Rkreigh

I'm interested in upgrading my fuel system

I have a ttix car making 800 at the tire on a heavy meth dependent tune and I'm looking to switch over to E85 and hit 900 at the tire so I'll need LOTS more capacity

here's what I have in mind but honestly I don't know if this will work and need feedback

I'd like to convert the 2003 to a return style with a boost referenced regulator at the back of the fuel rails with a feed to each

can you run a pump in each of the tanks?

these pumps look like a good value. I got a price of over 2100 to implement a magnafuel which seems very high to me (un installed!)

the magnafuel setups look nice but the pump only costs under 500, regulator around 300, and all those little fittings add up but it seems a bit excessive

thanks for any advice!

Rkreigh

top it

umrjmac

You can make the 2003 return-style. You will need to know if you have the early C5 or late C5/C6 fuel system before you start ordering parts. (there is a breakpoint between the two that you can figure out using your vin...I don't know it offhand, but you can find it here or on vendor sites that sell fuel pump kits)

I have the late c5/c6 fuel system, so the info below should be mostly true regardless, but if someone has contrary info please post it.

The way that the tanks work is that the driver's side tank is the primary tank and it pushes all fuel forward to the front of the car. The pump that is in the passenger tank is only used to push fuel from that tank to the driver's side tank. In theory you could change that dynamic up, but I'm not sure that it is a good idea. For instance, when you put fuel in the tank, the passenger side tank only fills when the driver's side is full. Additionally, when the tanks are nearly full and you experience some lateral acceleration, you could slop fuel from one tank to the other through the umbilical between the two tanks. This may net a situation where the fuel level is not identical between the two tanks and could lead to you not having fuel to squirt when you are expecting to have fuel available because the gas gauge doesn't show "E".

There are a number of drop in options and there are a number of secondary external pump options. I went with what is mostly the ECS external secondary pump system. I think both styles have their advantages, but its up to you to figure out what makes the most sense for you, your time, and your wallet.

If you use the stock in-tank pump and a secondary external pump, and if you go return-style with the fuel system, you will have to pull the in-tank pump to swap the fuel pressure regulator out for a plug. ECS and Lingenfelter both make them. I'm sure others do as well. They aren't terribly expensive but dropping the tank is a gigantic pain in the ***. There are a couple of decent youtube videos for the late c5/c6 style system that helped me.

The -AN hose and fittings REALLY add up. They will not be an inconsequential part of your build cost. One thing to be aware of is that the standard fuel line in a braided steel jacket is gas permeable...so if the car sits in the garage you have the possibility that the car will smell like gas. PTFE hoses are not gas permeable and they are what I used. PTFE hoses have their own specific hose ends. I would stay with the same manufacturer for both hose and hose end since everything may not be one size fits all.

I would recommend figuring out how much fuel you need to deliver and work backwards through the entire fuel system (injectors/pump) to ensure that the sum of parts delivers what you are looking for. I would also aim high because its not that much more expensive to go bigger than you need and it may save you a ton of time and money later on by not having to replace a lot of things. For my setup, I started by figuring out the max fuel mass that I can squirt through a set of ID1000s, subtracting the pump rating for the stock pump, and then using that figure to go shopping for the secondary pump. Having said that, I am slightly overkill now because I had to replace the stock pump, so I dropped in a C6Z06 pump...because overkill is fun?

The space between the back of the fuel rails and the firewall is pretty tight. You won't fit a regulator on the back of the rail. Some feed each rail from the back, put the regulator on the front of one of the rails, run a crossover from the other rail to the regulator, and then run the return line. Others have the regulator mounted elsewhere in the engine compartment. I am doing it a little differently in that I am feeding the rails from the back and then running line from the front of the rails to the regulator which I have bolted to the master cylinder with a little mounting bracket that I made out of right angle steel.

Oh, on the topic of fuel rails, with feeding from the back (or really having any connection on the back), aeromotive rails will amost guarantee that you have to cut a hole in the fiberglass to get some clearance. I think I saw something recently about someone using Holley fuel rails and those were a touch shorter and allowed him to have a right angle hose end on it without making firewall contact.

You can use the stock fuel line with your new setup. I am using mine as the return line. I ran -8AN as a feed, then stock as a return. The connections for it are 3/8" quick connect. You'll have to take it apart a bit to figure out how many male and female adapters to -AN you will need. 3/8" quick connect is roughly equivalent to -6AN.

Building a fuel system is a lot easier than it sounds...the parts just have to make good logical sense. When you break it down everything has a simple function and it just works together. I was very intimidated at first, but once I dug into it I wound up doing a ton of the design work and all of the installation work myself.

