The LFX is an excellent high efficiency design and in a Fiero swap gives over twice the horsepower of the 2.8L. If you purchase a wrecked Impala or Lacrosse with reasonable miles on it, you'll have almost everything needed for a swap. With the addition of the AEM series 2 ECU to run the engine and a PCS TCM 2650 transmission controller to shift the 6T70 transmission everything should run fine . Wth proper oil changes and maintenance this combo should run well for many thousands of miles. As for previous info, at this point I do not believe that the OEM PCM can be programmed to run stand alone. That was false info that I gut from someone else. It should be noted that this swap has been done before on other vehicles but the Fiero swap from a few members here seems to be in the works.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
One of the things I have learned thru my research of the LFX engine is that, according to the GM Service Manual, a Fuel Pump flow Control Module (FPCM) is used to control the electric in-tank fuel pump via a PWM output which varies the in-tank fuel pump speed (and output pressure) according to engine load demands and fuel pressure sensor feedback. The FPCM communicates with the ECM over the high speed GMLAN (CAN) data bus. The fuel pressure sensor the FPCM uses is located somewhere in the fuel line between the tank and the engine; and this is a sensor separate from the one mounted on the fuel rail that connects to the ECM.
The service manual information states that GM replaced the old mechanical fuel pressure regulator with this “electronic” fuel pressure regulation method, although there is still a fuel pressure relief regulator valve inside the fuel pump (or tank) to prevent an over-pressure condition. The service manual does not specify the exact pressure this mechanical relief valves opens at; however, it does say the fuel pressure from the in-tank pump should be between 50-100 psi (possibly operating between 72-87 psi). The fuel pressure at the engine fuel rail should operate between 279-305psi – but this higher pressure is produced by the mechanical direct injection pump.
Looking at the diagnostic information, it appears the ECM takes no action for FPCM problems aside from just setting codes (which I can disable in a custom tune). This suggests it might be possible to omit the FPCM from a swap and the engine may run fine without it, assuming whatever fuel pump used provides enough pressure and flow for the engine to operate.
If one chooses to omit the FPCM, I would recommend trying to use a Corvette fuel filter that has the fuel pressure regulator integral to it and see if that works - along with an aftermarket performance 255lph high pressure in-tank pump. Even if someone doing this swap was going to use the FPCM, I would still recommend using some kind of high pressure relief regulator if an OEM LFX fuel pump assembly is not going to be used.
The pictures I’ve seen of the factory in-tank fuel pump for a few LFX vehicles make the pump appear too large to fit in the opening at the top of the Fiero fuel tank. So it probably won't be possible to use an OEM LFX in-tank fuel pump in a Fiero fuel tank (without significantly modifying the Fiero fuel tank).
------------------ More is more. Less is not enough. Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com
[This message has been edited by Darth Fiero (edited 12-04-2018).]
One of the things I have learned thru my research of the LFX engine is that, according to the GM Service Manual, a Fuel Pump flow Control Module (FPCM) is used to control the electric in-tank fuel pump via a PWM output which varies the in-tank fuel pump speed (and output pressure) according to engine load demands and fuel pressure sensor feedback. The FPCM communicates with the ECM over the high speed GMLAN (CAN) data bus. The fuel pressure sensor the FPCM uses is located somewhere in the fuel line between the tank and the engine; and this is a sensor separate from the one mounted on the fuel rail that connects to the ECM.
The service manual information states that GM replaced the old mechanical fuel pressure regulator with this “electronic” fuel pressure regulation method, although there is still a fuel pressure relief regulator valve inside the fuel pump (or tank) to prevent an over-pressure condition. The service manual does not specify the exact pressure this mechanical relief valves opens at; however, it does say the fuel pressure from the in-tank pump should be between 50-100 psi (possibly operating between 72-87 psi). The fuel pressure at the engine fuel rail should operate between 279-305psi – but this higher pressure is produced by the mechanical direct injection pump.
