LS1 Swap Fuel Pump Question
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 904
Likes: 0
From: Murphy NC
LS1 Swap Fuel Pump Question
Hi all. Im going to pick some parts to start off my ls1 swap this weekend. Ive been doing some research on the fuel system and am wanting to do an in-tank pump. My question is, will a 82 sending unit fit my mid year 77 tank? Or can I modify my sending unit to hold a fuel pump? Ive heard that fuel slosh can be a problem without the baffles that the 82 tank has. Or should I just go out and find an 82 tank and be done with it?
Also what fuel pump should I run? Ive read a lot of guys are running a walbro but I dont know if that is a "bolt in" or not. Not sure of the output (lph or gph) Ill need either. Motor will be putting out roughly 500hp, Im hoping. Also, I will be running the C5 fuel filter/regulator if that makes a difference. Any suggestions on the fuel line? I was planning on using the stock hard lines if they will flow enough. Im not sure what pressures the pump needs to opperate at so will I need to be running AN fittings as well? Seems like that would cause a problem if I run a factory sending unit.
Sorry for all the question and thanks for any input! Justin
Also what fuel pump should I run? Ive read a lot of guys are running a walbro but I dont know if that is a "bolt in" or not. Not sure of the output (lph or gph) Ill need either. Motor will be putting out roughly 500hp, Im hoping. Also, I will be running the C5 fuel filter/regulator if that makes a difference. Any suggestions on the fuel line? I was planning on using the stock hard lines if they will flow enough. Im not sure what pressures the pump needs to opperate at so will I need to be running AN fittings as well? Seems like that would cause a problem if I run a factory sending unit.
Sorry for all the question and thanks for any input! Justin
Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
I would install a sump in the bottom of your stock tank and run a Walbro GSL392 inline pump. They are cheap and supposedly handle 550 HP. That will give you plenty of fuel and with the sump, you won't have to worry about fuel slosh.
You could use your stock line, but it is 20 years old. I would replace it with a new 3/8" line. The engine will run at 59ish PSI so everything should be made to withstand that pressure. You don't have to use AN fittings, but they are high quality and really not that expensive.
For what its worth, I have a rubber line running from the stock outlet on the tank to the pump and a rubber line from the refulator return back to the top of the tank. 5 years and no leaks or issues.
You could use your stock line, but it is 20 years old. I would replace it with a new 3/8" line. The engine will run at 59ish PSI so everything should be made to withstand that pressure. You don't have to use AN fittings, but they are high quality and really not that expensive.
For what its worth, I have a rubber line running from the stock outlet on the tank to the pump and a rubber line from the refulator return back to the top of the tank. 5 years and no leaks or issues.
Last edited by 70 LS1; May 3, 2007 at 03:38 PM.
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
Mine's twice that size and mounted externally (I like accessibility). It makes a slight hum or buzz that can be heard coming from under the car - that is, until the engine fires up!! 
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
82 sender only fits 78-82 tank. You can't use a 78-82 tank in a 68-77 because the filler neck is in a different place. I use an 88 ford truck external pump with my TPI, I think it should have enough volume for an LS1. If cost is no big object, you can probably get Rock Valley to make you a tank with internal pump provisions and use a stock LS1 pump-at least a stock TPI or LT1 pump.
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 904
Likes: 0
From: Murphy NC
It looks like the GSL392 might be borderline for me. Especially if I do any upgrades in the future. On the plus side its only $105 on ebay. 70 LS1 thanks for the pictures. I will most likely do something very similiar unless I go with the truck intake. The I will have to figure out how to plumb a return line as well
Z-man what pump are you running?
Z-man what pump are you running?
Le Mans Master
Joined: Sep 2000
Posts: 9,078
Likes: 7
From: DFW TX
Cruise-In VII Veteran
St. Jude Donor '07
I'm using the 82 sending unit with a LT1 intake pump. You will need to add a harness or pigtail. Fuel slosh is a problem when turn hard with less than an 1/8 tank. Now I'm talking autocross hard turn, not putt putting around town.
If your sending unit is good, just graft the new pump on and add a brace to support it.
If your sending unit is good, just graft the new pump on and add a brace to support it.
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Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
You can always add a second pump in parallel if you need more. I like the Walbro inlines because they are so cheap, easy to find replacements if you need one, and easily accessible. They have a nice whine to them, but once the engine is running, you have to be listening for it to hear it.
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
I've got an Aeromotive mounted on rails that I installed. The Walbros are good pumps, but their output was too small for my application. My pump is insulated by using rubber mounts. Seriously, unless you want to drive a sewing machine, you'll never hear the pump once the engine gets going. I'm also thinking of installing a voltage controller which will step the pump down when idling. Right now it runs at full blast all the time (most pumps do). The Aeromotives are also installed in-tank from several tank manufacturers.
