I am by no means an expert but have been doing a lot of research on this same subject. I haven't really read where some tuners hate this method. Can you enlighten me as to why they hate it? I would think as long as your fuel pressure is always stable there wouldn't be any issues. Plus the benefit of the fuel not going through the fuel rails and back to the tank continually heating up is huge. I am very interested in learning more on this also as I ultimately would like to run e85.

 

I'm about to switch to a dead head setup as well. The only negative side effect I read about was struggling to start the car after it sits for a day or so. The fuel, after sitting, will evaporate. When you start the car, the only place for the air to go (from lines between regulator and rails) is into your engine causing a few more cranks to be need before it fires. On a traditional setup, the air in the lines can be flushed past the rails as new fuel is pumped from tank since the rails aren't capped.


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I'm about to switch to a dead head setup as well. The only negative side effect I read about was struggling to start the car after it sits for a day or so. The fuel, after sitting, will evaporate. When you start the car, the only place for the air to go (from lines between regulator and rails) is into your engine causing a few more cranks to be need before it fires. On a traditional setup, the air in the lines can be flushed past the rails as new fuel is pumped from tank since the rails aren't capped.
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I have read about it taking a little longer to start also but I can't remember why right now. Seems like it was something else? How does the fuel evaporate out of the fuel line? It seems if fuel evaporated out of the fuel lines, we would have the same issue with our stock returnees systems. Again, just trying to learn.

 

Here are the two different plumbing alternatives you are looking at in a schematic form, Dave.

I fished the basic diagram with a Google search and added the dotted red line in the type 1 system. More on that in a bit.

The type two system can appear in several configurations. Sometimes the supply line is split off with a "Y" connector before the pressure regulator and another just before the rails providing a dedicated supply path for each rail. It is also possible to run separate returns back to the tank. I am not sure separate return lines would provide adequate benefits to warrant the expense and effort. This type of system is sometimes called a balanced system.

The Type 1 system can be configured as drawn with the rails in series like the drawing but without the circuit represented by the dotted red line. This serial configuration will likely provide reduced volume to the injectors towards the end of the second rail.

A better alternative to the serial placement of the fuel rails would be creating a balanced system by using a "Y" fitting, usually at the firewall after the regulator providing a dedicated supply path for each rail. Although the individual fuel supply path to any injector is now shorter than the previous serial installation model, at high fuel flows, the front cylinders on each bank will get short-changed compared to the rearmost cylinders. For a daily driver on gasoline, this is not a significant concern. For engines like we are talking about with high fuel flow requirements, the potential risk is a lean cylinder and detonation.

The easiest fix is to place a small balance line across the front of both fuel rails. That balance line is represented by the dotted red line in the Figure 1 image. The line does not have to be big. A #4 or #6 size AN line is adequate. The line completes the fuel rail's fuel path equalizing the fuel pressure differential at the frontmost fuel rail extremities. This will provide a more uniform delta pressure at each injector and uniform fueling for the engine, assuming the injectors flow the same.

The idea of removing the pressure regulator from the engine compartment and the heat present in the compartment plays a significant role in preserving the octane rating of the gas and the parts in the engine. At atmospheric pressure, virtually all of the octane enhancers in gasoline will boil off before the fuel hits 100˚F. When that happens, the fuel and the octane enhancers separate in the return system on the way back to the tank, where the pressure in the return line is near atmospheric. Like an unopened bottle of stale soda or beer, once the fizz is gone - it's gone! No amount of shenanigans we go through can get it back into the beer. Precisely the same thing with octane enhancers. How many times have we opened our fuel tank at fill-up only to be met by a whooshing sound as we remove the fuel cap? What you heard as you opened the filler cap on your tank were the octane enhancers that had already been boiled off, escaping through the filler neck.

Removing the pressure regulator from the heat of the engine compartment is a good thing to do. BTW the fuel already in the fuel lines, in the engine compartment, can not lose the octane enhancers it carries because, at the base pressure you set for your fuel system, neither the gas nor the octane enhancers can vaporize in the fuel lines. It is the same effect as selecting a higher-pressure radiator cap to allow the coolant temperature to rise above boiling without boiling. Your return fuel gets recycled back to the tank without ever experiencing the engine compartment heating or subsequent fuel and octane enhancer additives vaporizing in your fuel lines before reaching the tank.