Looking at the diagnostic information, it appears the ECM takes no action for FPCM problems aside from just setting codes (which I can disable in a custom tune). This suggests it might be possible to omit the FPCM from a swap and the engine may run fine without it, assuming whatever fuel pump used provides enough pressure and flow for the engine to operate.
If one chooses to omit the FPCM, I would recommend trying to use a Corvette fuel filter that has the fuel pressure regulator integral to it and see if that works - along with an aftermarket performance 255lph high pressure in-tank pump. Even if someone doing this swap was going to use the FPCM, I would still recommend using some kind of high pressure relief regulator if an OEM LFX fuel pump assembly is not going to be used.
The pictures I’ve seen of the factory in-tank fuel pump for a few LFX vehicles make the pump appear too large to fit in the opening at the top of the Fiero fuel tank. So it probably won't be possible to use an OEM LFX in-tank fuel pump in a Fiero fuel tank (without significantly modifying the Fiero fuel tank).
Great info. I am constantly researching the requirements for an LFX swap too and have been corresponding with a guy who has done this swap in other cars. He indicated that he does use an in tank pump along with the engine mounted fuel pump but he didn't mention the FPCM and how he gets the proper PWM signal to it. My opinion is that if the Corvette fuel filter regulator unit is used you would only have a controlled 43.7 psi from the tank pump. If I am not mistaken the engine feed for the LFX is 60 psi to the engine. As above the guy is using the AEM stage 2 ECU so I would say a call to them may supply an answer. We do know that this ECU can control VVT and DOD On my opinion of using the factory PCM; being that its a CAN computer, on a stand alone application you would not have the ABS, BCM, instrumentation, or traction control inputs There would be so many other inputs missing on the CAN bus that it would be unlikely that closed loop operation would be possible, but having never tried this swap yet I cannot say. There is an answer as many LFX swaps has been done but not in a Fiero as yet. When we have a successful LFX swap formula, this engine may be the logical choice to upgrade the Fiero to modern specs. Up to 325 HP stock with 150 lbs less weight than a 3800SC would make for a very fast and economical car.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
My opinion is that if the Corvette fuel filter regulator unit is used you would only have a controlled 43.7 psi from the tank pump. If I am not mistaken the engine feed for the LFX is 60 psi to the engine.
According to the GM service manual, the Corvette fuel filter w/ integral regulator has a pressure setting of 55-60 psi.
On my opinion of using the factory PCM; being that its a CAN computer, on a stand alone application you would not have the ABS, BCM, instrumentation, or traction control inputs There would be so many other inputs missing on the CAN bus that it would be unlikely that closed loop operation would be possible, but having never tried this swap yet I cannot say.
I've done two LS4 swaps to date - both using factory CAN computers. And the ECM's don't care if the ABS, BCM, IPC, or other modules aren't present on the high speed GMLAN data bus - aside from setting a few insignificant trouble codes. The last LS4 swap I did used a 2008 ECM and TCM with no other modules whatsoever from the donor car present - and it ran fine (operated in closed loop, no problem).
Based on this, I suspect an LFX ECM isn't going to care if those other modules are missing either. The only thing that is a question right now is the FPCM issue.
I've done two LS4 swaps to date - both using factory CAN computers. And the ECM's don't care if the ABS, BCM, IPC, or other modules aren't present on the high speed GMLAN data bus - aside from setting a few insignificant trouble codes. The last LS4 swap I did used a 2008 ECM and TCM with no other modules whatsoever from the donor car present - and it ran fine (operated in closed loop, no problem).
Based on this, I suspect an LFX ECM isn't going to care if those other modules are missing either. The only thing that is a question right now is the FPCM issue.
Unless you use the donor car gauge pod But jokes aside, I think you may be right..for the most part. I am not a technician, but my 2006 LS4 ran fine with a few of the modules disconnected or "unpaired". The smog referee made me reflash all of the modules with the same factory VIN# (for some reason) but had NOTHING to do with how it ran. But I have no idea how the system would run if for example the automatic transmission were swapped for a manual and the TCM were left out of the loop. My guess is that it would not run properly and TDC would be unavoidable. As far as PCM voodoo,......I am out of the game.
