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Fuel injection day tank?

blubuckaroo

Grease Monkey
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Jun 11, 2007
Messages
11,796
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Ridgefield WA
I'm thinking of a Fitech FI unit, but I'd like to maintain full functionality of the dual tanks.
Has anyone had experience with the underhood daytanks that are available?
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DirtDonk

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Never heard that term used. What does it mean? Is that the separate units with integrated reservoir and pump like the FiTech Command Center, or one of the others like it?

Several ways to keep the dual-tanks functional, and many here have done all of them most likely. But the reservoir-with-pump is a great concept. Just doesn't always work as hoped. You've likely seen some of the threads about the Command Center.

Paul
 
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blubuckaroo

blubuckaroo

Grease Monkey
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Messages
11,796
Loc.
Ridgefield WA
Never heard that term used. What does it mean? Is that the separate units with integrated reservoir and pump like the FiTech Command Center, or one of the others like it?

Several ways to keep the dual-tanks functional, and many here have done all of them most likely. But the reservoir-with-pump is a great concept. Just doesn't always work as hoped. You've likely seen some of the threads about the Command Center.

Paul

I didn't know what to call it, but stand-by emergency generators use a similar principle, with a large remote fuel tank, and a transfer pump to a smaller tank by the generator.
 

Broncobowsher

Total hack
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Jun 4, 2002
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37,065
Well you say they are available, please post a link to one. That will really clarify what you are refering to.

Yes, you can run EFI with two tanks. And there are a half dozen different ways it can be done.
 

DirtDonk

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I think he means the Command Center and their ilk.
They can do the accumulating AND feeding AND bypass/return duties. They do simplify certain things, but it's not like they don't have their own issues.

Some people use the transfer pump idea to use the aux side tank as a backup and simply transfer fuel from it to the main tank, from where it feeds the EFI setup.
This is one way to save money, by only needing one of the (usually) more expensive high-pressure pumps for the EFI and a less expensive low-pressure one for transfer duties.
This would be true whether the pump was an in-tank or frame mounted high-pressure pump.

You can use a single pump for the whole system if you use a frame mounted high-pressure pump in front of the selector valve and just switch between tanks like normal.
This might be your best idea depending on how you wheel and the heat factor of your particular climate.

You can install a remote mounted reservoir with it's own in-tank high-pressure pump that gets fed from the stock mechanical pump on the engine. This is like the Command Center and all the others.
This lets the stock pump do all the high-volume, low-pressure feed pulling duties (that the high-pressure pumps are not so good at) even while mounting it up front near the engine.
The main claim to fame is the lack of plumbing hassle. They usually have an internal bypass that acts as the return line. Instead of plumbing one back to your tanks, it just recycles excess gas right back into itself.
And heat too unfortunately...

The accumulator setup was there for certain applications where the high-pressure pump just wasn't quite up to the task of pulling fuel up from the tanks enough to handle the power and odd angles of heavy off-roading. A low-pressure pump would keep the accumulator filled and the high-pressure pump could pull from that and feed the engine reliably. All the return line needed to do was go back to the accumulator and that simplified things too.
Well, if you consider all the extra "stuff" needed for this setup as "simplifying" anything.

The items like the Command Center and all the other brands of similar products were supposed to take care of all the little problems that made up a home-made EFI plumbing setup. They do almost, but sometimes have their own issues. Heat being one of them apparently.

You've been here so long blu I'm surprised to hear you didn't pay that much attention to all the discussions about this stuff. Were you really that dead set against EFI that you didn't bother looking into it? And are you now leaning towards EFI finally so curious about the ways to do it?
If so, I think you'll like it. But it's no different than any of the other mods we do to our old rigs. There is not just one way of doing it. And one thing always leads to another.

And there's probably a lot more to it than I'm just touching the surface of. I'm sure you'll get lots of good feedback for running two tanks. It's eminently doable.

Paul
 
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blubuckaroo

blubuckaroo

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Thanks Paul.
The Fitech Command Center is what I was referring to. I just didn't know what to call it.
That looks like a pretty good deal considering the price of a FI pump and high pressure lines.
Also, this unit works with the Fitech variable speed output for the fuel pump on the throttle body.
The dimensions are pretty small too. I wonder if it would ditch in the space for the drivers side vent bucket? That would keep it out of the engine compartment heat, and the fuel connections out of the passenger compartment.
Just a thought.?:?

And yes, i'm coming around to the idea of FI. We'll, sort of...
The reality is, our car gets a lot of use, and i'm tired of the issues of heat soak and fuel bowl dry-out, caused by modern fuel.
I still can't stand the thought of the monstrous Ford system under the hood of my car.
The Fitech looks enough like a carb to pass for me. And if I don't like it, I can still throw the carb back on.
 
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Broncobowsher

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The fuel commander is a giant carb float bowl. Only instead of feeding jets and an idle circuit and all that other carb stuff, it houses a fuel pump.

That is a lot of money to avoid running return line(s) to the tank.
And I've heard it isn't all that great of quality as well. You still need low pressure pump to feed it.

What I do see it great for is a shop selling someone fuel injection. Saves a little work under the car, and you get to make more profit selling the customer more parts.
 

DirtDonk

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Yep. Bought one of those long before I ever thought I'd want fuel-injection. Figured that a return line for a carburetor was a big bonus in both pressure at the needle-n-seat, as well as keeping things cool and the pump working well.
Never actually got around to plumbing in the return system though. Since I never actually had a problem to fix, it stayed low on the list of priorities.
But it's still a valid idea for either carburetors or EFI.

