Hilariously simple, yet ridiculously powerful fuel system

[engineermike]

Folks, lots and lots of discussion about fuel systems lately...but I think we've come up with "the" answer. We've been over the countless problems and shortcomings of bucketless systems, bucketed systems, return-style system, full-on-all-the-time systems, lack of diagnostics, lack of control, massive power wires run through the car, lack of venturis to keep the bucket full, high cost, the list goes on and on. Well, the following seems to address most of those shortcomings and delivers lots of fuel for a comparatively low cost.

For the record, my car is a 2018 GT PP1 with a Whipple setup, GT500 55# injectors, and the 3" pulley, which is good for 17-18 psi boost. I am currently running E85 as well. I have not had the car on the dyno in the current state, but research and talking to experienced folks have let me to the conclusion it is around 900 rwhp. It did run a sub-5 second 60-130 at full weight on the old 3.25 pulley. I do not test the e%, but the car maxed out the learning at 77.5%.

This fuel system consists of 4 basic components:

1. The bucket - I'm using a stock GT500 bucket/hanger assembly which can be purchased new for $798 (2020-2022 Ford Mustang Fuel Pump And Sender Assembly kr3z9h307b | TascaParts.com) or less than half that used. Two changes MUST be made to the bucket for it to work.
   1. The line that supplies the PS venturi must be capped. The GT does not have a venturi on the passenger's side so there's nothing to connect to. I used this, but it should be confirmed it's Ethanol compatible: Fitting Fuel Line Quick Connector 10mm (9.89) Bundy Female Plug Cap $12
   2. The venturi in the bottom of the bucket must be converted to the GT style, which entail simply removing the black dual-venturi from the bottom of the stock GT bucket and swapping it into the GT500 bucket. The GT500 bucket only has a single venturi since one was relocated to the PS in that model. Edit: Actually the entire bottom part of the gen3 bucket needs to be swapped onto the gt500 module due to the venturi throat size. It also helps to drill the venturi nozzles and throats to increase bucket filling rates, more on this in post 13.
2. The wiring adapter - The stock GT bucket uses a 4-pin plug, while the GT500 uses a 6-pin. A short adapter harness must be made connect it. This setup runs both pumps off the single stock FPDM. I believe this is how a popular dual pump system currently on the market also does it, plus I checked amps and temps and it's not run outside of what the community was previously doing with a BAP/DW400 setup. I did upgrade the fuse from 30 to 40 amps, but it should be ok on the 30 amp. The fuel level sender wires will just pass through, while the power and ground need to be split to feed the dual pumps. The connectors needed are:
   1. Amazon.com: Ballenger Motorsports - 4 way APEX 2.8 Receptacle Kit Compatible with Ford fuel pumps : Automotive$17
      1. Option: The same one might also be available here for $6, but I didn't confirm fitment: 54200414 (Aptiv p/n: 13754761) - FCI (Delphi/Aptiv) | APEX.28-4P-B - Corsa Technic | 4-Way Kit, Type B
   2. 54200609 (Aptiv p/n: 15412914) - FCI (Delphi/Aptiv) | APEX.28-6S-B - Corsa Technic | 6-Way Kit, Type B $7
3. The fuel filter - As has been previously discussed, the GT500 bucket and some other options lack the filter in the tank that the Gen3 specifically needs in order to protect the HPFP and injectors. I purchased a stock GT500 filter and a pair of pre-made Bundy-style fuel lines. This snapped together in a bout 2 minutes and puts a filter under the hood.
   1. FG-1152 FG1152 - Genuine Ford Fuel Filter Assembly $27
   2. Russell Performance 651121 Russell Stainless Steel Braided Fuel Hose Kits | Summit Racing$22 x 2 = $44
      1. Option: For an OEM alternative, this works the same: 84307609 - Genuine GM Pipe Assembly, Fuel Cooler $38 x 2 = $76
   3. Aeromotive 12701 Aeromotive Fuel Filter Mounting Brackets | Summit Racing $31 (haven't confirmed fitment but will in coming weeks)
4. The tuning - Since this fuel module is an OEM module, the tuning was pretty simple and mostly done for us. The feed-forward voltage table can be copied from the GT500 into the Gen3, but the number of columns and rows is different and the flow rate doesn't go quite high enough. Some interpolation and extrapolation is needed to fit the GT500 data into the Gen3 table. For instance, the GT table max flow is 6 lb/min, GT500 is 9.4 lb/min, while my car is using 12 lb/min so the table needed to be extrapolated out to 12 or more lb/min while also making 9 flow columns fit into 4. Also, the max voltage needs to be increased to 15.2. It helps to use the high-fuel-demand smart alternator feature to lift system voltage to 15.2, and lower the low-rpm fuel pressure to 40 psi to take some electrical load off the single FPDM during normal driving. This helps keep it from getting warm. All in all, the tuning piece of this was the easiest part, and the rest was pretty easy.

