http://www.erzperformance.com/produc...rebirdpump.htm

Alright, well ima go ahead and order it.

That pump will push SIGNIFICANTLY more volume than the stock pump for your TBI.

I just replaced my TBI pump with an ACDelco TPI pump which pushes I believe about 155 LPH. Even that is significantly more volume than the stock TBI pump. It worked just fine for my TBI setup.

That one however, as you can see, pushes even more. I'm sure somebody has run that with TBI before. You might want rebuild your TBI with new seals all around as well as a new fuel pressure regulator diaphragm. Make sure your fuel filter is fresh too, and replace the in-tank strainer.

I see you plan on going into your engine. You will need to pump up the fuel pressure for the extra HP and that pump will be great for that. Good choice on learning to tune your own stuff.

Thanks man, I was thinking of getting a TPI pump... But I figured might as well get the walbro 255 in case i decide to do an engine swap, or get some power adders.

I ordered a new AC delco fuel filter as well. I dont even know when that thing was last replaced, lol.

Ill go ahead and get a rebuild kit for the TB later this week.
http://marine-performance-parts.com/...ebuildkit.aspx

will the stock return line be able to flow enough to return all that fuel to the tank?? I mean on a stock motor?

Between the return line and the TBI unit probably not. The 255 lph pump is too much volume when use at TBI fuel pressures (12 psi). The fuel pressure increases as not enough fuel can be returned to the tank. Better off with the 190 lph when used with stock fuel pressures.

Once the fuel pressure has been increased (25 - 30 psi) then a 255 works OK. With the higher pressure the flow is lower. And it more easily passes through the TBI.

RBob.

http://marine-performance-parts.com/...843505774.aspx

Should that make the pressure what I would need it to be?

Probably not. They don't list any pressure range. And it doesn't have a vacuum port on it. So at the higher pressures it isn't the best way to go.

Best bet is to get a better idea of how much fuel is required for the HP. Then calc back to the required injector flow and fuel pressure (FP) to obtain that flow. Once the FP is over 18 psi then a VRFPR can be used.

Once over 20 psi or so a VRFPR makes a big difference in how the engine runs. Highly recommended.

RBob.

Tim,

The reason I asked this question is:

The fuel pressure regulators on these cars are called "bypass regualtors." What that means, is that the pump throws as much fuel up to the throttle body as possible. The throttle body has a regulator, but being a bypass style one, it sits in the return side.

What it does, is decided how much fuel to let into the return line, or send back to the tank. The more fuel going back to the tank, the less the pressure will be at the injectors. Get what I am saying?

Now, lets imagine you got that big walboro pump. Its gonna pump significantly more fuel up to the engine than the stock pump did. Now, the FPR will try and send most of it back, in order to keep the right pressure at the injectors. However, if the return line itself isnt big enough, the fuel pressure will still remain too high because not enough will be able to make its way back to the tank!

One way to combat this, would be to install a bigger return line. Another option, is to get a little smaller fuel pump. The most common option, is to make a motor that puts out more power, uses more fuel; so therefore less will need to go to the tank.

Since you have the EBL, there should be some kind of way you can play with the injectors, so that they can run at a higher pressure, but stay open for a shorter duration, to give the engine the same amount of fuel. This is RBobs area of suggestion, though.

So what VRFPR should I get then?

And I guess ill just wait to put it in til I get more upgrades.

Once I get the 454 throttle body, which size injectors would be best for my set up? And what pressure should I be running? Ill adjust it later when I go to the dyno if I need too.

Thanks for the help though guys.

Bump because id really like to know how to run the Walbro 255 safely

I cant say personally about the VAFPR. I really like the aeromotive one, but you have to modify (remove) the stock one to get a full pressure range. I have no idea how to do that, but I could probably figure it out if I started taking apart the TB.

If you are dead set on a 454TB and bigger injectors, that would be the time to upgrade the fuel pump and add a VAFPR.

http://www.jegs.com/p/Aeromotive/750091/10002/-1

http://www.jegs.com/p/Aeromotive/962877/10002/-1

http://www.jegs.com/p/JET/748464/10002/-1/10323

Those look like the ones that might work. Wish someone who has already put all this stuff in would chime in and let me know what to get.

The first one you listed, I have seen used by another member, on his pickup. He had a link to a site with pictures of it installed. That was the one I had in mind.

The last one, would probably fit right in where the stock one goes. However, it does not seem to be vacuum referenced, or specify a specific range of fuel pressure.

-------------------

One thing I want to figure out, is, What exactly does the charcoal canister do? Because, if you follow the fuel lines, the inlet line from the fuel filter comes up from under the car, goes into the charcoal canister area, and then comes back out to the throttle body.

