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Parts of this has been covered in builds already, but thought I would provide a full compilation of parts I am using and step through a few issues as I put it all together. Feel free to step in if you see/know of a better way to do any part of this install, as well as add your own installation tips or ideas.
For this setup I will be reusing my stock 89 Firebird tank and will connect the new wiring harness to the stock third gen connector in front of the gas tank. All components are from Racetronix, which took many discussions, emails and purchases to gather all the right parts and wiring adapters to make this true plug and play. For my application, the battery is located in the trunk, so a few modifications will be required, however if you have a front mount battery, no mods to this wiring harness should be required.
Single pump will be operating under 7 PSI boost, which upon greater boost the second pump will kick in. This can easily be adjusted to your setup by purchasing the right pressure switch for your application.
Parts List, starting from the fuel pump end is as follows:
Part Number --- Description
FFS-122A --- Fuel Filter Sock (104 x 42mm, 22mm ID, G-D)
DPM-001 --- Dual Pump Mounting Bracket (GSS340M / G77)
RXP255 --- 255L / Hr Fuel Pump, High Pressure / Volume (x2)
DPC-G7 --- Double Pump Coupler G7 CNC Billet Aluminum
DP-ITWH-014 --- Dual Pump Wiring Component (ITWH, DP, C44) - In Tank wiring
BCA-4W --- Tank bulkhead connector, 4 pin for dual pump operation with fuel level
IDPH-C4X --- Intermediate Double Pump Harness C4X (IDPH modified for FL98 application) - This is the wiring harness "Y" Connection Point
WHEXT-001 --- Extension from Y connection to stock tank connector on chassis
UDPH-005 --- Universal Double Pump HD Harness (MP280) - Power relays and pump control circuits
UDPH-HA --- UDPH 004/005 Series Adapter (Sold as add on component to UDPH-005, STD to HD wiring upgrade)
HIH-001 --- Hobbs Interface Harness, 72" - DPK - Extension cable to Hobbs switch
HPS-7 --- Hobbs Pressure Switch, 7 PSI (MP280 connector)
BGK-001 --- Body Ground Kit, 8", includes Body Ground Cable 8Ga., 3/8" Terminal, 8" long
FIT-BUNGSS6M --- Weld Bung, -6AN Male, Stainless (Optional - return line)
FIT-BUNGSS8M --- Weld Bung, -8AN Male, Stainless (Optional - supply line)
With everything else being new, I couldn't put these new components on the old rusty sender, so picked up a new unit from RockAuto. Check for your year before purchasing, this is the one i am using for the 89 gas tank. http://www.rockauto.com/catalog/more...nid=459&jpid=2
Starting with the new sender, I carefully removed the bottom support that the single pump would have bottomed out on.
Next I revised the location and bend of the pump side bracket to allow it to support the bottom pump in its new location with the dual pumps installed.
Prior to checking the fit of the DPC-G7 double pump coupler, I noticed a few slivers of metal within the internal ports, so very carefully cleaned up the leftovers. I also mildly ported the square edges found on the dual port side to allow a smoother flow to the single outlet, as well as cleaned up the center transition. With two pumps in operation, I suspect the fuel will be screaming though this coupler, so any efforts to limit turbulence should improve its fuel flow capabilities. Make sure you do not nick the O-ring channels, I start my dremel after I had it inside the port at the point I was looking to smooth.
Even with the outlet lightly ported, you can still see a bit of a square edge on the outlet.
I'm glad you posted this, I built the same set up for my SC 408LS swap but with a 4 PSI hobbs switch and all from Racetronix,ended up using what was mostly from the D.I.Y. page and Buick GN pieces for that dual in-tank kit.
It wasn't easy and Racetronix made it clear I was on my own.
I understand, that is what drove me to this thread. I received the same kind of response, even when I noted that their pictures on their store do not always align with the actual product and then there is the multitude of custom codes and part numbers that only they know of, or what the part number contains.
They build great products and being a Canadian company I should be proud of them, however their support is much to be desired. They have always provided me the information I was after, but it was never a smooth process.
