Mean Green z28

iTrader: (19)

What are you guys with forced induction doing for fuel pumps when an upgrade is needed? Is there a drop in pump option that would work with my truck?

Do our pumps work PWM by the FPCM or using voltage regulation? Anyone with experience tuning such a setup please chime in.

Thanks in advance

gravedigger472

Depends on a lot. Myself and a lot of others who have the factory flex fuel pump make good power on a stock pump. I made 500 hp at the wheels on a factory flex fuel pump. (on gasonline of course. If you want to run E85 and forced induction, forget it)

Depending on who you ask, 550whp is somewhat near the limit of the FF pump.

The factory pumps are PWM controlled by the FPCM.

Pretty sure you cannot tune the FPCM.

A few members on here have upgraded to a Walbro 450 and kept pulsewidth modulation control successfully, but the pump is not a drop in upgrade. It takes some fiddling and modification to retain the bypass and venturi tube that fills the pump bucket.

gravedigger472

check out
https://www.performancetrucks.net/fo...ogress-536284/

Also, member Byrdman11 did the same thing, but took a little different approach.

Mean Green z28

iTrader: (19)

thanks guys! We're trying to figure out the tuning now, that's the hard part. My buddy has never tuned a E38 PCM before; but is a really good at the old LS1 setup. It's a slow process...

adunphy

I have been trying to come up with my own flavor of the walbro 450 returnless install in a non-Flex Fuel Long bed (34 gal tank). I am basically modifying the stock bucket and lid slightly. If I am successful I will be glad to write a detailed post on how I did it. I am determined to keep all the factory functionality intact such as the venturi system and pressure relief with stock o-ring and clip mount just in a different location.

I did also check with Walbro who sells a drop-in unit for my 2007 (PN# TU464) but apparently that is only a 190 LPH pump and can only support up to around 540 HP per the walbro tech I spoke with.

I would love nothing more than a drop-in that can support ~700 HP but I've yet to find one.

0235SS93

iTrader: (1)

I put a 450 in the stock bucket in like an hour, including pulling the bed. Works perfect. Haven't dyno'd yet, but I'm at 11psi on e55 with fuel to spare.

Mean Green z28

iTrader: (19)

Thanks guys. I'm all about doing things to be drop-in/reversible whenever I can. Would love to see a step-by-step guide if you do it.
The last guy who did the drop in 450 didn't really detail what he did.

SLCviaAK

For tuning wise for the FPCM, i read some where that you can swap in the tuning of an '09 CTS-V FPCM parameters. Just food for thought

05GMC4.8

where did you read that? did they take a spare module to a dealer and have them reprogram it?

0235SS93

iTrader: (1)

Yes, I was the one that figured it out and posted on a few different forums. The key is that the stock 5.3 fpcm sometimes doesnt accept a cts-v vin. Here is what i found to work and this is the only way.
Buy the fpcm for a 2009 Sierra Denali, i can get the part number off mine
Have a dealer or capable shop program a 2009 cts v vin into the module
compare your tune file to a 2009 cts v file. Under the fuel system tab in hpt, copy and paste everything different. then go under the system and voltage tab and copy the fuel system min voltage table.
now, the 09 cts v has the low flow pressure set to 36psi. however, all 2010-up cts have this set to 50psi. Its ok to go ahead and change this to 50.8 psi.
Now your truck will use the calculations and fuel pressure sensor to "crank the pump up" under higher flow conditions. This wont hurt anything or affect the tune as the ecm will adjust pulse width by fuel pressure.

This will take you a little farther. Once the stock pump is run out, tear apart the fuel pump bucket and put a walbro 450 in it.

My truck has this done with a walbro 450 in an absolutely otherwise stock fuel system, and i have 50-60 psi cruising and moderate throttle, then 70-80psi once boost starts really coming on. The increase in pressure is nice as it makes your injectors run bigger. I have 2013 ford mustang gt500 injectors and i havent hit injector or pump limit yet experimenting with 12psi of boost up to 65% ethanol fuel. Working towards full e85 and a maximum of 14psi boost