Magnus

iTrader: (4)

I just finished my walbro install.... few tips for those who plan the install..

After you remove your stock pump, cut a hole a little smaller than the diameter of the walbro pump in the bottom of the rubber holder that the stock pump sat in.. your new walbro pump will be pushed through this hole.

Now, in the casing, Remove the stock sock on the bottom of the assembly and punch that whole black plastic piece out. Remove the small black baffle out from the other side.

Cut a nice rectangular hole extending from both newly formed holes in the bottom of the casing a little larger than the walbro pump inlet. Your new fuel pump pickup will be here.

The reason you want to do this is the stock setup has a pickup down there that keeps the stock pump submerged in fuel. Even though the stock pumps pickup is inside the casing, you can still run your car on very low fuel levels.

And now the why the walbro isn't for everyone...

Because the stock pump always kept itself submerged in fuel, a tank in a tank if you will, at 2 gallons of gas, you could launch hard and take turns without losing fuel PSI... Well guess what happens when you just have the walbro's inlet sitting at the very bottom of the tank? During turns, and hard G forces, fuel PSI gets a little shaky.. not +/- 5psi.. it may dip down to 30 or so.. It's very shaky.

Imagine takign a ride in your car with a big 15"x12" lasagna dish filled with 1" of water. When you launch the car hard and take turns, where does that water go? It shoots to the ends of the tank leaving your fuel pickup dry.

I didn't know this but wish I had.. I would have kept the stock setup. I had an extra walbro laying around so I decided what the heck.. why not.. a mistake on my part.

So, in conclusion.. if you don't NEED a walbro.. don't do it. The stock pump tank-in-a-tank feature is pretty damn kick ***.

This is my story, may it live on for years to come...

good night, god bless.

Black LS1 T/A

I have not experienced the problem you describe and I've run over a second quicker with shorter 60' times.

Installing the Walbros is the best thing I ever did, fuel-pump wise.

Magnus

iTrader: (4)

Do you ever run on low fuel?

The problem doesn't happen when your at say a 1/4 of a tank.. but more so when your at an 1/8th of a tank or lower..

The LS1's fuel pickup is a few inches away from the rear wall.. so when fuel sloshes toward the back, there is room for it to slosh away from the pickup. The LT1's style pickup is at the rear of the tank.. less problematic.

Black LS1 T/A

No... I rarely ever run on 1/8th tank. That is a bad idea even with the stock pump. Running on that low a tank risks picking up more trash, etc, as well.

I try to find a gas station when I'm on 1/4th tank.

Magnus

iTrader: (4)

That's exactly my point of this post..

I've looked in several fuel tanks... and I've never seen "trash" in there. I think that's popular misconception.

FYI, The stock pumps pickup setup is dual filtered.

Pro Stock John

iTrader: (34)

I think something is wrong with your install.

Big drops in fuel pressure sometimes indicate the pickup coming off.

Magnus

iTrader: (4)

John.. my install is ok. Anything more than a 1/4 of a tank and the fuel psi is SOLID... I put in 3/4 of a tank yesterday and did some more blasts down chi-town streets of havoc... no problems at all.. PSI is solid at idle and 10 seconds of WOT no problem.. it also doesn't bleed down indicating a pickup or fuel hose problem.

It's a problem everyone will have at very low fuel levels if they don't sump their tank. Refer to my lasagna dish example.

The reason the stock pump doesn't have this problem is because it's a tank inside of a tank. The fuel pump housing itself is a tank John.. It pulls fuel in from the very bottom to fill its own tank up which the fuel pump pulls fuel from. When you go WOT, yea you will lower the fuel level inside the inner tank.. but probably not enough to cause a shaky fuel psi at low levels. It's a fairly deep resevior.

Just to note, this is only a problem at very low fuel levels.. In case I didn't make that clear already.

And yes, my pickup is as low as it can go.. as I previously stated

Black LS1 T/A

You are wrong about the trash. People who sell pumps disagree with your assessment on whether trash can make it thru the filter or not. They cite instances of people stirring up trash in their tank during an install and a pump (which has a filter on it when it goes in) manages to pass enough trash to ruin the new fuel pump.

A pump with it's own tank? I haven't heard that, though I won't dispute it (unless I find out differently ). I have a 1998 F-Body.
If you are talking about your '97, things may be different.

I don't knock you trying to inform people of a problem you have that they may avoid. That's great. But, I believe it is bad counsel to steer people AWAY from installing the in-tank Walbro. A second opinion is DEFINITELY needed with advice like that.

This install is a GREAT investment.

Pro Stock John

iTrader: (34)

Yeah there are hundreds of folks have installed intank Walbro's without major issues.

Sure you can uncover the pump if you run the tank down to E.

Magnus

iTrader: (4)

Black LS1 T/A, I'm just saying that the few tanks I've opened up were clear. I also have confirmation from others that have done swaps theirs were clean as well.. Perhaps they become contamindated during a messy install.

You have a 98 so yours is the older metal style tank.. You should be even more fine with a walbro due to the pickup location, It's all the way in the back of thet ank.

I did the 99+ fuel tank swap... so I have the newer setup.. These setups are the ones that have the mini tank in a tank.

I am not trying to steer people away from a walbro.. I too think its an awesome investment.. YOu just need to be careful when your running low on fuel.. You can't run a walbro as low as you can a stock pump.. For a guy like me who has a pretty stock car.. the stock pump setup is adequate. A walbro is deifnately a good investment if you need more fuel.. Heck, even if you don't but are worried about it.. do it up..

