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So I really did it this time..

14K views 63 replies 11 participants last post by  kjb302ho 
#1 ·
I ran out of Fuel Pump.. The tune is coming along, but lately I was having a lean issue.. This perfectly coincided with the warmer weather.. I'm simply out of fuel pump.

I think the Walbro 450 will take up the slack where my 340 left off.. Will this fit on the SN95 Hanger?? I'm trying to kick around some options..

https://www.summitracing.com/parts/vpn-f90000274/overview/
 
#4 ·
I used pliers to pry the opening up large enough to drop the pump in, then flattened it all back out with a brass punch and hammer and locked it in.

It's a little bit of a pain. My plan b was an Aeromotive eliminator stealth tank for 1300.

Also had to run a new relay and fuel pump wire upgrade, 8 or 10 guage i think.
To keep the amp draw low.
 
#8 ·
7-750-775. My 340 can't maintain pressure at this level. It's falling flat the hotter it gets outside..
The Hellcat should be good for the limits of 93 octane. That's what my goal is..15ish psi on the street.

I like the King King pickup they have. If I was going racer I'd consider that one with an external pump.

http://www.glennsperformance.com/product_info.php?cPath=28&products_id=251
 
#10 ·
Yes I was thinking about going that route. I was looking at the aeromotive stealth hanger, but I like the fact that the Glenn’s has the larger fittings. I’d like to run some -10 and -8 lines and be done with it.
 
#11 ·
So I got the Hellcat in there.. I hit 85% duty cycle today! killin it..

I death wheeled about 1-1/4" off the bottom of the Hanger and drilled a couple of holes so I could safety wired it in there. It's not moving.. I just soldered the wires, wrapped them in vacuum hose and zip tied them to the Hanger so they won't move or chafe.. The connector that came with the Pump is too big to cram in the Tank opening. Otherwise, it all fit in the opening real nice with no mods to the Tank at all.







 
#12 · (Edited)
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#13 ·
I'm using a "450" in my stock fuel system as well without issue for the past 3 years. I have stock hanger, lines, and rails, then installed a 450 with 80lb injectors running e85 and haven't seen any indication of a lean condition so far in my tuning so we'll see if it becomes an issue as i increase the boost more.
 
#14 ·
That's an SN95 Hanger with -8 and -6 fittings welded to the tubes upgraded with 12 gauge wire. I got it from Quantum a few years ago. 1/2" id rails in parallel with ss braided lines. Separate relay with 10 gauge off the battery. Got it covered.

I don't see it available separately but here it is with a pump.

https://www.highflowfuel.com/i-7199...-mustang-5-0l-4-6l-qfs-350ft-340lph-pump.html

But yeah, anything above this and I would think about a new system.
 
#16 ·
That's an SN95 Hanger with -8 and -6 fittings welded to the tubes upgraded with 12 gauge wire. I got it from Quantum a few years ago. 1/2" id rails in parallel with ss braided lines. Separate relay with 10 gauge off the battery. Got it covered.
Based on the link, and photos you posted it looks like the return tube has been enlarged which is important. The return line should be lengthened, and extend all the way to the bottom of the hanger, this will allow fuel to flow directly to the bottom of the tank, preventing fuel aeration. Aerated fuel is not good situation to have.

Good luck with your setup
Michael Plummer
 
#18 ·
I wouldn't use that garbage if you gave it to me. It's a -6 fitting welded on. It's still a 1/4" return and a restriction, no matter how small is a restriction.

Look into the pro m hanger or the new aeromotive fox body hanger and swap a 450 on to it.

Also look into the Deatchwerks 400. E85 compatible and quiet. Supposedly outflows the 525.
 
#15 ·
With a near full tank of fuel the aeration of fuel would be mitigated due to the return fuel now being below the fuel level. Once you get 1/2 tank or below, I could easily see were the fuel system could struggle to deliver the correct fuel pressure and volume.
 
#30 ·
If your running 3/8 line to a 1/4" line, shows up in low speed drivability and idle where the pump is running at it's output and 95% is being returned back to tank. Then the 1/4 line is a restriction.

At wot, the engine is using a lot more fuel and less is being returned back to tank. I bet looking at a fuel pressure gauge, you would see a spike in pressure as soon as you let off the pedal during a wot blast/Dyno pull whatever.

Driving wot and driving around town are 2 different animals.
 
#38 ·
How does a 1.3 psi drop effect a system where there's say a 30 psi drop across the FPR at idle that has a tiny orifice of, say 0.1"? There's a reason AEM sells regulators with different sized orifices. Michael's issue above was likely the orifice in his regulator, using a variable pump drive fixed it, the -6 return line is more than adequate up to maybe 1500 HP or more.
 
#32 ·
Stock mustang 88lph right? Put on a 255lph and watch pressure jump up. Aside from putting an adjustable fpr on and using stock. Pressure will definitely increase and this will cause driveability problems and cause fuel pump cavitation.

Ever wonder how everyone knows you have a 255 in tank? Loud as hell because it's trying to flow 255lph through tiny lines. It's impossible. So the pump is fighting itself.
 