Thread Starter
Burning Brakes
Joined: Oct 2004
Posts: 904
Likes: 0
From: Murphy NC
No sewing machine here but I am worried about the pump resonation through them frame and into the interior. Im sure the exhaust will mask it outside the car but I plan to REALLY insulate the interior to keep the exterior noise down. I dont think the sound deadener can kill the resonance through the frame but then again, I really dont know. Im sure with enough rubber between the pump and its mounting point there will be no transfer.Now would it be possible for me to keep my gas tank stock and run a seperate sump like Z-man is running? Im not sure if the inline pumps are rated to work with a siphon feed setup like on the later model tank I have.
Racer
Joined: May 2005
Posts: 462
Likes: 0
From: Tracy Ca
Go external
Aeromotive
If i had quiet exhaust i MIGHT be able to hear it in the car but with the open sidepipes i dont think i will be able to hear it
800hp capable and $305
http://store.summitracing.com/partde...5&autoview=sku
Aeromotive
If i had quiet exhaust i MIGHT be able to hear it in the car but with the open sidepipes i dont think i will be able to hear it
800hp capable and $305
http://store.summitracing.com/partde...5&autoview=sku
Last edited by PolishMike; May 4, 2007 at 12:42 PM.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I been using a cheepy from AZone for 12 years now...frame mounted under the tank....double FI hose clamped to the stock lines, supply and return...they fine....running a TPI with optimistic 400 hp....
think it had Master Craft on it....they about all alike far as I can see....
does 45 psi no sweat....will jump to 60 if I block the return hose....
as for noise....just wrap the pump in a old radiator hose, and I use a hose clamp to hold it into position....
think it had Master Craft on it....they about all alike far as I can see....
does 45 psi no sweat....will jump to 60 if I block the return hose....
as for noise....just wrap the pump in a old radiator hose, and I use a hose clamp to hold it into position....
Pro
Joined: Dec 2004
Posts: 590
Likes: 2
From: Fairfield CT
Good stuff.
hosspowerinc,
Sorry to hijack your thread, but this is great stuff! I posted a thread titled Back in a StingRay last week asking questions about C3 LTX / LSX upgrades and sources for interior parts. Only got answers to the interior parts question.
I have a '94 LT1 6 spd and just picked up a solid, low AZ miles '73 coupe project car. It was a BB (no motor in it now), 4spd car. Can you guys suggest where I can find info on the conversion or links to other threads? I've tried to search the forum with no luck.
I know there are many factors to consider, i.e. I'll probably have to run a separate electronic tach since the '73 is a mech drive tach. How do you hook up the e-tach to the ECM, etc?
What mods for the 6 spd install? Etc., etc., etc.
Now I'm learning about fueling, hadn't thought of it!!
Thanks for any help and again, sorry to hijack but this is the most info I've seen yet.
Carl
Sorry to hijack your thread, but this is great stuff! I posted a thread titled Back in a StingRay last week asking questions about C3 LTX / LSX upgrades and sources for interior parts. Only got answers to the interior parts question.
I have a '94 LT1 6 spd and just picked up a solid, low AZ miles '73 coupe project car. It was a BB (no motor in it now), 4spd car. Can you guys suggest where I can find info on the conversion or links to other threads? I've tried to search the forum with no luck.
I know there are many factors to consider, i.e. I'll probably have to run a separate electronic tach since the '73 is a mech drive tach. How do you hook up the e-tach to the ECM, etc?
What mods for the 6 spd install? Etc., etc., etc.
Now I'm learning about fueling, hadn't thought of it!!
Thanks for any help and again, sorry to hijack but this is the most info I've seen yet.
Carl
Advanced
Joined: Oct 2003
Posts: 78
Likes: 0
From: Lenexa Kansas
I'm using this setup in mine: http://www.tanksinc.com/index.cfm/pa...prod/prd84.htm Sorry if that's a bad link to include, I think I originally got it from this site.
The one I'm using is actually the PA-4P. Looks like a simple insall, I know it comes with just about everything you need. I bought a tank from the same place, as I wasn't too thrilled with the 8 patches I found on mine (and i know only 3 of them were from me!). Looks like a nice setup, we'll see in about a month!
The one I'm using is actually the PA-4P. Looks like a simple insall, I know it comes with just about everything you need. I bought a tank from the same place, as I wasn't too thrilled with the 8 patches I found on mine (and i know only 3 of them were from me!). Looks like a nice setup, we'll see in about a month!
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
It looks like the GSL392 might be borderline for me. Especially if I do any upgrades in the future. On the plus side its only $105 on ebay. 70 LS1 thanks for the pictures. I will most likely do something very similiar unless I go with the truck intake. The I will have to figure out how to plumb a return line as well Z-man what pump are you running?
Z-man what pump are you running?
Rick B.
Le Mans Master
Joined: Oct 2001
Posts: 5,145
Likes: 125
From: The Motor City
I run the same external Walbro pump and 99+ Corvette filter/regulator as the guys above but I spent the extra dough and went with AN fittings and braided hose. No problems in 3+ years.
The answers to all of your questions (and even the ones that you don't know that you need to ask yet) can be found in LS1Tech's Conversions and Hybrids. 70LS1 and I are both moderators there.