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Thread: LF3 or LF4?

  1. #1
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    LF3 or LF4?

    Has anyone tried to transplant &/or tune and LF3 or 4? It's the twin turbo version of the LFX and comes in the XTS, CTS, & ATS-V.

    I have a home for an LFX, just haven't found the right donor car yet and suddenly I have a project that could benefit from the LF3 or 4.

    In case you haven't heard about them here's what Wiki says about them:

    LF3

    The 3.6 L twin-turbocharged version for the 2014 Cadillac CTS and 2014 Cadillac XTS has been announced at the 2013 NYAS.[15]

    The engine is rated at 420 hp (313 kW) of power @ 5750 rpm and 430 lb⋅ft (583 N⋅m) of torque @ 3500-4500 rpm (with 90% of torque being available at 2500-5500 rpm) and helps the CTS achieve 0-60 mph time of 4.6 seconds with an 8-speed automatic transmission.

    In essence, the twin-turbo 3.6L V6 is the force-inducted variant of the popular LFX V6 currently found in the Cadillac ATS, XTS, and SRX, among many other GM models, with several important upgrades, including:

    All-new cylinder block casting
    All-new cylinder head castings
    Strengthened connecting rods
    Forged steel crankshaft
    Continuously variable valve timing
    Large 38.3 mm intake valves and 30.6 mm sodium-filled exhaust valves
    Machined, domed aluminum pistons with top steel ring carrier for greater strength
    10.2:1 compression ratio
    Patented, integrated charge air cooler system with low-volume air ducts
    Two turbochargers produce more than 12 pounds of boost (80 kPa)
    Vacuum-actuated wastegates with electronic control valves
    All-new direct injection fuel system
    Tuned air inlet and outlet resonators, aluminum cam covers and other features that contribute to exceptional quietness and smoothness

    Applications:
    Year(s) Model Power Torque Dyno chart
    2014?present Cadillac XTS 410 hp (306 kW) @ 6000 rpm 369 lb⋅ft (500 N⋅m) @ 1900-5600 rpm link
    2014?present Cadillac CTS 420 hp (313 kW) @ 5750 rpm 430 lb⋅ft (583 N⋅m) @ 3500-4500 rpm link
    LF4

    The LF4 is a higher-performance variant of the LF3 for use in the Cadillac ATS-V. Changes to the LF3 include:

    Turbochargers with low-inertia titanium-aluminide turbines and vacuum-actuated wastegates for more responsive torque production
    Compressors matched for peak efficiency at peak power levels, for optimal track performance
    Patent-pending low-volume charge-cooling system that optimizes packaging efficiency and maximizes boost pressure
    Lightweight titanium connecting rods that reduce inertia of the rotating assembly, complementing the quick-spooling turbochargers[16]
    Peak boost increased to 18 PSI (from 12 PSI)
    Higher-flow fuel injectors
    Oil pan baffling for better oil flow at high cornering speeds[17]

    Applications:
    Year(s) Model Power Torque Dyno chart
    2016?present Cadillac ATS-V, Cadillac ATS-V Coupe 464 hp (346 kW) @ 5850 RPM 445 lb⋅ft (603 N⋅m) @ 3500 RPM 2016 link

    Also it looks as if the LF4 is the block to have if you are going to be racing your LFX
    Last edited by Carguy123; 10-29-2018 at 09:29 PM.
    "mobilito ergo sum"
    I drive, therefore I am.

  2. #2
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    The LF4 is an amazing powerplant. Here's a link to the coolest swap I am aware of.

    https://www.cadillacforums.com/forum...rx8-build.html
    1998 Grand Prix GTP (first 3800 FWD in the 10s), 9.499 @ 145.13 mph
    1998 Firebird (first 3800 RWD in the 8s), 843 whp, 8.991 @ 152.12 mph, driven by Tim King
    1999 Grand Prix GT (first 3800 FWD in the 8s), 8.902 @ 154.90 mph, driven by Bob Cook
    2000 Bonneville SSEi (first 3800 Bonneville in the 12s, 11s and 10s), 10.711 @ 125.71 mph, driven by Ed Morad
    2008 Pontiac G8 (first G8 in the tens), 10.727 @ 129.87 mph
    2016 through 2019 Cadillac ATS-Vs (eleven cars in the 10s so far!)

