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Fuel System for E85

batmanntexas

Full Member
Joined
Mar 14, 2010
Messages
95
Location
Sanford, NC
With the new mods to the Avalanche, I decided to run it predominantly on E85.  I have already installed a physical ethanol content sensor to use instead of the crappy 'virtual' sensor, as well as some 95lb/hr injectors.  To keep up with fuel flow, i needed to address the fuel pump assembly.  My search on the web was less than fruitful.  I found a few twin/ triple pump setups, but they were always listed for the pickups, and I couldn't seem to find one that would fit within our tank dimension (depth wise, it's ~7.5" IIRC).

So, I decided to make my own.  See below.
 

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I'm terrible at taking pictures during a project.  I get focused on the task at hand, and when I think about pictures, it's usually almost wrapped up.

I utilized 3 pumps for this setup, and converted to a return-style system.  I believe the stock pump (flex fuel vehicle) is rated at 255l/hr, and I bought two additional 255l/hr pumps (E85 compatible), for a total flow rate of 765l/hr.  Granted, those flow rates are probably at 43.5psi, and I plan to run a base pressure of 58-60psi, so I'm probably in the 700l/hr range for total flow.

Anyways, here are the steps I took to get it done (2007 Avalanche).  You want to do this on a lift ideally, but it could be done on jack stands as well, you just need about 20" clearance between the tank and the ground.

1. start with a fuel tank that is 1/8 full.
2. disconnect the following items:
  - Rear portion of fuel tank:
      -- fuel filler hose,
      -- 3 plastic lines for the charcoal canister (2 @ 17mm, 1 @ 13mm),
      -- 2 plastic lines on top of the fuel tank (one is about 17mm, the other is about 10mm),
  - Front portion of the tank:
      -- 1 plastic line, 10mm diameter (front right top corner of tank)
3. Grab a buddy, or place a floor jack with a 2x10x38" or 2x12x38", and support the tank
4. Using a 15mm socket, remove the bolt that secures each tank strap
5. Slowly lower the tank about 4-5".  The rear has to come down first, as the front of the tank sits in pocket created by a chassis brace.
6. Once down about 4-5", wiggle your way up so that you can see the top of the tank.  There are 2 electrical connectors and 2 more plastic lines that have to be disconnected BEFORE you can lower it the rest of the way.  I found that a pair of curved jaw needle nose pliers worked nicely for removing the 2 plastic lines.
7. Once everything is disconnected, you can finish lowering the fuel tank.
8. Once the tank is on the ground, or workbench, you need to remove the fuel pump locking-ring.  There is a special tool for this, but I have found that a drift punch and hammer work also, just have to use a little patience and care.
9. With the lock-ring removed, the fuel pump module can be lifted partially out of the tank to expose the last plastic hose connection.  Once disconnected, remove the pump module from the tank.  It will be full of fuel, so once out, just tilt it on its side to drain the fuel back into the tank.

-- additional posts to follow --

-Scott
 
Interested in hearing more details since I will need to do something similar with my '03. I am a little ways out yet for the fueling system so I will not have the blower on my truck yet but I am definitely interested in how you accomplished this. As in what parts etc...

What are you using for fuel lines?Are you replacing the fuel rails with something bigger?  What HP will those injectors support?

Since I am looking at over 1000 hp eventually on mine I want to go a route that will support it.

Thanks!
 
Redheadedrob - For fuel lines I ran a new 1/2" fuel line from the pumps all the way up front to the new filter, regulator and fuel rails.  I used the stock fuel feed line (3/8") as my return line.

These injectors will support 800+ rwhp on E85, probably close to, or over, 1000rw on 93.

The Whipple came with billet fuel rails, so they are plenty big.  By the way, the stock fuel rails have been used in applications over 1000whp.