I built the same set up for my SC 408LS swap but with a 4 PSI hobbs switch
My build is a SC 408LS as well. Curious how the 4PSI switch has been working for you? I thought that would have been the better choice as well, however they said to turn on the second pump as late as possible and recommended the 7PSi switch. Single 255 pump maxes out around 500HP.
Nice work! I made mine from scratch using Racetronix parts also. Barely fit in the tank, but the flex fuel lines they sold me made it possible. I used 2 Walbro 255 pumps, and a 7 psi Hobbs switch activated by boost. This is on an 89 Turbo TA running E85. 10.99 @ 121.6 so far.
Stock unopened motor, 5858 Turbo, 29 psi boost. According to HP calculators approximately 530 at the wheels. Dual pumps should be good for 700+. Stock fuel lines too!
Curious how the 4PSI switch has been working for you? I thought that would have been the better choice as well, however they said to turn on the second pump as late as possible and recommended the 7PSi switch.
I can't answer that yet, as I'm finishing the IC install, Radiator and new fan(s) placement. I should be ready it fire it up by late March. Actually, I was thinking that your 7PSI is right and my choice may not be, I was talked into the 4 PSI switch by some of the C5/6 guys who run 1 in tank and a second inline pump and they swear by it. Racetronix never really said either choice was better. I guess I'll have to watch the run logs and see where the duty cycle ends up right where the second pump tips in. Their thinking was that we'd be passing by the 4 PSI so quickly that the second pump's engagement would be fully online by 7-8 PSI thereby eliminating any transitional lean spikes. But like I mentioned, I'm just not sure.
There's not many of us 3rd gens running this set up so I figure we're in undocumented results phase.
It's funny how you had the same experience with Racetronix and I treated them as I would try to feed a wild squirrel by hand...careful not to scare them off and deny me their business. But you're right, darn nice parts and really the only place to go to build this set up.
and dvernst, I think I followed you're success over on the TTA forum, I'm WS6 over there and sold my TTA to fund my LS 3rd gen swap. Glad your set up is proving the right thing to do. I hope ours yields good and reliable results, I was so unsure about this that I set up my fuel tank for the possibility that I'd have to abandon the intank system and I have it ready to be used as an ext and I sumped it.
One thing I'm really sketchy on is my my choice to leave the stock fuel lines in place. Racetronix was adamant about their ability to support 700 H.P. and their proof was the high H.P. Turbo buick guys running 3/8 feed and 5/16 return....so we'll see about that too.
I've done the double pumper setup you're doing as well. I'm on the stock feed lines up to the engine bay. My combo is a 420 minirammed sbc. D1sc at 10psi. I have my hobbs switch set at 3 psi and it's perfect. No rich spikes. As for the lines not being enough I'll say this: when my injectors were too small and going static I was seeing afrs in the 10s at 6500 rpm. Haven't dyno'd since the supercharger install but I'm trapping 130-135 in the quarter mile. 3650lbs race weight.
I stage my pumps. One runs normal like stock. I got one pump on a 1 psi hobbs. Comes on at wot. No problems. Last pump on an adjustable hobbs, about 15 psi.
So why run multiple pumps vs. a single rated for the same? Is it better for street use? I get using intake pumps for quieter operation and lower temps, just wanting to understand the reasons for this setup.
They simply dont make a single intank pump that will make 1300 whp on gas. For oem tanks i mean
External sump pumps or a cable drive setup, then yes can run 1.
But one large external may not operate well at light demands. Aeromotive made controllers for their pumps for street use i believe
Multiple pumps are cheap. 300$ for triple 255's. But there are more things that could fail. Gotta keep up on maintenance
Hot ticket is holley hp or dominator efi, or equal that monitors fuel pressure and afr. If a pump fails and pressure drops or afr leans out, it can save the motor by trying to command more injector pulse if inj are large enough, or yank timing to help save things
Ah I see. Wasn't aware they didn't make intake pumps for that much power. I kind of figured as about the larger external pumps not working under light loads, plus I'm sure they are noisy as all hell. It seems the multiple setup is the hot ticket, but like you said it also means more things to keep up with. Always a price to pay somewhere somehow for performance I guess.
Getting support from racetronix is next to impossible. i ordered the wrong components the 1st time around, but made it work with some tweaks. The yellow 4-prong bulkhead connector wouldn't fit on my sending unit without clearancing with a die grinder/dremel to remove some plastic that was preventing it from seating 100%. it would help if there were instructions but it is simple enough to figure out if you study the stock system.
