. I plan to keep it forever. We'll still drive it ~1,000 miles each way every summer to Colorado, towing a small M416 trailer. So 20% less cost in fuel is another day I can afford to stay & wheel.

I know coming to JKO for reassurance is a stretch but can you guys help me out before I drop $5,000 for a swap kit? Will I be happy with this? Last chance....

2011 5.3L GM LC9 Aluminum LS V8 Conversion w/ Custom Dyno Tune
Aluminum Genright Bumpers Front & Rear - Aluminum Nemesis Rockers
PR44/RCV/Reid Front - Superior Rear - ORF Front / Poly Rear Cage - ORF Tire Carrier
RK 3.5" Springs - Fox 2.0 Adjustable Shocks - JKS Arms & Trackbars - Poly Steering

Last edited by Jeep2.0; 12-26-2011 at 09:10 AM.
Jeep2.0 is offline  
Sponsored Links
Advertisement
 
post #2 of 49 Old 12-26-2011, 09:48 AM
Rock God
 
Join Date: Dec 2009
Location: Dallas,Texas
Age: 31
Posts: 828
Feedback: 0 reviews

I'm personally saving up for a LS3/6L80 swap. The LS engines are pretty light, Last forever, and get better MPG. They are also pretty easy to mod. You could tweak them to get pretty good MPG, For a Jeep. Luckily I have a friend with a lift so we will be doing the install. I figure then I should be able to pull it off for $10K.

I would email the JK-LS guys. I'm sure they can answer any of your questions considering they do Hemi and LS swaps. The LS swap kit they have is really clean.
wranglerblackout08 is offline  
post #3 of 49 Old 12-26-2011, 10:16 AM Thread Starter
Rock God
 
Jeep2.0's Avatar
 
Join Date: Aug 2010
Location: Buda, TX
Age: 57
Posts: 1,303
Garage
Feedback: 3 reviews

Quote:
Originally Posted by wranglerblackout08 View Post

I would email the JK-LS guys. I'm sure they can answer any of your questions considering they do Hemi and LS swaps. The LS swap kit they have is really clean.
Is that Motech you're referring to?
Who has done the LS/JK swap that has actual mileage numbers (and success of integration) to report?

Edit: One more thing to add: I am doing the swap in my garage, do not have access to a 2-post lift, and will mostly be doing it alone.

2011 5.3L GM LC9 Aluminum LS V8 Conversion w/ Custom Dyno Tune
Aluminum Genright Bumpers Front & Rear - Aluminum Nemesis Rockers
PR44/RCV/Reid Front - Superior Rear - ORF Front / Poly Rear Cage - ORF Tire Carrier
RK 3.5" Springs - Fox 2.0 Adjustable Shocks - JKS Arms & Trackbars - Poly Steering

Last edited by Jeep2.0; 12-26-2011 at 10:20 AM.
Jeep2.0 is offline  
Sponsored Links
Advertisement
 
post #4 of 49 Old 12-26-2011, 10:24 AM
Rock God
 
Join Date: Dec 2009
Location: Dallas,Texas
Age: 31
Posts: 828
Feedback: 0 reviews

Quote:
Originally Posted by Jeep2.0 View Post
Is that Motech you're referring to?
Who has done the LS/JK swap that has actual mileage numbers (and success of integration) to report?

Edit: One more thing to add: I am doing the swap in my garage, do not have access to a 2-post lift, and will mostly be doing it alone.
Yes, That is who i'm referring to.
They have reported actual mileage numbers somewhere in their thread.
wranglerblackout08 is offline  
post #5 of 49 Old 12-26-2011, 11:21 AM Thread Starter
Rock God
 
Jeep2.0's Avatar
 
Join Date: Aug 2010
Location: Buda, TX
Age: 57
Posts: 1,303
Garage
Feedback: 3 reviews

Quote:
Originally Posted by wranglerblackout08 View Post
Yes, That is who i'm referring to.
They have reported actual mileage numbers somewhere in their thread.
I just read all the pages of their thread, and the install pdf's. While the mileage looks good, I'd like to hear from the customers themselves - who have nothing to sell - on mileage reports. Even the Hemi swap end users report varying mileage - what do the LS swap customers report? Are there many out there yet?