Paul
 

Scoop

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I have been helping my brother in law install his FITech. He started out with the Command Center but then swapped it out for a frame mounted high pressure pump. Personally I would not use the Command Center - seems to be a source of issues for a lot of FITech installs. Although once you get the bugs worked out I know of several that are working well.

That said it's probably a decent way to go to keep a 2-tank set up. You don't need to run a return line to either tank - the fuel return is done at the Command Center which houses the high pressure pump. You would just need a low pressure pusher pump after the tank selector valve.
 

76 bronco J

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The fuel commander is a giant carb float bowl.

>> pretty much & that will be a problem for lots of bronco owners ... quote from Bryce at Fitech >> "The Fuel Command Center has a needle and seat with a float in it. Because of this it is susceptible to running out of fuel at a cambered angle just like a carb."
 
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blubuckaroo

blubuckaroo

Grease Monkey
Joined
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Messages
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Loc.
Ridgefield WA
The fuel commander is a giant carb float bowl.

>> pretty much & that will be a problem for lots of bronco owners ... quote from Bryce at Fitech >> "The Fuel Command Center has a needle and seat with a float in it. Because of this it is susceptible to running out of fuel at a cambered angle just like a carb."

OK, good point!
I never thought about that.
No use repeating fuel level issues, when you're trying to eliminate them.%)

Another question...
These are available in 400 & 600 horsepower versions.
My car has a mild built 302. But even if I were to build a 351W it still wouldn't be in the 400 HP range.
The 400 HP Fitech version doesn't have some of the nice options, like timing control & fuel pump speed control like the bigger 600 HP version has.
Will using the bigger Fitech hurt my driveability, mileage, or performance?
 

DirtDonk

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I think they mis-named the units myself. Too confusing.
While there are supposedly some differences in ability to support different HP levels, the primary difference is in fact the software to control the ignition timing.

So don't make a choice based on your expected power level. Make it ultimately based on whether or not you want the computer to control the timing.
Of course, if your timing is pretty dialed and you want to save a hundred bucks or two, nothing wrong with the 400. But personally I like having the option and would prefer the 600 and letting it do the timing duties too.

Unfortunately there isn't a lot of feedback from members here yet who are using the 600 AND using it to control timing. Maybe someone will chime in with their back-to-back results.

Paul
 

KeithKinPhx

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Jan 8, 2017
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There is a cheaper option with no engine bay clutter.

Run main tank as EFI. No valves.

Get cheap electric fuel pump for Aux. Run Aux pump to a newly installed tee I n main tank fill breather hose (5/8 inch). If main is low on fuel, flip switch and pump fuel from Aux to main. You can place switch where factory manual valve is under driver seat.

Regarding the 600 Jon at Nashville Bronco has some YouTube videos on installation and tuning. You can also Email him and he usually good about responding.
 
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blubuckaroo

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,796
Loc.
Ridgefield WA
There is a cheaper option with no engine bay clutter.



Run main tank as EFI. No valves.

Get cheap electric fuel pump for Aux. Run Aux pump to a newly installed tee I n main tank fill breather hose (5/8 inch). If main is low on fuel, flip switch and pump fuel from Aux to main. You can place switch where factory manual valve is under driver seat.

I've seen this done.
It doesn't look safe, unless it's set up so fuel can only be transferred when the engine is off.
In my family every car can be used by every member. Others might inadvertently flip that switch. If you try to pump fuel into an already full tank, you could be headed for trouble.
Fuel is going to leak out of the filler, and vents.
 
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AZ73

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Mar 28, 2012
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3,813
My system is complicated, but it allows me to run 2 separate fuels if desired (think 87 and 91). I use a similar switch as noted before, but it's a 6 port.

http://products.pollakaftermarket.c.../light-truck-6-port-motor-driven-valve/42-302

Because the pressure rating on it is below the pressure required by the FItech (or in my case, the Holley Sniper). I run a carter LP pump to draw through it, then a Bosch HP pump to feed the carb. I did this set-up because my Holley will control the distributor timing, taking advantage of cheaper 87 to get where I'm going, then switching to 91 for power. Or just running both tanks the same fuel.

The only weird thing was mounting the switch. It was designed for a GM I believe and the mounting bolts were on a weird 45 degree angle. I had to build a bracket to mount to the frame, then bolt the switch to the bracket. I just made the bracket a complete wrap around to protect the plastic switch.

Don't forget an inertia switch to cut off the pumps in case of rollover.
 

Broncobowsher

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37,065
I've seen this done.
It doesn't look safe, unless it's set up so fuel can only be transferred when the engine is off.
In my family every car can be used by every member. Others might inadvertently flip that switch. If you try to pump fuel into an already full tank, you could be headed for trouble.
Fuel is going to leak out of the filler, and vents.

It is done all the time. Countless trucks with in bed fuel tanks transfer to the main tank for long drives. They even have them built right into the bottom of tool boxes. Sometimes they are found with a dispensing handle for refueling equipment in the field. But most are set up on the transfer system to top off the main tank while cruising down the road.
 

Cortez

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Jan 29, 2009
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I'm using both tanks, with the 6 port electric switch. I have the inline frame mounted pump after the 6 port and within 3 feet of both tanks placed at the lowest fuel level. Works great. I found a moroso return port that I plumbed into the filler tube which handles the fuel return. For the record, the Fitech inline pump is way too loud for most people and there are alternative options...I ended up going with a Bosch which was a good improvement over the Fitech pump. Doing a search on the forum you should find a couple threads that have parts for all these or you can PM me and I will share what I used.
 
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