I have the 4 psi switch and have no issues with fuel spikes.
Prior to installing the coupler with o-rings installed on any fuel line, ensure you lube the O-rings so they slide on without tearing. You may want to relube later upon final assembly as well.
When pushing the DPC-G7 double pump coupler onto the fuel lines, it is possible to push all three lines into the coupler deep enough that all three lines can almost touch, which when in this position can partially block the flow of each line. To prevent this from occurring, I measured the couplers connection point to where the o-rings are best seated on the fuel lines. (Just beyond lip of pump outlet.)
To limit the travel of the coupler into the pump lines, I built a couple 0.400" spacers from 1/2" SS tubing to prevent any further downward movement.
With pumps tied downward towards the coupler bracket, further upward movement of the pumps will not occur.
Next, I measured where the coupler bottoms on the supply line and marked this location. From there I marked my insertion depth again at 0.400" and inserted coupler. This will now allow maximum flow through the lines with sufficient line overlap for the o-ring seals.
A little wresling with all the brackets to get the pumps and lines trued up, then pumps tied down temporarily with plastic tywraps. (Will be replaced with stainless tywraps on final assembly.)
Before I can go any further with the pumps install, I need to get my awesome weld bungs installed on the supply and return lines of the fuel sender, which due to the amount of heat that will need to be applied, I have to remove the pumps from the lines prior to silver soldering.
These are the weld bungs I noted as "optional" before. And before you decide to buy these nice SS fittings, read on.
Supply line fit on well with perfect clearance, return line, not so. Doesn't fit the 5/16" line, so what size line would it fit? Due to them being SS, a cobalt drill bit is required, off to the store I go.
After calling every hotrod shop I know of in the city, I came to the conclusion that no one silver solders fittings on their tanks these days. They have heard of it, but never done it.
Looks simple enough to perform with the right products... order in!
OK, let's recap:
$20 for fittings
$30 drill bits
$70 Hi Temp / Hi Content silver solder and flux
Oh yeah, need to buy some MAP gas to reach sufficient temp. for silvers soldering...
Man, wish I would have bought adapter fittings like the rest of the world.
Onto a positive note, having the wiring harness full plug and play is very nice, although I will be shortening the fused wiring to connect up with my rear mount battery.
Solid connectors and quality relays throughout.
I really like the control circuits wired in for each pump. Both come with jumpers circuits installed, which can be used if you want both pumps to run at all times, or as I have the one running through a boost switch to turn on the second pump at 7PSI boost. With having the control circuit connectors mounted at the same location, you can easily switch jumper and pressure switch connectors to test each pump or switch the primary pump, should it fail.
Fuel sender bulkhead harness comes with additional ground wires to mount to the fuel sender itself, further ensuring a solid ground for the in tank pumps.
Before I can go any further with the pumps install, I need to get my awesome weld bungs installed on the supply and return lines of the fuel sender, which due to the amount of heat that will need to be applied, I have to remove the pumps from the lines prior to silver soldering.
These are the weld bungs I noted as "optional" before. And before you decide to buy these nice SS fittings, read on.
Supply line fit on well with perfect clearance, return line, not so. Doesn't fit the 5/16" line, so what size line would it fit? Due to them being SS, a cobalt drill bit is required, off to the store I go.
After calling every hotrod shop I know of in the city, I came to the conclusion that no one silver solders fittings on their tanks these days. They have heard of it, but never done it.
OK, let's recap:
$20 for fittings
$30 drill bits
$70 Hi Temp / Hi Content silver solder and flux
Oh yeah, need to buy some butane gas to reach sufficient temp. for silvers soldering...
Man, wish I would have bought adapter fittings like the rest of the world.
That looks like a lot of effort.
I bought the swagelock 3/8 tube to -6an fittings to adapt the stock steel tube to the AN fittings. They make a 3/8 to -8an also. Get extra ferruls in case you need to take it apart, the fittings are re-usable, but the ferruls crush and can't be re-used. The 3/8 to -6an fitting was $14.30 each and I think the 3/8 to -8an was a little more.