I'll post on that thread too.

2011 5.3L GM LC9 Aluminum LS V8 Conversion w/ Custom Dyno Tune
Aluminum Genright Bumpers Front & Rear - Aluminum Nemesis Rockers
PR44/RCV/Reid Front - Superior Rear - ORF Front / Poly Rear Cage - ORF Tire Carrier
RK 3.5" Springs - Fox 2.0 Adjustable Shocks - JKS Arms & Trackbars - Poly Steering
Jeep2.0 is offline  
post #6 of 49 Old 12-26-2011, 04:13 PM
V8 dreams
 
jvandy50's Avatar
 
Join Date: Sep 2010
Location: jonesboro, ar
Posts: 3,549
Feedback: 0 reviews

Send JJ-4 a pm and ask him some questions. He did the LS swap I believe.

I don't have the coin yet, but have been anxiously waiting to see some mpg numbers with a bigger tire than 32". And I think Robbie said they were putting together a 35-37 tire package on their 6.2 soon. Doesn't really help ya much if your wantin the 5.3 though.

...and I do wish jss could spell better too lol. Hey at least they got the v8 thing down!


Vandy


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
2010 Silver JKU
jvandy50 is offline  
post #7 of 49 Old 12-26-2011, 04:54 PM
Rock God
 
Join Date: Oct 2007
Posts: 840
Feedback: 0 reviews

The only issue with Motech I'm seeing is they're running around at stock height and stock tires. I want some numbers with 3-4" of lift and 37's for referance. I would love an LS, the 5.3 in my work truck is great and the 6L80 seems like a great transmission. The 6.2 can only be better. Like someone posted before, "at some point all Jeeps get small blocks Chevys".
Alaska-HWY JK is offline  
post #8 of 49 Old 12-26-2011, 06:59 PM
Granite Guru
 
Join Date: Jul 2010
Location: Louisiana
Age: 48
Posts: 115
Feedback: 0 reviews

I smell ya. In same boat. Do you stick with all Mopar crap, keep tach and computer playing nice or go all Bow Tie E-Rod and auto or T56? Expensive damn gamble. Milage sucks with minivan shitbox v6; gas is cheap. If you want milage, put up with the smell and vibration of a 4bt. Life is short, drive a V8. Preferrable a real big one. My wife's LQ9 in her fricking Escalade ESV gets better mpg then my p.o.s. 3.8! Phuck it. Aftermarket goodies alone point me toward Chevy 6.0, 6.2 or 5.3 e-rod. Although a 6.4 Hemi sports wood of it's own; $26 phuckin thousand is a big nut to justify. If i move back to South Carolina where emmisions are useless. LS7 or 9 here i come. And a huge fuel bill to match the smile.
earfixr is offline  
post #9 of 49 Old 12-26-2011, 08:19 PM Thread Starter
Rock God
 
Jeep2.0's Avatar
 
Join Date: Aug 2010
Location: Buda, TX
Age: 57
Posts: 1,303
Garage
Feedback: 3 reviews

Quote:
Originally Posted by jvandy50 View Post
Send JJ-4 a pm and ask him some questions. He did the LS swap I believe.

I don't have the coin yet, but have been anxiously waiting to see some mpg numbers with a bigger tire than 32". And I think Robbie said they were putting together a 35-37 tire package on their 6.2 soon. Doesn't really help ya much if your wantin the 5.3 though.

...and I do wish jss could spell better too lol. Hey at least they got the v8 thing down!


Vandy
Quote:
Originally Posted by Alaska-HWY JK View Post
The only issue with Motech I'm seeing is they're running around at stock height and stock tires. I want some numbers with 3-4" of lift and 37's for referance. I would love an LS, the 5.3 in my work truck is great and the 6L80 seems like a great transmission. The 6.2 can only be better. Like someone posted before, "at some point all Jeeps get small blocks Chevys".
I sent JJ4 a PM - thanks.

The 32" tire mileage numbers are what has me askin' around for some real-world, 35" to 37" mileage numbers - and with 4.11's to 4.88's or so.

Thanks guys.

