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 LT1 Fuel pressure and volume?

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AzDon

AzDon


Posts : 359
Join date : 2011-08-05
Age : 68
Location : Lake Havasu, AZ

LT1 Fuel pressure and volume? Empty
PostSubject: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeThu Feb 09, 2017 4:55 pm

So, I'm considering having a fuel tank made for my 69 van that uses a stock wagon module.... Initially, I'd be using a TBI module, but would want to upgrade to an LT1 module when converting to FiTech EFI which requires 58 lbs of fuel pressure.... I don't have access to pump specs for the LT1 pump.... Can anybody hook me up with pressure and volume specs and reassure me that an LT1 module can be installed in place of a TBI module?
Thanks Guys!
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Fred Kiehl

Fred Kiehl


Posts : 7290
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeThu Feb 09, 2017 7:31 pm

The TBI module can mount any pump that the LT1 module can. The difference between the two modules is that the plastic mount for the pump in the LT1 module can move up about an inch to make sure the pump is at the lowest point in the tank. The TBI module is fixed, and if the tank balloons, and the bottom flexes downward, the pump can starve for fuel at a "fuller" tank level. The modules are completely interchangeable.

I do not know what the maximum pressure the LT1 pump can provide. A Walbro 255 pump may provide the pressure you want. You will have to inquire with the different manufacturers for the pressure ratings of the individual pumps. FiTech has an inline frame mounted pump that is a 255 lph pump. You could modify the wagon module and use the frame mounted pump instead of an in tank pump. You would still need a sump, or something like the Hydramat.

Depending on the HP you are going to produce, you may need a bigger pump than will fit in either module. You do not state the projected HP output.

I read a little on the FiTech system, and you may want to look into Holley's Hydramat for in the tank. It will pick up fuel anywhere it runs until the tank is virtually empty. They may not make a Hydramat for your tank size though. FiTech recommends a sump to keep the pickup covered with gas at all times. Self learning fuel injection systems learn immediately, and if you get a shot of air instead of gas, it can throw the system off for a few seconds. Hydramat is extremely expensive (Holley has a lock on it), but worth looking into if you are not going to have a sump.
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jayoldschool

jayoldschool


Posts : 2728
Join date : 2009-06-14

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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeThu Feb 09, 2017 7:47 pm

LS pump is what you want. LT1 pump puts out mid 40s.
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AzDon

AzDon


Posts : 359
Join date : 2011-08-05
Age : 68
Location : Lake Havasu, AZ

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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeThu Feb 09, 2017 8:04 pm

I was looking at Walbro pumps at tanksinc and it looks as if I could put one of those pumps in my module..... Are pumps pretty universal in the way they fit into the modules?
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Fred Kiehl

Fred Kiehl


Posts : 7290
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeThu Feb 09, 2017 8:13 pm

Make sure the pump will deliver the required pressure. The 255 will deliver the volume for up to about 450 HP. The pump will fit in either module. You must use a straight hose in the TBI module. The LT1 module can use an S shaped hose.
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AzDon

AzDon


Posts : 359
Join date : 2011-08-05
Age : 68
Location : Lake Havasu, AZ

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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeFri Feb 10, 2017 6:32 am

Cool!.... So since I'm having a tank made and don't actually have a module yet......The LT1 module is a superior design because it presses down against the bottom and it would also be preferable to have a dropped sump in addition to baffles?
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Fred Kiehl

Fred Kiehl


Posts : 7290
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeFri Feb 10, 2017 8:49 am

If you are having a metal tank made, the LT1 module does not provide any advantage, unless the height of the tank is variable. The metal tank will not flex like a plastic one. The sump is the superior design aspect. Most tanks with a sump do not run an in the tank pump. Properly designed baffles would also help insure the gas stays in the sump. It is also important to have a properly designed/placed sump. A foam insert would be another option, to keep the gas from sloshing, but that would restrict the volume of gas in the tank. The sump will use up some of the ground clearance or make the tank smaller to maintain the ground clearance. The plastic part on the LT1 module is what I would have concern about, because it can get brittle with age. The Hydramat would eliminate the need for a sump, although you would probably end up with a frame mounted in line pump, and a thinner wallet. There are some trade-offs. A small square/rectangle, tall tank, and a sump with baffles, or Hydramat is the optimum for keeping fuel over the intake for the pump. If you look at fuel cells for racing you will see that design.
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AzDon

AzDon


Posts : 359
Join date : 2011-08-05
Age : 68
Location : Lake Havasu, AZ

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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeFri Feb 10, 2017 12:44 pm

Thanks Fred!
The van has plenty of ground clearance and a very short rear overhang..... The stock tank is 10" deep and hangs 1/2" below the floor and I'm going to add an inch of floor clearance and add a service door......I believe our wagon tanks are 9" deep....I hadn't considered a frame-mounted fuel pump, as that would be easier to change in the future.....
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Fred Kiehl

Fred Kiehl


Posts : 7290
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

LT1 Fuel pressure and volume? Empty
PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitimeFri Feb 10, 2017 12:52 pm

Just make sure the frame mounted pump is below the bottom of the tank.
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PostSubject: Re: LT1 Fuel pressure and volume?   LT1 Fuel pressure and volume? Icon_minitime

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