91_5.7_TPI

iTrader: (2)

I admit I don't know much about the TBI setup, so I've came to the experts. My pump is dead...so, if I install a Walbro 255 (plan on LS1 swap) now, will the stock FPS work with it or will it go blooowm!? Thanks!

Timothayyy

iTrader: (2)

When I put my 255 in with new steel braided lines going to a from the tank along with an adjustable regulator. I had to lower the pressure to about as low as it would go [like 10 or 11psi after that the pressure would just go all weird] and I had to get a simple dyno tune because it was SUPERRRRR rich.

I would just get a walbro 190 unless you want to get an adjustable regulator and tune it.

ownor

iTrader: (5)

i also have a wal255 kicking around here but from what i read so far, it aint a stock replacement type of deal. you need at least an afpr, steel lines would be a necessary addition as well. then there are other problems like return line too small to return excessive fuel, or having to adjust the injector settings on the prom, etc..

would like to know about other opinions, maybe i'm a bit too biased towards this topic. let's hear some thoughts, folks!

greetz

dimented24x7

iTrader: (2)

The walbro 190 will be a pretty much stock replacement. The 255 is too much, and will overwhelm the stock regulator. To use the 255 properly, you would need one of the later high pressure TBI pods with enlarged regulator return passages.

91_5.7_TPI

iTrader: (2)

Alright, thanks for the info guys. I guess I'll just install a replacement pump til the time for the swap comes. Thanks again!

Timothayyy

iTrader: (2)

Go with the Walbro 190, it should be enough for an LS1 swap and changing pumps is a pain in the rear.

robertfrank

iTrader: (27)

I heard that some guys go with a regular TPI pump. What kind would be good? Not to hijack but I think it would be relevent to this thread.

Timothayyy

iTrader: (2)

I thought the 190 and the TPI pump were about the same. Probably a little more flow from the 190.

DM91RS

I did the 190 and wished I'd done the larger one but mine ain't stock and needs mid twenties psi. FWIW...................

86z/92rs

I went with the W/255 and aeromotive fuel regulator. See pic. No problems at all. Fuel pressure at 18 PSI with vortec heads and LT4 hot cam. Chip wise that's another issue.

DM91RS

What lb. injectors do you have?

86z/92rs

454 injectors #17112560.

Dewey316

Here is a really random idea I just had. The Aeromotive regulators have multiple feed ports. Could you block off the factory pressure regulator area, and then use that port as another fuel inlet? since the bypass style regulator like the aeromotive, would allow for 2 feed lines that see the exact same pressure, with a single return line coming from the regulator.

That would solve a couple of issues, you would have a lot more fuel flow to the injectors, you would also not have the return line passage issue inside the TBI unit, all the return stuff would be through the regulator.

dimented24x7

iTrader: (2)

Its been done, and is the preferred way to go IMO. If you'll be using stock fuel pressures, you can simply plug the return port on the pod. If youll be running high pressures, you will also need to replace the diaphram with a plate or weld up the regulator housing. Under high pressure, the diaphram may burst. Ive had them up to 80 PSI with no ruptures, but I wouldnt want to run it like that for extended periods of time. Otherwise you may find your car turning into a flaming gas fueled fireball going down the road.

One thing I did find, though, is that in the older pods with the smaller passages, and especially the holley units, the supply passages also become a restriction. This causes the pressure at the injectors to fluctuate. I had this problem with my holley unit. One possible solution is to use both the return and supply ports to feed the injectors, or try to find a later high pressure BBC pod, which has larger internal passages.

Dewey316

Yeah, I am thinking I might just give it a try, and use both the inlet and outlet as supply lines. I'm really thinking about tossing at least one of my eatons, on this 305, just to see how much more abuse it will take. I am thinking with an aeromative regulator, I can plumb the boost reference to manifold vacuum, this should lower my fuel pressure at idle to help with the PW, and then it will raise it in a 1:1 ration under boost, so it will negate the boost pressure, all i have to do is set static pressure with zero vacuum, so that I have enough PW based on something like a .60 BSFC. Then use EBL to tune it all with my WB, and see what happens.

With 235k miles on this 305, I don't imagine I can actualy build enough cyl. prssure to actulay hurt anything, it will all just blow past the rings anyway.