2011 5.3L GM LC9 Aluminum LS V8 Conversion w/ Custom Dyno Tune
Aluminum Genright Bumpers Front & Rear - Aluminum Nemesis Rockers
PR44/RCV/Reid Front - Superior Rear - ORF Front / Poly Rear Cage - ORF Tire Carrier
RK 3.5" Springs - Fox 2.0 Adjustable Shocks - JKS Arms & Trackbars - Poly Steering
Jeep2.0 is offline  
post #10 of 49 Old 12-27-2011, 08:16 AM
Rock God
 
peanut's Avatar
 
Join Date: May 2009
Location: Bellevue, NE
Posts: 1,669
Garage
Feedback: 0 reviews

Quote:
Originally Posted by wranglerblackout08 View Post
I'm personally saving up for a LS3/6L80 swap. The LS engines are pretty light, Last forever, and get better MPG. They are also pretty easy to mod. You could tweak them to get pretty good MPG, For a Jeep. Luckily I have a friend with a lift so we will be doing the install. I figure then I should be able to pull it off for $10K.

I would email the JK-LS guys. I'm sure they can answer any of your questions considering they do Hemi and LS swaps. The LS swap kit they have is really clean.
I was looking at the LS info this weekend. Seems like it is a clean install and if I were to do a swap probably the way I would go. Hemi's are nice but it seems like most people do not get that great of mileage with them. Granted not that any of them really get great mileage
peanut is offline  
post #11 of 49 Old 12-27-2011, 08:30 AM
JKO Addict!
 
ALASHA's Avatar
 
Join Date: Oct 2009
Location: Denver, CO
Posts: 8,227
Feedback: 0 reviews

Nemesis is partners with BOR and do a TON of hemi installs in Denver. They are also alot more active on here and Paul/Rob/Aaron are all very easy to talk to and can answer all of your questions. You may want to shoot them a PM (SN: Nemesis Industries) or give them a call because I believe their kit doesnt have some of the problems you mentioned.

As for mpg, the BIGGEST factor that I have experienced first hand is tire size. Everyone can claim that the LS is significantly better than a hemi in that department but until you slap a set of 37s on it, you havent seen how close the two really are.

I dont have a hemi but I personally lost 2-4 mpg going from the stock BFGs to a set of 37" MTRs on Walker Evans beadlocks.
ALASHA is offline  
post #12 of 49 Old 12-27-2011, 08:56 AM
Rock God
 
peanut's Avatar
 
Join Date: May 2009
Location: Bellevue, NE
Posts: 1,669
Garage
Feedback: 0 reviews

Quote:
Originally Posted by ALASHA View Post

As for mpg, the BIGGEST factor that I have experienced first hand is tire size. Everyone can claim that the LS is significantly better than a hemi in that department but until you slap a set of 37s on it, you havent seen how close the two really are.

I dont have a hemi but I personally lost 2-4 mpg going from the stock BFGs to a set of 37" MTRs on Walker Evans beadlocks.
LOL I think this has more to do with your driving then just a tire swap... I have swapped just a few times and only noticed Maybe 1-2. Add your driving skillz with a larger tire and I can see 4
peanut is offline  
post #13 of 49 Old 12-27-2011, 09:01 AM
JKO Addict!
 
ALASHA's Avatar
 
Join Date: Oct 2009
Location: Denver, CO
Posts: 8,227
Feedback: 0 reviews

Quote:
Originally Posted by peanut View Post
LOL I think this has more to do with your driving then just a tire swap... I have swapped just a few times and only noticed Maybe 1-2. Add your driving skillz with a larger tire and I can see 4
My driving style remained the same regardless of tire size.
ALASHA is offline  
post #14 of 49 Old 12-27-2011, 09:11 AM
The Wheelin Man's Friend
 
RiverCityOffroad's Avatar
 
Join Date: Aug 2010
Location: Austin, TX
Posts: 8,649
Garage
Feedback: 60 reviews

My response is in direct comparison of the 5.7L Hemi (VVT model) and the 5.3L GM motor with AFM. The Hemi was in our '10 WK and the 5.3L is in our '11 GMC Crew Cab.

The HEMI runs way hotter in terms of performance. It is very unrefined in terms of power delivery and definitely gives you that seat of the pants, head tossed into the headrest, smile on your face reaction when you push the throttle. But that's where the joy of ownership ended for me.

