im trying to decide what would be the best route to go. whats the best fuel system setup as far as cost and power capabilites go between option 1. a sump with an external pump, option 2. aftermarket in tank fuel hat, or option 3. a stock tank and pump with a surge tank? all would be return-style with a -10 feed and -8 return. what about a fuel pressure regulator?
fuel systems for big power, whats best?
kyle2002stang!
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Your thinking old school my friend. Do external fuel pumps warm fuel up more than internal. Yes but not by enough to make a difference. Alot of desighn has gone I to fuel pumps the past 10 years. If it is a problem for you put a fuel cooler on. It is not needed but it works. Return fuel sysem has been run on mustangs for 11+ years witbout a problem. Returnless came out cause the lapping of the fuel creats more fuel vapors which the epa wanted changed. The new pass threw compact fuel pumps also generate heat but are stuck in gas yes they stay cooler. External large pumps actually run cooler but warm the gas more cause it is outside of the fuel.
Modular Head Shop - Magnafuel MP-4303 ProTuner 750 Electric Inline Fuel Pump - (2,000HP Rated)
this pump is bad ass and will do a better job than any intank pump. Does it draw power hell yeah but it is comparitive to running 2 or 3 internal pumps. Now take this to heart. If you only have one pump and it goes car wont run and they are loud so you will know it is not working. if 1 pump out of 2 or 3 pumps go out car will run but driver does not know initially that one of the pumps failed. The dead pump will acts as a drain to the tank dropping fuel pressure to a point where you could wind up loosing the motor. Another point is the fpdm, lots of people with big pumps and baps thermal lock or fry it the fpdm. hell lets throw I the frps and we all know he headache that sensor gives. People blow them out, get lean spikes and just another sensor to go bad. Another advantage of external pumps is a fuel filer BEFORE the fuel pump. Ask anyone on this site how often they change the fuel sock. All it takes to crap out a pump is a small piece of sand and we know how clean the gas out of the pump is. People get a lot of miles out of both return and returnless fuel systems and I believe they should be judged on price and goals cause enough money thrown at both will work.
---------- Post added at 12:44 AM ---------- Previous post was at 12:38 AM ----------
Modular Head Shop - Magnafuel MP-4303 ProTuner 750 Electric Inline Fuel Pump - (2,000HP Rated)
this pump is bad ass and will do a better job than any intank pump. Does it draw power hell yeah but it is comparitive to running 2 or 3 internal pumps. Now take this to heart. If you only have one pump and it goes car wont run and they are loud so you will know it is not working. if 1 pump out of 2 or 3 pumps go out car will run but driver does not know initially that one of the pumps failed. The dead pump will acts as a drain to the tank dropping fuel pressure to a point where you could wind up loosing the motor. Another point is the fpdm, lots of people with big pumps and baps thermal lock or fry it the fpdm. hell lets throw I the frps and we all know he headache that sensor gives. People blow them out, get lean spikes and just another sensor to go bad. Another advantage of external pumps is a fuel filer BEFORE the fuel pump. Ask anyone on this site how often they change the fuel sock. All it takes to crap out a pump is a small piece of sand and we know how clean the gas out of the pump is. People get a lot of miles out of both return and returnless fuel systems and I believe they should be judged on price and goals cause enough money thrown at both will work.
---------- Post added at 12:44 AM ---------- Previous post was at 12:38 AM ----------
8an hose will feed well over 1000hp as long as the pump and Injecters are up to the challange.
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The new factory style return systems have gotten a lot smarter but they are pretty different from the standard aftermarket return type system.
The factory ones are modulating the pump drive like the returnless systems did so they minimize the fuel heating and churning problems, otherwise they wouldn't pass the EPA evap limits.
But generally the aftermarket ones run the pumps flat out. Even if the pump is pretty efficient the energy its consuming has to go somewhere and it goes in to heating up the fuel.
I'm not against return systems, they definitely have their place on high HP cars and if I can't get my returnless system to work well enough on the build I'm working on now I'm going to go to a return system.
But for a DD its a tradeoff, I'm going to try to stay returnless if I can.