  3. #3
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    Hmm, my reply disappeared. I'll try to recreate it.

    Thanx for the link and thank you for another sleepless night going down this rabbit hole.

    I've seen an LFX in an RX8 and a NC Miata and it looks as it were meant to be there. I see the turbos make the package a bit of a big box so that might be an issue in what I wanted to put it in.

    He's basically turboing an LLT or LFX instead of getting an LF4, but I'd have lots of the same issues. I wonder why he didn't just go with a donor car? I haven't looked for one, and since I'm being picky about the LFX engine I want for the other car I know it's not been easy to find on Copart. I've seen several but always at a time I couldn't bid due to sick family issues

    Did any of the LF4s come with a manual trans? How would I look that up?
    "mobilito ergo sum"
    I drive, therefore I am.

  4. #4
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    Quote Originally Posted by Carguy123
    Did any of the LF4s come with a manual trans? How would I look that up?
    Yes, the TR6060 M6 was an option for 2016 through 2019 Cadillac ATS-Vs.

  5. #5
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    I have and LFX Custom single turbo setup ... runing 8psi but I?m looking for more boost and recently I bought and LF4 and I?m going to try start with my custom single turbo setup (FMIC) 🤔 .

    I don?t know ... but hope that the E39A PCM could manage that ..

  6. #6
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    If you've got the LF4 why not just use the turbos that come with it?
    "mobilito ergo sum"
    I drive, therefore I am.

  7. #7
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    First its because, the engine don't arrive with the turbo's.
    And I think that my single turbo HX40 would move more air than the two stock turbo's, and would be more difficult manage the LF4 setup (two maf, wastegates, sensors that .... I don't know) with the lfx pcm

  8. #8

  9. #9
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    After a great deal of research, I just purchased the only LF3 used engine listed on the Automotix website. It has 54K on it. I plan to completely tear it down and rework it with GM stock bearings and seals. Then I am going to replace my LFX block with the LF3 block. I have a 2016 Colorado that has had a RIPP SC kit on it since19K miles, and I was running the original tune by RIPP which is essentially the same tune they provide for the Camaro LFX. Twice now I have had to pull the engine, once at 34K miles, and now again at 48K miles, for broken piston (first time) and now broken rings. The first time I replaced the damaged parts with OEM GM parts, but not again. The stock LXF bottom end just cannot take hard off-roading with a supercharger, or at least mine could not. After the first break I had my truck retuned by East Coast Supercharging, who told me that the original RIPP tune was not very good. They also spent a good deal of time retuning the stock TCM and the trans was far better after they tuned it than it ever was stock. My stock LFX had 11.5:1 compression, a hardened forged crank, powdered rods, sintered CU infused main bearing caps, and cast pistons with rings of unknown quality. The LF3 bottom end comes stock with 10.2:1 compression, forged steel crank, forged rods, nodular iron main bearing caps, and forged pistons with different (unknown difference) rings. The rings have a different stock number from the LFX rings is about all I know about them, but I am assuming they are an upgrade to take the extra boost. The LF4 engine I know has even more upgrades, but at some point the extra money doesn't really buy that much extra HP and that seems to be the case with the LF4 over the LF3. Anyway, I am not sure about using the stock LF3 heads or whether I will just use my LFX heads on the LF3 block. It all depends on whether my intake manifold will bolt up to the LF3 heads and I won't know that until I get the LF3 in the shop and tear it down. After the new install I will be searching for a tuner to help with the rest because one thing I am certain of is that I do not know nearly enough about the E92 and torque-based tuning, not to mention VVT, to tune this engine. I know somebody will ask, why not go the whole hog and just get the turbo's, the wiring harness, and everything else and just transplant the entire system into my Colorado? Answer: money. Anyone with experience tuning the E92 for V6 boosted performance is welcome to help!
    Last edited by Big_Bubba; 11-13-2019 at 02:08 PM.

