LSA Transplant Question
 

For those who utilized and LSA from a production car (versus crate), did you utilize the OE PCM and thus the PWM control for the fuel pump?

I am planning out what I would need to do if I bought a takeout LSA, and tried to use as many OE components as possible (opposed to say a Vapor Worx).

In advance, thanks.

Tim

Lots of chatter about he stock PWM controlling the pump, as I believe it needs the BCM to work correctly. I searched extensively for a solution, but got burnt out trying to find one....finally pulled the trigger on a Vaporworxs setup. It has worked flawlessly.....

T,

I've used OEM FSCM (Fuel System Control Module) to control fuel pump in several builds.

Advantage: Vs VaporWorx is feedback of actual line pressure (which is then used for pulse-width calculations based on delta-P across injectors). So more accurate for fuel delivery.

Disadvantage: Carl can put together system with more capability - stock FSCM is current limited so can only handle so much electrical power which limits fuel flow capability. Since flow rate of injector change is square root of delta-P, even slight variation of actual pressure is not overly significant - especially for most applications not concerned about production level emission requirements.

Stock systems have various executions:
LSA CTS-V is PWM until commanded to 450 kPa - then runs straight voltage to pumps (there are 2 in CTS-V fuel pump module) due to current limitations of FSCM. Fuel pressure is then regulated by internal fuel pressure regulator in fuel pump sending unit.

LSA Camaro ZL1 is PWM over entire range of pressure control. Single pump in fuel sending unit. Commanded pressures same as CTS-V (250-450 kPa)

LS9 Corvette is PWM over entire range - but also adds 3-phase pump control module since pump is 3-phase. Also runs to higher fuel pressures than either LSA (250-600 kPa). This is primary reason anyone wanting to install LS9 into hot-rod needs larger injectors as controlling to 600 kPa (~90 psig) is very difficult - if you want to keep fuel pump temps and fuel temps in check.

Carl has done a wonderful job in executing a robust solution for controlling multiple pumps to cover broad range of fuel flow requirements on returnless system. I use VaporWorx exclusively now due to the simplicity, robustness
and reliability of PWM control over entire range of engine operation. Never thought controlling from 600 rpm idle on gas to 1200+ hp on E85 with same system could perform so flawlessly!

Dave

Thanks for the explanation Dave. I appreciate the time you spend in your replies!

Tim

Dave hit the nail squarely on the head. Thanks for putting it so eloquently.

It's been a great experience working with Dave and Mark on some very challenging builds. The large returnless fuel systems can be tough to make work well at low fuel demand. Like tuning, the WOT is easy, it's the idle, cruise, cold start, etc. that is tough. The bigger the pump, the harder it is to control. We have customers that are running three (yes three) TI450lph pumps on a fully returnless PWM system.

Another thing to consider is that the GM FSCM does need to be married to the ECM via a TECH2. Hence, if the FSCM need so to be replaced the car will need to go to the dealer to have the work done. The VaporWorx controller is stand alone.

Oh, and for those that might consider adapting the LS9 fuel pump and controller that Dave describes, the last time I checked it was $3k+ for parts. Replacing the injector is a much better option.

I believe we may see similar FSCM controller limited conditions on LT1/4 crate engines. Time will tell where the limits of the controller are, but GM is not one to put an excessive amount of overcapacity into such a system, and we're working with near 1000hp builds already.

Go with Vaporworks and you won’t have anymore fuel problems. My biggest issue over the years on Power Tour and other long drive events has been fuel pumps overheating. Since using Carl’s setup that is no longer a worry. My stress level has gone down. I guess I owe Carl a beer.

Considering what a rollback costs --- maybe even a short case..... LOL

Whats the consensus on filters?


From my understanding the CTS-V / ZL1 modules that uses a filter sock in the bucket. Is there a need for an additional filter?

Great input guys! Hell, I thought everyone was at SEMA but me!

Charlie, I'm buyin' ;-)

No filters are needed as long as good fuel lines are used. If all PTFE lines or a stainless hardline/PTFE flex are used there is no issue. When inexpensive elastomer lined hoses are used the chances of hose deterioration goes way up. There are instructions in the VaporWorx kit on how to flush the lines prior to final connection to the fuel rail. I've not run a downstream filter on the Camaro since 2009. Plus, it's really nice having all that stuff (regulators, filters, etc.) gone.