Fuel system question
Thread Starter
Former Vendor
Joined: Mar 2004
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From: Winchester CA
Fuel system question
I have a 04 z06, i had a 408 stroker in it before, and on the motor right around 550rwhp, i started to see pressure drop from the fuel system, but was able to compensate in the tune. now i am building a 434 stroker, ls7 heads, and the whole nine yards. i am curious to see what i can do for more fuel with the quirky 04 fuel system. i know a boost a pump might work, but how would i set it up on a N/A car. any fuel pump mods out there??, maybe a inline pump, i would rather do a pump then do a boost a pump, trying to keep it simple. thanks for your guys help.
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Joined: Jul 2003
Posts: 6,486
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From: http://www.mphparts.com 800-364-1975
I had the same style (FFS) fuel system you do. Here's the problem...
The fuel sender goes into the fuel tank from the top. The only way you can access the sender (and thus, the pump) is to drop the tank. As far as I could tell, you couldn't just unbolt the tank and get it low enough without dropping the driveline and rear cradle (but I could be mistaken here, since I didn't try).
The fact that you can't easily get in there kind of eliminates the idea of swapping for a stronger aftermarket in tank pump. It also sort of eliminates the idea of throwing a voltage booster on to the pump, since you'd have to modify OEM wiring further up stream since you can't reach the fuel sender connection.
I saw this situation as one you just have to throw money at to get it right and not have to drop the tank multiple times. I ended up buying an ECS fuel kit that includes aftermarket rails, regulator (at the front, where it should be), a high flow Bosch fuel pump, a filter, and all the necessary plumbing. This can be installed without dropping the tank, and there's some real ingenuity in the way they designed the kit.
Mine is setup in such a way that the factory fuel pump does its OEM thing and nothing changes. It just feeds into the fuel supply line for the aftermarket rails. The aftermarket Bosch pump however is check valved near the rails and when I go into WOT, it kicks in and starts throwing a lot more fuel at the rails -- the pressure gauge shows an increase in fuel pressure of around 3-4ish psi when this happens.
I drove it at low fuel demands (naturally aspirated) under a variety of conditions and the setup worked great. It will get its real workout in the next few weeks as I am finishing up a TT install on that car.
FWIW, the ECS fuel kit is around $1800.
If you decide this is too complex/too much, you might have another option... if you can figure out how to get fuel out of the tank and into an aux pump. There are a few shops like MDMC (I think ECS too) that make an adapter that will take the damper on your OEM rails and allow a -6an output to a different regulator. You could plumb in your own regulator plus an auxillary fuel feed from your aux pump and either run it all the time or only on WOT. Just a thought.
The fuel sender goes into the fuel tank from the top. The only way you can access the sender (and thus, the pump) is to drop the tank. As far as I could tell, you couldn't just unbolt the tank and get it low enough without dropping the driveline and rear cradle (but I could be mistaken here, since I didn't try).
The fact that you can't easily get in there kind of eliminates the idea of swapping for a stronger aftermarket in tank pump. It also sort of eliminates the idea of throwing a voltage booster on to the pump, since you'd have to modify OEM wiring further up stream since you can't reach the fuel sender connection.
I saw this situation as one you just have to throw money at to get it right and not have to drop the tank multiple times. I ended up buying an ECS fuel kit that includes aftermarket rails, regulator (at the front, where it should be), a high flow Bosch fuel pump, a filter, and all the necessary plumbing. This can be installed without dropping the tank, and there's some real ingenuity in the way they designed the kit.
Mine is setup in such a way that the factory fuel pump does its OEM thing and nothing changes. It just feeds into the fuel supply line for the aftermarket rails. The aftermarket Bosch pump however is check valved near the rails and when I go into WOT, it kicks in and starts throwing a lot more fuel at the rails -- the pressure gauge shows an increase in fuel pressure of around 3-4ish psi when this happens.
I drove it at low fuel demands (naturally aspirated) under a variety of conditions and the setup worked great. It will get its real workout in the next few weeks as I am finishing up a TT install on that car.
FWIW, the ECS fuel kit is around $1800.
If you decide this is too complex/too much, you might have another option... if you can figure out how to get fuel out of the tank and into an aux pump. There are a few shops like MDMC (I think ECS too) that make an adapter that will take the damper on your OEM rails and allow a -6an output to a different regulator. You could plumb in your own regulator plus an auxillary fuel feed from your aux pump and either run it all the time or only on WOT. Just a thought.
Last edited by Tony @ MPH; Oct 4, 2006 at 10:02 PM.
Burning Brakes
Joined: Aug 2006
Posts: 789
Likes: 38
From: Shreveport LA
You can get the pump out of the tank without dropping the rear cradle. I went with a Lingenfelter 255lph pump with a racetronix hotwire kit. This is suppose to be able to handle quite a bit of horsepower. I got the lingenfelter pump because it is a plug and play system that you don't have to do any modding to.
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Joined: Jul 2003
Posts: 6,486
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From: http://www.mphparts.com 800-364-1975
Originally Posted by Blue02ws6
You can get the pump out of the tank without dropping the rear cradle. I went with a Lingenfelter 255lph pump with a racetronix hotwire kit. This is suppose to be able to handle quite a bit of horsepower. I got the lingenfelter pump because it is a plug and play system that you don't have to do any modding to.
, and please share your method of getting the pump out -- it would make me very happy to know that when my OEM pump goes I have an easy way to swap it!
Thread Starter
Former Vendor
Joined: Mar 2004
Posts: 3,442
Likes: 18
From: Winchester CA
Originally Posted by diynoob
I had the same style (FFS) fuel system you do. Here's the problem...
The fuel sender goes into the fuel tank from the top. The only way you can access the sender (and thus, the pump) is to drop the tank. As far as I could tell, you couldn't just unbolt the tank and get it low enough without dropping the driveline and rear cradle (but I could be mistaken here, since I didn't try).
The fact that you can't easily get in there kind of eliminates the idea of swapping for a stronger aftermarket in tank pump. It also sort of eliminates the idea of throwing a voltage booster on to the pump, since you'd have to modify OEM wiring further up stream since you can't reach the fuel sender connection.
I saw this situation as one you just have to throw money at to get it right and not have to drop the tank multiple times. I ended up buying an ECS fuel kit that includes aftermarket rails, regulator (at the front, where it should be), a high flow Bosch fuel pump, a filter, and all the necessary plumbing. This can be installed without dropping the tank, and there's some real ingenuity in the way they designed the kit.
Mine is setup in such a way that the factory fuel pump does its OEM thing and nothing changes. It just feeds into the fuel supply line for the aftermarket rails. The aftermarket Bosch pump however is check valved near the rails and when I go into WOT, it kicks in and starts throwing a lot more fuel at the rails -- the pressure gauge shows an increase in fuel pressure of around 3-4ish psi when this happens.
I drove it at low fuel demands (naturally aspirated) under a variety of conditions and the setup worked great. It will get its real workout in the next few weeks as I am finishing up a TT install on that car.
FWIW, the ECS fuel kit is around $1800.
If you decide this is too complex/too much, you might have another option... if you can figure out how to get fuel out of the tank and into an aux pump. There are a few shops like MDMC (I think ECS too) that make an adapter that will take the damper on your OEM rails and allow a -6an output to a different regulator. You could plumb in your own regulator plus an auxillary fuel feed from your aux pump and either run it all the time or only on WOT. Just a thought.
The fuel sender goes into the fuel tank from the top. The only way you can access the sender (and thus, the pump) is to drop the tank. As far as I could tell, you couldn't just unbolt the tank and get it low enough without dropping the driveline and rear cradle (but I could be mistaken here, since I didn't try).
The fact that you can't easily get in there kind of eliminates the idea of swapping for a stronger aftermarket in tank pump. It also sort of eliminates the idea of throwing a voltage booster on to the pump, since you'd have to modify OEM wiring further up stream since you can't reach the fuel sender connection.
I saw this situation as one you just have to throw money at to get it right and not have to drop the tank multiple times. I ended up buying an ECS fuel kit that includes aftermarket rails, regulator (at the front, where it should be), a high flow Bosch fuel pump, a filter, and all the necessary plumbing. This can be installed without dropping the tank, and there's some real ingenuity in the way they designed the kit.
Mine is setup in such a way that the factory fuel pump does its OEM thing and nothing changes. It just feeds into the fuel supply line for the aftermarket rails. The aftermarket Bosch pump however is check valved near the rails and when I go into WOT, it kicks in and starts throwing a lot more fuel at the rails -- the pressure gauge shows an increase in fuel pressure of around 3-4ish psi when this happens.
I drove it at low fuel demands (naturally aspirated) under a variety of conditions and the setup worked great. It will get its real workout in the next few weeks as I am finishing up a TT install on that car.
FWIW, the ECS fuel kit is around $1800.
If you decide this is too complex/too much, you might have another option... if you can figure out how to get fuel out of the tank and into an aux pump. There are a few shops like MDMC (I think ECS too) that make an adapter that will take the damper on your OEM rails and allow a -6an output to a different regulator. You could plumb in your own regulator plus an auxillary fuel feed from your aux pump and either run it all the time or only on WOT. Just a thought.
Supporting Vendor
Joined: Jul 2003
Posts: 6,486
Likes: 2
From: http://www.mphparts.com 800-364-1975
Originally Posted by RyneZ06
how hard was the install?, i heard its a real pain in the butt i do all my work myself, right now the motor is out of the car, i can drop the rear cradle and such pretty easily
I just reread your post and noticed you were going big cubes NA and not FI so maybe you can do just fine with an aftermarket in tank pump. Speed Inc. has found a way to mount a Bosch pump inside the bucket in the tank, that might do it for you.
Good luck with your decision! And my sympathies, these FFS fuel systems really complicate modding a C5.
Thread Starter
Former Vendor
Joined: Mar 2004
Posts: 3,442
Likes: 18
From: Winchester CA
Originally Posted by diynoob
I did my install in about 10 hours but I also did a few custom things like mounting the fuel pump away from the exhaust on the outside of the rail, running the lines up the rocker, putting in the check valve near the rails, wiring the relay to a WOT switch, etc.
I just reread your post and noticed you were going big cubes NA and not FI so maybe you can do just fine with an aftermarket in tank pump. Speed Inc. has found a way to mount a Bosch pump inside the bucket in the tank, that might do it for you.
Good luck with your decision! And my sympathies, these FFS fuel systems really complicate modding a C5.
I just reread your post and noticed you were going big cubes NA and not FI so maybe you can do just fine with an aftermarket in tank pump. Speed Inc. has found a way to mount a Bosch pump inside the bucket in the tank, that might do it for you.
Good luck with your decision! And my sympathies, these FFS fuel systems really complicate modding a C5.
Supporting Vendor
Joined: Dec 2001
Posts: 1,573
Likes: 31
From: A dealer near you.
Thunder Racing carries our C5A-FPK-2 Fuel Pump kit for the late model C5's.
The harness is shown here :
http://www.thunderracing.com/catalog...&sid=650#P4551
The harness is shown here :
http://www.thunderracing.com/catalog...&sid=650#P4551
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Former Vendor
Joined: Aug 2001
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From: Atlanta GA
Originally Posted by RyneZ06
I have a 04 z06, i had a 408 stroker in it before, and on the motor right around 550rwhp, i started to see pressure drop from the fuel system, but was able to compensate in the tune. now i am building a 434 stroker, ls7 heads, and the whole nine yards. i am curious to see what i can do for more fuel with the quirky 04 fuel system. i know a boost a pump might work, but how would i set it up on a N/A car. any fuel pump mods out there??, maybe a inline pump, i would rather do a pump then do a boost a pump, trying to keep it simple. thanks for your guys help.
We have a twin pump return style system with no boost a pump that support's 1200 rwhp as tested to date for C5 and C6. After that we have no clue, it might go more. This is the same system we use on the MDMC 07 Z06 1350R packages just like the Z1100 packages 05 and 06. If you are looking for a mail order system that does wonders call Chris at ESC it will support i think up to a 1000 hp or more and they dont need your car to install it.
Thanks
OpticZ
MDMC
Melting Slicks
Joined: Jun 2004
Posts: 2,836
Likes: 110
From: El Paso TX.
Originally Posted by Racetronix
Thunder Racing carries our C5A-FPK-2 Fuel Pump kit for the late model C5's.
The harness is shown here :
http://www.thunderracing.com/catalog...&sid=650#P4551
The harness is shown here :
http://www.thunderracing.com/catalog...&sid=650#P4551
i just recieved you harness and will be using a KB BAP with it. your description says the harness will only supply power to the BAP when it is needed. so does this mean i do not have to use the vacumn switch that comes with the KB? i was planning not to use the vacum switch, i was going to turn on the BAP with my N2O arming switch. if you harness turns on the BAP only when fuel is needed then i can bypass the vacum switch and not have to wire it into my arming switch. if this is the case how does the harness know when to turn on the BAP for the extra voltage?
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Joined: Dec 2001
Posts: 1,573
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From: A dealer near you.
Originally Posted by algZO6
i just recieved you harness and will be using a KB BAP with it. your description says the harness will only supply power to the BAP when it is needed. so does this mean i do not have to use the vacumn switch that comes with the KB? i was planning not to use the vacum switch, i was going to turn on the BAP with my N2O arming switch. if you harness turns on the BAP only when fuel is needed then i can bypass the vacum switch and not have to wire it into my arming switch. if this is the case how does the harness know when to turn on the BAP for the extra voltage?
http://www.racetronix.com/product/RX...C5A-FPWH-2.jpg
The BAP is always passing power from the relay output to the pump when the pump is required (PCM controlled).
The BAP's voltage boosting is a function of a pressure switch (KB) or MAP sensor input (MSD).
Install the PBIC connector set onto the KB unit keeping the wires as short as possible (8-12" is good)
The male connector is installed on the KB input (+BAT ).
The female connector is installed on the KB output.
These connectors plug into the harness as indicated in the picture here:
The KB ground can be hooked to the same ground location as the relay here (driver's side rear fenderwell behind rear seat):