Update 7.02.2023

Although I did not intend to ignore the potentially slower start with the deadhead approach — I unintentionally did! Here is how to correct the problem.

When the car sits after shutdown, and in particular for those of us who have removed our PPRV, the fuel in the lines will drain back to the tank on the feed side of the circuit. The fix is to replace the PPRV with a more effective equivalent. The current best offering for this job is manufactured by Improved Racing <= Clickable.

The check valve is a very high flow (higher than we will need) with an exceptionally low opening pressure of 0.05 psi. It offers literally no restriction in the fuel delivery lines! It has a holding pressure capability that can lock up to 300 psi in the fuel rails at engine shutdown. Fortunately, we only need to lock in about 45 psi. The check valve's maximum operating pressure has a ceiling of 1000 psi which none of us will ever get near.

This device will hold fuel, at pressure, in the fuel lines when you shut down. If you still have a Schrader valve on your fuel rails, it will show fuel under pressure just like an OEM fuel system from Ford. Most importantly, it will provide an OEM-style instant startup instead of having to wait for the pumps to repressurize the entire fuel system before you can start your engine.

This check valve needs to be positioned back at the tank where the fuel line first leaves the fuel tank and before any filters you have installed to keep the fuel free of particulate matter. Do not err on the small side with this valve. There is no downside to going big. There is one for going too small.

A good rule of thumb is -10 AN for 650 RWHP and up. If you are space constrained (I don't think so, but maybe?), you could go down to a -8AN line. If you do, you should be well below 650 RWHP. There is no pricing advantage to going small, there can be a performance and fueling disadvantage if you starve the engine for fuel with too small a check valve.

 

Great post Ed.

One thing looking at the diagrams, shouldn't setup 2 have the supply and return labels switched? It should go into the regulator first right?

By no means am I an expert.

 

Actually no. The regulator is in the right location. The diagram is an example of what Josh (Godstang) was referring to and it does provide a sort of fail safe in the event of certain types of regulator malfunctions.

The best failsafe for regulator malfunctions is an aftermarket ECU that offers engine protection monitors on various key systems like fuel, oil and cooling. Usually the aftermarket engine management systems are among the last items to be purchased and frequently only after a fairly impressive engine failure that did not have to occur.

The primary impediment to acquisition is cost. The good ones tend to be pricey but then so is a new engine. Most owners have not even purchased a Vampire detonation detection and correction system because it approximates $600. The price of a good aftermarket engine management system when you are done will be nearly an order of magnitude greater.

 

^^^ that's a good thread. I've emailed the thread author a few times on this topic as well as a fuel delivery supplier and both have confirmed that in some cases, the car will start in a lazy fashion due to fuel vaporization. No first hand experience as I haven't switched to a dead head setup yet.


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From an engineering stand point on the dead head if the fpr fails close then you lose fuel to the engine and the last injects can lack fuel. With the fpr after the rails they have equal fuel and if it fails close you are still getting fuel just not returning it. Now Thousands or racers run dead head with zero issues so to each their own. I just don't like adding an extra fail point.

I built mine with lines from www.aeroquip.cc they had amazing prices. I came in from tank -10an y-ed into two -8an to feed both rails then returned both of them to a fpr then -10an to trunk. Was cheaper than most "budget" systems and way better setup.

 

I currently have the dead head setup on my car, which is the kit I purchased from Lethal. While I was installing it I thought I was missing parts because I have never heard of this setup before. Speaking with Jared, he assured me it will work. Installed it and the car runs fine, races fine and dynoed fine. I have no trouble at all with this current setup or with starting. Do I like this type of setup, no. I will change back to figure 2 as Ed shows. To me, it makes logical sense to run that setup. My tuner looked at my fuel lines and also mentioned to change to the normal setup. But to answer the question, yes it works and my car currently puts down a good amount of power. During either dyno runs or racing, my AF stays in the low 11's high 10's.

 

Here is an easier to visualize version of a figure 2 style system guys;

This is probably more like what most of us intuitively think of. The problem with this type or design is that the fuel that is not used by the engine is returned to the tank after being cooked to a temperature above the point where the octane enhancers boil off, all because it had to go through the engine compartment before returning to the tank. When that fuel finally hits the low pressure return line all the fuel's octane enhancers exit stage left!

