Fuel system design considerations and injector selection
Burning Brakes
Joined: Jan 2011
Posts: 1,203
Likes: 2
Great information Bret!!
You must be waiting on parts for your car...
The only thing in there that I question is the heating of the fuel while running multiple pumps. On paper it makes total sense but I have set up two early C5's over the last couple years (one being josh's that you tuned) and in both cars I ran dual in tank pumps with the RSI hangar in a constantly on configuration and have not seen any issues with hot fuel that I am aware of. Both cars had the feed and return lines ran through the tunnel as well, so there was no lack of heat generated from other sources aside from pump turbulence/cavitation.
Under what circumstances have you seen this issue? The reason I ask is that I am getting ready to replace the pumps as its been about 5 years and its kind of a preventative maintenance thing and I was going to go from the current twin 255's to a set of ethanol friendly 340's.
You must be waiting on parts for your car...
The only thing in there that I question is the heating of the fuel while running multiple pumps. On paper it makes total sense but I have set up two early C5's over the last couple years (one being josh's that you tuned) and in both cars I ran dual in tank pumps with the RSI hangar in a constantly on configuration and have not seen any issues with hot fuel that I am aware of. Both cars had the feed and return lines ran through the tunnel as well, so there was no lack of heat generated from other sources aside from pump turbulence/cavitation.
Under what circumstances have you seen this issue? The reason I ask is that I am getting ready to replace the pumps as its been about 5 years and its kind of a preventative maintenance thing and I was going to go from the current twin 255's to a set of ethanol friendly 340's.
Navigator
Joined: Oct 2012
Posts: 9
Likes: 0
From: Martinsville VA
Bret,
Great write-up!
Have you found anything that prevents the fuel from siphoning back into the passenger tank when the engine (and fuel pump) is shut off?
It looks to me that if the fuel transfer entered the drivers tank up high (in the airspace), then it couldn't siphon back to the right-side tank.
For allowing air inflow into the tanks during high fuel usage, do you think a -6 or -8 line with a check valve to prevent any outflow?
Great write-up!
Have you found anything that prevents the fuel from siphoning back into the passenger tank when the engine (and fuel pump) is shut off?
It looks to me that if the fuel transfer entered the drivers tank up high (in the airspace), then it couldn't siphon back to the right-side tank.
For allowing air inflow into the tanks during high fuel usage, do you think a -6 or -8 line with a check valve to prevent any outflow?
Navigator
Joined: Oct 2012
Posts: 9
Likes: 0
From: Martinsville VA
[QUOTE=5 Liter Eater;1589047099]I have a bit of a worry about my transfer. I have the block off in the passenger side, no worries there. But my line from the main pump to the siphon pump is restricted, which makes sense, you don't want to be sending a ton of fuel over there. But I haven't seen any data to say how much flow/volume is required for the siphon to work, just pressure. I'll be running ~50# at idle. Still buttoning it up so haven't tested it yet.
I don't have any info on the later type transfer jet pump, but I disassembled an earlier (98 or 99) jet pump and the orifice in the pressure nozzle measured only .017"
I don't see a need for any upstream restrictor to the early-style jet pump.
Has anyone here pin-gauged the orifice in the later jet pumps?
I don't have any info on the later type transfer jet pump, but I disassembled an earlier (98 or 99) jet pump and the orifice in the pressure nozzle measured only .017"
I don't see a need for any upstream restrictor to the early-style jet pump.
Has anyone here pin-gauged the orifice in the later jet pumps?
Racer
Joined: Aug 2004
Posts: 397
Likes: 1
From: Andale Kansas
I put 04 tanks in my 02 Z06, cross-referenced the wiring diagrams, dropped in a Aeromotive A1000, ran fuel lines in rocker, added a fuel pump controller(I made this sound easy-it is not, especially on jack stands). Had some fuel heating problems but it was due to not enough fuel pressure to siphon the fuel from the passenger tank. Turned up fuel pressure to about 56 lbs and it works great. I don't let it go below a half of tank on the gauge, this keeps the driver side full. Still not sure I will drive it when it is above 100 degrees out.
