New higher performance fuel system setup and a modification how-to - Performance Forum

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New higher performance fuel system setup and a modification how-to
Monday, July 29, 2013 3:41 AM
I started this project out of sheer necessity. My first fuel system upgrade for my turbo Sunfire was the Racetronix/Walbro 255lph fuel pump. I also purchased the upgraded Racetronix wiring harness. This sends alternator voltage to the fuel pump instead of battery voltage. With the upgraded Racetronix setup, the pump supplies more than adequate fuel for most any car on the .org. However, the last time I went to the track, my car started cutting out mid-track; Before I shut it down, I saw AFR's in the range of 17:1 while boosting over 20 psi!!!

After doing some diagnosis, I came to the conclusion that the fuel pump was on it's way out. This didn't make me happy AT ALL, since I have less than 10K on the Racetronix setup. However, instead of going with a direct replacement, I decided now was a good time to upgrade past the Walbro 255. This new setup should be more than enough fuel for just about any car on the .org.

I started by dropping the tank and disassembling the sending unit. Pulling the defective Walbro unit out of the sending unit.



The factory GM setup uses a smaller second pump outlet along side the main fuel supply outlet. This second outlet is used to fill the sending unit bucket with fuel, keeping the pump submerged in fuel at all times. It has the advantages of keeping the pump cooler, and the pump will not be starved of fuel due to sloshing of the liquid during hard cornering or other maneuvers.

Racetronix has came up with a solution to replicate this setup by modifying the Walbro pump they use in their kits. This is accomplished by adding a small brass nipple to the top of the pump near the main outlet.



This nipple unscrews from the top of the pump easily,.




The top of the Walbro pump underneath the plastic cap is a large empty cavity that fills with fuel, so the brass venturi nipple outlet receives the same amount of fuel as the main outlet. The only difference is the nipple receives fuel BEFORE the main outlet check valve, so the pressure and volume of fuel going to the engine is unaffected by the addition of the nipple.



This is my new pump. The Aeromotive stealth series in-tank fuel pump. It outflows the Walbro 255, putting out over 340 LPH at 45 psi. It is also a more efficient turbine style pump, compared to the gerotor Walbro design. It is also noticeably quieter than the Walbro pump.



The Aeromotive pump comes with its own outlet adapter, filter sock, pump sleeve, wiring harness pigtail, hose, and clamps.



And it is virtually identical to the Walbro in all exterior dimensions....





...except for the secondary venturi outlet nipple.



Fortunately, the pump is easily modified to accept the venturi nipple. Similar to the Walbro setup, the Aeromotive pump has an empty void underneath the top plastic cap, so the addition of the venturi nipple is relatively easy and straight forward. All that is needed is to CAREFULLY drill a small hole in the plastic cap, being careful to stop drilling as soon as you break through the plastic cap.



Then using a tap with the same threads as the nipple, carefully tap threads into the plastic housing. The plastic is soft and fragile, so be careful not to strip out the hole or break the plastic cap or your new pump will be ruined.



Pretty close to the same spot as the Walbro pump if I do say so myself.





Then carefully screw the nipple into the new pump. Now the Aeromotive pump is fully compatible with the GM venturi setup!



Now reassembly of the sending unit with the new pump begins. The Walbro pump uses a sleeve to make up the size difference between the housing and pump. This same setup is used on the Aeromotive pump.





One of the few differences between the Walbro and Aeromotive pumps is the style of filter sock used. The Walbro pump uses a sock that attatches directly to the pump, the Aeromotive uses an adapter and different style sock filter on the bottom of the pump. This adapter wiont fit on the bottom of the stock pump retainer.



So it was necessary for me to cut out the bottom of the retainer slightly.



Now the adapter and sock filter fit perfectly on the bottom of the reatainer.





Now it's just a matter of reassembly of the sending unit components, making sure that all lines are tightly clamped, the pump is seated in the bottom of the reatainer, and nothing is binding or twisting while compressing the sending unit assembly.







Be careful when handling the float level assembly while reinstalling. It is easy to bend or break the unit or pinch the wires.





The Racetronix pump setup uses the exact same plugin style for the pump wiring as the Aeromotive 340 pump. In fact the wiring was a slightly larger gauge on the Racetronix setup than what was supplied with the Aeromotive pump, so I just left it in place and secured everything with a nice dollop of dielectric grease.







One last check of everything, then installation of the sending unit in the tank.




Once everything was assembled and ready to go, I reinstalled the tank, connected the lines, and primed the fuel system. Once I confirmed there were no leaks, I took the car for a test drive. Works amazing!!! Instead of the 17 AFR's I saw before, my AFR's are in the low 11 range. Everything seems to be working great, and I even threw in a new adjustable fuel pressure regulator for good measure.




As far as flow characteristics and power potential, there were tests done showing the differences between different popular pumps. As seen here, the Aeromotive was the best flowing in tank fuel pump, and delivers over 100 LPH more than the Walbro pump at any given PSI level.



Due to the higher amperage draw of the Aeromotive pump, it is STRONGLY recommended to upgrade your fuel pump wiring harness above factory spec. I am using the upgraded Racetronix plug and play harness, which should be more than enough for anything you can throw at this pump.

I hope this post is useful to some of you, and if anyone has any questions about this fuel system setup just ask.




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!


Re: New higher performance fuel system setup and a modification how-to
Monday, July 29, 2013 3:50 AM
Mike this is great. Thanks for posting all of this.






PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: New higher performance fuel system setup and a modification how-to
Monday, July 29, 2013 4:10 AM
glad someone tried this pump out...im sure it will out perform the racetronix






RIP JESSE GERARD.....Youll always be in my thoughts and prayers...



Re: New higher performance fuel system setup and a modification how-to
Monday, July 29, 2013 4:10 AM
great work. very good to know!






Re: New higher performance fuel system setup and a modification how-to
Monday, July 29, 2013 5:53 AM
Amazing info thanks for the hard work! With the racetronix w body pump failures lately I'll definitely be keeping this in mind as a replacement.



"In Oldskool we trust"
Re: New higher performance fuel system setup and a modification how-to
Monday, July 29, 2013 7:39 AM
Nice write up.

Do you think you could use the racetronix sleeve on the aeromotive pump?


What about starting the car. Are you having to prime the fuel system?



FU Tuning



Re: New higher performance fuel system setup and a modification how-to
Monday, July 29, 2013 2:28 PM
I'm also curious how this one will preform with upgrade fuel lines (size wise).

I have seen a few cars with larger fuel lines on a racetronix need a booster pump to keep pressure up under boost.



FU Tuning



Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 2:22 AM
The little brass nipple is interesting.

If I upgrade, Aeromotive will be the route.
.



Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 3:06 AM
If my racetronix dies, I'll be going this route for sure.




PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 4:53 AM
Once my 2nd racetronix dies I'll be doing the same. Thanks for all the pics.








Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 5:32 AM
very cool. hate how so many have had bad luck with aftermarket pumps in our cars.



RIP silver car. You will be missed.

Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 5:52 AM
I'll be receiving my pump Friday. Let's do this.

Thanks for posting this sir, I wanted something more without going racetronix and walbro. Always liked aeromotive and have used their parts in other vehicles numerous times with much succcess.





"A car just isn't a car without a little blood, sweat, and beers." -- Shadowfire
Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 7:02 AM
Great write-up. I've tucked this away in my files, as it will surely do the job I need for the 3400.






Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 10:54 AM
This is awesome, I will be running this in my Z



Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 1:08 PM
You could post up with the drill bit size as well as the thread tap size to help people out!



Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 3:54 PM
what is that secont nipple for, mine does not have that.
Re: New higher performance fuel system setup and a modification how-to
Tuesday, July 30, 2013 4:07 PM
I don't remember the drill bit size Vince, but the thread pitch for the tap I used was M4X.75. Can't guarantee that its the right size bit, but its close enough that it screwed together securely and no leaks.

Hope this setup works good for everybody!




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!

Re: New higher performance fuel system setup and a modification how-to
Wednesday, July 31, 2013 2:34 PM
I didnt have a racetronix pump in hand, but compared to the blazer pump this is much heavier. More than 2x the weight.

I cant wait to install it and see what itll do.





"A car just isn't a car without a little blood, sweat, and beers." -- Shadowfire
Re: New higher performance fuel system setup and a modification how-to
Friday, August 02, 2013 12:48 PM
Installed this today in the morning. The nipple modification allowed the car to start without a cut cup on approximately 3qts of fuel (I didnt add back all the gas that I took out).

Very happy.

Props on this find.




"A car just isn't a car without a little blood, sweat, and beers." -- Shadowfire
Re: New higher performance fuel system setup and a modification how-to
Monday, August 05, 2013 5:36 AM
Good stuff in here, Thanks for the write up Roofy!



Re: New higher performance fuel system setup and a modification how-to
Monday, August 05, 2013 11:20 AM
It seems that my pump may be DOA. It kicks on and wont go over 35psi at the rail and then kicks off and cycles in this matter no matter what (even hooked straight to the battery). it starts and runs the car but it leans out horrifically.

I spoke to aeromotive and they told me that as long as the nipple that was added to the pump isnt the direct cause of this problem that they will still warranty it. I think thats awesome.

I still have a few things to check to determine where fault may lie though. Perhaps I screwed up the install lol. Im going to try running it in a bucket and see what happens.





"A car just isn't a car without a little blood, sweat, and beers." -- Shadowfire

Re: New higher performance fuel system setup and a modification how-to
Friday, April 04, 2014 8:48 PM
A little bit of resurrection here but a couple of questions. Matt, how did your issue with this pump turn out? Roofy, would this the the correct harness? Racetronix F99 Harness



Re: New higher performance fuel system setup and a modification how-to
Saturday, April 05, 2014 3:25 PM
Yessir that is correct.




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!

Re: New higher performance fuel system setup and a modification how-to
Saturday, April 05, 2014 9:24 PM
Roofy,

Are your fuel lines all stock or larger by any amount?



FU Tuning



Re: New higher performance fuel system setup and a modification how-to
Sunday, April 06, 2014 5:25 AM
Quote:

A little bit of resurrection here but a couple of questions. Matt, how did your issue with this pump turn out? Roofy, would this the the correct harness? Racetronix F99 Harness


I did actually. I took it out and sent be back to Aeromotive and they just sent me a new pump. The new pump worked great for about 500 miles and then the brushes went out on it (also got it replaced under warranty again). When i talked to Aeromotive, they told me that it could be the fuel lines are a bit small, the fuel filter may have been an issue, *basically* that there may have been a restriction somewhere that caused the pump to fail. When I first had it in, somehow the ground for the pump got chaffed when I installed the tank and I think THAT was the cause, it left me on the side of the road till I could re-wire the pump. Once I did that however it ran great for a long time before it died.

I did a bit of reading and it turns out that a LOT of people have issues running e85 with this particular pump. I tend to believe that many of the "this pump sucks" things you read are the installers fault. I mean Aeromotive wouldnt put on there that the pump is e85 compatible if it wasnt I wouldnt think. For my new setup I have 2 of these pumps in the tank (one will be on a boost pressure switch); -8 supply; -6 return; short fuel filter and 10awg wire thats on a relay setup I have in the trunk that I made. Probably overkill on wire size, but it should last forever (basically I made my own larger awg wiring harness for $5 instead of whatever Racetronix charges).

Ill be sure to post up how the setup works once I get it going this season. If the pump(s) do fail, I have been looking and AEM makes an e85 pump that many seem to be happy with that is the same structurally as this one and is 320lph and costs almost half the price.

Summary: pump failure was from when it was received initially. Had one unknown failure replaced under warranty. Still not unhappy with the pumps.




"A car just isn't a car without a little blood, sweat, and beers." -- Shadowfire
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