  10. #10
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    Sorry to hear about your experience with the supercharger tuning, definitely not right. I'm Will at Overkill that does Vortech kits for Camaros and Cadillacs. Do you have an email address we can chat at, I have a few suggestions and thoughts.

  11. #11
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    Big Bubba. Thought I would chime in as i am I am working on lf3 swap myself. I did get a complete engine pull, but like you am looking into what companies support tunning a e92 ecu. I have been looking into getting a standalone harness for the LF3 engine and have someone tune the ecu to run as a standalone. ( I have the stock harness but that thing is a huge and I would prefer not to try to pair it down) I tried one company but they failed to deliver and am still looking for a company who works these engines. If you find anybody would you please post. Also if anyone has a e92 pinout diagram for a lf3 engine they are willing to share that would be greatly appreciated.

  12. #12
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    Just adding to the mix here.. I'm swapping an LF3 into a Fiero however will be going single turbo layout similar to the LP9.

    A few facts and directions I've taken based on what i've learned thus far.

    The LF4 ATSV manual setup can be run in standalone mode with only the ECM, FPCM, and Fan Controller. The LF3 would require the BCM.

    Went with an ATS-V LF4 manual harness and ECU. It's 99.5% the same layout and mates to the LF3 with almost no modifications other than a few extentions I needed for my layout.

    LF3 and LF4 are more or less the exact same engine sans oil pan, turbo sizes, and titanium connecting rods.

    If you want a pinout or wiring diagrams for the LF3 or LF4 sign up for Mitchell DIY... The wiring diagrams in the FSM for both LF3 and LF4 are next to worthless for any major work.. pay for the DIY subscription or find someone who has to get the wiring diagrams.

    As I work through the wiring fun I noticed in HPTuners for the LF4 hpt file that it has the option for none, single turbo, and twin turbo. I assume this is for the 2.0L turbo ATS.

    Does anyone at HpTuners have any knowledge of the impact of flipping this to single turbo? Does it enable only one of the MAFs and two of the O2 sensors and one of the boost control solenoids, etc..etc..??

    dgbb, was the company that failed to deliver based out of Michigan, Alpha Fab Motorsports?

    BTW, for anyone interested, I have the turbos from my LF3 setup that I will not be utilizing..
    Last edited by mweldon; 12-11-2019 at 02:31 PM.

  13. #13
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    So, my plans to use the LF3 block and heads have gone out the window. There are way too many differences in the external mounting points, i.e. welded bosses, additional bosses on the LF3 block, heads, and timing chain cover where there are none on the LFX, etc. I have torn both engines down and the internals are interchangeable so that is the route I will take. I cannot use the LF3 heads but I can use the camshafts and the rest of the head internals. I plan to use the LF3 tune as a starting point to develop a custom tune for my converted LFX. The compression ratio will be lowered to 10.2:1 as it is on the LF3.

  14. #14
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    mweldon...thanks for sharing....I will sign up for Mitchell DIY the wiring diagram....funny I almost chose a fiero for the chassis as well...but finally decided to do a c4 corvette...What transmission are you running in your fiero setup?

    You nailed it right on the head...Alpha Fab did fail to deliver....had to go through the credit card to get the money back too (i have to hand it to them they can really make some great excuses I almost thought I was going to get the dog ate the wiring harness excuse:-), really not a fun experience....sounds like you had some experience with them that was along the same lines.

    I also looked for other shops who might do the work...swap specialties.com..said they can do it, but after reading their reviews I get the feeling they are about the same as alpha fab....I was hoping to for a standalone option but I may have to do more wiring work than I wanted too. t

    hanks again for sharing...

  15. #15
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    Quote Originally Posted by dgbb View Post
    mweldon...thanks for sharing....I will sign up for Mitchell DIY the wiring diagram....funny I almost chose a fiero for the chassis as well...but finally decided to do a c4 corvette...What transmission are you running in your fiero setup?

