Upgrade wire size in EFI fuel sender

[81cutlass]

Anybody changed the passthrough on the EFI G body fuel sender? I made my own for my dual 450 in tank setup but want to make it a bit less intrusive for this single pump setup I'm putting in my Olds.

The replacement EFI fuel senders have maybe 16 gauge wiring. I'm putting a Hellcat 525 pump in the tank and it has a 18-22 amp requirement for where I plan to run it. The stock wiring for sure isn't up to the call.

Racetronix markets these kits but I don't know if the geometry of the plug is the same as the G body. They certainly look different but they are for TPI 3rd gens and C4's which I assume use the same geometry.

Here is a C4 one

C44 Bulkhead Wiring Assembly (BCWA-C44): Pump Bulkhead Wiring Systems

Purchase C44 Bulkhead Wiring Assembly or shop other Pump Bulkhead Wiring Systems and Racetronix products.

www.racetronix.biz

And here is a universal kit

Universal Bulkhead Wiring System, 4-Way (BCWS-001): Pump Bulkhead Wiring Systems

Purchase Universal Bulkhead Wiring System, 4-Way or shop other Pump Bulkhead Wiring Systems and Racetronix products.

www.racetronix.biz

TPI 3rd gen

FL98 / F7 Bulkhead Connector Assembly (BCWA-FL98HD): Pump Bulkhead Wiring Systems | Racetronix

Purchase FL98 / F7 Bulkhead Connector Assembly or shop other Pump Bulkhead Wiring Systems and Racetronix products from Racetronix.

www.racetronix.biz

They come with 14 gauge wire which is again a bit small for 20 amp continuous but I can duel-feed the pump since they are 4 wire.

Any experience?

 

[L92 OLDS]

My first thought before completely reading your post was Racetronics. They make good stuff. I’d give them a call to talk about the connector. Connecting the two feeds in parallel is probably your only option. Worst case is you could solder the correct plug ends on for your pump connection.

 

[81cutlass]

I emailed racetronix and they tried upselling me on a $450 drop in assembly.

Looks like they used to offer a kit but must be distributing the drop in assembly through Holley or elsewhere and disco'ed the harness.

Fuel Pump /Bulkhead wiring Upgrade.

I have a new in box fuel pump/bulkhead wiring kit for sale. This is the complete external/internal wiring assembly. This kit is no longer available and now you have to buy the hanger and pump as an assembly. I believe the old # was a G77 kit. $100 plus the ride. Thanks

www.turbobuick.com

 

[Streetbu]

Get a steel 90° elbow, weld it to the sending unit. Fish wire thru it, fill with JB Weld. Done.

 

[87National]

Get a steel 90° elbow, weld it to the sending unit. Fish wire thru it, fill with JB Weld. Done.

Good idea.....I'm stealing that one.

 

[Northernregal]

I did the racetronix when I put dual pumps in my cutlass. It's quick and easy to install, and the wire is nice, looks like tefzel or something similar.

I can measure gauge if you want?

 

[81cutlass]

I did the racetronix when I put dual pumps in my cutlass. It's quick and easy to install, and the wire is nice, looks like tefzel or something similar.

I can measure gauge if you want?

Sure!

Did you buy the universal kit?

 

[Northernregal]

Sure!

Did you buy the universal kit?

No, I bought a couple of pieces and fabricobbled something workable together. It wasn't pretty but it fit 2 340s in a secure hanger.

Here is the in tank side of the dual pump harness.

 

[81cutlass]

No, I bought a couple of pieces and fabricobbled something workable together. It wasn't pretty but it fit 2 340s in a secure hanger.

Here is the in tank side of the dual pump harness.
View attachment 190944View attachment 190945

So 14 gauge, cool.

I've been looking for a way to build a +20 amp passthrough without spending the $450+ for the prebuilt holley drop in pump since Racetronix discontinued their upgrade harness and only offers the universal harness. The stock/ repop harness has maybe 16 gauge wire which is good for ~12 amps continuous. The Racetronix upgrade harness was really made for Walbro 255/340 pumps back 20 years ago with 14 gauge wire which is good for like 16 amp continuous which is really too small for a 450 or 525.

So you need to switch to dual feeding the pump with 2 14 gauge wires.

I got my new Spectra Premium turbo buick fuel sender in the mail it has 25% of the stuff you need included. The passthrough that comes with the spectra sender has the wires molded in the outside part of the plug and the 4 pin metripack square plug on the inside. The Racetronix passthrough is plugs on both sides, the fuel side is the same plug as the spectra harness and the outside plug is the same as a 90's through 00's GM IAC motor solenoid.

The $50 racetronix kit is great but you get stuff you don't need. It's universal so you are going to end up rebuilding half of it anyways,

So my plan is to just buy the passthrough which from what I can tell is a Racetronix custom molded part.

The Spectra hanger has the wrong plug for the Walbro pump (and its not included on the universal harness) so you cut it off and crimp the Walbro spec plug onto it dual feeding both the power and ground. One power wire goes to the existing red wire pin on the existing 4 pin plug and you need to pull a new 4th wire pin into that plug that comes in the Spectra hanger. The other dual feed ground wire gets connected to the spade connector on the fuel sender 'hat'

Throw away the Spectra molded passthrough and replace with the Racetronix one.

Need the outside plug too, but since its a standard IAC plug I have them sitting around from scrap harnesses so I just need to run a big 8 gauge wire from the relay under hood to a junction where it splits to 2 14 gage that feeds 2 pins on this 4 prong connector. The 3rd pin is ground and 4th pin is fuel level signal. So basically you just add a 2nd feed wire to the pump.

So between what comes in the Spectra fuel sender and what you need for the walbro pump install anyways you just need
1. The Racetronix passthrough for $10
2. A GM IAC plug
3. 5 Metripack 150 pins
4. Some 14 gauge teflon wire to add a 4th wire inside the tank
5. Wire to run to the plug on the outside of the tank which you need anyways

So if you have what I consider a normal pile of 'scrap/inventory' stuff hanging around for metripack connectors and pins and some teflon wire the only thing you need is the $10 racetronix passthrough to convert the Spectra hanger from being acceptable for maybe 12 amps to being OK for the 22 amp draw of the Wally 450/525 stuff.


And other stuff, the stock hanger has the 3/8" output/feed line and with the walbro 525 flowing about 420-380 LPH at 42.5 psi it ends of flowing about 2 GPM at maximum case. The fuel is flowing at 5.7 ft/sec which is really at the top limit of what you should flow. 5-10 ft/sec is the limit before you have risk of emulsifying, large line loss and potential noise from high fluid velocity (adding heat/air/wear).

So the math pencils out to a single 525 being all you should run on a single 3/8 feed line stock sender. Dual pumps exceeding 2 GPM or roughly 400 LPH should have a 1/2" line coming out of the sender and all the way to the engine. A 3/8 line should work and have 'reasonable' line losses, but I gotta crunch the math.

Putting a Tee or Y in the tank and jamming over 2 GPM through a single 3/8 line (anywhere) is kinda sketch in this fluid power system engineers math opinion. 1/2" line from the tank to the engine helps reduce line loss but keeping fluid velocity under 5ft/sec anywhere is really critical to not jamming a ton of heat, wear, or air into the system.

I need to do a video on this since theres quite a bit, Tangent off.

 

[Northernregal]

So 14 gauge, cool.

I've been looking for a way to build a +20 amp passthrough without spending the $450+ for the prebuilt holley drop in pump since Racetronix discontinued their upgrade harness and only offers the universal harness. The stock/ repop harness has maybe 16 gauge wire which is good for ~12 amps continuous. The Racetronix upgrade harness was really made for Walbro 255/340 pumps back 20 years ago with 14 gauge wire which is good for like 16 amp continuous which is really too small for a 450 or 525.

So you need to switch to dual feeding the pump with 2 14 gauge wires.

