TBI fuel pump?

[Critter]

I quoted this from the main "they gave it to us thread" but I separated it to a new thread (obviously).

Originally Posted by glock35ipsc

You have three choices.... well, maybe more, but these are what come to mind.....

* Use the stock in-cab tank with an external pump. You will need to install a return line back into the tank.

* Use an 87-91 Blazer or Surburban tank that mounts behind the rear axle between the frame. These were TBI trucks and already have the fuel pump in-tank, so you can use an inexpensive OEM pump.

* Use a custom made aluminum tank with an in-tank pump.

Ok, I have a question. I have a 72 Blazer with a 73+ fuel tank and I have thought about the 87-91 TBI in-tank pump. I was under the impression that the TBI systems worked at around 30 psi, not 60 psi like the LSx engine requires. Am I missing something???

[clinebarger]

TBI system spec is 9-13 PSI. You can use a 94 through 96 B-body pump on a TBI sending unit. Be sure to use high pressure hose between the pump and sendor.

[Thealien]

You can change to a higher pressure pump. The Pump, return line, wiring connections (and maybe a baffled tank) are all there already. Cheaper to change pumps (or maybe the whole pump assy) in a tank that was already designed for EFI.

[Critter]

Cool. So what I was planning to do was to go to the salvage yard and get a TBI sender/pump setup, put a new pump in it, and stick it into my existing 73-86 tank. Sounds like that is a viable way to do it. Thanks guys.

One more thing, I have heard that some tanks are baffled, some are not. Were carbed tanks open and TBI baffled??? Or did I hear that incorrectly?

[clinebarger]

The TBI tanks are baffled. The carb tanks are not. If you stay above 1/4 tank it wont be an issue. Im running a 91 40 gallon suburban tank in my 85, the 91 was baffled the original 40 gallon tank was not.

[Critter]

Hmm, that's what I was worried about. I guess I will mock up the build with this one and maybe keep my eye out for a baffled one. For some reason I really like the way this tank fits between the frame rails AND I have 30+
gallons!

[glock35ipsc]

Originally Posted by Critter

Cool. So what I was planning to do was to go to the salvage yard and get a TBI sender/pump setup, put a new pump in it, and stick it into my existing 73-86 tank. Sounds like that is a viable way to do it. Thanks guys.

What I mentioned a few posts down, and should have mentioned in the post you quoted is........ An ACDelco EP381 fits in the 87 truck and 87-91 Blazer/Burb sending units, and provides more than the 58 PSI needed for the LS engines. They run about $70 and are available over the counter at any parts house.

Before I put the 5.3 in my 85, the PO had converted it to TBI with parts from an 87, but had left the 85 tanks in place. The 87 tanks have a shallow bowl that the pumps sit in to keep fuel sloshing away from the pickup during cornering and hard stops. It's not baffles in terms of what you might think of regarding baffles, but rather a bowl. I did have a couple instances of the engine stalling out when I was around 1/8 to 1/4 tank, although I try not to let mine get that low.

You must have the 31 gallon tank? Just FYI, a new one would run you about $130.

[Critter]

Thanks Glock. I guess I just need to make a decision and go with it. I have also considered getting the Walbro universal intank pump and modifying my existing carb style sender. To be honest now that I know there are a couple viable solutions I might jut put this concern on the back burner and concentrate on the stuff I haven't decided on...like which way I want to go with my wiring harness!

[turbostar]

Good thread guys-very helpful. I need an EFI tank for my 65 SWB swap. Sounds like the best candidate is the 87-91 Blazer/Sub tank. What would be very helpful is the dimenesions of the tank/tanks. Sounds like some have more capacity so if anyone has access to these tanks,I would be very grateful for some measurements.

[Oilbrnr]

Originally Posted by turbostar

Sounds like some have more capacity so if anyone has access to these tanks,I would be very grateful for some measurements.

25 gallon tanks measure 29"x28"x11". 31 gallon tanks measure 29"x28"x13". 40 gallon tanks measure 35"x29"x13"

(copy/pasted from Classic Parts www page)

Think I'll do the 40 on my K5.

[Indian113]

Is there any truth to this statement I heard "to much fuel line pressure can overheat the fuel by returning it to the tank to fast? I was looking at a tbi camaro and a guy told me to try and use the stock fuel pump.

[chevy-fun]

any one know what yr i can find the 25gal tank. looking on rockauto an can only find 31 gal. my truck is dropped an prefer the 25gal one. thanx in advance

[BR3W CITY]

Originally Posted by chevy-fun

any one know what yr i can find the 25gal tank. looking on rockauto an can only find 31 gal. my truck is dropped an prefer the 25gal one. thanx in advance

I do know where you can find a 5 year old thread...

The person who put up the dimensions said they were from Classic Parts, so it might be worth looking there.

edit: I was nice and did the finger-work for ya; all 3 25 gal options

http://www.classicparts.com/1973-81-.../#.VNZEoy6GOok
http://www.classicparts.com/1982-86-.../#.VNZErC6GOok
http://www.classicparts.com/1987-91-.../#.VNZEsy6GOok

[chevy-fun]

Thanx brew city. The 87-91 is one i need for my ls swap. Thanx a bunch ordering it monday

[First c10]

Anyone know the part number to the sender/intank pump assembly for this tank? I have seen a bunch but none say the measurements of the mounting flange/ring. And not sure if the size is universal other than depth based on the capacity of the tanks.

[chevy-fun]

im guessing it would be this one. http://www.classicparts.com/1987-Gas...tinfo/23-569/#

took me a few times to find the one for 25gal. then all that would be needed is to switch out the pump to the EP381 pump for the 60psi. Brew City does this sound correct

[Andy4639]

I have a 93 surbarban tank in mine with a aftermarket LS pump at 62lbs I think is what they said it rated at. My tank is 40-42 gallons has baffels with the little circular part around the bottom of the tank to keep the gas close to the pump.
I had a 30lbs pump in it before for the 305 TPI motor. I just had them swap it out. I did drive the truck for a week with the old pump. It gave out though thank goodness in the drive way.

[BR3W CITY]

The ep381 or any of the Walboro-style in tank pumps. The 255 is sold by like 20 companies under different names. It does just under 100psi, which is regulated to 58-62.

[kitsbeach]

Originally Posted by chevy-fun

Thanx brew city. The 87-91 is one i need for my ls swap. Thanx a bunch ordering it monday

Shoot us a pic of the tank once it is installed.

I also want to try the smaller tank so it doesn't hang down too far (I'm one of those guys who's all picky about seeing the tank).

[chevy-fun]

finally got around to ordering it last night. may be a few wks before pix