    You nailed it right on the head...Alpha Fab did fail to deliver....had to go through the credit card to get the money back too (i have to hand it to them they can really make some great excuses I almost thought I was going to get the dog ate the wiring harness excuse:-), really not a fun experience....sounds like you had some experience with them that was along the same lines.

    I also looked for other shops who might do the work...swap specialties.com..said they can do it, but after reading their reviews I get the feeling they are about the same as alpha fab....I was hoping to for a standalone option but I may have to do more wiring work than I wanted too. t

    hanks again for sharing...

    yes I went with AlphaFab Industries/Motorsports and got totally burned too.. and heard every excuse in the book... they wouldn't even return my XTS-V E92 ECU either after 'agreeing' to return the money, which never happened.... they even said that their squaretrade account wouldn't let them return funding due to it being over 90 days since purchase LOL! They even use the 'Veteran owned business' line to invoke some trust up front from potential customers... what a bunch of schlubs…

    dgbb, we should definitely keep in touch as it looks like we will be knocking down the same doors. I'm running an F40 6speed transverse with the GM global pattern bellhousing and spec aluminum flywheel and stage 3+ clutch (not my first choice for a clutch but ClutchNet took my money and never delivered, had to go through bank to get money back, spoke with 3 companies about a custom setup and only RAM clutches accepted, great guys there, they had everything drawn up for a twin disc setup with anti rattle fingers, etc..etc... would hold 700hp but the input shaft on the F40 isn't long enough

    Unfortunately there is no cost effective standalone option out there given the direct injection nature of the engine. I spoke with Haltech directly and they will 'eventually' support DI but it's not in their future anytime soon..... maybe MOTEC but you'd spend 3 times the cost having someone do it for you... I'll report back here with my findings with my setup....currently taking a break from the electrical and fabbing engine/transmission mounts..

    M
    Last edited by mweldon; 01-28-2020 at 08:33 PM.

  16. #16
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    Yeah the standalone options are slim to none....sounds like alphafab runs the same scam on everyone. They keep my ecu as as well and also pulled the "veteran owned BS" as well....i was succesfull in getting the credit card to refund my money, alphafab lost big time in the dispute....the funny thing is they put more effort into making excuses than harnesses.

    From what i found out motec does support the 3.6l gm highbfeature engine family, specfically the llt. They have a file on there website with a base map for the llt. The m142 ecu seems to work and you would need the grp-di version which is pricey. You can download there software and base map for free if you want to take a look.

    My orginal plan was to run the 8 speed auto that came with the car. I got the engine and trans as a complete pull. If in go motec i will have to do a standalone for the transmission. i figured out tci does a bellhousing adapter for the lf1 lf3 lf4 lfx type engines to a 6l80e.

    Like you i am doing other things while i figured out the wiring. I was thinking of talking to companies that do lfx swap harness to see if they would do a lf3. I really would like to find a reputable company to do the harness. thanks again for sharing.

  17. #17
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    Quote Originally Posted by dgbb View Post
    Yeah the standalone options are slim to none....sounds like alphafab runs the same scam on everyone. They keep my ecu as as well and also pulled the "veteran owned BS" as well....i was succesfull in getting the credit card to refund my money, alphafab lost big time in the dispute....the funny thing is they put more effort into making excuses than harnesses.

    From what i found out motec does support the 3.6l gm highbfeature engine family, specfically the llt. They have a file on there website with a base map for the llt. The m142 ecu seems to work and you would need the grp-di version which is pricey. You can download there software and base map for free if you want to take a look.

    My orginal plan was to run the 8 speed auto that came with the car. I got the engine and trans as a complete pull. If in go motec i will have to do a standalone for the transmission. i figured out tci does a bellhousing adapter for the lf1 lf3 lf4 lfx type engines to a 6l80e.

    Like you i am doing other things while i figured out the wiring. I was thinking of talking to companies that do lfx swap harness to see if they would do a lf3. I really would like to find a reputable company to do the harness. thanks again for sharing.
    What's keeping you from using the stock harness with stock E92 ECU and TCM? I'm essentially turning my Fiero into an ATS-V with as few modules as possible running.