The MDS is absolutely horrible on that engine. It cycles in and out of 4CYL mode almost constantly and the drone, even with stock exhaust, was enough to drive me insane. It also averaged 11 -13 MPG with Jennie driving it to work. We have alot of traffic, but that's ridiculous for such a small vehicle with that much torque and horsepower pushing it down the road.

The transmission also made alot of racket and helped dilute my faith in the whole package. I really could not see that motor and transmission going 100K miles with the noises it was making at 15-20K.

On the other hand the 5.3 in our new truck is silky smooth, quiet on the road, AFM (active fuel management) is seamless and only kicks in on the highway. It has plenty of power, but it's a much more linear power band in comparison to the HEMI.

We just returned from Houston and on 23 gallons of gas we averaged 18.26 miles per gallon. I drove from South Austin to Kingwood at an average speed of 75 - 80 MPH and then we drove all over Houston visiting family and rarely used the highway. I filled up on my way out on Sunday night with about an 1/8th of a tank remaining. It held about 23 gallons.

My vote goes to the GM engines. I've never had any issues with them and they are plenty strong for pulling the JK around. Loaded down or not. My last GMFS was on 35" Mud Grapplers with heavy 20 x 10 KMC wheels and 4.56 gears. I towed our wake board boat from Houston to Austin frequently without any issues. I never paid attention to the mileage at that time in my life.

If I were you I'd lean heavily on the 5.3. I know how you are and I think you'll nitpick that HEMI like I did. A little more work for the silky smooth power delivery that the GM setup will give you is well worth it in my eyes.

Marcus


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
RiverCityOffroad is offline  
post #15 of 49 Old 12-28-2011, 10:25 AM Thread Starter
Rock God
 
Jeep2.0's Avatar
 
Join Date: Aug 2010
Location: Buda, TX
Age: 57
Posts: 1,303
Garage
Feedback: 3 reviews

Quote:
Originally Posted by ALASHA View Post
Nemesis is partners with BOR and do a TON of hemi installs in Denver. They are also alot more active on here and Paul/Rob/Aaron are all very easy to talk to and can answer all of your questions. You may want to shoot them a PM (SN: Nemesis Industries) or give them a call because I believe their kit doesnt have some of the problems you mentioned.

As for mpg, the BIGGEST factor that I have experienced first hand is tire size. Everyone can claim that the LS is significantly better than a hemi in that department but until you slap a set of 37s on it, you havent seen how close the two really are.

I dont have a hemi but I personally lost 2-4 mpg going from the stock BFGs to a set of 37" MTRs on Walker Evans beadlocks.
I know Nemesis is on this board & surfaces now & again, and I've sent them PM's and even emails before. Their responses are not only slow (like over a week) but generally don't contain the answers to the questions I posed - only a "we'll get back to you". (More often than not, and especially in the last few months). While they seem like nice guys, for my purposes they are ineffective.

When I called BOR directly ~9 months ago to begin my swap research, the guys on the phone weren't very knowledgeable when it got to more than price & donor year/make/model. Nor did they offer to get the answers to the questions (which were primarily around overheating).

AEV at least put me on the phone w/ Dave Harrington when "phone guy" couldn't answer the question. But the Truck Hemi won me over, and Todd answered all questions and then some.

Quote:
Originally Posted by RiverCityOffroad View Post
My response is in direct comparison of the 5.7L Hemi (VVT model) and the 5.3L GM motor with AFM. The Hemi was in our '10 WK and the 5.3L is in our '11 GMC Crew Cab.

The HEMI runs way hotter in terms of performance. It is very unrefined in terms of power delivery and definitely gives you that seat of the pants, head tossed into the headrest, smile on your face reaction when you push the throttle. But that's where the joy of ownership ended for me.

The MDS is absolutely horrible on that engine. It cycles in and out of 4CYL mode almost constantly and the drone, even with stock exhaust, was enough to drive me insane. It also averaged 11 -13 MPG with Jennie driving it to work. We have alot of traffic, but that's ridiculous for such a small vehicle with that much torque and horsepower pushing it down the road.

The transmission also made alot of racket and helped dilute my faith in the whole package. I really could not see that motor and transmission going 100K miles with the noises it was making at 15-20K.

