1: Is the GT500 fuel pump hat/bucket assembly a drop in unit into a 19 GT?
It drops into the drivers side. You only have to cap off one of the venturi lines.
Just the drivers side unless you want to replicate the gt500 passenger side setup.
Iām not convinced thereās a higher capacity brushed pump than the dw400, once you account for the check valve and venturi. The stock gen3/gt500 are very close behind in flow but much more efficient.
Gt500 fuel line, to get the filter setup, gt500 bucket, wiring/connectors, and tuning software and hardware.
I doubt it.
For 850 whp on e85 Iād just run a single dw400 at 20-22 volts. Very simple and low cost.
The jms 22 volt units will lower the voltage at low demand. The factory fuel pump control will lower it even more, as low as 1 volt in some cases.
So I take it the BAP takes a signal control Input from the stock fuel pump harness to do this?.
On a regular non-variable 18v BAP, the BAP simply boost voltage feeding the FPDM. The FPDM is the PWM controller that can cut the voltage down. The only issue here is that the max and mins may need adjustment in the tune and most tuners don't bother. The 22v BAPs can usually or ramp between high and low voltage as a function of boost, pedal, or even the stock PWM signal (JMS EZ version). In these, you really have both the FPDM and the PCM ramping voltage up and down to the pump. Again, the issues here are the tune really needs to be set up to make sure you're getting the full range.
The factory FPDM performs diagnostics on the pump and there are something like 3-4 possible faults it can communicate back to the PCM. I don't know if this triggers a limp mode. However, on my own car, I actually ran 39# injectors on E85 and confirmed it will cut the throttle when it runs out of injector, and and the injector pulsewidth increases if fuel pressure falls. So basically, at least what my own tests indicate, if my fuel pump fails and it doesn't go into limp, it will shut the throttle anyway due running out of available pulsewidth. Another protection that most tuners neglect, is that you can pull timing when it goes lean.
Hey Mike. Does anyone make a BAP or equivalent which varies pump volts accordingly to fuel demand so the pump doesn't run at 18vdc all of the time?
Yes thatās what I was describing in the first part of post 68. The jms 22v has a number of inputs, with one being pedal position, and will ramp voltage up and down. The jms ez version ramp up and down with fuel pump commanded duty cycle and it works pretty well. However, with the stock fpdm doing its thing, thereās not much reason to ramp voltage down since thatās what the fpdm does.
I heard some tuners don't like pedal demand switches. I would prefer one that takes its signal from a taco wire and vary in accordance with RPM. Also, with a BAP installed, is it the soul source of voltage to the pump or does it add voltage above 12vdc?
I'm not a big fan either but mine has worked so far. If I could do it over again I would probably do the EZ BAP now that my friend has proven it works.
RPM doesn't dictate fuel demand. The FPDM duty cycle does, which is why the EZ version works well.
In order to add voltage it has to be in series. The BAP is basically an inverter, step-up transformer, then rectifier. That's the only way to increase DC voltage.
Let me research the JMS Fuelmax EZ, if that is what your talking about?. Running your fuel pump(s) on demand would be more efficient and extend pump life.
Yes
Thatās what I like so much about factory own control. Bap or no bap it turns the voltage way down when it isnāt needed, as low as 1 volt. It just has to be tuned right.
I read some info on it and like what I see. It does what I am wanting with regard to a voltage booster, but a fully controllable one. I will email JMS and ask specific questions as to its function and capability.