Fuel tank question

[aany001]

So what your saying is that for street cruising and you dont let the fuel go below 1/4 tank I should be good to go?? Also do I have to install a return line for a 99 LS1?
thanks

[deuce_454]

return depends if you are running a referenced fuel pressure regulator.. if not then you could run a single feed and keep the pump and reg in the tank.. and im by no means saying its a good solution... but if you keep the tank atleast half full... or more it shouldny be a big issue...

but i dont get why you are so set on not doing it right.... its always cheaper to do it right the first time.. you are going to end up changing it anyway when it bugs you enough ....

[aany001]

reason why is that I already bought a carb style stainless tank... just trying to use what I already have.

[GregWeld]

I started out with a carb tank -- it's stainless steel from Rock Valley... it's already baffled. What you really will need is a SUMP... and of course a return line for the the LS style motors (almost all EFI engines use a return system). This is all very simple and can be added when ready.

I use an external pump and can't hear it with my motor running. Tis a hot rod not a mercedes benz! EEEEEEEEHHHHHHHHHAAAAAAAAAAA

[aany001]

Does anyone know if the carb tanks have any baffles at all? I am willing to sump my stainless tank.

[GregWeld]

Depends......


As in - what kind of tank it is - and who built it. Without that info nobody could answer that kind of a question. Stock factory tanks had no baffles... including the SS replacement versions. Rock Valley and Ricks Tanks etc - would be baffled. Baffles would take care of fuel SLOSH... they DO NOT take care of cavitation at the intake caused by a lack of coverage.

EFI draws large amounts of fuel at all times... Think "toilet bowl flush". Fuel boils under suction... so the supply lines to the pump need to be sized for the application... and they need a nice clean flooded "head" for supply. Think -10 AN for the supply side MINIMUM. A SUMP helps to keep the supply flooded. It needs to be at the rear and bottom of the tank (unless you're internally sumped and baffled). You need adequate fuel going UP HILL and when you're accelerating hard. You don't need much coasting downhill or just cruising on a level street. EFI will not run on air bubbles and fumes... there's no pressure made in that instance. You can use your existing supply line as the return. Again depending on the proper size for the application. If you're planning a 900 HP blown EFI motor -- the factory line would be totally inadequate.

[aany001]

My tank is a rock valley piece and I spoke with a friend of mine that said he can tig weld a sump in no problem.Now does anyone make a stainless sump?? As for what I will be running its a stock 99LS1 and maybe a cam change in the future.With that said do you think I could use the original feed line as a return?? Thanks guys for all this info it really helps.First LS1 install and first time building a first gen camaro I must admit its pretty scary.
Steve

[GregWeld]

Steve --

The rock valley would be baffled.

Anyone can build you a simple SS sump. Aeromotive makes a complete weld in unit with pump and filter included - but it's about a grand.

A mostly stock LS1 could certainly use the 3/8" return line (also known as a -6 AN)

[aany001]

Thanks Greg this is some great info