I'm just trying to bring a little REAL technical knowledge and an FYI to this board of FACTS.


John, I know. I already posted that. I'm just letting people know that a walbro is less forgiving of low fuel levels than the stock 99+ setup.

I really didn't think I made this post that hard to understand. Perhaps I need to re-word it????

Chris99WS6PWTMET

If you cut away a good amount of plastic from the 99+ fuel module and mount the Walbro in the lowest possible point with the sock near the tank floor you should have no problems. I run mine at the track with 1/4 tank and have ZERO fuel pressure problems. Cutting away the plastic basically makes it similar to a 98 type set up. In a stock set up, the 99+ is a better system as the module is like a mini sump, always keeping the pump surrounded by fuel (like in excessive G manuvers). But since we have no way to FILL the module with a Walbro we must open the module up (cutting away plastic). This design characteristic is EXACTLY why Racetronix has not yet come out with a direct plug-n-play for the 99+'s.

Magnus

iTrader: (4)

yea, at a 1/4 of a tank, you still have 4 gallons of fuel, enough not to cause an issue. The issue becomes more apparant as you reach the 1-2 gal level depending on how deep you set your walbro.

I had the older style metal tank with the SAME walbro pump and had ZERO problems. The fuel assembly goes in and stretches outward to the back of the tank, very nice.

I was actually thinking... If you didn't modify the bottom of the stock housing at all, but instead removed that rubber sock the stock pump sits in, cut up the upper housing part and slid in the walbro so it was still in the sump, ran the fuel feed from your stock pump in a little arc right back into the bottom of the housing, thus keeping the stock housing filled, the walbro too always submerged and thus giving you no problems at very low fuel levels. Note: Just to make it clear... This isn't needed for everyone.. just an idea for those of you who like to run at very low fuel levels (to make it clear again.. I'm not talking about 1/4 of a tank).

Magnus

iTrader: (4)

Black LS1 T/A, I took a look at one of my spare metal tanks.. Inside where the fuel pump sits, there is a plastic casing to hold fuel. It has pretty high walls and a little mouth in the front where the fuel pump arm assembly sits on as the pump inlet extends to the bottom of this casing. I'm sure this plays a BIG part in why it is possible to run the older tanks much drier without problems.

Just another FYI.

2001CamaroGuy

iTrader: (6)

I am very happy with my Walbro. When I installed it, I had already run the tank down to less than a gallon of gas in it (less weight to work with). When it went back together, I fired it right up, and went for my 5 min driving to the gas station.

Now that said, your never supposed to run below a 1/4 tank anyways. The fuel keeps the pump cool so running down to 2 gallons (where you would have problems) is a BIG NO NO anyways . When your racing, a full tank is actually an advantage. On a launch, it helps plant the rearend, and in turns it helps prevent fuel slosh (more stable).

Walbro GOOD....

stock pump BAD....

MIGHTYMOUSE

iTrader: (59)

maybe its something with the location of the pump inside the tank on a metal vs plastic tank..

can the plastic tank guys modify further and move the pump to the very bottom of the tank like the 98 guys?

i have run with less than 1 gallon before, no problems.. my walbro pumps are exactly the same depth into the tank as the stock pump was.

Magnus

iTrader: (4)

The 99+ cars can definately move the pump to the bottom of the tank.. I gave directions how to do so in a previous reply..

But, the pump is still maybe 6" from the rear of the tank and perhaps 15" from each side wall... The Pre 99 pumps are right near the back in its own built in casing.. the casing is built right into the tank, so it remains untouched when doing a walbro swap.

I too was able to run my 97 tank with very little fuel and no problems at all.

I have a few ideas for 99+ setups but it seems nobody really cares. So I'll just leave it be.

buschman

My gas gauge is about to slip off the empty hash mark and I'm still seeing 60 psi. Granted I'm heading to a gas station first thing. But I almost always run my tank down and never run into issues. Even after removing the stock tan and examining the sock and components. I noticed no trash or debris that had accummulated. Everything was clean as a whistle and running fine(including external fuel filter). I've never noticed a full pressure drop when G-Forces are exserted on the fuel tank. Maybe I just got lucky.

With as little gas as I have right now, I dare not try a hard launch, but I'll run her hard into a few corners and see if I notice a FP drop.

Mike

Black LS1 T/A

Yep... that's what I recall. I think you are right.

rodent

iTrader: (1)

For those that haven't seen one, here's some pics of my 02 pump housing:



All 99+ have this.

I tried to leave my plastic housing alone by not drilling any holes. It has two rubber baffles in the bottom that let fuel in but won't let it out. I was having pressure problems above 4k rpm so I drilled 5-6 3/8" holes in it at the bottom (sorry, no pics). This seemed to fix my pressure problem along with the kinked rubber hose. The holes will let the fuel escape but not as quick as one large opening.

I never drilled my sock out. The Walbro sits low enough with the filter on it. To make it fit tight in the sock, I used the shell from the old stock pump.

And if I'm not mistaken, the 99+ fbodies pump sits farther back than a 98.

Magnus

iTrader: (4)

Rodent, good pics.

I have both tanks and setups in my warehouse, the 98 style definately sits farther back then the 99+.

The thing about just sitting the pump in the old sock is the pickup is still almost an inch off of the tank floor.

I know exactly what your talking about the fuel pressure issues when not drilling out the bottom too. I tried severeal options, and the best one for me was to just extend the pump right through the bottom of the whole assembly (still in the rubber sock too).