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LLT TO LFX ENGINE CONVERSION

56K views 54 replies 14 participants last post by  hjeremy688 
#1 · (Edited)
I own a 2010 LLT Sequential Twin Turbo V-6, Automatic. My shop engineered, fabricated and installed the entire system. Vince at Trifecta did the tuning, which was great and still using today. He did a wonderful job and the car runs spectacular. It is a daily driver and I have driven 30,000 miles to date with no issues. As most LLT owners know, computer programming has limitations due to the Bosh ECM and very difficult to tune for maximum efficiency. In 2012, GM introduced the LFX engine, which is a much stronger engine and has higher horsepower capabilities. It uses a Delphi ECM, making it easy to tune by most tuners and more HP can be extracted through these tuning capabilities.

With LLT's now getting higher mileage on them and possibly needing new engines, my thoughts are to transplant a LFX engine with the Delphi ECM into the LLT. After much research over the past year, I purchased an LFX engine assembly, complete with wiring and ECM. It is in my shop on an engine stand and I have been evaluating feasibility.

So far, I have verified that the physical engine bolts right in with very few issues except for exhaust connections and very minor plumbing hook ups. Really easy. The in-tank fuel pumps on LLT'S and LFX's are the same, so no issue there. All other mechanical hook ups are the same. There are (2) body plugs that come off the engine wiring harnesses of both the LLT and the LFX's. After carefully looking at them, both of the physical plugs are the same. The pin outs of these (2) plugs are the same, as well, with the exception that one of the LFX engine side plugs have (4) additional pin outs and the LLT has (1) additional pin out in the fuse block plug. I feel pretty confident that these are for later model Camaro's that GM added features to.

My thoughts are that I could install the LFX complete engine/ECM assembly into my LLT, hook up the exhausts and minor cooling connections, etc. and plug the (2) body plugs into the existing mating body plugs on the vehicle and it should work. The extra pin outs on the LFX body plugs would simply terminate at the plugs and do nothing. I can't imagine GM changed anything that would not allow this to be done. Most everything is the same on the Camaro's from 2010 to 2015. Just additional options and features as the years progressed.

I need someone to chime in on the feasibility of this conversion concerning the extra pin outs on the LFX harness and help me further understand the compatibility. I am 95% verified on everything else. So darned close. If this works, this opens up the many, many LLT's that would qualify for this major improvement in a transplant. LFX engines are plentiful and cheap and the engine is a refined unit with much stronger internals, larger valves and better breathing characteristics for those who want more HP. Let's get our heads together to make this happen. I'm ready to do a transplant just as soon as I get my ducks in a row.
 

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#3 ·
Well Phil, I am so close, yet so far away. Just got to figure out those few remaining pin out on the LFX harness. My guess is that they will dead end into the Body plugs and not do anything, thus the connections should work. Just need to find someone that can help me define those pins for function. I do have the GM pin out diagrams with definitions but need to understand function as it relates to this conversion. I may be making a mountain out of a mole hill and could plug them in and everything works. I don't know.
 
#5 · (Edited)
These are the only (2) body plugs that the engine/transmission entities communicate with the Camaro body/chassis. Each and every one of the wires from the LLT plugs are in the exact same location and defined by GM as the exact same function as the LFX plugs. They are the same physical plugs and plug into the body side on all 2010 thru 2014 V-6 Camaros. This makes the conversion 95% feasible.

As you can see, there are many pin voids in both plugs, allowing for GM to add further features to later model Camaros. Beginning in 2013, GM did, in fact, add several extra pins in some of those voids. My guess is that SOME features were added to the newer vehicles. But the rest of the pins functions the same in all models. The million dollar question is, since we would be installing the LFX into the LLT, we do not need those extra features because the LLT's did not have them, so why wouldn't simply plugging the LFX plugs into the LLT work and the extra pins from the LFX harness would simply dead end into the LLT's body side plugs because the body side of the LLT plugs do not have receiver pins in their sockets?

This is the only question that remains to do this conversion. Please note that the ECM's of both vehicles are completely married to the harnesses of each respective engine, thus no other wiring issues need to be considered.

The LFX plug on the left of the picture (X102) has (4) additional pins in new locations that were originally void on the LLT. The picture of the plug on the right (X50A) shows only (1) additional pin in the LLT, which is not in the LFX plug. That's it.
 

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#9 ·
We are 95% there on confirmation of a successful conversion but we have a few pin outs yet to identify. This is tricky stuff but it looks very promising. I have a brand new LFX engine waiting on a stand for my transplant when I am sure it will work. Note that if you have an automatic transmission, you will have to use the transmission that is same year as the LFX. Can't use the LLT, period, due to communication differences between the Delphi computer to the TCU.

Everything mechanically bolts up except a modification needs to be made to marry the exhaust pipes to the LFX heads, which is silly simple. In tank fuel pumps are the same on all Camaros, so no issue there. The (2) body plugs are the same, as well and will plug right in, so no issue there. We are trying to identify a few additional pin outs to be sure nothing will interfere with this transplant but it sure is looking very promising.

You will use the LFX engine wiring harness complete with it's computer and MAF. A few changes in hose connections and should be good to go with programming IF we confirm just a few remaining pin outs on the LFX harness. I am very excited about this and if it works, this is the only way to go if LLT engines should ever need replacing for any reason. LFX is a much stronger and advanced engine and can be precisely tuned for more power.

If anyone out there wants to try it, we have brought the level of feasibility up to 95% certainty. Will keep you informed. Please keep me informed of anyone that can add to the information on this potentially beautiful transplant.

Monty
 
#10 ·
Were at probably 98% certainty as I only have to confirm 2 more minor questions I have. This will be a huge plus for any with a failed/blown LLT to be able to do the conversion. The Auto trans as Monty states cannot be used from the LLT, it must be the MYB 5L60E version that started in 2012. The same controller works for the 2013-2015 and I am confirming 2012 as well (pretty sure it is the same).

We can put together a transplant "Kit" after all is confirmed, but so far there does not appear to be any real problem that can't be easily overcome. And with good used LLT's getting so hard to find (nearly all seem to already have substantial timing chain stretch and ALL have severe intake valve coking) there are plenty of low mileage LFX's out there.

:thumbsup:
 
#13 ·
As far as transmission compatibility is concerned, I have confirmed the following: 2012-2014 manual transmissions are interchangeable and should be compatible with 2012-2014 LFX engines.

Concerning automatic transmissions, 2013-2014 transmissions are interchangeable with 2013-2014 LFX engines.

2010-2011 automatic transmissions are NOT compatible with any year LFX engine. These are specific to LLT models only.

No confirmation on compatibility on 2012 automatic transmission on other years LFX engines except 2012. I am further investigating this exception.
 
#15 ·
That may and could be true but for some reason, 2012 stands alone and if my research is correct possibly the ECU for that year might also be alone. It doesn't make sense to me why 2012 would not be included with 2013 and 2014. I am also trying to confirm this. I am also in the process of getting schematic on the 2010 and the 2014 Camaro LT body control modules to be sure pin outs are close or the same. Fuel pump modules should be checked as well due to the fact that GM has different part numbers on both body control module and fuel pump control module but if pin outs are similar possibly some added features were included in the later year. Just don't want to overlook anything but this is getting exciting.
 
#16 ·
Update. Still at it. Still confirming just a few issues. I need to double check everything before diving into this conversion. Closer than ever but still researching pins outs and confirmation. Takes so much time to get to am absolute answer but I am convinced that it can be done. It ALL hinges on electrical. Mechanical is a piece of cake and very easy and straight forward. Stay tuned.
 
#18 ·
On my way to work this morning, it dawned on me that if this conversion works, 2010-2011 LLT owners who do not want to go to the trouble of changing engines to the LFX, could simply get a LFX wiring harness, Delphi ECU, LFX throttle body and MAF and convert their LLT's From Bosch to Delphi for a huge improvement in tuning capabilities.

confirmation is slow going but positive, so far.
 
#19 ·
Its been a long while since I have been on. I can look up the pins as long as you give me a year/make/model of the connector and which connector.



One thing I would be worried about is the CAN and the hi/lo speed lines. GM may have changed some things as far as code goes so that modules are receiving incorrect data and things like that. I have not looking into the data networks but I suppose I could if I get some time at work. I'm not sure that it WILL be an issue but I wouldn't be surprised if trouble arises. But I suppose if you have tuning capability you could probably make the ECM happy 'enough' to still run the engine.

The new TR6060's in the ATS-V will bolt up to the v6's too. Its rated for some retarded torque numbers... Something in the 600-700 lb/ft range.
 
#21 · (Edited)
Thanks for chiming in S. Bretz. I do not know anything about CAN and the hi/lo speed lines. This is my concern as well. I have most everything else worked out except this detail. SC2150 has been a huge help in getting to the final stages. I did not discuss this particular issue with him but I need help in this area from him or anyone who has expertise in this area of computer control. If you could check into this further and post a reply, I would really appreciate it. This is an exciting project that will be very beneficial to many LLT owners and there are a bunch out there. I am ready to go, once these potential computer issues are known to be resolved. I have a new 2014 LFX engine and transmission in my shop waiting for confirmation. Thanks to anyone who can answer this question. Attached are pictures of my 2010 LLT Limited Edition Twin Turbo.
 

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#23 ·
Hey Sal,

Looks like were on the final stages and have it pretty much figured out. Monty is starting the swap any day now (he is so detailed in all he does as his build pictures show he want's every single connection and nut/bolt verified before).

