nomad350Z

After going through my third 0169 Walbro 255, I've decided on getting something reliable.

I've heard of people using AC Delco fuel pumps from Grand Nationals, I was wondering what year. Should I get the 1987 GN-X pump, I figure that one would flow the highest volume.

Does anybody know what years would work? Does anybody know what the flow rates are? I looked on AC Delco's website, and did a search here, but they don't offer any technical data.

Somebody know?

Guest

I dont know that the pump is different on the gnx. The GN pump is the same as the TTA pump. It flows about 25% more than the stock TPI pump.

50-60GPH wide open (190-227lph)
80-90psi shutoff pressure

nomad350Z

Will any Grand National pump work? What years will work?

Is there anything closer to the Walbro output, in the 250+ lph flow rate? I may go forced induction down the road, I'd hate to get another fuel pump.

Guest

Its easy enough to check years and see what part numbers are the same. Its the same pump as a TTA (Turbo Trans Am). Thats a 1989.

I dont know of anything else that would be for a stock app, probably nothing other than what you already bought. The TTA pump, depending on how much fuel your motor wants, should be good for 420-500 crank HP +/-.

nomad350Z

I did a search, just wanted to see if there was anybody out there using the pump. It looks like the '89 TTA is AC Delco part EP 242.

MadMax, where did you get your data from? I did a search on other forums and it says the free-flow rate is 40gph......

I just want to get the facts straight before I make another purchase. 3 Fuel pump installs is 4 too many for me.

Guest

From the AC Delco buyers guide.
I have the TTA pump in my car, its been in there for about 15 years now.

Dyno Don

iTrader: (7)

#25163473
AC EP381

Cyclone /Typhoon pump

50 GPH @ 55 PSI

nomad350Z

I'm guessing that the Cyclone would flow more, simply because it was intended for a 4.3 instead of a 3.8.

Anybody have any experience with Walbro GSS340 pumps? I know they're intended for Mustangs, and they flow the same as the 0169's, but do they have the same issues that the 0169's do? I did a search, but all the posts are from 2003, before Walbro sold out.

I think I'm gonna go withe the Delco pump, simply for reliability. If the eventual boost necessitates it, I'll put a second one in.

Thanks for the help guys!

1989GTATransAm

iTrader: (3)

"#25163473
AC EP381

Cyclone /Typhoon pump

50 GPH @ 55 PSI"

That should be made into a sticky. If you are replacing a TPI fuel pump that is the way to go.

nomad350Z

I know its been awhile, but I've got more fuel pump issues....

I installed the EP381 from the Cyclone-Typhoon, worked great. Took the car on a road trip, noticed a whining noise during long-term use (about 500 miles a day), which was made more noticible when the temperatures were high. At this point, I noticed when unscrewing the fuel cap, I could hear a hissing noise (gas escaping). I've replaced the 1 psi check valve attached to the tank, and checked all fuel lines. I didn't want the pump to be working against vacuum pressure, so I disconnected the fuel tank hose at the vacuum canister (to alleviate pressure buildup) and also removed the o-ring in the gas cap for the same purpose. This seemed to stretch out the regularity of the whining noise.

The whine starts out low pitched, then increases higher and higher until you can't hear yourself think. Only happens when the car has been running for awhile and it is hot out (+80 F).

Today I was sitting in traffic, in 90 degree heat, and the noise started. I noticed I was low on fuel, so I filled up and let her cool off for a bit. But instead of the noise going away (like it usually does), it continued.

Anybody have any problems like this before? Suggestions? As mentioned a few months ago in this post, I've done it all before, and I'd hate to do it again. At this rate, I'm about ready to sell the heap. Its been nothing but trouble for the past 3 years, and it'd be a nice down payment on a fresh LS1.

nomad350Z

Anyone have any clue?