I got my new Spectra Premium turbo buick fuel sender in the mail it has 25% of the stuff you need included. The passthrough that comes with the spectra sender has the wires molded in the outside part of the plug and the 4 pin metripack square plug on the inside. The Racetronix passthrough is plugs on both sides, the fuel side is the same plug as the spectra harness and the outside plug is the same as a 90's through 00's GM IAC motor solenoid.

The $50 racetronix kit is great but you get stuff you don't need. It's universal so you are going to end up rebuilding half of it anyways,
View attachment 191109





So my plan is to just buy the passthrough which from what I can tell is a Racetronix custom molded part.

View attachment 191108

The Spectra hanger has the wrong plug for the Walbro pump (and its not included on the universal harness) so you cut it off and crimp the Walbro spec plug onto it dual feeding both the power and ground. One power wire goes to the existing red wire pin on the existing 4 pin plug and you need to pull a new 4th wire pin into that plug that comes in the Spectra hanger. The other dual feed ground wire gets connected to the spade connector on the fuel sender 'hat'

Throw away the Spectra molded passthrough and replace with the Racetronix one.
View attachment 191110

Need the outside plug too, but since its a standard IAC plug I have them sitting around from scrap harnesses so I just need to run a big 8 gauge wire from the relay under hood to a junction where it splits to 2 14 gage that feeds 2 pins on this 4 prong connector. The 3rd pin is ground and 4th pin is fuel level signal. So basically you just add a 2nd feed wire to the pump.
View attachment 191111


So between what comes in the Spectra fuel sender and what you need for the walbro pump install anyways you just need
1. The Racetronix passthrough for $10
2. A GM IAC plug
3. 5 Metripack 150 pins
4. Some 14 gauge teflon wire to add a 4th wire inside the tank
5. Wire to run to the plug on the outside of the tank which you need anyways

So if you have what I consider a normal pile of 'scrap/inventory' stuff hanging around for metripack connectors and pins and some teflon wire the only thing you need is the $10 racetronix passthrough to convert the Spectra hanger from being acceptable for maybe 12 amps to being OK for the 22 amp draw of the Wally 450/525 stuff.


And other stuff, the stock hanger has the 3/8" output/feed line and with the walbro 525 flowing about 420-380 LPH at 42.5 psi it ends of flowing about 2 GPM at maximum case. The fuel is flowing at 5.7 ft/sec which is really at the top limit of what you should flow. 5-10 ft/sec is the limit before you have risk of emulsifying, large line loss and potential noise from high fluid velocity (adding heat/air/wear).

So the math pencils out to a single 525 being all you should run on a single 3/8 feed line stock sender. Dual pumps exceeding 2 GPM or roughly 400 LPH should have a 1/2" line coming out of the sender and all the way to the engine. A 3/8 line should work and have 'reasonable' line losses, but I gotta crunch the math.

Putting a Tee or Y in the tank and jamming over 2 GPM through a single 3/8 line (anywhere) is kinda sketch in this fluid power system engineers math opinion. 1/2" line from the tank to the engine helps reduce line loss but keeping fluid velocity under 5ft/sec anywhere is really critical to not jamming a ton of heat, wear, or air into the system.

I need to do a video on this since theres quite a bit, Tangent off.

Another option.

Knock a hold in the cell/tank top and pass through with this. Ground stud on sending unit base for pumps to chassis and 12ga through these. Metripak connected to 8 or10ga for each pump from relay. Under a foot of 12ga isn't going to have voltage drop on 20amps of load. Use hole from stock cable pass through for second 3/8 feed and solder/weld in AN fitting.

You also have a lathe, I would have turned a new sending unit and made a -10 single exit with a -6 return and -4 vent by now with this pass through bulkhead.

ATL Fuel Cells CFD-506 4-Wire Aluminum Wire-Thru Bulkhead Fitting

ATL Fuel Cells CFD-506 4-Wire Aluminum Wire-Thru Bulkhead Fitting Bulkhead fitting for passing electrical wiring through bulkheads such as firewalls or fuel cells. Compatible with 12 or 14 gauge wiring Fitting for two-wires to pass through Constructed of durable aluminum Fuel and air tight seal...

www.speedwaymotors.com