Finished the dual fuel pump assembly using a couple SS tywraps to maintain the pumps in position.
Filters on and ready for install in tank.
Install into the tank was not too difficult. Installed float first, then folded the filters back under themselves, then wiggled the lower support into the cavity. Some minor adjustments on the outer lines to best align the sending unti with the tank and voila, she's in!
After the major failure attempting the weld bungs, I picked up the Swagelok fittings to connect to the fuel lines.
SS-600-7-6 female connector 3/8" tube to 3/8" FNPT for fuel line
SS-500-7-4 female connector 5/16" tube to 1/4" FNPT for return line
Picked up my fuel lines from Racetronix during their Black Friday sale. Lines are Teflon inner housings with SS Braided Hose covered with Hytrel black covering. I choose the version with the conductive liner, just as a safety precaution should I have to connect/disconnect after pump operation.
Initially was shipped the version without the outer casing, so took the opportunity to weigh the difference. Black covered lines were 4#, whereas the straight SS lines came in at 3.5#. Pretty light for 12' of -6 and 15' of -8 line.
I have that same black teflon line from racetronix. Make sure you line the hose out where you want it before you mark you locations to cut it, because the black line is not as flexible as the braided outer. Might need to rethink any really sharp turns you would have made with the normal braided outer.
Thanks for the heads up. Planning to run down driver side, then into existing frame rail opening on bottom. Will create new holes for exit from frame, thinking one near front of engine for feed into Y to fuel rails and one near firewall for connection to a Y return from my reg.
I was only going by the 'experts'. Racetronix said that a single 400 pump was good for 900hp after you factor in the drop thru the lines and higher pressure drop because of boost.
I was only going by the 'experts'. Racetronix said that a single 400 pump was good for 900hp after you factor in the drop thru the lines and higher pressure drop because of boost.
(Walbro F90000262) (@ 6lb specific gravity)
At 43psi it's about 400lph / 105 gallons or 630lbs/hr
At 14psi boost using a 1:1 rise regulator, it's 350lph / 92 gallons or 552lbs/hr
So 1100 n/a at .50 BSFC, or 1000 @ 14psi boost and .55 BSFC.
The BSFC could be anywhere between .45 and .60 depending on intercooling.
Either way, in a 3800lbs Fbody a single Walbro 410 should support the car going into the high 9s. That was my point. How fast are you guys going?
Fuel heating is a big reason to use dual pumps in a return style system. If you put street miles on your car like I do, it's an issue. A single 255 will get warm enough to drop fuel pressure 4 psi on a hot day. I'd imagine a 410 will be a little worse.
Fuel heating is a big reason to use dual pumps in a return style system. If you put street miles on your car like I do, it's an issue. A single 255 will get warm enough to drop fuel pressure 4 psi on a hot day. I'd imagine a 410 will be a little worse.
My old red formula I had back in 2000-2004 had a single walbro 255. It would make 560hp without pressure drop, and that was with elevated base pressure and 14lbs boost.
The pumps efficiency may diminish, I wouldn't argue that, but your rail pressure shouldn't drop - that's the whole purpose of having a regulator.
Maybe it's my application (stock lines, stock regulator) but I know I'm not the only one that has seen it. Could also be the way current pump fuel is formulated. I'm talking about real street driving too. Stop n go traffic, hour long cruising, etc. I have a pressure gauge in the car and I can watch it on a warm day. It will drop 4-5 psi with a corresponding leanout on the wb (open loop). I'm north of 750 horsepower so a single 255 isn't enough. 410 could be if the pressure drop wasn't severe.
Maybe it's my application (stock lines, stock regulator) but I know I'm not the only one that has seen it. Could also be the way current pump fuel is formulated. I'm talking about real street driving too. Stop n go traffic, hour long cruising, etc. I have a pressure gauge in the car and I can watch it on a warm day. It will drop 4-5 psi with a corresponding leanout on the wb (open loop). I'm north of 750 horsepower so a single 255 isn't enough. 410 could be if the pressure drop wasn't severe.
Are your fuel rails on the miniram modified for a front crossover?
That's the only concern I have with mine. The single crossover in the rear with feed on one side and exit on the other seems to me like a recipe for making the front cylinders lean. And since the air distribution sucks and the rear cyls run rich anyway, it probably only compounds the problem.
Should be feeding from the front of the right rail, and returning form the rear of the left with dual crossovers. GM improved the design of the LT1 intake in '94 when they added the second crossover, I suspect for the same reasons. Even so, the $EE mask has a pretty substantial cylinder trim.
The feed line is split to feed both rails from the front. The rear crossover is still in place with the regulator mounted on the rail. So far this configuration is working fine. I tried to get away with drilling the divider inside the rails at the injector holes and leaving the rear feed like it came from tpis. 1 and 3 cylinders went lean and it cost me a head gasket. The air distribution sucks at idle and causes some bucking at part throttle, but it doesn't seem to be an issue at wot although I run it a little rich for peace of mind.
Yup the 400-450 walbro stuff can make big power on gas alone. 1000-1200 flywheel depending on pressure and how well setup your motor is.
They didnt have those pumps when i did dual 255's. Then it was triple 255's since one more 255 was cheaper and easier to add
I don't get why you guys run dual pumps. A single 400/410 lph pump will do 1200 horsepower.
How much power are you guys making?
-- Joe
The way I am building my car is to have total flexibility of what type of use the vehicle can be setup for. With the 408, I am planning to have two tunes, one naturally aspirated for road course, one boosted for drag racing; with street driving in either setup.
When not running boost, only one pump will run. I am able to switch which pump is primary within seconds, simply by switching the pump controlled by the boost switch. This extends the life of both pumps; I will always have a backup pump on track day and will be recirculating less fuel and creating less heat in the system when not required.
On the initial boosted setup, I am planning to start mildly, however want to be able to turn it up later without further modifications. Taking that tank out is a PITA.
Parts of this has been covered in builds already, but thought I would provide a full compilation of parts I am using and step through a few issues as I put it all together. Feel free to step in if you see/know of a better way to do any part of this install, as well as add your own installation tips or ideas.
For this setup I will be reusing my stock 89 Firebird tank and will connect the new wiring harness to the stock third gen connector in front of the gas tank. All components are from Racetronix, which took many discussions, emails and purchases to gather all the right parts and wiring adapters to make this true plug and play. For my application, the battery is located in the trunk, so a few modifications will be required, however if you have a front mount battery, no mods to this wiring harness should be required.
Single pump will be operating under 7 PSI boost, which upon greater boost the second pump will kick in. This can easily be adjusted to your setup by purchasing the right pressure switch for your application.
Parts List, starting from the fuel pump end is as follows:
Part Number --- Description
FFS-122A --- Fuel Filter Sock (104 x 42mm, 22mm ID, G-D)
DPM-001 --- Dual Pump Mounting Bracket (GSS340M / G77)
RXP255 --- 255L / Hr Fuel Pump, High Pressure / Volume (x2)
DPC-G7 --- Double Pump Coupler G7 CNC Billet Aluminum
DP-ITWH-014 --- Dual Pump Wiring Component (ITWH, DP, C44) - In Tank wiring
BCA-4W --- Tank bulkhead connector, 4 pin for dual pump operation with fuel level
IDPH-C4X --- Intermediate Double Pump Harness C4X (IDPH modified for FL98 application) - This is the wiring harness "Y" Connection Point
WHEXT-001 --- Extension from Y connection to stock tank connector on chassis
UDPH-005 --- Universal Double Pump HD Harness (MP280) - Power relays and pump control circuits
UDPH-HA --- UDPH 004/005 Series Adapter (Sold as add on component to UDPH-005, STD to HD wiring upgrade)
HIH-001 --- Hobbs Interface Harness, 72" - DPK - Extension cable to Hobbs switch
HPS-7 --- Hobbs Pressure Switch, 7 PSI (MP280 connector)
BGK-001 --- Body Ground Kit, 8", includes Body Ground Cable 8Ga., 3/8" Terminal, 8" long
FIT-BUNGSS6M --- Weld Bung, -6AN Male, Stainless (Optional - return line)
FIT-BUNGSS8M --- Weld Bung, -8AN Male, Stainless (Optional - supply line)
What was cost for all this? I'm thinking of doing a 4th Gen tank swap and then $775 for a drop in dual pump setup, hot wire and 4psi hobbs switch from a guy on ls1tech. Plus $125 or more for the tank itself.
