Snook

iTrader: (12)

Lets see if I can get some help please team!

Right now I have a nice boshe pump. It flows 310lph which is 30 more than 1 supra pump. I think I want to go for more hp so it was suggested for me to run 2 supra fuel pumps. Can someone post pictures of how they got this to work with the stock fuel pump assembly and how they wired it up.

I appreciate any help

jimlab

Why not just run a second Bosch pump?

Basically, if you're feeding one fuel line, you'll need to Y the output of the two pumps int one line. I'd also upgrade the wiring, if possible, to handle the extra current required.

Broken09

iTrader: (1)

I ran new thicker gauge wire to the pumps and spliced them in the tank to the two pumps. It was suggested to me by numerous people to use hose clamps to hook one up to the other. That's what I did and have had no problems so far. Do you plan on running new lines or using the existing lines?

jimlab

FWIW, I'll be running dual Bosch pumps, exiting the tank through two separate bulkhead fittings, but Y-ing into a single -10 line to the fuel rail outside the tank. For the return line, -08 through another bulkhead fitting, and heavy gauge wire for both pumps running through a fourth bulkhead fitting (sealed), bypassing the stock wiring with the exception of the fuel level sensor.

Snook

iTrader: (12)

What gauge wire should I have Jim?
And I think I want to run a SS line all the way to the front of the car. Should I use the same size as you? And is the return line also a restriction?

I already have it hardwired to the battery right now temporarily using a fuse each time I get into the car. How would you suggest doing the wiring so its convenient? I'm looking for a specific source to tap into for ignition or whatever else you suggest please be specific because wiring is not something I understand enough to make logical guesses about.

I could run 2 boshe pumps but I know the 2 supra pumps are proven to be able to handle crazy numbers, are reliable, quiet, and the same size as the stock pump which will fit easier than the HUGE boshe pump especially when I use 2. Also a big part of it is that I have 3 available to me locally.

Here are my mods for some background. I basically can only get ~475rwhp with my turbo maxing it out but I want to have the best fuel setup for safety.

1994 RX-7 53k Miles
New Ported Engine 2mm 2 piece Mazda Seals - 62-1 Turbo 1.00 Divided - HKS SS Divided Manifold - HKS 50mm Racing Wastegate - HKS SSQV BOV - Modified Greddy 3 Row FMIC - Apexi PFC + Commander + Datalogit - New # GM 3 Bar Map Sensor + Connector - 50/50 Water/Alcohol Injection - Custom Spec Clutch with M2 Lightened Flywheel - 1680cc Secondary Injectors - 850cc Primary Injectors - Aeromotive Fpr - M2 Boshe Racing Fuel Pump - Custom LIM - Crane Cams HI-6 Ignition - Magnecore 10mm Plug Wires - Greddy Racing Plugs - Custom Air Intake - Custom Downpipe With Cutout - Midpipe With Borla XR-1 Muffler - Greddy SP Catback Exhaust - Greddy Pulley Kit - Greddy Profec B - PFS Boost Gauge - Pettit Aluminum AST - Relocated Battery - M2 Trailing Links - Gotham Racing SS Braided OMP lines - Koyo Radiator - Engine Tq Brace - Little bit of Polishing ; )

jimlab

I ran 10-gauge power and ground for each pump directly from my battery, which is behind the driver's seat. I used separate wiring and two Bosch 30-amp relays so that I can trigger the second pump based on rpm (with an MSD rpm switch) if I want to, or just turn them on at the same time and run both pumps full time.

Here are some rough sizing guidelines...

Up to 250HP - 5/16" or -04 AN
Up to 375HP - 3/8" or -06 AN
Up to 550HP - 1/2" or -08 AN
Up to 800HP - 5/8" or -10 AN
Up to 1200HP - 3/4" or -12 AN

To determine return line sizing based on fuel pump output...

Up to 45GPH - 5/16" or -04 AN
Up to 90GPH - 3/8" or -06 AN
Up to 180GPH - 1/2" or -08 AN
Up to 360GPH - 5/8" or -10 AN
Up to 720GPH - 3/4"or -12 AN

Sounds like a plan. The Bosch pumps are big...

Trexthe3rd

Maybe I remembered wrong but I have seen many setups in excess of 450 RWHP using only -6AN line.

jimlab

You can get by with smaller lines by increasing line pressure and making your pump(s) work harder. Like I said, it's a rough sizing guide. Rough means "not exact".

manatecu

iTrader: (6)

When searching for a fuel setup Shawnk and I set his up almost exactly like Jims. It did not work very well. We had problems with the pressure fluxing and pressure at the block.

I ended up going with dual Wal's and 6an lines to the front, each dedicated to a rail. They then tie back into the regulator and back via 8an to a bulk head fitting. This minimized the break points in the line and transfers the fluid needed to travel over/through.