On the other hand the 5.3 in our new truck is silky smooth, quiet on the road, AFM (active fuel management) is seamless and only kicks in on the highway. It has plenty of power, but it's a much more linear power band in comparison to the HEMI.

We just returned from Houston and on 23 gallons of gas we averaged 18.26 miles per gallon. I drove from South Austin to Kingwood at an average speed of 75 - 80 MPH and then we drove all over Houston visiting family and rarely used the highway. I filled up on my way out on Sunday night with about an 1/8th of a tank remaining. It held about 23 gallons.

My vote goes to the GM engines. I've never had any issues with them and they are plenty strong for pulling the JK around. Loaded down or not. My last GMFS was on 35" Mud Grapplers with heavy 20 x 10 KMC wheels and 4.56 gears. I towed our wake board boat from Houston to Austin frequently without any issues. I never paid attention to the mileage at that time in my life.

If I were you I'd lean heavily on the 5.3. I know how you are and I think you'll nitpick that HEMI like I did. A little more work for the silky smooth power delivery that the GM setup will give you is well worth it in my eyes.

Marcus

Me, nitpick? Who, me?

Here's my impressions after my 45 minute drive in the 2012 5.3 Tahoe I rented up here in Colorado (with the 6-speed auto): yucch. Kind of boring. It may be the gears, or the altitude (?), but it seemed to be hunting gears up & down, always in the wrong one & wouldn't hold it there as we climbed the mountain. Now, it was smooth, I'll give you that, but it seemed lethargic - like I had to really get into it to wake it up. It wasn't "fun" in the least bit. It did do everything I asked of it, and I'll check it out all this week, but its benefits weren't power. I will need to check the gear ratio somehow using the vin, because if it's 3.07 or so I'd feel a little better about putting it in a 4.88 JK w/ 35's.

Here's my scorecard so far:

LS:
+Mileage (although needs more verification w/ 35's & 37's)
+Runs cooler (no need for AEV Hood)
+Cheaper (if you pick a 5.3)
+6L80 6-speed auto seems to be a bonus
+Don't have to mod the steering column hole in the firewall
-Major wiring harness hacking
-Requires a change in direction from what I've started on
-Won't work with my Rubicon transfer case. This is huge, but if I choose a 5.3, I can pay for an Atlas & be just about straight across with the Hemi.

5.7VVT Truck Hemi:
+There's one sitting in my garage
+Powerful
+Lots of reports of truly happy customers (the fun factor)
+Well established swap procedures
+Plenty of comparison data from lots of swaps (35's, etc)
+Plug & Play wiring
-Mileage is often an issue
-Overheating (many reports of this, but not universal)
-Tranny concerns
(Overheating and mileage are my top 2 concerns)

So it's not a slam dunk for me just yet. Here's what I want to find out:
1) More driving of this Tahoe
2) Confirm Tahoe gearing
3) Get real mileage reports from both 5.3's & 6.2's with 35's & 37's
4) Solve my transfer case issue. (I just can't see downgrading my Rubi transfer case to a regular one)

2011 5.3L GM LC9 Aluminum LS V8 Conversion w/ Custom Dyno Tune
Aluminum Genright Bumpers Front & Rear - Aluminum Nemesis Rockers
PR44/RCV/Reid Front - Superior Rear - ORF Front / Poly Rear Cage - ORF Tire Carrier
RK 3.5" Springs - Fox 2.0 Adjustable Shocks - JKS Arms & Trackbars - Poly Steering
Jeep2.0 is offline  
post #16 of 49 Old 12-28-2011, 11:16 AM
The Wheelin Man's Friend
 
RiverCityOffroad's Avatar
 
Join Date: Aug 2010
Location: Austin, TX
Posts: 8,649
Garage
Feedback: 60 reviews

You and I both enjoy picking stuff apart. LOL!

That Tahoe probably has the 3.42s that are in our truck. I can imagine they bring the suck in the mountains.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
RiverCityOffroad is offline  
post #17 of 49 Old 12-28-2011, 12:00 PM Thread Starter
Rock God
 
Jeep2.0's Avatar
 
Join Date: Aug 2010
Location: Buda, TX
Age: 57
Posts: 1,303
Garage
Feedback: 3 reviews

Just looked online.
http://www.chevrolet.com/tahoe-mid-s...eatures-specs/

This says that even the 4x4 (which we rented) had 3.08's. Blech.
You have to order the trailering package to get 3.42's.
I may need to come drive your truck.