I'm still not finished my swap but a quick summary: I'll be using the OEM ECU as a stand alone and a Corvette filter/regulator with a non-PCM fuel pump. Weight of the ready-to-run LFX (starter, alt, wiring, clutch, etc) with an F23 is 498 lbs. The LX9/282 weighed 526 lbs when I pulled it out.
[This message has been edited by mender (edited 12-05-2018).]
I'm still not finished my swap but a quick summary: I'll be using the OEM ECU as a stand alone and a Corvette filter/regulator with a non-PCM fuel pump. Weight of the ready-to-run LFX (starter, alt, wiring, clutch, etc) with an F23 is 498 lbs. The LX9/282 weighed 526 lbs when I pulled it out.
Swapping from an automatic transmission to a manual will be lighter. The Fiero 3 speed auto is the lightest, then the 4T60 is a big jump up in weight. For example the 4t80 weighs about as much as the engine. I don't know what the new automatics weigh? But I bet they are still heavy.
[This message has been edited by Rickady88GT (edited 12-05-2018).]
Sorry, meant 150 lbs with the steel flywheel. 112 lbs for the F23 and 35 lbs for clutch and flywheel package = 147 lbs. The aluminum flywheel takes about 10 lbs off that.
[This message has been edited by mender (edited 12-05-2018).]
I've done two LS4 swaps to date - both using factory CAN computers. And the ECM's don't care if the ABS, BCM, IPC, or other modules aren't present on the high speed GMLAN data bus - aside from setting a few insignificant trouble codes. The last LS4 swap I did used a 2008 ECM and TCM with no other modules whatsoever from the donor car present - and it ran fine (operated in closed loop, no problem).
Based on this, I suspect an LFX ECM isn't going to care if those other modules are missing either. The only thing that is a question right now is the FPCM issue.
Great that you had good results with the factory PCM's for the LS4 engines but I am advised by a guy that did the later LFX swaps that he could not get the oem PCMs to control the engine.( just one persons opinion) I obviously cannot say what will result with a reprogrammed LFX PCM but there is a guy on the HP Tuners Forum that had success putting this engine and running it in a Miata. He did omit many items normally seen on the CAN bus. Claims engine ran well so its possible he just used a reprogrammed PCM, standard in tank pump and just omitted FPCM and the LFX pump.. The internal engine pump controls the fuel pressure with RPM's so perhaps an adjustable standard regulator for the in tank pump is the answer but the pump must put out about 63 psi. .
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Sorry, meant 150 lbs with the steel flywheel. 112 lbs for the F23 and 35 lbs for clutch and flywheel package = 147 lbs. The aluminum flywheel takes about 10 lbs off that.
You freaked me out, I thought you had a "heavy" duty trans.
[This message has been edited by Rickady88GT (edited 12-06-2018).]
Great that you had good results with the factory PCM's for the LS4 engines but I am advised by a guy that did the later LFX swaps that he could not get the oem PCMs to control the engine.( just one persons opinion) ...
There were several PCMs used for the LFX. There was a Delphi version and a Bosch version. General consensus is that the Bosch PCMs are pretty much useless for tweaking, while the Delphi work just fine. That might be what you are hearing about.
This is all from memory, from a thread I read on one of the Camaro forums.
Edit - Changed Delco to Delphi
[This message has been edited by Raydar (edited 12-28-2018).]
Great that you had good results with the factory PCM's for the LS4 engines but I am advised by a guy that did the later LFX swaps that he could not get the oem PCMs to control the engine.( just one persons opinion) I obviously cannot say what will result with a reprogrammed LFX PCM but there is a guy on the HP Tuners Forum that had success putting this engine and running it in a Miata. He did omit many items normally seen on the CAN bus. Claims engine ran well so its possible he just used a reprogrammed PCM, standard in tank pump and just omitted FPCM and the LFX pump.. The internal engine pump controls the fuel pressure with RPM's so perhaps an adjustable standard regulator for the in tank pump is the answer but the pump must put out about 63 psi. .