Since I have an auto car the transient fuel pressure issue isn't as bad as manual cars so that gives me a better chance.
I'm hoping to be able to hit 650 whp with this build so I'll be pushing the limit where a lot of people get into trouble with a returnless system but I'm going to give it shot.
I used pumps that work well both returnless and return so it will be easy for me to switch.
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Why try something to see if it works?. That is double spending. Yes a returnless fuel system will work but will it be enough money saved, well that is up to you. Car projects get expensive when you wast money on parts. I cant tell you what to do and like I said both systems work. I am not going to talk down on one or the other just recommend. If fuel heat is a big concern to you than stay returnless OR put a fuel cooler on the return line and then you have best of both worlds. Is the heat such a problem where people with return are running out and changing to returnless, I dont think so. People switch to retun because it is better for dd driving and supporting big power. Why wait for your pumps to push fuel in a returnless system when it is always there in a return system. Have your tuner expand your af ratio with a returnless fuel system and you will see how shaky it is wih a big lean spike at the start. Return has a vary small lean spike at the start and it stays real consistant. Return done right can be your cake and eat it too fuel system.
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I hear ya but don't forget I'm one of the cheapest f***s out there, I'm trying to win the most HP per penny battle (why, who knows, its just ingrained).
I fabbed the system from the start to be able to run either return or returnless and also be E85 compatible so its easy for me to switch to return if I have to and as far as I can tell I've got less $ in this system than anybody elses.
Started with a used GT hat and and used some scrap metal to mount two improved (higher flow, E85 compatible) GT Supercar pumps Cobra style, cost so far $200. for the pumps.
Fabbed up 2 AN-6 outlets in the GT hat for the pumps, probably $30. in parts for those outlets.
Spend $25. on a E85 compatible plastic gas can to cut the bottom out to use as a tank baffle.
Spent about $20. for E85 compatible wire and wire terminals.
Splurged $25 on Deutsche connectors for the dual pumps.
Bought a second used FPDM for $25.
Strangely, instead of taking the cheep way out and hacking a second FPDM connector directly into the stock harness, splurged on 3 new FPDM connectors for ~ $100. to make up a plug and play dual FPDM harness.
Spent around $100. on AN-8 line and fittings to run from the back to the front.
Splurged $130. on an E85 compatible Fuelab inline filter.
Spent $30. on 2 AN-6 to AN-8 wye blocks to merge the pumps at the back and split them to the fuel rails at the front.
Hacked up the stock injector rails to convert them to dual feed and improve the flow, $0.
Total cost is $660. and the system should be good to 700whp or so (whoa, less than $1. per HP!!!).
If I have to switch to return I'll just need to buy the return line and a regulator so that won't be too bad.
I fabbed the system from the start to be able to run either return or returnless and also be E85 compatible so its easy for me to switch to return if I have to and as far as I can tell I've got less $ in this system than anybody elses.
Started with a used GT hat and and used some scrap metal to mount two improved (higher flow, E85 compatible) GT Supercar pumps Cobra style, cost so far $200. for the pumps.
Fabbed up 2 AN-6 outlets in the GT hat for the pumps, probably $30. in parts for those outlets.
Spend $25. on a E85 compatible plastic gas can to cut the bottom out to use as a tank baffle.
Spent about $20. for E85 compatible wire and wire terminals.
Splurged $25 on Deutsche connectors for the dual pumps.
Bought a second used FPDM for $25.
Strangely, instead of taking the cheep way out and hacking a second FPDM connector directly into the stock harness, splurged on 3 new FPDM connectors for ~ $100. to make up a plug and play dual FPDM harness.
Spent around $100. on AN-8 line and fittings to run from the back to the front.
Splurged $130. on an E85 compatible Fuelab inline filter.
Spent $30. on 2 AN-6 to AN-8 wye blocks to merge the pumps at the back and split them to the fuel rails at the front.
Hacked up the stock injector rails to convert them to dual feed and improve the flow, $0.
Total cost is $660. and the system should be good to 700whp or so (whoa, less than $1. per HP!!!).
If I have to switch to return I'll just need to buy the return line and a regulator so that won't be too bad.
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ok I will play your game of 660 dollars, now you say those 2 improved ford gt pumps will support 700 rwhp. but lets say they cant on e85 (which I don't think they will), now you can spend 450 dollars on the KB dual bap and right there you are over the cost of a return fuel system that I posted had you gone with it at the start.
lets throw another curve ball, you have a make shift baffle with a cut up gas can which has a good chance of working but what if it doesn't. now you have to buy a cobra or glens baffled tank for 400 dollars and now you have to make shift your home made hat and fuel level sensor to fit that tank. now you can say someone messed up when installing a sump and it doesn't baffle well enough and that is also a risk but there are more people who have sumped tanks that work perfect than people with gas can remains as a baffle
lets say you go option 3 and buy a 3rd fuel pump for you setup and go return, now you have 100 in an additional pump and 160 for a regulator, and 100 dollars for fittings and return line. once again you saved your penny's but at what expense?
the magic number to stay under was 1100 for a return fuel system, you can save 100 dollars off that return system if you go with the a1000 pump, and since my parts list was made in 10min I am sure someone who is pinching pennys can save even more money if they shop around
risk maybe worth the reward if you can keep your budget $660 fuel system and make it work but greed does get most of us and out growing is the biggest problem for fuel systems.
I am not trying to push big return fuel systems on everyone, what I am trying to do is bring to light the options. for the majority staying returnless is perfectly fine but for the people who want to push the big power return is a good option. People need to set goals and plan ahead to decide ahead of time what way is right for them so they don't waste money on parts they have to swap out later.
lets throw another curve ball, you have a make shift baffle with a cut up gas can which has a good chance of working but what if it doesn't. now you have to buy a cobra or glens baffled tank for 400 dollars and now you have to make shift your home made hat and fuel level sensor to fit that tank. now you can say someone messed up when installing a sump and it doesn't baffle well enough and that is also a risk but there are more people who have sumped tanks that work perfect than people with gas can remains as a baffle
lets say you go option 3 and buy a 3rd fuel pump for you setup and go return, now you have 100 in an additional pump and 160 for a regulator, and 100 dollars for fittings and return line. once again you saved your penny's but at what expense?
the magic number to stay under was 1100 for a return fuel system, you can save 100 dollars off that return system if you go with the a1000 pump, and since my parts list was made in 10min I am sure someone who is pinching pennys can save even more money if they shop around
risk maybe worth the reward if you can keep your budget $660 fuel system and make it work but greed does get most of us and out growing is the biggest problem for fuel systems.
I am not trying to push big return fuel systems on everyone, what I am trying to do is bring to light the options. for the majority staying returnless is perfectly fine but for the people who want to push the big power return is a good option. People need to set goals and plan ahead to decide ahead of time what way is right for them so they don't waste money on parts they have to swap out later.
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Man there is a lot of good info in this thread! Reps to everyone that helped!
One more thing I need help visualizing: if I was using a stock tank with a sump, where would the return line connect to the tank? Would connecting to the stock fuel hat work?
Thanks again!
One more thing I need help visualizing: if I was using a stock tank with a sump, where would the return line connect to the tank? Would connecting to the stock fuel hat work?
Thanks again!
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That was my plan was to just drill a hole and bung into the factory fuel hat and let it pour back in. I'm curious to hear responses to verify if this is fine.
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All of that is easily worked around by proper part selection and design.
Avoid the aeration by returning down low into the fuel. Easy as that. (Away from the pickup of course)
Keep the heat low by using a fuel cooler on the return line, and using a PWM controller of some sort on the pump. They're designed to run at full voltage, so instead of varying voltage, you use pulse width modulation (PWM). They sell controllers for this, but it's also pretty easy to build yourself. Personally I went with the Fuelab pump since it has a PWM controller integrated into it.
If your return rate isn't that high, you can return in through the original fuel output on the hat.
If it's going to be higher, I'd advise drilling a hole and using a bulkhead fitting. There's plenty of fitting options you can go with depending on how creative you want to get. I like the bulkhead so you can run an additional hardline into the tank to keep the fuel from aerating.
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i dont see why you couldnt get a fitting that connects to the factory outlet on the hat to use for a return line.
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Keep in mind when you go big single you put all your nuts in one basket, One of the main reasons I didn't use a sump this time is because mine is also a street car. With a triple pump setup or a double if you have a pump go down you can still get to your destination. your not stranded. Even with my setup if I have a pump go down the other two 340LPH pumps will support enough to keep me from leaning out during a WOT pull up in the 700RWHP range hell they can support that alone so having another pump is a security measure.
As far as being easier to work on the tank does not take any more then 20 minutes to drop and having the Pumps submerged in fuel keeps them cool and from over heating unlike an external pump which is exposed to atmospheric temperature. 20 minutes of driving in Texas or where I live it gets pretty darn hot and the smoking Asphalt will add to the stress.
If I had a track only vehicle Sump would be the way to go but on a street car I had to weigh the options and it made more sense to stay in the tank.
As far as being easier to work on the tank does not take any more then 20 minutes to drop and having the Pumps submerged in fuel keeps them cool and from over heating unlike an external pump which is exposed to atmospheric temperature. 20 minutes of driving in Texas or where I live it gets pretty darn hot and the smoking Asphalt will add to the stress.
If I had a track only vehicle Sump would be the way to go but on a street car I had to weigh the options and it made more sense to stay in the tank.
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Big single pump fails while cruising, car dies and you pull over. One of 2 or 3 pumps die and you may not notice the difference cruising, then go WOT and KABOOM! Personally, I have AAA so I'll take a tow home over a blown motor.
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Not if your Big single died during a pull your heading to more then a Tow truck. I had a pump die which is why I knew this for me was the best route and I still was putting down over 600 without any issues. You can certainly tell if your pump goes out when you have a pressure gauge such as I do that allows you to monitor the pressure.
OP I am not telling you the route I went is the best way I am simply showing you the protection a third pump offers.
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you can use the stock inlet on the fuel hat as a return, the diameter of the oem inlet is close to -6 an. in the past i just hooked a long submersible fuel hose on the end and threw it in the tank. i know it was not right but i never had an issue with aerating.
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I think that is probably what I will do. Lethal sells an adapter for the stock hat to -8AN. I can use a reducer to a -6AN hose fitting and be in business. I saw some people weld in a bung then thread a -6AN hose end into the tank near the filler tube, but it seems like this could aerate the fuel just as much as hooking to the hat.
How would aeration affect performance, anyway?
Edit: 1000th post. Don't know if I should celebrate or be depressed that I spend so much time talking to strangers on the internet. :bubba:
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If you're running a new AN supply line, cut the old one at the rubber flex hose connection, and just stuff a 3/8 barbed fitting into it and you're in business. Then just use your choice of hard or flexible line to clamp on the inside of the tank and run to the bottom. Alternatively find an adapter for the quick disconnect on the fuel hat itself, but I know barbed fittings are cheap and plentiful in a pinch.
Alternatively, a bulkhead fitting is way easier than welding any bungs onto it:
You just drill a hole, slide the fitting through it, and then tighten the nut on it, which clamps and seals to whatever wall it passes through. Piece of cake. You can get both types with only one end, if you're passing through low into the tank, or with a union on each side, so you can run a line down into the bottom.
Aeration is a very bad thing. I think it's Aeromotive that has a video on youtube where they demonstrate what it can cause. You can hear the pump surge and fuel pressure fluctuate.
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I would like to do things right, so if reusing the hat or stock lines could cause issues, I will avoid that. I don't know what a low return rate would be considered as, but the fuel pump I'll be going with is very, very over kill, so I imagine there will be quite a bit of fuel going back into the tank.If you're running a new AN supply line, cut the old one at the rubber flex hose connection, and just stuff a 3/8 barbed fitting into it and you're in business. Then just use your choice of hard or flexible line to clamp on the inside of the tank and run to the bottom. Alternatively find an adapter for the quick disconnect on the fuel hat itself, but I know barbed fittings are cheap and plentiful in a pinch.
Alternatively, a bulkhead fitting is way easier than welding any bungs onto it:
![Image]()
You just drill a hole, slide the fitting through it, and then tighten the nut on it, which clamps and seals to whatever wall it passes through. Piece of cake. You can get both types with only one end, if you're passing through low into the tank, or with a union on each side, so you can run a line down into the bottom.
Aeration is a very bad thing. I think it's Aeromotive that has a video on youtube where they demonstrate what it can cause. You can hear the pump surge and fuel pressure fluctuate.
Those bulk head fittings look very appealing actually. For some reason I had it in my head that they needed to be welded in place. What kind of hose would I need to run from the inside section of the bulkhead down into the tank? Would it need to be something different than the stainless hose linked earlier since it would be submerged in fuel?
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You can reuse the stock line for a return if your return line will be a -6. If you're going -8, which is pretty damn big, then you'll need to do a bulkhead fitting.
It depends on the hose, but it would need to be rated to be submersible. Personally I'm just taking a short piece of aluminum fuel line and putting a 37deg flare on the end to mate to a bulkhead fitting. I'm also running a crap ton of flared aluminum fuel line all over the car.
Of course if you're re-using your existing fitting on the hat, you can just use a piece of submersible hose (and fuel injection clamps) as stal mentioned.
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My return will be a -6AN. As long as the stock line, or the submersible fuel line inside the tank won't serve as a restriction. I have no idea how large -6AN is inside, but I imagined it being larger than the nipple on the stock hat. I could totally be wrong in this, but that was why I was apprehensive.
If I were to go the bulkhead fitting route, I like the fuel line idea much better than using a soft hose of some type. Post some pictures up of your setup when you get to that point, please!
Another question for those of you that have ran external pumps for some time: how much run time can I expect to get out of one of these safely? I read the posts earlier on about the modern advancements in return system technology, etc, but there has to be a limit correct? I mean we are talking about using 2000hp capable pumps in 600hp cars, so there will be quite a bit of fuel going back to the tank at part throttle.
I Google'd around a bit, and it seems like an hour is the number that comes up a lot. My car isn't a DD by any means, but I do like to alternate between car meets and the track. One of the shows I like to go to is a 2 hour drive at interstate speeds. Can I expect this to be an issue without a fuel cooler or some time of pulse width modulation controller?
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AN-6 hose has an ID of around .34", a little less than 3/8".
Depending on the wall thickness, AN-6 tubing runs can have even less than .34" ID.
The outlet nipple on a GT hat is about that same size so its likely ok to use for a AN-6 return. Keep in mind that the pressure drop across a restriction is proportional to the length of the restriction so if you are a little reduced in size for a short section (like the hat inlet) you'll probably be ok.
You might even be able to use the whole stock fuel line as the return line but this depends on the size of your fuel pump, since you said you overkilled it the stock line might be too small.
But its easy to see if your return line or any section of it is too small. When the car is at idle if the fuel pressure rises higher than your regulator setting then your return line is too small.
Regarding your 2 hour drives, that's fine as long as you realize that your fuel is getting heated up, just don't go WOT during this long drive and let the tank cool down a while after the drive before getting on it hard.
If you have an infrared heat gun it would be interesting to shoot your tank temperature after one of those long drives.
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The AN number is basically how many 1/16"s it is, so -6AN is going to be 6/16, or 3/8. Same as the stock fuel line/hat.
Your run time is going to depend on your duty cycle, pump size, and if you use a cooler. Coolers are pretty small and cheap, and help somewhat. If you've got a massive pump, moving way more fuel than you need it's going to heat it up versus a smaller one closer to your limit.
You can run them indefinitely if you control the output, like with a PWM controller. That's essentially what an FPDM does with the stock pumps. I know Aeromotive has their own, but it's pricey. The Fuelab ones are supposed to have that feature built in. It also shouldn't be too hard to build or source a PWM controller.
EDIT:
Further details on the Fuelab pump; there's a few options
1.) Use their 529 regulator which will control the pump via PWM
2.) Use a switch, manual or hobbs to switch between 50% and 100% duty cycle
3.) Use some sort of standalone at 500-1500Hz to control it via PWM
I'm probably going the hobbs switch route, to kick it to 100% duty cycle as soon as it hits boost. Clean and simple.
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