I emailed the makers of the last one and asked them about the pressure range and how well itll work in my car, ill tell ya what they say.

As for the charcoal canister "designed to trap and store fuel vapors that evaporate from the fuel tank, throttle body and intake manifold"
Based on what my Haynes manual says it appears to be something that trims fuel away when the engine doesent need it [idle, deceleration]

That doesent make sense. Why would they run pressuruzed fuel into it, if it was to store vapors from the tank??

Beats me but apparently it has a valve in their that opens and closes as needed.

WTF?? lol. Every *** system on these cars is over complicated...

I have a question. I have a walbro 255 and an xtremefi regulator. I plan on running nitrous in the near future. Will this pump still be too much? sorry to hijack but I felt it was relevent to this thread.

yes, its way too big. you should send it to me.

Do you have it installed and would you recommend the xtremefi regulator to me? Or should I get that JET thing i linked to above?

I don't have the 255 installed as of yet. I've been waiting for my tuning stuff to put it in. I already have the xtremefi regulator installed and it works fine. comes with 2 springs for adjustablility. It's pretty too, lol.

One item to be sure of when the new fuel pump is installed is a good connection hose. Inside of the tank is a short length of hose to connect the pump outlet to the fuel line. These are known to split open.

The piece of hose needs to be rated for the pressure along with being rated for complete immersion in fuel. Notes show: SAE J30R10 spec


For a regulator and such, we are working backwards, but should be able to make this work. Not knowing how much HP we need to cover, we'll assume that the stock injectors at 30 psi will do the trick. The 30 psi is used to be sure that the pump flow is low enough and the flow through the TBI is high enough to prevent pressure creep.

The 55 #/hr injectors at 30 psi will flow about 83 #/hr. This is good for about 316 HP (flywheel). If you need more then the 61 #/hr 350 injectors flow about 92 #/hr at 30 psi for 350 HP.

We could modifiy the stock regulator with a heavier spring for the 30 psi. However, then we don't have the varying fuel pressure. The GM marine unit has a port on it. But it may also have been discontinued (GM TBI regulator P/N 17113186).

If you can find the marine FPR it will need a heavier spring for 30 psi. The spring for that regulator is good for 18 - 20 psi.


This brings us to external FPR's. To properly use one the stock regulator should be removed. Then a block off plate installed in its place. Some say to leave the stock regulator, I just see that as another failure point along with a restriction in the return line.

I looked at the links you posted. I don't see any real info on the Jet FPR. Whether it comes with a spring or if it has a vacuum port.

There are several Aeromotive FPR's running from pricey to reasonable. Also watch what is required for fittings. One of them required AN -10 threaded O-ring fittings. While others are 3/8" NPT, which is easier & less expensive to get fittings for.

Of the ones listed the 13301 which is the universal bypass type appears to be a good choice. Priced at $126, has 2 springs (3-20 psi & 20-60 psi), 3/8" npt ports and a boost/vacuum port.

Of course also need to plumb it in. Which calls for opening the return line and placing the FPR into it. There are off the shelf fittings that can be used. Along with some AN stuff if so inclined (at 30 psi I wouldn't be using rubber hose).

If you can't do everything at once then do the FPR first. Can run it at stock FP until the 255 lph pump is installed. Then bump the pressure up, change the BPC vs VAC table, turn the key, and continue tuning.

RBob.

Tim, here was the other member I was talking about:

Alright, thanks for the replys everyone.

The Aeromotive unit looks like my best bet then. I guess ill just get all metal fuel lines so i dont ever have to worry about them breaking.

As for the tube inside the gas tank I think the Walbro i got came with it. The place I ordered it from sends you a free install kit for free that has a little bit of hose and some other stuff in it.

I plan on making around 300hp to the wheels with the 454TB and all the parts im getting in the coming months.

What size injectors should I be running?

What fuel lines should I get? I wanna just get it all new so I dont have to worry about any leaks forming. Should I get a larger return fuel line?

And I guess im going to be getting that Aeromotive regulator. Any idea what else I need to get? Or just the same things the guy used on that link?

Also I just bought a new stock fuel filter, was that a waste of 15$ or can I use it with the new fuel lines?

I'm running the Walbro 255 on a pretty much stock 305 TBI and stock FPR. The car runs great. I used the big pump so I can continue to make mods in the future and not have to ever change it again.

Alright, so Im guessing my car has the 55 injectors. 30psi seems like alot if stock their like 13?

Could I get away with the 55 injectors though with the mods I plan on getting? [see my sig]
Or which ones do you guys think would work best in my application?