#34 ·
I checked my pressure after I got the new pump on and it was rock solid at 45 just where I set it 2 years ago. I don't think I have any problems. But thanks for the insight. I wish I would have added some hose to bring the return to the bottom of the Tank.. Not taking it down again unless it breaks!
 
#41 ·
Here's a good article that explains fuel line sizes needed (noting that "people run way more diameter fuel line than they need" :

Fuel Line Sizing — What Size Do I Need?


This one is fun to get an idea of psi drop in fluid lines (1.4 gpm ~ 1000HP, specific gravity of gasoline ~0.72, viscosity ~ 0.5 cP) :

https://www.gates.com/us/en/resources/calculators/fluid-flow-pressure-calculator

For S&G I plugged in 2.1 gpm (~1500HP), -6 line (.355"), 12' length (tough to estimate length/fittings used, but most people run a line straight from regulator to tank). Calculated drop is 3 psi which isn't much for a return line IMO.

I probably missed something somewhere, I'll be sure to post this -> :( when it's pointed out to me.
 
#45 ·
Thought I said it....

Would you pay $100 for a "lifetime guarantee" fuel pump?

Nowhere near advertised flow rate
Last less than 2 weeks under na conditions
Wouldn't even try on a supercharged engine.

I used them when I first did my 408. All sorts of driveability issues. Pump would intermittently stop and start. Returned under warranty. That one didn't even fire out of the box. Took a good used 190 walbro out if my tool box. Ran fine for over a year before I went to a Deatchwerks 200.

Use them if you like doing the job 3x. I've learned my lesson. Take budget and add $1000 for labor lost on sub par parts. Never ever again.

Their hanger? Stock sn95 with a -8 and a -6 fitting brazed on them. Fine if you use up to a 190lph pump but go any bigger, and cavitation is sure to follow.

I'll bet poor fuel system design is a large portion of why people bring their car to a tuner...

For instance, I gave my friend the same layout as my old system. -6 ptfe lines, Vortech blue fuel rails 340lph intank from aeromotive, pro m hanger and aeromotive regulator. This went on a hci sced 302. 0 driveability issues from first key hit. Brought it to the tuner, they tuned it in a very short time because of proper fuel system. No cavitation, no surging nothing. Set fpr at 43 and left it there. That was the same setting with the stock regulator so he left it there.
 
#42 ·
If you are going to be building a fuel system, I would think it would be best to go with bigger lines than what you need. The cost difference between a -6 return and a -8 return is negligible. Most cars/projects evolve over time and it is much cheaper to build it once than building it 2 or more times. Larger than needed does not have any net negative. Smaller than what you need later has a big net negative on the budget.
 
#53 ·
Wow a great thread and great read. I’ve not seen such good tech and thoughtful logical and polite conversation all combined in years! Kudos to all! Reminds me of what this forum was like 18-20 yrs ago... :cool:

I found the fluctuating fuel pressure description very Interesting & possibly helpful. I run a 255lph in tank with 42#/hr injectors for my dry NOS use. I would never have considered the need for a larger than stock return line and the info here may be on my list down the road.

Thanks All!! Great Job!
 
#59 ·
The 1st one is EEC Analyzer. The fuel calcs work on the unregistered version, or at least my version does. It's mostly for adjusting ECU parameters based on datalogs, but it has some useful calculations as well.

The 2nd I linked to above, here it is again -> https://www.gates.com/us/en/resources/calculators/fluid-flow-pressure-calculator

It's useful because not only can you calculate fluid pressure drops in the line, but you can add all of your fittings (elbows, Y's etc.) to get a decent approximation of pressure loss (especially useful for the feed line as it tends to have more fittings in it.) Note: for gasoline use 0.72 for Specific Gravity (g/ml) and 0.5 for Viscosity (cP). The only other issue is converting your gasoline flow to gallons per minute. I've independently confirmed the accuracy of the calculations in a MathCAD sheet. Note the 0.1875" ID calculation is wildly off as far as pressure drop!
 
#61 ·
I would love to see the dingbat that runs a -6 return on a 1,500 hp set up. And I would like to see the proof that it makes 1,500 hp with that set up. I have see a lot a bad ass vehicles making stupid power and not a one has that small of a return.
 
#62 ·
Q: What does the return line have to do with the amount of power the engine makes?

A: Nothing. The return only becomes an issue at idle/light load and depends only on the flow from the fuel pump under those conditions. The person I linked to above had a controller that makes the issue mute by reducing output at light loads. BUT, the poster mentioned that the controller was turned off. I'm copying and pasting the post since people are too gd lazy & arrogant to even see things that disagree with their position these days!



D-2035-A pump:

Fuel Injected Engines:
1600 HP @ 50 PSI (Naturally Aspirated)
1800 HP at 80 PSI (Boosted)
Carbureted Engines:
2000 HP @ 7 PSI (Naturally Aspirated)
1800 HP @ 30 PSI (Boosted)

Flow data

Note that I use a Boost-A-Pump to accomplish the same as a pump controller. It's not rocket science - people have been doing this for decades.
 

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