canbaufo

For years I've wanted to switch to a better (and intercooled) blower setup. Whether I do it or not I'd like to upgrade my fuel system, as it's the OEM-1994 in-tank pump and Powerdyne booster (even the booster has been there for a LONG time). I want the new fuel system to be QUIET, simple, and adequate for up to 10 PSI on my mild built 355. It makes 450 - 475 RWHP with the Powerdyne at 5 - 6 PSI so I would expect roughly 535 RWHP (625 flywheel) at 8 - 10 PSI intercooled.

I'm having trouble getting consistent data with regard to what's required when I do searches, so if anyone's ever used a single Walbro (or maybe TRE) 255 pump successfully at similar power levels please chime in.

I am hoping that the single 255 lph combined with a hotwire kit for adequate voltage (and maybe a volt blaster to boost the alternator to 14.5 volts at WOT) would be enough. This way if I have problems I'm only tracing them to one pump and I don't need to upgrade the fuel lines for dual 255's. Perhaps there's a better pump to use as a single?

Check out TRE's (have to scroll down for details about their own pump). Theirs is only $78 and has a 1-year warranty ..and they claim it's much quieter than the Walbro:

Real Walbro 255LPH High Pressure Flow Intank Fuel Pump | eBay

I never heard anyone say the Walbro was "noisy" ....has that been any of your experiences? I thought that was usually only an issue with booster pumps. My Powerdyne booster pump is sometimes noisy but not always ...weird.

Thanks in advance for any info provided. I am also hoping to stick with my 42# injectors.

Purple Poncho

I would say yes but you are at the limit of that setup. I would get the volt booster for sure and you might need bigger injectors. I bet with a little bigger injector you could get to 550rw.

Kevin Blown 95 TA

Your blower engine needs more fuel than a NA engine so it might fall on its face if you don't have enough fuel when you mat it (clue #1), but if it does that, you'll know pretty quick if you don't have enough gas unless it is just real borderline - in that case you will be tuning it trying to add fuel and nothing changes on the wideband, so that is clue #2. Also, I don't think you have enough injector for that power level.

"boost the alternator to 14.5 amps at WOT" - I think you mean volts here...

Let us know how it turns out.

canbaufo

haha yes I meant volts of course. Well, one thing I've learned is not to take chances. Sounds like it's not really a sufficient setup, or at least not "plenty sufficient" which is what I'd like. I already suspect there's an issue with my current setup, as it seems to run a tad lean at high revs in spite of me adding 6% to the PE vs RPM table a few times.

I like the idea of a single pump though. Could I run a better single pump and stock fuel lines and get there? 50# injectors or even more? My engine is not built sufficiently for more than 10 PSI so that is the max it will see until it grenades. If it grenades I'm probably doing an LS3 or LS7 swap and getting out of this FI stuff....so I don't need to plan for more than 550 RWHP.

97WS6SCharged

A lot of people have been having good luck with Aeromotive's 340 lph pumps. Might look into going that route.

canbaufo

Thanks. You think stock lines are adequate for that? ...or should I be upgrading lines anyway with this 1994 car? If the 255 lph Walbro is borderline sufficient then maybe the 340 Aero would be "plenty enough". 50# injectors should maybe be used as well. Food for thought on fuel lines, this car has always been in a garage and only has 60K miles ...so even the rubber suspension bushings are still in great shape. However, perhaps upgrading the fuel lines has more to do with allowing flow.

Approx how involved / expensive is it to upgrade the fuel lines? I've never done fuel pump/line work but have done a lot of other stuff, so maybe it's within my ability.

Purple Poncho

From what I have seen stock fuel lines can take you pretty far as long as you have enought pump and injector. Stock lines can handle 600rw easy.

97WS6SCharged

The stock lines should be fine for what you're trying to do. A 340 with a Racetronix harness should be more than adequate. One nice thing about the stock lines is they are all metal and plastic except what is actually inside the tank so the alcohol they put in the gas these days doesn't affect them much.

I'd look at a set of 60lb injectors since the price difference will be negligible and they should idle just as well while giving you a little more wiggle room.

Upgrading to aftermarket lines is done when volume becomes an issue. One of the major bottle necks in the stock system is the cross over between the stock fuel rails. The ID of the rails is 5/8" while the cross over is 3/8" (it's also a bad angle) which can lead to the #5 & #7 injectors getting less pressure.

It's really not hard to change the lines, you simply remove the old stock hard/plastic lines and run the new larger lines. The cost is what gets most people. $6+ per foot of line with the $5-30 a piece assortment of fittings adds up very quickly.

canbaufo

Thanks for the info guys, I may go with the 340 and see if stock lines do ok from what I can tell. Injectors seem to be a non wear item so I may try to get a deal on some good used ones and sell my 42's so that's not really an expense.

Will my old OBD1 and old style LT1 Edit (I think it's the version used around Y2K) allow for 60# injectors? I have no issue with the 42# constant FWIW.

97WS6SCharged

Honestly, buying a set of 60's new isn't that bad. FIC has them for $370 and they should just drop in though you may want to call them to be sure.

FUEL INJECTOR CONNECTION - Flow Matched Siemens 60lb injectors

As far as tuning goes, set the constant (63 lbs at 43 psi) and it shouldn't take more than a few minor tweaks to the fuel curves to get it running well.

canbaufo

Thanks for the info. I'm hoping you mean that only the PE vs RPM will need to be tweaked (it's so easy) and not the Load vs A/F vs Temp ...argghh, I hate that one but I've done a lot of good work on it since I run open loop only (I have a wideband gauge mounted in A-pillar). Injectors are an easy swap too, just gotta be careful with the fuel rail (don't ask me how I know).

97WS6SCharged

Temp tables shouldn't change just the RPM tables you mentioned may need + or - a % here and there to clean them up. There's always a little difference between spray patterns and such that adjusting the constant won't quite fix.

Ringmaster72

I have Siemens 60 lb injectors, they fit fine in place of stockers.
Also, you might want to check out deatschwerks for a fuel pump. I have this one:
Fuel Pumps : DW300 In-Tank Fuel Pump | DeatschWerks

Oh and i am pushing 10 lbs of boost and 500hp to the rear wheels.

canbaufo

Thanks a bunch, link saved in favorites. Is it quiet? Seems like a fair price too.

Ringmaster72

If it is any louder than stock at all, it isnt much.