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LLT TO LFX ENGINE CONVERSION

48252 Views 51 Replies 13 Participants Last post by  CamaroPA
5
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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Monty,
You are great at fabbing up the modifications. I cant wait to see how it does with a new computer!
Phil
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.
Let's get some brains on this conversion. Somebody out there must be able to understand if this is feasible. Come on, guys!!
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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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Will be over this week to help Monty. See you then. :thumbsup:
Great! You understand these Camaro's and I am sure you will be of great help.
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
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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:
Glad to hear that we are getting very, very close. This is so exciting. So glad that you are able to help SC2150, you understand these Camaro's better than anyone I know. You are a wizard!!!
Glad to hear that we are getting very, very close. This is so exciting. So glad that you are able to help SC2150, you understand these Camaro's better than anyone I know. You are a wizard!!!
Should know more by tomorrow, but I think were good to go!:thumbsup:
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.
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.
It appears the 2012 is also compatible but I am not 100% sure yet.
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.
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.
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.
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.
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.
Excellent news on the 6060!
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