How big an intank pump have people run on TBI cars and the stock TBI fuel pressure regulator could keep up?

I just picked up a TBI car that needs the fuel level sender replaced, and eventually, I want to make some real HP with it and am thinking, "while I'm in there I should swap the pump." I have a GSS340 and a 450LPH which would be MUCH more appropriate for what I eventually want to do with this car, but I have no idea if the TBI regulator can bypass enough fuel to regulate those down to TBI pressures.

 

I know of multiple folks, including myself that ran the Walbro 255 for years without issue.

 

I ran a 255 in my Van as well, but also ran a 30 psi regulator. Never tried to regulate the 255 down to ~13 psi.

 

I have used the Vortec ('96-'98 Chevy Silverado) pump on a few cars, including my own with zero problems. But if you want to make BIG power, then you should probably get something with a higher flow rating, and upgrade the wiring while you are at it.

Are you planning on making "big power" with the factory TBI unit? Can you elaborate on your plans?

 

My 97 van has a Delphi replacement pump and a Racetronix hotwire kit. It holds a perfect 58 psi fuel pressure at about 500 hp at the crank on E85. The Vortec pumps move a ton of fuel if the wiring is upgraded.

 

Thanks, guys, I figured as much since the diaphragm + passages are similar sized to the stock ones on the TPI and LT1 cars, I just wanted to make sure I didn't cause myself any stupid problems.

 

LOL, this isn't either of my 3rd gen projects. What's considered "big" power in the TBI world?

I just picked up a '93 Fleetwood Brougham with a L05 with 55K miles on it, I'm selling my newer SHO because it's becoming too needy and this will sort of be my daily (well plus my Cummins ram and I can drive things like my TA on nice days). Since it's replacing my SHO I want something with similar performance, which means I'll need to get it solidly into the 12's, and I've had a few TBI cars before (the ones that I messed with the most was my original '83 Crossfire TA and my '92 K1500 Blazer with an L05), so I somewhat know what I'm getting into.

I'm thinking heads (haven't decided what yet, I have a few in my basement that will work but I'm debating buying something, I wish I could find better specs for the '93 Cadillac L05, I know that it's got a roller cam and 64cc swirlports on it, but I don't know the stock compression or what the cam is like), a mild cam (I'm tempted to go bigger than most would in this combination of engine and chassis, again, I have a few choices sitting in the basement I'm considering), headers and dual exhaust, I'll probably do something with larger injectors/higher fuel pressure, I think I have a 454 throttle body in a box somewhere. I've never been all that comfortable with the GM ECM programming that I've done but I have had MUCH better luck with Megasquirt and have a few extra laying around (also curious about speeduino). Higher stall converter, not sure about gears...

Then see what I have. If it's not fast enough I have a set of headers that I've welded up for another project and a very appropriately sized turbo that would surely prove interesting. In that case I've had some thoughts about how to make that work with a TBI (TBI does have some advantage that the fuel in the intake does do some intercooling), and if I just can't make the numbers work I have a few small block manifolds with injector bungs, and just to be difficult I'd slap the TBI on one of those and then use the dual staged fuel maps features in MS to control a second set of injectors under boost... or something 😎

 

AC Delco EP241 for a mild setup and an AC Delco ep381 for something more wild. Both are direct bolt ins and work great

 

What kind of power are you making with TBI setup that you need such a large pump? I use TRE 255lph pump with my 383 and works just fine to feed the beast, currently at 30psi. Also, the TRE pumps are whisper quiet than ANY Walbro pump.
TRE PUMP

 

4400 lbs? Sounds like he's going to need about 500hp to get solidly into the 12's. At least 450 horse, IMO. I don't think heads, mild cam,TB and exhaust are going to get that done.

 

The math works out to about 372hp, and I've pushed a 4300# car to a 13.03@103 with 361hp, so it should be close. I've consistently gotten 360-365ph out of stock LT1's with only external mods, not even pulling the valve covers, so that should be possible with something that breaths like an LT1/vortec head and a mild cam with the rest of the package optimized.

And if that doesn't make me happy I'll probably pick something from this shelf or the next one:

 

FWIW, pre screwing with it:

The pump I pulled out of my pile of parts (an Edelbrock 3581 which is just a rebadged GSS340):


The abortion that I pulled out of the tank... no **** that the fuel gauge wasn't working. The guy that I bought the car from had literally thousands of dollars worth of receipts for work that was done this spring to get it on the road and through a PA safety inspection, so far ALL of it that I've looked at has been about this quality:


Big pump fitted to the factory replacement hanger/sender so it fits in the tank baffles:


And at idle with the engine running... dum dum dum... the regulator will only regulate it to 2psi more... yep, it's running rich at 16psi: