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Atomic MSD fuel injection 77, 454, K15

77snowwheeler

77snowwheeler

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Hey all. Looking to get the Atomic 2900-2, for my 454, k15 short bed. Currently getting 7 miles to the gallon. Trying to get ten, possibly 12, would be ideal. I don’t have return lines, so definitely don’t want to open that can of worms, because I have a third 20 gallon tank in the bed. Any opinions? I have a guy that installs them, that told me the 2900-2, has an option, in the ecm, to put no return lines. He said he would weld the bung in, even though they have the quick bung in the kit. Also, to gain more mileage, I want to add, an electric fan, and take out the drag, on the clutch fan?

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Run the return line. It will help the electric pump run cooler which equals longer life.

As for electric vs fan clutch, on a fat truck the difference will be negligible. A good clutch set up is super efficient (otherwise manufacturers would have eliminated them on trucks years ago) plus an electrical fan swap with likely force an alternator upgrade, how long will it take to recoup the total cost of the swap? Years.
 
nvrenuf said:
Run the return line. It will help the electric pump run cooler which equals longer life.

As for electric vs fan clutch, on a fat truck the difference will be negligible. A good clutch set up is super efficient (otherwise manufacturers would have eliminated them on trucks years ago) plus an electrical fan swap with likely force an alternator upgrade, how long will it take to recoup the total cost of the swap? Years.
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Do I just run one line from any tank?
 
your setup will be custom for return as its best to run the return to the tank getting fuel from .

and best is intank pump this also keeps the pump cooler and also better for high psi pumps to push rather than draw and then build psi and push .

my efi swaps i do a primary tank and the rest are on a switch with a RED light so i dont forget there on and also there power is pulled from the key on side only so if trucks off no fuel flow from the 2nd tank . this lets me pump fuel from the extra or extras to the primary and not need to run a high pressure crazy money switcher valve . i just tee in to the filler neck small vent line and dump it in there no problems .
 
Man, that is a ton of work. I’ve had to replace both tanks already from leaking, and now I d have to drop them again to put in, in take pumps. I thought fuel was supposed to be cool anyway? Now I have to recycle it, to make it cooler? Holy Crap. Lol
 
Big blocks are thirsty, you might see better fuel mileage but it's not a guarantee. At least with the fuel injection you'll know the engine is getting the proper AFR at any given time. (Well, whichever cylinder Bank you have the O2 sensor on)
I would keep the mechanical fan any day over an electric unit. They always seem just to plain work.
 
Gasoline is cool. The return line isn't used to make the fuel cooler, without a return line the pump pressure will deadhead which creates more load on the pump (backpressure) which in turn raises the pump motor temp. Heat kills electronics.

In tank pumps are nice because it is surrounding the pump with the cool fuel so the electric motor runs at a cooler temp. External electric pumps are available as well (Iirc, an Airtex # E2000 is the common pump used) but both types are happier with the return line.
 
So if the Atomic is designed to run without the return line, you think maybe the right pump might be figured in?
 
77snowwheeler said:
Man, that is a ton of work. I’ve had to replace both tanks already from leaking, and now I d have to drop them again to put in, in take pumps. I thought fuel was supposed to be cool anyway? Now I have to recycle it, to make it cooler? Holy Crap. Lol
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if just moving fuel 1 tank to the other just use a inline universal pump . not building efi pressure just moving fuel is all .
 
Later (somewhere between 1995 and about 2010 I'd guess) Corvettes used a combination fuel pressure regulator/fuel filter/return didn't they?

Is that an option? Still going to need tank returns, but that would prevent having to run a line up to the engine bay and a regulator up there.

Sorry, clueless on that system in general, but if the Corvette piece would resolve the issues up to the engine, it would seem easier.

Starting to complicate while simplifying, you could probably tee two tanks together on the fuel outlet side, and make the third tank your "primary". Two auxiliary tanks as storage, switched however you currently switch them, but only used to fill the primary. Then your primary tank is the only one that needs a return line. There are problems I see with that idea, but safety isn't really one of them as long as the connections are done right. Fuel/return lines on three tanks isn't even possible using factory components, so you'd run into problems there anyway. Not putting a ton of thought into it, you could do this with one later/TBI sender with the three fittings (Fuel out, EVAP, return) on the primary tank, or you could dump the auxiliary tanks into the vent line on the fill side of the "primary" tank.

Electric fans really aren't worth the effort unless space is an issue, or you are starting from scratch. I'd say leave it be. From what I can see you've got one of the HD clutches and fans. You won't save noticeable MPG from the clutch fan, which generally works better than electrics anyway. As long as that's a thermostatic clutch, its as efficient as a clutch fan will get.
 
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From what I see in a bunch of videos from Trailmater, the MSD system works pretty well. He installed a 2nd system on his blue truck too.

I had electric fans on my BB in my K10 for a while, but they cycled a bunch because of the A/C. I went back to a clutch fan and didn't notice much of a difference anywhere. I imagine that a variable speed fan control would have been better.
 
A few ideas:

  1. FITech has an underhood surge tank setup. Could that setup work with no return to a fuel tank, just circulating through the fuel rails?
  2. Weren't there dual-tank applications in the early 90's that have the required double electric valves required to return to multiple tanks?
  3. Can the return line go to just the main tank, with the aux tank pump transferring fuel to the main when needed? That's how my GMT800 Suburban works. The user has no idea there are 2 tanks when filling or using.
 
Blue85 said:
A few ideas:

  1. FITech has an underhood surge tank setup. Could that setup work with no return to a fuel tank, just circulating through the fuel rails?
  2. Weren't there dual-tank applications in the early 90's that have the required double electric valves required to return to multiple tanks?
  3. Can the return line go to just the main tank, with the aux tank pump transferring fuel to the main when needed? That's how my GMT800 Suburban works. The user has no idea there are 2 tanks when filling or using.
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To answer your number one, that fi-tech surge tank does require a return line to a fuel tank. It has a built-in regulator, so it needs a return line.
Also I tried out an older version of that in my truck for a bit and it's not recommended. It seems there's not enough fuel in that little tank to keep the fuel pump cool, and then it's under pressure trying to pump fuel all the way back to the main fuel tank, I had a lot of problems with vapor lock.
 
The problem is he has three tanks. No way to run a return using factory components for that. At least that I'm aware of.

It makes sense to just run the other tanks without returns as simple storage tanks to transfer out of. Although Id be worried about running the tanks dry and the pumps too without being able to watch the fuel level.

I'm curious how the 800 transfers fuel without the user doing something to fill the primary tank? Would seem the best way to do it, if it's something simple I'm not envisioning.
 
i already said easy fix to the 3 tank problem .

1 tank is primary with pump feed and return .

the rest on a switch to pump there fuel to the primary tank only and basicly be a built in jerry can .

problem solved . i have been doing this problem free for years now .
 
dyeager535 said:
I'm curious how the 800 transfers fuel without the user doing something to fill the primary tank? Would seem the best way to do it, if it's something simple I'm not envisioning.
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Both tanks have a regular pump and sending unit. The main tank is the regular SUV tank - 28 gallons or whatever and feeds the fuel rails. The aux tank mounted above the spare tire is 10-12 gallons and only feeds the main tank. Both levels are monitored by the PCM, which does the transfer. https://www.tahoeyukonforum.com/threads/can-someone-explain-the-dual-fuel-tank-set-up-i-have.133271/
 
I
dyeager535 said:
The problem is he has three tanks. No way to run a return using factory components for that. At least that I'm aware of.

It makes sense to just run the other tanks without returns as simple storage tanks to transfer out of. Although Id be worried about running the tanks dry and the pumps too without being able to watch the fuel level.

I'm curious how the 800 transfers fuel without the user doing something to fill the primary tank? Would seem the best way to do it, if it's something simple I'm not envisioning.
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sweetk30 said:
i already said easy fix to the 3 tank problem .

1 tank is primary with pump feed and return .

the rest on a switch to pump there fuel to the primary tank only and basicly be a built in jerry can .

problem solved . i have been doing this problem free for years now .
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That would work, but now I have to get the three port tank unit to accommodate the service line, return line and feed line from other tanks. Lol I guess at least one of the tanks would have to be drop down, again. Ug. Lol
 
Didn't see this discussed, but isn't a gauge the easiest part? Meaning the dash gauge or an added gauge can switch between tanks with a simple toggle switch. That let's you watch the levels while transferring fuel between tanks, as you don't want to overfill a tank (it should be able to enter the emissions lines or spill out on the ground) and don't want to run a pump dry.

The bed tank is 20 gallons, how big are the others? Why do you need so much fuel? A week of backcountry?
 
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