Rkreigh

not all that worried about dropping the tank as I will have the drivetrain out during the rebuild. what I currently have is a racetronix 255 lph pump with a boost a pump car pulled 800 at the tire on a very heavy meth dosage and I'm sure I'm stressing that fuel system

as I'm going e85 I need a TON more fuel. not sure how big the 450 LPH pumps are, but they do look like they are compatible with E85

thanks VERY much for the detailed explanation at times it's tempting to put a fuel cell or a "surge tank" in it and call it a day.

none of the "dual pumps" that are intank that I know of will support 900 at the tire on E85. the magnafuel certainly has the capacity, and a single pump would likely do the job activated with a hobbs switch.

I did alot of turbo work on the old turbo buicks with "double pumpers" but they were "old school tanks" and not as complex as the C5

I'll be doing lots of research and asking alot of questions and thank you very much for taking the time to create such a detailed response.

I'll have even more expense going the e85 route, but I think in the end it will be worth it.

I have the bosch 127 injectors from FIC as they fit the power goals I'm looking for.

I also have a fancy Haltech to control all this but that will go in at the same time as the fuel system upgrade.

you said it right "do your homework" and the build will come together!

Milan

I would add a Bosch 044 at your current setup. 900 whp and E85 here

mdaniel

This is why I still run meth and pump 93 with Lonnie's Double Pumper fuel system which utilizes twin intake 255s.

I'd love an elegant intake no fuss solution that could support big boost with E85 and do away with the meth system altogether - I just haven't found it yet.

Smoove

I maxxxxxed out my racetronics intank 255/hotwire kit on 93 octane at about 787rwhp..at 5600rpm fuel dropped off nasty,,,never pushed it passed that(5500rpm) with that pump, no meth used. I Would keep your intank setup..then TAP the tank and run another inline on a hobbs switch. You can T the factory feed into the auxiliary..which is what I do on most builds. Just run a check valve on the auxiliary so it doesn't back feed into the external. I usually use the magnafuel 4303 for the 1000rwhp E85 guys.

On a side not...I happen to have a walbro 450 in front of me as well as a stealth pump from aeromotive(a standard drop in replacement pump for most vehicles).... I took some pics for comparo reasons...I have a lot of good feedback on the 450's....and E85.

Rkreigh

great pics, can you squeeze two of those into the tank?

looks like they are designed to be submerged.

might just get the megafuel 4303 external but it seems a bit of overkill

can you just run "one pump" external and put in a return system

one megafuel has enough gas for 1600 hp which should still be plenty for 900 at the tire on E85

rather just have one pump going but I'm worried about the noise and heating the fuel up

anyone know if the ractronix pumps last on E85??

my ultimate (*albeit complex*) idea is to just run the existing pump and bap on pump gas, and have a secondary fuel system and another set of 8 injectors to run E85 on demand. I'd need to weld up a custom intake but to me it's the best of both worlds. pump gas + meth on "crooze" street mode

pump gas + e85 + meth if desired on "kill"

the haltech ecm I have can do this and more, much more complicated to tune that way, but it's kinda what I'm looking to do so I don't use up so much e85 as my car is primarily a street car

90% of what I do will be fine on pump gas + meth, but those rare occasions at the track E85 makes sense to me

I already have the computer and some FIC 127 bosch injectors which will be more than adequate for the secondary injectors

I have 70 lb injectors on the "primary side" for pump gas

and the haltech has a driver box so it can spin the alchy pump on demand and replace the progressive controller

anybody game for this? I just need to get an intake and another pump

been looking at the polished profession products 96 mm intake which I would likely open up to 102 and run a bigger throttle body

I'm building up a 383 iron block short block for the foundation plus the .82 housing and champion 3" down pipes on the ttix turbo system

this will now be a "fall project" as I will finish out croozin season with the car as is.

Smoove

In my own car, I run a single magna fuel 4303. I run no internal pump, and it is a return style.

However...I do have both of my fuel tanks joining at the bottom, for equal level reasons....since I am no longer using jet siphon.

The pump is kinda loud but, I don't really notice it..and mine is sitting in my drivers side rear brake duct.

I figured if 1 4303 wasn't enough... I would just buy another one and link it to the other tank...on a hobbs...

Milan

I still think the 044 is better than the magnafuel. You should look to see how bad the pressure drops off at 80+ psi fuel pressure on the magnafuel.

Bosch 044 is high pressure king. If needed run 2

Smoove

Drop your base fuel pressure below 50psi.

No need to run that pressure for me, unless you have a venturi(factory) style system. Drop it to the 40's and no issue. 044's work like a champ though, proven pumps. bargain priced as well.

Milan

True but then you don't get a lot out of your injectors. The new injectors can handle 100 psi fuel pressure, no point in running them below 40.

JoeyG

I run a 255 and boost activated Magnafuel 4303, -10 line to rails and -8 return with my FIC 96# injectors and aeromotive 1:1 fpr at 48psi base. This should carry me to over 1100rwhp according to rough calculations. If I ever swap from pump/meth to e85 and could make that power level.

Smoove

43-45psi...injectors won't care.


proper.