I also remember the Vortec 350 in my CJ7 (admittedly a lot lighter than a JKU). With 'only' 255HP & 335 ftlbs running 4.56's with 33's, it was a HOOT to drive. So maybe this 5.3 idea has some legs to it in a JK w/ 4.88's & 35's.

I'm doing the budget now. Assuming I sell off the Hemi parts I've accumulated, it looks like I may be able to swing a 5.3 and an Atlas and break even.
(My rubi transfer case looks like a no-go with a 6L80)

And later on, if it doesn't have enough power, I can add a blower or swap it for a 6.2.

Hmmm.....

2011 5.3L GM LC9 Aluminum LS V8 Conversion w/ Custom Dyno Tune
Aluminum Genright Bumpers Front & Rear - Aluminum Nemesis Rockers
PR44/RCV/Reid Front - Superior Rear - ORF Front / Poly Rear Cage - ORF Tire Carrier
RK 3.5" Springs - Fox 2.0 Adjustable Shocks - JKS Arms & Trackbars - Poly Steering
Jeep2.0 is offline  
post #18 of 49 Old 12-28-2011, 12:03 PM
The Wheelin Man's Friend
 
RiverCityOffroad's Avatar
 
Join Date: Aug 2010
Location: Austin, TX
Posts: 8,649
Garage
Feedback: 60 reviews

You should be enjoying your vacation instead of stressing about that stupid Jeep. LOL!

Marcus


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
RiverCityOffroad is offline  
post #19 of 49 Old 12-28-2011, 12:04 PM
Rock God
 
Join Date: Apr 2010
Location: Rocky Mountains
Age: 59
Posts: 568
Feedback: 0 reviews

Surprised the AEV kit isn't on your list. Anyways, do you really want to be a guinea pig with a LS swap? You'll have tons of bugs to work out with anything but a tried and true kit that comes with programming so everything works together after the swap. That means using the hemi and BOR or AEV. No experience with JSS but hear good things too. I've got 5K miles on my 5.7vvt AEV swap and absolutely love it. Milage around 13 up at altitude, whereas 3.8 was getting 16 MPG. No overheating, just get the proper radiator set up.

Last edited by Vince1; 12-28-2011 at 12:07 PM.
Vince1 is offline  
post #20 of 49 Old 12-28-2011, 12:36 PM
Granite Guru
 
SSrubi07's Avatar
 
Join Date: Dec 2011
Location: Mexico
Age: 39
Posts: 129
Feedback: 0 reviews

It seems that this ls vs hemi swap debate is becoming more and more famous this days.... I am having the same doubts, i placed an order for the aev kit, and cancelled it today!, i saw the conversion made, and it actually scared me, that i have to buy that many extras, like srt-8 power steering pump,air filter hose, truck 4x4 adapter, and so on.. besides i was dropping 5,249 for the kit, (plus shipping), and what i had paid for the engine and trans, i figured it would come out to if not next to 10 gs..... and still do it my self?... and having doubts on heating problems, and i read a post or two that 5.7 does not feel that powerful at all! specially in hot days... got me thinking... ALOT!

So now, im talking to motech, and since ive driven 5.3s for a long time, it seems that is my best bet now... my wife has a 09 yukon, and i love driving it on Sundays, not sure about the mpgs, but she only asks for gas money once a week! LOL!!!

please post on your decision, since i am in the same cross road that you are at this time.

What ever decision you make, it ill be way better than that 3.8 that it has now...

07 Sahara Unlimited, D44s Supercharged LS on 37s....
SSrubi07 is offline  
post #21 of 49 Old 12-28-2011, 01:00 PM
JKowners Vendor
 
MoTech's Avatar
 
Join Date: Apr 2011
Posts: 1,251
Feedback: 2 reviews
Mileage

Guys we have one customer running around with 37's and Dana 60's right now. We also have 35's and full armor going on our shop truck this week. We have a 5.3 AFM running 35's which averages about 16-17 mpg; however, it is running a 4l65 not the 6l80. GM rates the same truck with the 6l80 better than if it was equipped were the 4l60.