Stay tuned! Good things coming!!!
 
#25 · (Edited)
Here is where we are at this point in the project. Wiring identification and functions from LFX engine to LLT body has convinced us that this has a very strong chance of working. So much so, that we are moving forward with the new 2014 engine prep work. Lots to do because this is a twin turbo LLT and we want to minimize transplant time due to this car being my daily driver.

The idea here, is to do as much prep work on the engine stand and at some point early in the new year, we will simply have to dive in and do the engine/transmission transplant. These are uncharted waters, for sure, and don't think it has ever been done, so it should be very interesting. To be honest, the one and possibly only potential issue here is that the CAN BUSS communication issues between the LFX engine to the body could create issues but we are retaining all LLT body control modules in order to not upset any downstream functions.

Engine prep is slow going due to the many details and additions that must be done so that previous LLT modifications and additions will marry to the LFX engine. This project demands no detail to be overlooked and double and triple checks be completed so we aren't chasing down elementary problems that would have nothing to do with the actual engine conversion. This is the latest update.

Notes: Notice in (1) picture of the drivers side, below the valve cover, I have removed the factory oil filter and it's massive casting and replaced it with a custom machined billet remote oil filter plate using a larger remote spin on oil filter mounted on chassis. Also note on the passenger lower side that I have added a billet fuel filter that is a must have, as far as I am concerned. Billet vacuum/boost ports manifold, fuel distribution manifold, etc.
 

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#26 · (Edited)
Elite catch can

As I am slowly working on the LFX engine, I am also installing the Elite Catch Cans on the LLT vehicle. I have always had the RX earlier version and have had great success with them. Catches so much oil that it makes me shake my head that all of it would go into the intake and coke up the valves. Very disgusting. In preparation for the new LFX engine, I have stepped up to the Elite Catch Cans for my project. I have had experience with a number of top cans but in looking at the design differences in them, it is my opinion that the Elite offers me the best protection. Yes, there are a very few others that do a great job, very few but in evaluating the design and research that went into this unit, I feel it to be among the best or even "the best" unit on the market. Opinions differ and I respect that but for me this was my choice. Due to the very high investment in my Camaro and the forthcoming LFX engine conversion, I am using (2) Elite catch cans, in series. Though not necessary, the ongoing oil ingesting problems with DI engines have convinced me to go overboard in this area. We will see if the second can catches anything. If nothing else, I will have peace of mind. I have found an interesting place to mount these monsters, although a bit of effort. I wanted them in a cooler place than the engine compartment in order to take advantage of any better oil condensation due to temperature differential.

I moved the horns from their present location and am mounting the Elite Catch Cans in those areas, under the headlights, just in back of the front fascia support beam. I will have pictures soon and will post.
 
#28 ·
Update! FINALLY, I am at the point of engine completion and ready for the first initial test. Tracy has agreed that before going to all of the effort of installing the engine/transmission assembly in the vehicle and finding our that problem/problems exist, it would be wise to pull the new LFX engine along side the car, unplug the LLT computer and the (2) body plugs that connect the LLT engine to the body harnesses and body control modules, match the VIN numbers to the LFX computer, then load the stock GM programs for the LFX engine and transmission from the ODB2 port in the car. Then, we can note can buss communications and body control modules compatibility. This should give us a very clear indication if we have a potential winner or not.

Being this vehicle is my daily driver, I can't afford to have the car down for extended periods, so we have decided to perform this very important, interim step. One of the LFX engine harnesses had to be extended 10" in order to do this but it was only 18 wires and only took several hours. The other engine wiring harness was long enough, as is. GM doesn't give you any excess wiring, so this was necessary. That operation is completed and my GM programmer is scheduled to come to my shop next week to program the LFX computer and transmission module with a stock 2014 program. Today, I even decided to make a temporary fuel line extension so I can hook the fuel system to the LFX engine at the same time we do programming. Of course we can't start the engine at this point. This is as far as we can go on this critical test with the engine sitting beside the car but should reveal a significant amount of information and data.

If, and that's a big if, all goes well on this test, we will fabricate the new exhaust and schedule an install into the vehicle and see what happens. Vince at Trifecta has also been helping out with the can buss compatibility and electrical & component modifications to the LFX engine, so if and when it comes time to bring him in for programming, he can give me one of his superior tunes. Stay tuned and a BIG thanks to Vince and Tracy for all the collaboration on this "first time" conversion.
 
#29 ·
Have a LFX swap going into a CTS shortly as well.

Monty has the wiring diagrams all cataloged into a nice binder he shared so after these first 2, this should be finalized and perfected for any others wanting to do this.

See so many LLT failures (mainly due to the lack of a low oil level warning and engines run low or out of oil,) so this will give owners an option of replacing with a LFX. Lot's of good LFX's out there for reasonable prices.

Looking for your results!
 
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