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GM Gen 4 conversion including LS

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conversion
963K views 3K replies 280 participants last post by  LandDefender 
#1 · (Edited by Moderator)
O.k. I got permission from the forum member to post a few pics.

This is a GM Gen 4 mated to a 6 speed and then to the LT230. Guess what...no change needed in your drive lines as this mates up to your LT 230.

Imaging all the HP and gas mileage you could want. WOW. More to come from the forum member.
 

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#323 ·
Weekend Trip

Took the D90 to BigBear this weekend for trail running and camping. Some observations...

The vehicle never overheated. Even at 8000ft and continuous uphill climbing. Currently running two 1000cfm Spal electric fans. These are controlled by the ECU and staged.

The low first gear is awesome for crawling over boulders. Fantastic torque and very well behaved. Especially pulling a crippled D2 up over obstacles. (broken TC) On the down side, too much up-shifting/down-shifting between first and second gear on normal trails. I am planning on reprogramming one of the shifter detents to "start in second gear" to eliminate this. I spent half the time in high range. Loads of torque.

The only issue I ran into was making the mistake of starting the vehicle in gear. The TCU faulted and put me in limp mode. (second gear only) A two minute disconnect the of the battery cleared the fault. Hence, hooking up a neutral safety switch is advised.

The trip up and back was nice. Doing 85mph on the highway and passing Jeeps is always fun. Of course, there was one new JK that was intent on showing me how powerful his new Pentistar V6 was. Left him in the dust around 100mph. :cool: I guess the prospect of getting a speeding ticket in my D90 is now a reality. ;)

I am finding other issues with my D90 at these speeds. I now know my doors whistle and my fiberglass top buffets over 85mph. Overall very happy. :thumb:
 
#335 ·
GM Performance

There have been several people asking what engine or package to buy from GM. (new engine)

Currently, GM Performance doesn't offer a suitable engine/trans package for this conversion. They have three different offerings...

Crate Engine
Connect & Cruise
E-ROD

Crate Engine
GM does offer the LC9 (5.3L aluminum) truck engine as a crate option. Part number 19259918. (~$5,000) This can be used on this conversion. Available from Summit, Jegs...

Connect & Cruise
This package comes with a wiring harness, ECM, and optionally a transmission. Problem is GM Performance doesn't off the 6L80e transmission, yet. Therefore, any package engines won't have the correct ECM and wiring harness.

E-ROD
This package is the Connect & Cruise plus down pipes/cats and is California legal. Here again, since the 6L80e is not offered, it has the same problems as Connect & Cruise. Don't wast you money on this one. You will have to scap the down pipes/cat, exhaust manifolds, ECM and harness. Then you are left with the Crate Motor and no CA compliance.

So what are the options? You can purchase the LC9 Crate Motor from GM Performance, a 6L80e trans from the dealer (~$2800), and a wiring harness from the dealer (~$200), and an ECM from Amazon. This won't work in California as a donor VIN is required for an "engine change". I an not sure what other states require.

Will a Car Engine work?
Car engines can be used outside of California. However, the oil pan and pickup, water pump, and possibly the crank pulley will have to be changed. There are three pulley offsets. Close, medium, and long. The truck water pump is required here and uses the long pulley.

Hope this helps.
 
#337 ·
So to summarize and reiterate

There have been several people asking what engine or package to buy from GM. (new engine)

Currently, GM Performance doesn't offer a suitable engine/trans package for this conversion. They have three different offerings...

Crate Engine
Connect & Cruise
E-ROD

Crate Engine
GM does offer the LC9 (5.3L aluminum) truck engine as a crate option. Part number 19259918. (~$5,000) This can be used on this conversion. Available from Summit, Jegs...

Connect & Cruise
This package comes with a wiring harness, ECM, and optionally a transmission. Problem is GM Performance doesn't off the 6L80e transmission, yet. Therefore, any package engines won't have the correct ECM and wiring harness.

E-ROD
This package is the Connect & Cruise plus down pipes/cats and is California legal. Here again, since the 6L80e is not offered, it has the same problems as Connect & Cruise. Don't wast you money on this one. You will have to scap the down pipes/cat, exhaust manifolds, ECM and harness. Then you are left with the Crate Motor and no CA compliance.

So what are the options? You can purchase the LC9 Crate Motor from GM Performance, a 6L80e trans from the dealer (~$2800), and a wiring harness from the dealer (~$200), and an ECM from Amazon. This won't work in California as a donor VIN is required for an "engine change". I an not sure what other states require.

Will a Car Engine work?
Car engines can be used outside of California. However, the oil pan and pickup, water pump, and possibly the crank pulley will have to be changed. There are three pulley offsets. Close, medium, and long. The truck water pump is required here and uses the long pulley.

Hope this helps.


Best bet is to get a used gen 4 truck motor with a 6l80e and all the accessories and engine harness, emission to go with it! Correct.
Since I have the gen 111 with the 4l60e I can says I am very pleased with being able to put my foot in it and continually have a smile on my face during acceleration. I fell my truck is tom cruise and my drive line is Renee zeliwiger. And Tom keeps saying from jerry McGuire "you complete me!" What a tear jerker and some sh't after downing a dark bear and an extra strong Bloody Mary so I can sleep on this red eye from Cali to DC
 
#342 ·
That's the engine (LMG) I am running in my D90. It weighs 650 lbs compared to 320 lbs for the 3.9. I think the LC9 is 150 lbs lighter. (don't quote me, I haven't weighed one yet) I find the extra weight on the front axle gives me more climbing traction with the short wheelbase. Front springs are running 1/2" lower than with the 3.9.
 
#344 ·
Wow!!
Great to see this is happening!

I actually mated my 6L80e to the LT230 (also with 1:1 ratio from ashcroft) using a Marks adapter and a custom piece to attach to the trans.

I think Nicks part is MUCH nicer and may even swap mine out.

I have posted long ago about mine, but the specs are:

L92: from a 2007 Escalade ESV, 403hp/417tq. But with a cam swap and headers, along with a ECU flash is an easy 450hp/450+tq. Mine has VVT and no DOD

6L80e from the same

LT230 from ashcroft with 1:1 ratio

Ashcroft underdrive

I bought it from a ESV that a tree fell on and it only has 27 miles on it.

I did all this..... back in 2007 and yes its still sitting assembled on my garage floor!

I also wanted to mention I have the Marks kit for a 4L80e to LT230. If anyone wanted to document it to know the sizes, let me know.

I also have a new never run 4L85e built by Monster. Was planning to use it but when the 6L80 came out I never did as I wanted the overdrive. If anyone goes that route its for sale.

I am glad Nick has done this as it always seemed the little things which are really HUGE things like the shifter, interfacing, pedal, etc kept me from proceeding.

His work looks amazing.

Nick, did you change the engine mounts at all since the prototype I got over a year ago? If you remember my intake touched the bonnet no matter how the intake was mounted.
 
#347 ·
National Rally

Trip update. Drove from San Diego, CA to Moab, UT and back. Averaged 15.4 mpg with the 5.3L, 6 speed auto, 4.11 gears, 35" tires, 1.003:1 LT230. Drove at 70-75 mph (2000 to 2150 rpms). Previously got 10 mpg with the 4.6L, ZF auto, and 1.4:1 LT230.

Spent 14 hours on Poison Spider/Golden Spike/Gold Bar trails. Idled the engine for 14 hours with the A/C on and 93 degree temperatures. No overheating. No issue. Very happy. :)
 
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