I guess I'm missing something in your statement. Did the first guy that attempted the LFX swap try to do it with an stock programmed ECM? If so, I have no doubt he would have issues getting that setup to work in a swap application unless he at least transferred the BCM and VTD modules from the donor car into his swap.
The FPCM question aside, the LFX ECM shouldn't need any other modules present on the GMLAN bus to communicate with in order for it to work in a swap application as long as it is custom tuned. That is if you are running a manual trans and are using a factory manual trans based tune in the ECM. If you are using an auto trans based tune in the ECM, then it might need to be able to communicate with a TCM in order to prevent a reduced engine power mode from being implemented.
There were several PCMs used for the LFX. There was a Delco version and a Bosch version. General consensus is that the Bosch PCMs are pretty much useless for tweaking, while the Delco work just fine. That might be what you are hearing about.
This is all from memory, from a thread I read on one of the Camaro forums.
To the best of my knowledge all 3.6L engine management switched to Delphi PCM control along with the introduction of the LFX in 2012. The bulk of the complaints I gathered regarding tuning was when boost was applied, as a fair degree of tuning has taken place in all of the popular boosted GM platforms (Cobalt, Solstice) although with smaller engines that were managed by BOSCH PCMs. The trouble was sparking enough interest in developing programming software for it. The Camaro came aboard in 2010 to help open the door, but before a good foot hold was developed GM switched to the easier to understand and manage Delphi PCM so there is still a lag in tuning experience with it but, it is much better now than it once was.
Initially FPCM was not used for the direct injected V6 and apparently started around 2010.
[This message has been edited by Joseph Upson (edited 12-07-2018).]
I guess I'm missing something in your statement. Did the first guy that attempted the LFX swap try to do it with an stock programmed ECM? If so, I have no doubt he would have issues getting that setup to work in a swap application unless he at least transferred the BCM and VTD modules from the donor car into his swap.
The FPCM question aside, the LFX ECM shouldn't need any other modules present on the GMLAN bus to communicate with in order for it to work in a swap application as long as it is custom tuned. That is if you are running a manual trans and are using a factory manual trans based tune in the ECM. If you are using an auto trans based tune in the ECM, then it might need to be able to communicate with a TCM in order to prevent a reduced engine power mode from being implemented.
It should be noted that I am passing on second hand info gathered from communicating with folks who are involved with LFX swaps so the info might not be 100% correct. I would say the hobbyist trying trial and error methods is who is suplying most of this info. The first guy that I spoke attempted this swap tried to use the OEM PCM with an automatic for an RWD application and experienced problems. Then I came across a You Tube video by a pro that calls himself SwapTime who regularly does LFX swaps. He shows what he did in the videos but is a bit shy about sharing info. Apparently he has completed quite a few of these swaps. There is also a guy on HP Tuner forum that has done successful LFX swaps in the Miata. Info is hard to find but since you are involved in this swap, I'm sure that you will share the experience. .
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 12-10-2018).]
Info is hard to find but since you are involved in this swap, I'm sure that you will share the experience. .
I will be happy to share whatever I learn on this forum. However, my "involvement" in Daryl's swap project is going to be limited to what I can do from a distance.
Sorry, meant 150 lbs with the steel flywheel. 112 lbs for the F23 and 35 lbs for clutch and flywheel package = 147 lbs. The aluminum flywheel takes about 10 lbs off that.
You can knock another 20+ lbs off that by going back to a 282. I have at least one Quad 4/HTOB box in my stash.
F23's have the same ratios as the V6 282's, except for the Saturn Vue box, which has 0.81 fifth. The Quad 4 282's frequently have the 3.94 final, just like the 2.4 F23's do. Some of the Quad 4 boxes even have a 0.81 fifth (although I don't think GM ever used both 0.81 and 3.94 in the same gearbox in any US product) Rodney Dickman makes urethane mounts and heavy duty brackets that bolt in.