The parts list:
- 2 each 255lph pumps
- 3 each 8mm x 500mm Fuel tube
- 1 each 3-way round manifold (3/8 NPT to 1/4 NPT)
- 3 each 1/4" x 1/4 NPT hose barb
- 8AN Bulkhead connector (90*)
- 8AN to 3/8 NPT adapter (90*)
- 1/2" fuel line
- fuel filter (10 Micron)
- various 8AN fittings
- 12V relays (1 for each pump)
- Oetiker clamps (3/8")
- Fuel pump bulkhead wiring system
- Hobbs switch for pump activation (if boost referencing pump activation)

Pics to follow...
 
So you are using the original pump and two additional pumps in your system? Makes me wonder if I shouldn't expect to just purchase 3 of those 255lt/hour pumps.

I need to see if anyone out here is running Flexfuel with a 4l80e transmission. Has to be a 2003-2005 variety truck.

Apparently my tuner is having problems with this configuration as he has not found a tune for this yet that works. He has suggested otherwise I will want to go with a fully hydraulic 4l80e and he will disable the transmission portion of the tune.

I have the original return system in my truck still that needs to be replaced anyhow(Changed in the end of the 2003 model year, apparently after my truck.). The lines to the fuel filter are bad enough I don't dare pull the filter out or I assume the lines will break off. They seem to be rusted to the filter. Looked under my truck a couple times recently and other than some surface rust my truck is still very solid so I am not scared to work on it and get it back to better than original.

Rodney
 
Correct, stock pump plus two additional aftermarket pumps.

Do you know if your tuner has performed a segment swap (I'm assuming that he is using HP Tuners)? 

If he is using HP Tuners, you might have him contact HP Tuners directly for support.  Several iterations, my Camaro received a custom OS from HP Tuners to add some additional tables that were not there in factory form.  I don't recall paying anything for the service, just had to wait a few days for them to get to it.

-Scott
 
Pics, in order of listing in previous post.
 

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batmanntexas said:
Correct, stock pump plus two additional aftermarket pumps.

Do you know if your tuner has performed a segment swap (I'm assuming that he is using HP Tuners)? 

If he is using HP Tuners, you might have him contact HP Tuners directly for support.  Several iterations, my Camaro received a custom OS from HP Tuners to add some additional tables that were not there in factory form.  I don't recall paying anything for the service, just had to wait a few days for them to get to it.

-Scott
Yea he uses HP Tuners... And has done segment swaps but no matter what he has tried so far it never registers the alchohol level.
I will see him tomorrow so I will ask him if he has tried contacting them for it. I have months before I will be ready for the 4l80E so I do have time to figure it out.

Rodney
 
By the time I work on the fuel system it will have a sensor in it... I want to be able to go flex fuel with it.. Either E85 or Premium.
 
Well, I knew I was on borrowed time when I put the 383 in my Avalanche back in 2016, however, with careful tuning of the TCM, and not beating on her to bad, the transmission held up fine...until I went for round 2 of modifications.  It DID NOT like the added power that the Whipple supercharger brought to the party though.  It made it about 5 miles before it said 'Ohhh, Hell NO!!!'  Before it gave it's life though, it did go out in a blaze of tire smoke!! (at that point I already knew it was done, so I figured it couldn't get any worse).

  So, I looked around on line, and decided to go with a PerformaBuilt Heavy Hauler Max 4L70E package.  It is basically their Level 3 Race transmission with a softer shift kit.  It comes with a 2 year warranty, unlimited miles, and free shipping within the continental US.  They build each transmission to order, so I should receive it within 2 weeks...then I can get back to getting the tune finalized.

-Scott
 
How did this turn out? I want to see a 1000HP Av
Pretty good. It's not a 1000hp Av, though....maybe 700;)

Seriously though, I haven't gotten it on the dyno, and the fueling is still pretty fat currently. But, I can tell you that it will burn the tires off from a roll @30mph...

Come to Sanford, NC and you can see it in person! It's going up for sale here pretty soon.

-Scott
 
Hey that's "only" 6 hours from me. I'd definitely like to see some pictures if you end up taking them for the sale.
 
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