Supporting Vendor
Joined: Dec 2001
Posts: 1,573
Likes: 31
From: A dealer near you.
This is exactly what I'm talking about. When I read the specs on this pump assembly, it reads "For customers who need enough fuel to support upwards of 1400HP". That's pretty useless information for someone building a car making 1400hp. Is that carbureted? EFI? At what pressure? At what voltage? I don't understand why anyone wanting to move product wouldn't publish all the usable specs and if they don't have them and can't come up with them on their own, I would lean on the manufacturer. How does that fit in a C5? How much current do they draw?
All of the pumps listed in this thread are generic and do not support the factory C5/C6 fuel system's jet-pump scavenging system and therefore are considered DIY items which require alteration of the factory module. DIY customers tend to formulate their own way of doing things based on threads such as this and we have learned respect their willingness to experiment and learn as they go.
We will update our wiring matrix chart for single and dual-pump applications to include C5/C6 platforms. This will make it simple for customers to select the wiring components they require:
http://racetronix.com/press-release/...ing-harnesses/
Here are a few notable C5/C6 items we have recently introduced to help simplify installation, improve pump performance and reliability:
http://www.racetronix.biz/itemdesc.a...PH-008&eq=&Tp=
http://www.racetronix.biz/itemdesc.a...WH-033&eq=&Tp=
http://www.racetronix.biz/itemdesc.a...WH-034&eq=&Tp=
http://www.racetronix.biz/itemdesc.a...WH-008&eq=&Tp=
http://www.racetronix.biz/itemdesc.a...U475-1&eq=&Tp=
http://www.racetronix.biz/itemdesc.a...U476-1&eq=&Tp=
For customers who wish to retain the jet-pump functionality of their C5/C6 fuel system we will be introducing new PnP C5/C6 fuel systems incorporating our RXP 340LPH fuel pumps late this spring.
Thank you for your consideration.
Supporting Vendor
Joined: Dec 2001
Posts: 1,573
Likes: 31
From: A dealer near you.
DIY C56 Dual Pump Kit
This is our new DIY DPK for skilled installers. One complete solution with only the best components.
PLEASE CLICK ON THE LINKS TO VIEW DETAILS IN OUR WEB STORE.
http://www.racetronix.biz/customkiti...DIYDPK-C56&eq=
The DIYDPK-C56 is recommended for factory HP upgrades from 650-1000/1400HP (gas). HP support will vary based on many factors such as fuel pressure, pump voltage, fuel line type/size, motor BSFC etc. Racetronix recommends a 20% safety margin for fuel delivery.
This kit is designed to fit in all C5 Corvettes manufactured 2003 1/2 and later with VIN # 114931 (last six digits) and up as well as all C6 Corvettes through 2013 excluding the ZR1.
PLEASE CLICK ON THE LINKS TO VIEW DETAILS IN OUR WEB STORE.
http://www.racetronix.biz/customkiti...DIYDPK-C56&eq=
- For HP upgrades from 600-1400HP
- Twin Racetronix 255LPH or 340LPH turbine fuel pumps with reduced noise and enhanced reliability with E-85 enhanced fuels*
- Stainless pump bracket
- Billet dual pump coupler with Viton o-rings
- Teflon 10 gauge PnP dual in-tank harness - E85 Compatible
- High-pressure non-kinking fuel tube
- Intermediate PnP Harness - 10 gauge wire
- Dual PnP power harness - 10 gauge wire
The DIYDPK-C56 is recommended for factory HP upgrades from 650-1000/1400HP (gas). HP support will vary based on many factors such as fuel pressure, pump voltage, fuel line type/size, motor BSFC etc. Racetronix recommends a 20% safety margin for fuel delivery.
This kit is designed to fit in all C5 Corvettes manufactured 2003 1/2 and later with VIN # 114931 (last six digits) and up as well as all C6 Corvettes through 2013 excluding the ZR1.