I can't argue better shifting, but the 282's are not at all bad in that characteristic.
Come on, take this gearbox outta my shed
[This message has been edited by Will (edited 12-12-2018).]
Mender, why did you decide on the F23 over the F40?
I have a new 2006 F40 from a G6 (60 degree) but that was going to be used with a 3800SC.
The rules of my racing class changed and so did my plans, to using the LFX instead. The cost difference between a Saab F40 and the Quad4 F23 up here, the ability to use the stock Fiero axles, less weight than the F40 (only need five gears), gear ratios, and the ability to use a 60 degree F23 with the LX9 as a mockup and jig for mounts were the main reasons.
I've done two LS4 swaps to date - both using factory CAN computers. And the ECM's don't care if the ABS, BCM, IPC, or other modules aren't present on the high speed GMLAN data bus - aside from setting a few insignificant trouble codes. The last LS4 swap I did used a 2008 ECM and TCM with no other modules whatsoever from the donor car present - and it ran fine (operated in closed loop, no problem).
Based on this, I suspect an LFX ECM isn't going to care if those other modules are missing either. The only thing that is a question right now is the FPCM issue.
Just got word from a guy that did an LFX swap in a Miata. He advised that he could not get the stock PCM to work. He used a Bosch e9 (not e9a) PCM and put the Camaro code in. He did have TCM and ABS.control. (believe the Miata has wheel speed sensors) Maybe you can get the LFX GM PCM to work but I have not found anyone so far who has. The guy that you have been working with is undoubtedly blazing new trails but we can't keep doing 3800SC swaps forever. IMO, time for a new technology engine swap in the Fiero.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I just decided on how I was going to handle the VSS issue. Using a magnetic pickup on the intermediate axle shaft. Unfortunately we won't have an answer on if it all works for a while yet. Lots of work to be done before I am at the point where test drives start. Since I acquired my 88 as a project in progress, I plan on tearing everything down and starting from scratch. I found several things that were cobbled together. Don't want to tak a chance on trusting other peoples work. If I die from bad design or workmanship, I want it to at least be my own.
F23's have the same ratios as the V6 282's, except for the Saturn Vue box, which has 0.81 fifth. The Quad 4 282's frequently have the 3.94 final, just like the 2.4 F23's do. Some of the Quad 4 boxes even have a 0.81 fifth (although I don't think GM ever used both 0.81 and 3.94 in the same gearbox in any US product) Rodney Dickman makes urethane mounts and heavy duty brackets that bolt in.
I can't argue better shifting, but the 282's are not at all bad in that characteristic.
Come on, take this gearbox outta my shed
The main difference in gearing is the 3rd to 4th split, pretty important for road course racing as I use them the most. Some tracks I only use those two gears.
282 is 1.38 to 0.94; F23 is 1.35 to 0.98. Shifting at 6500 rpm (LFX) with the 282 would be a recovery rpm of 4421 rpm; F23 will be 4744 rpm, so 10% higher rpm. About 180 hp vs 200 hp.
I'm keeping an eye out for a Vue F23; even with the short fifth and 4.41 final, that still allows about 145 mph at 7000 rpm.
[This message has been edited by mender (edited 12-27-2018).]
The main difference in gearing is the 3rd to 4th split, pretty important for road course racing as I use them the most. Some tracks I only use those two gears.
282 is 1.38 to 0.94; F23 is 1.35 to 0.98. Shifting at 6500 rpm (LFX) with the 282 would be a recovery rpm of 4421 rpm; F23 will be 4744 rpm, so 10% higher rpm. About 180 hp vs 200 hp.
I'm keeping an eye out for a Vue F23; even with the short fifth and 4.41 final, that still allows about 145 mph at 7000 rpm.
Don't forget there's a 1.02 fourth AND a 0.81 fifth available for the 282