The figure 1 style system will work either with or without the balance tube across the front of the rails that I have depicted as the dotted red line. For high performance applications the balance tube is a smart system enhancement. The biggest deal however is the location of the pressure regulator. It can be located outside the hot engine compartment so the returned fuel never gets heated above boiling by the under hood engine heat.

The fuel in the lines to the injectors does not boil because the base system fuel pressure raises its boiling point above the engine compartment temperature. There is a simple litmus test that will tell you this. If the fuel in the fuel rails boils, the engine will vapor lock. If your engine is running it has not vapor locked! The Image 1 system with the regulator out of the engine compartment and with the use of a balance tube/hose across the front of the fuel rails is a better design for either street of track.

p.s. don't forget your pressure regulator is boost referenced so you want to keep the boost reference line as short as possible while keeping the regulator out of the engine compartment.

 

Here is an easier to visualize version of a figure 2 style system guys;

View attachment 145609

This is probably more like what most of us intuitively think of. The problem with this type or design is that the fuel that is not used by the engine is returned to the tank after being cooked to a temperature above the point where the octane enhancers boil off, all because it had to go through the engine compartment before returning to the tank. When that fuel finally hits the low pressure return line all the fuel's octane enhancers exit stage left!

Ed

A returnless fuel system eliminates the possibility of hot fuel in the tank because no hot fuel goes back to the tank. A bit off subject, but why do some people convert over to a return style fuel system when the factory Terminator Cobra returnless set up can flow plenty of fuel with simple modifications such as fuel pump electronic amplifiers and GT super car fuel pumps and with out the drivability issues ????

Jan

 

So in short, you're saying do the dead head setup but with the balance hose and keep the regulator out of the engine compartment?

 

You nailed it Russ.

Maintains the octane rating of the fuel, balances the system pressure at the front most injectors, and delivers the simplicity of the return style system.

 

Perfect, thanks Ed. I looked at the calculator briefly, wow that is intuitive. I need to take a look at it when I have more time and see if I can figure this out haha!

You nailed it Russ.

Maintains the octane rating of the fuel, balances the system pressure at the front most injectors, and delivers the simplicity of the return style system.

Ed

 

Thanks for the info Ed. I am pretty confident I am going to switch the setup to a dead head. I would rather take my chances with the regulator failing with the dead head and have the benefits of the fuel not being heated.

I was wondering about the balance tube and your info further confirmed my thoughts

My plan right now is to mount the regulator into the inner fender (not sure which side yet) and Y off of the regulator and feed the rails at the front and crossover at the back.

The last concern which you touched on a bit, the boost reference... I will be running a Sullivan intake and will reference boost directly from the intake to the regulator. Will there be any issue with length of the vacuum hose from the back of the intake to regulator at the inner fender?

 

Thanks for the info Ed. I am pretty confident I am going to switch the setup to a dead head. I would rather take my chances with the regulator failing with the dead head and have the benefits of the fuel not being heated.

I was wondering about the balance tube and your info further confirmed my thoughts

My plan right now is to mount the regulator into the inner fender (not sure which side yet) and Y off of the regulator and feed the rails at the front and crossover at the back.

The last concern which you touched on a bit, the boost reference... I will be running a Sullivan intake and will reference boost directly from the intake to the regulator. Will there be any issue with length of the vacuum hose from the back of the intake to regulator at the inner fender?

I don't think so Dave. The challenge comes when you attempt to put four or more feet of small diameter boost reference line on the regulator. The line is so long the air inside it alternately acts like a spring or a rubber band depending on whether the boost is going up or coming down. The elastic nature of the signal delivery makes it difficult to tune because the regulator is having difficulty properly responding in a timely fashion to the boost the engine is seeing in the intake manifold.

When you mount the regulator in the inner fender the effect of the minimal increase in line length is all but non-existent. If the regulator were to be in the back seat area or near the fuel tank the effect of the natural elasticity of the air in that small id line would be considerable. If you want to, you can further reduce any dead time in delivering the boost reference signal to the regulator by using a larger id hose like a 3/8 or 1/2 inch hose until you get close to the regulator and then using an adapter to drop it to the diameter of the hose the regulator nipple requires.

 

I first ran a dead head setup without a crossover line and had issues going lean on one bank. Put the crossover on and it cured my problem, car has been running great since then. My FPR is in the fender. As Ed pointed out, make sure you include a crossover line if going dead head.

 

I will be doing the crossover for sure. My plan at the moment is to feed the front of the rails and crossover at the back. i will also be mouting the FRPS on the crossover in the rear. I will be running a Sullivan intake and have a few ideas on the routing that I want to run. I have seen your car at the Pike a few times, it sounds good! Hopefully I will be back up there this year with my Cobra, if not I will be there in my M3.

I have my car configured in a deadhead setup and love it. Originally I had mine setup in the "conventional" return system where the regulator was post fuel rails. I can tell you this builds a ton of heat in your fuel. My fuel pressure was darn near capable of branding you after the car had run any real length of time.

After converting to a dead ead setup I can hold the filter in my hand after running the car hard...its a night and day difference. Malcolmv8 reduced his temperatures over 100degrees by going deadhead. You can see his thread here
http://www.svtperformance.com/forum.../forums/showthread.php?1030180-I-drastically-dropped-my-fuel-temps-by-over-100F

Originally I didn't have a cross over in my fuel rails and my fuel pressure seemed to see rather large spikes when transitioning in and out of heavy throttle usage (7-9psi maybe). Whatever the number was it was much larger than what I was use to in my "conventional" return setup, I decided to add a front crossover and this dropped the spikes down to 1-2psi when messing with the throttle.

In an effort to give my regulator the best boost/vacuum reference signal I used DOT hard plastic air line. This is similar to the stuff that Ford used on our vacuum harnesses from the factory. The stuff is durable, cheap (under $1.00ft) and best of all you can make solid quick connections with it. Its the same stuff Semi-trucks use on their air systems operating at over 120psi.
Here is a link
https://www.airliftcompany.com/shop/20914/

My local carquest carried it and for under $10 I had my FPR plumbed in with it.

I can't comment on if tuners don't like it as I self tune but if I can do it I'd think any professional could.

Good to know. I planned on converting my complete vacuum setup to hardline and ditching all of the rubber hose on my new build.

Im in the process of converting from the conventional Dead head to the method mentioned in here as well with the FPR in the fender. Anyone got a picture of their setup on the car? what kind of special fitting is required for the front left rail that receives the fuel from the regulator and also has a equalizer line running to it?

Do you want pictures of the Conventional style where you feed the rails first or do you want pictures of a dead head where you feed the rails after the regulator?

 

Ed, I am running my setup like diagram 1. except I have a Y into the back of each rail and I do not have a balance tube at the end of the rail.

In this configuration you would recommend a balance tube to ensure the front injectors are not losing flow compared to the back injectors?

 

Ed, I am running my setup like diagram 1. except I have a Y into the back of each rail and I do not have a balance tube at the end of the rail.

In this configuration you would recommend a balance tube to ensure the front injectors are not losing flow compared to the back injectors?

I would Bobby. For every day use it doesn't make a significant difference. When you stand on it and run the engine speed up to 6K rpm or beyond, it makes a difference. The balance line does not have to be very big. A #4 AN line will do the trick. The pressure differences you are trying to balance out are small enough that big diameter hose / tubing is not necessary.

 

I have been running a dead head setup for a while now. No balance tube. No problems. My tuner actually didn't mind at all. He didn't say it was any more difficult than a traditional return system. I did however keep my frps. I wouldn't recommend deleting it.

 

The FRPS is a real good idea to hang on to like you did, Jeff. The ECU uses it to calculate injector pulse width in both systems return and returnless. The car will run without the FRPS but it will run better with it.

 

Someone posted up a comment regarding this topic one time that claimed he saw more consistent Exhaust Gas Temps from cylinder to cylidner with the feed line "Y'd" off prior to the rails vs. running fuel into one acrosss, then out of the other. I can't find that post at the moment and don't remember him posting any specific data but I thought this was interesting.

 

I have my car configured in a deadhead setup and love it. Originally I had mine setup in the "conventional" return system where the regulator was post fuel rails. I can tell you this builds a ton of heat in your fuel. My fuel pressure was darn near capable of branding you after the car had run any real length of time.

After converting to a dead ead setup I can hold the filter in my hand after running the car hard...its a night and day difference. Malcolmv8 reduced his temperatures over 100degrees by going deadhead. You can see his thread here
http://www.svtperformance.com/forum.../forums/showthread.php?1030180-I-drastically-dropped-my-fuel-temps-by-over-100F

Originally I didn't have a cross over in my fuel rails and my fuel pressure seemed to see rather large spikes when transitioning in and out of heavy throttle usage (7-9psi maybe). Whatever the number was it was much larger than what I was use to in my "conventional" return setup, I decided to add a front crossover and this dropped the spikes down to 1-2psi when messing with the throttle.

In an effort to give my regulator the best boost/vacuum reference signal I used DOT hard plastic air line. This is similar to the stuff that Ford used on our vacuum harnesses from the factory. The stuff is durable, cheap (under $1.00ft) and best of all you can make solid quick connections with it. Its the same stuff Semi-trucks use on their air systems operating at over 120psi.
Here is a link
https://www.airliftcompany.com/shop/20914/

My local carquest carried it and for under $10 I had my FPR plumbed in with it.

I can't comment on if tuners don't like it as I self tune but if I can do it I'd think any professional could.

 

Im in the process of converting from the conventional Dead head to the method mentioned in here as well with the FPR in the fender. Anyone got a picture of their setup on the car? what kind of special fitting is required for the front left rail that receives the fuel from the regulator and also has a equalizer line running to it?

 

Has anyone data logged their fuel TEMPS to see if this is really making a big difference or not and produced some data before and after? Last year I datalloged my temp at the Fuel rail and it was about the same temperature as another guy that was running a returnless system.

Im running 3X 255 LPH pumps and what i did was put 2 pumps on a hobbs switch and only run one pump constant so doing it this way you really are not returning alot of hot fuel.

 

The place you want to log the fuel temperature is not at the fuel log. It is in the return line. In the return line is where you want to maintain cool fuel temps.

 

Dave,

If that is working for you, and you like it, you should not be fixing the things that are not broken.

 

Agreed, however i would like to know the benefits of going to a dead head cause i dont see them For instance the Temperature differences in the fuel at the rails, and the temp of the fuel coming to the rails... now if the temperature at the rails is For Instance 185 and the fuel coming into the rails is 140 then where is the benefit? because once it gets to the rails and it heats up to 185 the TEMP of a normal fuel rail then bringing in cooler fuel isnt doing anything cause the rails heat it as fast as it comes through.

With a dead head your fuel will get hotter because it cannot run through the rail it sits there and super heats until it is burned. You cannot burn all the fuel in the rails instantly and with it not passing through the fuel rails returning to the tank it actually has time to heat up which is why i asked for some data logging of the TEMPS of the fuel at the rails... From what ive read earlier in this thread it was mentioned that the heat pulls out the octane so if that is true then a dead head rail Will get hotter and lose more octane because it cannot run through back to the tank it sits in the rails waiting on its turn to be injected.....

Now the only benefit i see from cooler fuel is it being easier on the fuel pumps but hotter at the rails cause its sitting waiting to be burned rather then running though like a traditional return setup.

 

If your fuel entering the rail is already at 140˚ you have much larger problems than the temperature of the fuel in the rails.

The octane enhancers that allow the refineries and blenders to produce the high octane fuels we all prefer, will for the most part vaporize at or around 85˚F. I won't repeat the early explanations, it is easy enough to go back and reread them.

The actual rail temperature while not irrelevant is to a large extent not that important because the fuel pressure is sufficiently high in the rail that the fuel and its octane enhancers can not disassociate or vaporize. If they did you would get vapor lock. Once injected into the port/cylinder we now want them to vaporize as quickly as possible so as to become increasingly combustible. The high fuel rail temperatures both ensure and also enhance this. If the fuel's octane enhancers vaporize in the return line, like soda that has lost its fizz, you can not re-associate the two and you are down to base stock octane ratings whatever they were.

It is really not very complicated but it is very important, especially if you are running MBT spark, high boost and/or high compression with high boost.

 

I know you can get tanks that have coil tubing inside for the return fuel to keep ice water in. I bet that would help keep temps down going back into the tank.

 

The simple explanation of the problem Russ is that like an unopened stale bottle of soda, the fizz is gone. Just like the bottle of soda that has aged and lost its "fizz" even after refrigeration you can't put the fizz back into the soda. The exact same thing happens with the octane enhancers in the gas. The moment the hot fuel enters the low pressure side of the pressure regulator, on the way to the return line, the octane enhancers immediately vaporize out of the fuel. Just like the fizz in the soda bottle, you can't get it back in!

The old cool cans, which are essentially what you are describing, were used to keep the fuel temperature down prior to entering the carburetors. The carbs were hot and the vented float bowls would allow the "fizz" to escape through the float bowl vents leaving behind a relatively low octane gasoline base stock. The cool cans could mitigate but not eliminate the phenomena, significantly however they were on the feed side of the fuel system. Placing a cool can type of device on the return side of a fuel injection system does not provide any advantage because the "fizz" has already left the fuel as it passed into the low pressure return side of the fuel pressure regulator, before it ever gets to the cool can.

Best practices would keep the fuel to the regulator, in the regulator and in the fuel return line as cool as possible. The fuel in the high pressure lines to the engine is not at the same risk because it is under pressure. Just like the coolant in our cooling systems the increased system pressure raises the boiling point and prevents vaporization - until it is injected into the cylinder where and when we want everything vaporized for best combustion. The easiest way to accomplish the cool fuel pressure regulator is to remove it from the heat of the engine compartment and place it somewhere else that is cool.

 

In the FWIW bucket, Russ, the FRPS will provide the most accurate injector delta pressure (Δp). The second most accurate would be an electric gauge with the sensor at or close to the fuel rails. The electric gauge would allow you the ability to read the pressure w/o the requirement to data log it first. The mechanical gauges can be impaired by temperatures in the engine compartment and at the fuel rail so that they would provide the most suspect data.

 

Ed,

You mention that the balance line can be a small line such as a -4, is there any reason why it can't be the same size as the rest of the line? I use -8 to feed the rails and have an abundance of it left over, any reason why I couldn't use that to tie the rails together? I'm thinking that I'd most likely run my -10 feed to the regulator, run a Y block out of the regulator splitting into two -8 to feed the back of the rails and then a -8 line to loop the front of the rails and a -8 back to the tank.

 

There is no reason why you could not run -8..... The main reason he is telling you to run a small line is because it is easier to pressurize a smaller line, but when your running a a lot of fuel you need to maintain your line size ...

Dave, nailed it Jim. It is just convenience. Small hose bends and fits easily. Once the lines are filled the response to pressure changes along the length of the fuel line is essentially instantaneous because of the non-compressible nature of the liquid.

 

There is no reason why you could not run -8..... The main reason he is telling you to run a small line is because it is easier to pressurize a smaller line, but when your running a alot of fuel you need to maintain your line size.

Im getting ready to finish tuning my turbo setup which is 16-27PSI and runs 3 255LPH pumps 2 of which are on a boost refernece switch so they never come on until im in boost so ill data log and post up the fuel pressure coming in and out off boost and show how steady the pressures are. Even with a boost refence switch it doesnt see more then 1--2 PSI spike when the pumps are activated then immediately levels out. I would like to see a Dead head setup data log as well so we can compare apples to apples... Also I will log the PID which has the Fuel Temperature at the rail lets get some hard DATA in here on this.

Im stil not convinced this is the best way to do a fuel system. I have never seen a in tank fuel pump setup boil fuel, but i am certain the DATA logs that ive been asking for will tell my suspicion that the Fuel pressures are not stable using the dead head as the conventional way I can see leaning out on a cylinder or two but ill reserve my susposions for a couple datalogs to prove it. will someone who has the dead head please provide a data log that shows you coming into boost and out of boost? It would be nice to get a couple logs to read and compare on both setups.

One issue i see if folks putting a 400 LPH pump or dual 340LPH and triple 340LPH pumps setups and returning 2 to three pumps worth of fuel all the time which can range from 700-1000LPH of fuel. You cannot do this without heating the fuel which is why we use HOBBS switches or boost reference switches to activate the secondry or third fuel pumps only when your in boost or require extra fuel...

On the extrenal pumps you have no fuel to cool the pumps which is why those fuel setups will not get you far without burning up the pump they are a track pump and not made for the open road due to the sheer volume they push and lack of cooling. You cant return mass volumes of fuel and not expect the fuel to get hot..

 

Thanks for the info. I'll think I'm going to give this a try and see how well it works. I'm running dual Magnafuel 4303's in a modified BBRC tank and would be bypassing a large amount of fuel during normal driving on the street, so figured it was worth a shot. I never had issues with fuel heat running the single 4303, but with the added pump it might be a different story.