I originally had an issue with the transition from low to high with the wal's. I then decided to upgrade the wiring to 10 guage (Positive) - 8 guage (negative), ran to the battery through a relay - so now I only run on high. The fuel is now solid all they way up and down.

SPOautos

I run 8 gauge from the battery with a 40amp fuse by the battery and a 40amp switched relay using the stock pump's power wire as the ignition wire on the relay so it will trip it when the key is turned. The 8 gauge needs to Y into the two Supra power lines (14 gauge would be good) about a foot before the tank then on those 2 power lines you need to put 20amp fuses on each of them before they drop down into the tank.

Actually, I used a 30 amp at the battery and 20amps on each pump line but I'm running Walbros......I dont really know what the current draw would be for the Supra pumps so you need to find out and design accordingly.

Also, as for the fuel lines you can either Y together into one big line or you can run two -6 lines and run one to the pri rail and one to the sec rail then on the front side of the rails tie them together on either side of a regulator.

If you want some more info, you got my aim

Stephen

the_glass_man

iTrader: (2)

There was someone in the single section that had a dual Walbro setup. I've thought about switching out my Denso (Supra) pump for that. The Walbro's are smaller and would be easier to mount and install in the tank.

jimlab

Funny that people want the biggest intercoolers and radiators for cooling capacity, but when it comes to fuel pumps, they want the smallest...

teamafx

iTrader: (4)

did you guys that have independent -6 lines from the back forward for each rail have them go into the individual rails and them run into the regulator afterwards, and what size return line did you use?

the_glass_man

iTrader: (2)

The size has nothing to do with flow capacity.

jimlab

Show me where I was talking about size in relation to flow capacity.

the_glass_man

iTrader: (2)

Are you not trying to relate size to performance here? I assumed since you brought up intercoolers and radiators and their relative size (which does have to do with performance in this case) you were comparing it to the performance of a fuel pump.
Where as radiators and intercoolers benefit from increased surface area and thickness to a certain degree, a fuel pump is designed with one thing in mind, to flow fuel. If I were to run two pumps, the Walbro's would seem ideal to me, because they are both cheap and flow a good amount of fuel. Not to mention easy to mount due to their size.

jimlab

Let's try one more time...

"Funny that people want the biggest intercoolers and radiators for cooling capacity, but when it comes to fuel pumps, they want the smallest..."

Fuel pumps generate heat during operation. The Bosch pump has far more surface area than the Walbro or Nippondenso/Cosmo. Which is going to run cooler?

the_glass_man

iTrader: (2)

I don't know, I've never had a fuel pump over heat.
Since you seem to know the answer do you have an factual data to back it up?
Besides the Bosch doesn't look all that much bigger than a Denso pump. Sure the Walbro looks tiny, well because they are. Don't think anyone has ever complained about them heating up. They aren't coolant seals you know.
How hot is everyones fuel pump getting?

jimlab

Two things lead to fuel pump failure.

1. Heat
2. Contamination (dirt/debris in the fuel)

Overheating a fuel pump shortens its life. If two fuel pumps flow basically the same volume, but one has twice the outer surface area of the other, which one does common sense say you should choose?

the_glass_man

iTrader: (2)

You have to take more into consideration than just the surface area. Sure the bigger one acts as a better heatsink, but how efficient is it compared to the smaller one? Just because it's bigger doesn't automatically mean it runs cooler.
I agree with you the thermal properties for heat dissipation are better for the pump with more surface area. Are both made out of the same grade of materials? Which one draws more amps? I think in some cases (on paper) two smaller pumps are better than one large pump.

I don't think pump failure happens all that often, or at least nobody post anything about it on here. There are a lot of variables that come into play, if anyone can find the numbers for all the pumps and wants to crunch the numbers be my guest.

As far as picking one, I would choose the one that meets my needs, fits my budget and would be the easiest to install and maintain.

the_glass_man

iTrader: (2)

Here's a nice dual Walbro setup.

jimlab

Personally, I like the pump with the larger screened inlet on the bottom and a threaded outlet on the top as opposed to a little baggy on the bottom and a short plastic outlet tube that you have to use hose clamps on, but use whatever you want for whatever reasons you like best.

the_glass_man

iTrader: (2)

If your car was running I'm sure it would appreciate as well. However that still doesn't tell me anything about the thermal properties of the larger Bosch pump as compared to the inferior Denso/Walbro pumps.

jimlab

The point which was lost on you this time is that the debate is over...

the_glass_man

iTrader: (2)

There's no debate, I just want proof that the Bosch puts out less heat, is more reliable, more cost efficient, cheaper and easier to install than two Walbros.