On our trip to Tahoe we averaged 18.3 mpg with 32's. This was over 1280 miles and included Christmas stop and go traffic in Tahoe, a trip to the Rubicon and tempretures in the teens. My wife had the Jeep packed front to rear and top to bottom. I did drive at or below 70 mph most of the trip and was conservitive with the throttle since I had my wife and baby on board. The LS ran flawless even in single digit temps. I do notice the winter mpg is 1-2 mpg less than summer, we averaged 19.6 on the same trip when it was warm out.

The LS runs so smooth and effortless it's like being pushed along by an invisible hand and you need to back off on the throttle or you will speed. I agree the Hemi feels much more masculine, rumbles, vibrates and makes you want to rule the world. The Hemi VVT's have a good punch when you nail it, feels quicker than the LS. In the real world the LS is more than a match for the Hemi but it is so well mannered it just feels docile. With the Hemi you are constantly pushing on the throttle to keep it going, it is like you are fighting drag and friction constantly. I feel the 5 speed eats hp. The LS is simply more refined and well mannered, even at 400 hp. The 5.3 AFM would return better mpg and run on regular gas, the 6.2 prefers premium and if you don't run premium it will revert to the low octane spark timing table and you will lose mpg. The 5.3 will run well on 85 octane.

Here is a quick vid of a cold start at 14 degrees, the anti freeze was frozen

JK LS cold start - YouTube

I will report the real world mpg with the larger tires as soon as I have some reliable data.

Thanks Robbie.

MoTech
725-502-8507

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
MoTech is offline  
post #22 of 49 Old 12-28-2011, 01:24 PM
Rock God
 
RookieJK's Avatar
 
Join Date: Feb 2011
Location: Mantua, NJ
Age: 36
Posts: 937
Feedback: 0 reviews

I vote LS not to mention that you can even pick up a Vortech V8 and itll still work with the swap kit for the LS since they are just about the same. Vortech=iron/steel LS=aluminum. And Im not sure about out your way but around me you can find LS engine and trans combos low mileage for around 2-3grand.

Jersey

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Crew
RookieJK is offline  
post #23 of 49 Old 12-28-2011, 01:35 PM
JKowners Vendor
 
MoTech's Avatar
 
Join Date: Apr 2011
Posts: 1,251
Feedback: 2 reviews

Quote:
Originally Posted by RookieJK View Post
I vote LS not to mention that you can even pick up a Vortech V8 and itll still work with the swap kit for the LS since they are just about the same. Vortech=iron/steel LS=aluminum. And Im not sure about out your way but around me you can find LS engine and trans combos low mileage for around 2-3grand.
This is accurate. The iron engines work fine, they need to have one boss on the block drilled and tapped for the a/c mount which is already there on aluminum engines.

I find lift out 2009 5.3's with the 6l80 in the $2-3K range. Tell the yard you do not need the accessories, harness, ecm, etc and they will usually discount it for you.

I spoke with Gordon at Rock Solid this morning and he told me his 6.2 pulls the 37's effortlessly. He had the same impression as I that the LS is smooth and refined compared to a Hemi. He described it as driving an Escalade.

MoTech
725-502-8507

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
MoTech is offline  
post #24 of 49 Old 12-28-2011, 01:49 PM
JKO Addict!
 
terrahawk's Avatar
 
Join Date: Feb 2008
Location: Katy, TX
Posts: 4,511
Garage
Feedback: 1 reviews

Any chance for an adapter to make the NSG370 MT work in the 5.3 swap?

Pain heals, chicks dig scars, glory lasts forever.
terrahawk is offline  
post #25 of 49 Old 12-28-2011, 01:59 PM
Breaker of nice things
 
merlin4979's Avatar
 
Join Date: Jul 2010
Location: Olathe, KS (Kansas City)
Age: 39
Posts: 2,477
Garage
Feedback: 1 reviews

Quote:
Originally Posted by Jeep2.0 View Post
4) Solve my transfer case issue. (I just can't see downgrading my Rubi transfer case to a regular one)
If you downgraded to a "regular" transfer case, could you use something like the Advance Adapters Rubicrawler to help out there?
merlin4979 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JKowners.com : Jeep Wrangler JK Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome