geoguy1369

iTrader: (2)

I'm having trouble with my 4.8 turbo setup. I'm running as far as fuel system stock tank with 2 Walbro 450 lph pumps. It is 6an out of the tank with 2sseparate lines that go through a y to 8an up to the rails then reduced to 6an going into rail. 95lb injectors and 6an return. Ok now the problem is with 2pumps I can't keep the pressure below 100psi. With one pumpit holds stock pressure but the pump ooverheats after about 20min. I'm thinking the rails are too restrictive and are causing the pump to over heat. Anyone see this problem be for? Or know the limits?

directnosfogger

http://kennebell.net/KBWebsite/Commo...rFuelRails.pdf

Old Geezer

iTrader: (3)

Stock tank in what, a Yugo??
How about some details.

HexenLord

What regulator? How is your return line setup? The stock rails are large and hollow. Technically, they should have more volume inside of them than most aftermarket rails.

Are both pumps running all of the time?

geoguy1369

iTrader: (2)

It is a 87 firebird tank in a third gen. One pump at the moment. With both on go won't go below 90 with the car running. It is stock rails and regulator. The older black ones with feed and return on driver side. Not the new alluminum ones. The return line is 6an all theway back to the tank. I even put an aeromotive fpr after the rail on the return to see if it changed anything and the was no change other then the like 2 psi higher I set it at. I have already changed out one set of pumps thinking they were bad but these both do the same thing.

HexenLord

Those pumps are too much for a stock regulator to handle. Even one of those pumps is going to overwhelm the stock regulator. It can't flow enough back to the tank to bleed off fuel pressure.

Are you tuning the car to run on the higher fuel pressure? 90 PSI should cause the car to run VERY rich on a stock tune, maybe even enough that the car won't even run.

geoguy1369

iTrader: (2)

The car wouldnt run on the 95lb injectors if it were stock tune....

josh414

If the pump is oveheating then its overloaded. Due to excessive psi caused from inadequate return

89ROC-Z

iTrader: (11)

That's way too much pump for the stock reg and small return.

How was the fit of the twin 450's into the stock 3rd gen tank?

geoguy1369

iTrader: (2)

They were pretty tight. But they can be squezed in.

GMCtrk

iTrader: (23)

Truck rails flow plenty.

I'm running a single walbro 450 on a completely stock truck return fuel system and have actually maxed out the fuel pump on E85 north of 600 rwhp.

Parish made 1000 rwhp years ago on a stock truck rails and lines.

geoguy1369

iTrader: (2)

What rails? I have the 01 style black plastic ones.

tempoffroad

i also run a 450 with stock rails regualtor and lines. Im not saying is ideal but it seems to work.

geoguy1369

iTrader: (2)

Got the new rails on and I can even run both pumps with no pressure problems. Nobody ever did answer with what rails they were using saying it worked fine ......

geoguy1369

iTrader: (2)

Ok update car is now running 12psi and im not having any fuel issues. Conclusion is stock plastic rails and regulator could not flow enough for 1 450lph pump.

GMCtrk

iTrader: (23)

False. I'm running a 450 on a bone stock 2000 fuel system and have run up to 14 psi on E48 with no issues aside from running out of fuel pump (done on e85 at 12 psi). That's making significantly more power than a 4.8 on 12 psi.

geoguy1369

iTrader: (2)

Yes it is but now you through into the equation you are running stock lines and you are using a third more fuel then me even at idle meaning there is a third less fuel to go through the regulator. I dodnt say it couldnt flow enough to make the power. When you are making the power it is not running through the regulator. As I said with my set up 8an feed to stock rails with a 6an return I kept having my pump over heat. Now with same feed line same return with different rails and regulator there is no problem. So to me that means the problem was in what was changed. All these other people said they were stock but how many replied to what rails they were using and if the were the same style stock composite rails? You were the only one. Is you car a daily or is it track use only?

HRD

iTrader: (1)

Do you really think that a single AN-6 line is large enough return for 900gph worth of pump? I'm running AN-8 lines supply and return with only a single 450 Walbro.

GMCtrk

iTrader: (23)

You stated in your first post that when running a single 450 it overheated after 20 minutes. My truck drives as if stock and I've driven it all over the place for hours in houston summer heat with no issues. I could see 2 450s being run at idle overwhelming the stock regulator, but myself and others on the truck side have had no issues with the single 450.

geoguy1369

iTrader: (2)

I was only running a single when it was happening. The setup originally was for e85 but the closest place aroung here now is a 2hr drive away so 93 it is. I am just sharing my experience after this. I would like you to tell me what my problem was then if same single pump same 8an feed with 6an return and all that was changed was rails and regulator and problem is solved what the problem was??? Like I said noone wanted to say what rails they were running befor you....... and for the other guy the origainal plan was a hobs switch for high boostvfor second pump. And yes at higher power on e85 only above like 18psi yes I think a single 6an return would be enough.