Total cost: $925, not including injectors or tuning

To test this setup, I did a 5th gear pull and logged rpm, load, fuel pump duty cycle, desired rail pressure, actual rail pressure, fuel flow, pulsewidth, max pulsewidth, (window) etc. This was done at about 76 deg ambient. You can see the pressure hovering in the 85-90 psi range even at max fuel flow. I'm running high pressure to get the most out of my 55# injectors, so you can imagine it will supply much more fuel in the 65-70 psi range that most people run.

One shortcoming of this system is that using only one FPDM keeps it really simple, but you lose some of the OEM diagnostics. For instance, the FPDM will send an error code to the PCM if it detects an open circuit to the pump. With this setup, if one pump loses power, the FPDM will not know it because the other one is wired in parallel. The short circuit detection should still work, though. Also, the current draw of 30 amps causes a loss of about 2 volts through the FPDM, so as good as it performed it's still leaving something on the table. We are working on an adapter harness that not only incorporates a second OEM FPDM, but also combines the FPM (fuel pump monitor) signal from both FPDMs and sends it to the PCM. This will allow full factory diagnostics plus an increase in fuel flow if needed.

Hope you guys find this interesting and helpful.

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[SheepDog]

Amazing findings and implementation. Sometimes a wheel can indeed be reinvented.

All of this exploration into alternative ideas on how to fuel these cars confirms that with some ingenuity, there is plenty of room for improvement above and beyond the standard " you must run a dummy return system" approach.

 

[Killa_Coyote]

solid DIY but ill stick to my Fore system

 

[SheepDog]

solid DIY but ill stick to my Fore system

Totally. I loved the 1980's too. PEZ dispensers, Mullets, Return Fuel systems controlled by 20 bucks worth of relays, and Def Leppard tapes. Those were the days...

 

[Killa_Coyote]

Totally. I loved the 1980's too. PEZ dispensers, Mullets, Return Fuel systems controlled by 20 bucks worth of relays, and Def Leppard tapes. Those were the days...

LOL hell yeah brother

 

[wingnutt]

Totally. I loved the 1980's too. PEZ dispensers, Mullets, Return Fuel systems controlled by 20 bucks worth of relays, and Def Leppard tapes. Those were the days...

lol…don’t forget the Kenne Bell FMU with the interchangeable rubber(?) discs to control fuel pressure under boost

 

[robvas]

lol…don’t forget the Kenne Bell FMU with the interchangeable rubber(?) discs to control fuel pressure under boost

And the Vortech T-Rex inline pump

 

[Blueflash]

Awesome work, Mike. Your one helluva asset to this community. I inquired about a BAP to one of the vendors, and all he had to do was hear E85 to spout out "you're gonna need a fuel system". Thank you for your help getting a flex tune for my truck. I would not have tackled it without ya

 

[Whitedevil95]

Pretty awesome idea! I love the OEM style of it. Id love to know the details of the C8 ZR1 fuel system how they feed that 1064hp beast.

 

[wingnutt]

Might be a silly question…but how does something like that compare to the KPM bucket?

granted, this is for the 350/500 crowd and obviously this is a couple bucks more…but for some of us yahoos to be able to buy it from one source can worth the difference, if it does the same thing

https://kpmfuelsystems.com/product/kpm-1000hp-in-tank-fuel-module-mustang-gt500-2020-2022/

 

[engineermike]

The advantage of the GT500 module is the price, OEM-engineering, and very high capacity. Also, the ready-made tuning data is a big plus.

Both lack an adequate fuel filter.

The advantage of the KPM is the venturi system probably does a better job keeping the bucket full and it doesn't require a special adapter harness in the GT. I don't know the amp draw and how it works with the stock FPDM, but the 1000 seems to fall short of the stock GT500 module in terms of capacity. The 1500 seems more comparable.

In 1-2 weeks I'll post a thread on how to put together the under-hood fuel filter setup with pics, which is needed for the GT350/Sai Li, GT500, and KPM drop-in bucket systems.

 

[engineermike]

If anyone is interested in copying this setup I can share the wiring diagram for the adapter harness as well as the tuning data.

 

[engineermike]

Still working on the dual FPDM setup, but in the meantime I decided to go after the bucket-filling rate problem. We made a test stand to measure bucket filling rate from each side independently, and also the venturi nozzle consumption.

The idea here is that the stock GT500 bucket venturi filling rate from the driver's side is insufficient to supply 1000 hp steady state worth of E85 to the bucket, and the passenger's side venturi isn't even designed to be a venturi since the stock GT500 setup fills using a different mechanism (venturi is moved to the passenger's side).

For reference, at 2.0 load (whipple with a 3" pulley) and E85 the fuel flow rate hits about 12.3 lb/min which equates to about 450 lph after all the check valve, filter, line, and venturi losses take place.

Using a stock GT500 bucket and Gen3 venturi nozzle, the stock filling rate was 200 lph from the driver's side and 130 lph from the passenger's side. It became obvious pretty quickly that getting to 450 lph filling rate from the passenger's side would be basically impossible, so I concentrated on the driver's side. Also, the bucket itself holds about 1/2 liter of fuel so you have some cushion space even if the venturi doesn't keep up with the max flow rate.

After about a week and a half of playing with different venturi throat sizes, nozzle sizes, and pressures I was able to achieve a filling rate of 450 lph from the driver's side and 220 lph from the passenger's side. The cost of all this was about 50 lph of pump output, with stock being 20-30 lph. I took a log this morning and the GT500 pumps were still able to maintain over 70 psi rail pressure at max flow rate. It seems to have lost about 5 psi due to enlargement of the venturi nozzle holes. However, I expect the capacity to improve some and pressure to rise with the dual FPDM since about an extra volt will be supplied to the pumps.

 

[HKusp]

Still working on the dual FPDM setup, but in the meantime I decided to go after the bucket-filling rate problem. We made a test stand to measure bucket filling rate from each side independently, and also the venturi nozzle consumption.

The idea here is that the stock GT500 bucket venturi filling rate from the driver's side is insufficient to supply 1000 hp steady state worth of E85 to the bucket, and the passenger's side venturi isn't even designed to be a venturi since the stock GT500 setup fills using a different mechanism (venturi is moved to the passenger's side).

For reference, at 2.0 load (whipple with a 3" pulley) and E85 the fuel flow rate hits about 12.3 lb/min which equates to about 450 lph after all the check valve, filter, line, and venturi losses take place.

Using a stock GT500 bucket and Gen3 venturi nozzle, the stock filling rate was 200 lph from the driver's side and 130 lph from the passenger's side. It became obvious pretty quickly that getting to 450 lph filling rate from the passenger's side would be basically impossible, so I concentrated on the driver's side. Also, the bucket itself holds about 1/2 liter of fuel so you have some cushion space even if the venturi doesn't keep up with the max flow rate.

After about a week and a half of playing with different venturi throat sizes, nozzle sizes, and pressures I was able to achieve a filling rate of 450 lph from the driver's side and 220 lph from the passenger's side. The cost of all this was about 50 lph of pump output, with stock being 20-30 lph. I took a log this morning and the GT500 pumps were still able to maintain over 70 psi rail pressure at max flow rate. It seems to have lost about 5 psi due to enlargement of the venturi nozzle holes. However, I expect the capacity to improve some and pressure to rise with the dual FPDM since about an extra volt will be supplied to the pumps.

Mike, I sincerely hope that you are videoing some of this work that you are doing. It would make for some great content. There are a lot of people interested in this platform and you and a few others are pushing the envelope in a good way.

 

[engineermike]

Mike, I sincerely hope that you are videoing some of this work that you are doing. It would make for some great content. There are a lot of people interested in this platform and you and a few others are pushing the envelope in a good way.

I have some videos showing the bucket-filling rate in the initial and final states. However, they're just phone videos pretty badly done.

So far, this setup is really within the realm of what a DIYer can do. I listed all the parts on the first post. The tuning changes are not that complicated, the wiring is straight-forward and I can share, and I would be willing to share exactly what I did to the bucket to double the fill rates. The changes can be done with drills and an oscillating tool. I've been running both pumps off a single FPDM without issue. The dual FPDM harness will put less load on them and more volage to the pump. The wiring is simple enough for the dual FPDM, but we are working on a circuit that combines the FPM diagnostic signal which is the only part that I would say is beyond the DIY level. However, this part is not totally necessary and no aftermarket fuel system supplier is even worried about getting FPM from one, let along both fuel pumps.

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