Parts of this has been covered in builds already, but thought I would provide a full compilation of parts I am using and step through a few issues as I put it all together. Feel free to step in if you see/know of a better way to do any part of this install, as well as add your own installation tips or ideas.
For this setup I will be reusing my stock 89 Firebird tank and will connect the new wiring harness to the stock third gen connector in front of the gas tank. All components are from Racetronix, which took many discussions, emails and purchases to gather all the right parts and wiring adapters to make this true plug and play. For my application, the battery is located in the trunk, so a few modifications will be required, however if you have a front mount battery, no mods to this wiring harness should be required.
Single pump will be operating under 7 PSI boost, which upon greater boost the second pump will kick in. This can easily be adjusted to your setup by purchasing the right pressure switch for your application.
Parts List, starting from the fuel pump end is as follows:
Part Number --- Description
FFS-122A --- Fuel Filter Sock (104 x 42mm, 22mm ID, G-D)
DPM-001 --- Dual Pump Mounting Bracket (GSS340M / G77)
RXP255 --- 255L / Hr Fuel Pump, High Pressure / Volume (x2)
DPC-G7 --- Double Pump Coupler G7 CNC Billet Aluminum
DP-ITWH-014 --- Dual Pump Wiring Component (ITWH, DP, C44) - In Tank wiring
BCA-4W --- Tank bulkhead connector, 4 pin for dual pump operation with fuel level
IDPH-C4X --- Intermediate Double Pump Harness C4X (IDPH modified for FL98 application) - This is the wiring harness "Y" Connection Point
WHEXT-001 --- Extension from Y connection to stock tank connector on chassis
UDPH-005 --- Universal Double Pump HD Harness (MP280) - Power relays and pump control circuits
UDPH-HA --- UDPH 004/005 Series Adapter (Sold as add on component to UDPH-005, STD to HD wiring upgrade)
HIH-001 --- Hobbs Interface Harness, 72" - DPK - Extension cable to Hobbs switch
HPS-7 --- Hobbs Pressure Switch, 7 PSI (MP280 connector)
BGK-001 --- Body Ground Kit, 8", includes Body Ground Cable 8Ga., 3/8" Terminal, 8" long
FIT-BUNGSS6M --- Weld Bung, -6AN Male, Stainless (Optional - return line)
FIT-BUNGSS8M --- Weld Bung, -8AN Male, Stainless (Optional - supply line)
Hey there I know this old now but I bought pretty much the exact same parts list as this only dual 340 pumps, except after talking with Racetronix they replaced the IDPH-C4X harness that you modified for fl98 with IDPH-FL98 and eliminated the WHEXT-001 harness as the extension to the stock chassis wiring. Just thought I'd update this in case anyone else was going the same route. Take care and have fun
Hey there I know this old now but I bought pretty much the exact same parts list as this only dual 340 pumps, except after talking with Racetronix they replaced the IDPH-C4X harness that you modified for fl98 with IDPH-FL98 and eliminated the WHEXT-001 harness as the extension to the stock chassis wiring. Just thought I'd update this in case anyone else was going the same route. Take care and have fun
I know this thread is old but did you modify the intermediate harness (IDPH-FL98) with larger gauge wire to accommodate the 340 pumps? I know a heavy duty harness is needed for the in-tank and intermediate harness for the 340 single pump set-ups so I imagine it would be the same for the double pump set up and it doesn't appear Racetronix sells an upgraded intermediate harness for a double pump set up.
I know this thread is old but did you modify the intermediate harness (IDPH-FL98) with larger gauge wire to accommodate the 340 pumps? I know a heavy duty harness is needed for the in-tank and intermediate harness for the 340 single pump set-ups so I imagine it would be the same for the double pump set up and it doesn't appear Racetronix sells an upgraded intermediate harness for a double pump set up.
Nope I talked to one of the reps at racetronix and everything he sold me was good to go plug n play with the fl98 harness. They make very high quality harnesses. They over build what they sell
Last edited by thatsupnow; 10-26-2020 at 09:17 PM.
01-28-2016, 09:01 PM
