return-less fuel systems thoughts and ideas

[Angrey]

Not sure you are really considering the likelyhood of a failure at that voltage. Will it work, sure, but for how long? Using a BAP at 20 or even 22 volts doesn't seem like a long term reliable solution.

While I somewhat agree and I would be cautious about using this setup unless the tuner (like Mike) has put serious protections in place. I'd be more concerned with putting all my eggs in one basket and boosting at 20V and have a failure at the most crucial time.

The good thing about DW is unlike walbro/TI, you can actually have access to them and call them and ask what they've tested their pumps to withstand.

Which is why they generally give a dual rating, sustained and intermittent.

In fairness, an 850 rwhp car doesn't live there all the time and rarely sees full fuel flow requirements. With a variable system, it spends most of it's life at partial and low duty. And as I said, with certain protections in place in case you get a sudden loss of pressure, I wouldn't have a problem doing this if it's setup the way these guys are laying it out, boosted with a control/variable strategy that only overtasks the pump on a limited basis once in awhile. I would NOT continuously boost any pump that's meant to run 13.5V at 20+ volts. You're just begging for a failure. But sparingly, sure.

My bigger concern with these returnless setups is the lag time between engine demand, command and actual pump output. If the pump were sitting right in the engine bay, the dampening wouldn't be as much of an issue. Keep in mind that fuel isn't completely incompressible either. Even the open/close of large injectors creates pressure fluctuations which is why guys who run 4 and 6 cylinder motors on gobs of boost tend to have to employ fuel pulse dampeners.

Anything can be tuned, but it's asking a lot of the typical cookie cutter tuners to truly customize your setup and account for part throttle jam on the pedal situations where the demand spikes rapidly and now you have to tune in the ability of the PCM to modulate all this based upon the actual pressure at the rail. Of course it can do this nearly instantaneously (i.e widen or shorten injector pulse based off what's currently available vs what it would like or has commanded). Again, this can all be done, it's just fairly custom. Which is why most tuners just prefer to use a return line and let the physical regulator that's right there close to the rails adjust the return line flow in excess to maintain desired pressures.

I wouldn't run this type of setup unless someone like Mike was tuning my car. At some point, large demand spikes are difficult to manage and smooth out with a dead head, return LESS setup and the tuner would have to put a lot of time and effort into ensuring it's all functioning within the limits of the injector duty adjustments.

Which is again, above certain power levels, most tuners just ask for a return style and call it a day. They know that if they ask for it, the fuel is there. This is much more esoteric.

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[DougS550]

While I somewhat agree and I would be cautious about using this setup unless the tuner (like Mike) has put serious protections in place. I'd be more concerned with putting all my eggs in one basket and boosting at 20V and have a failure at the most crucial time.

The good thing about DW is unlike walbro/TI, you can actually have access to them and call them and ask what they've tested their pumps to withstand.

Which is why they generally give a dual rating, sustained and intermittent.

In fairness, an 850 rwhp car doesn't live there all the time and rarely sees full fuel flow requirements. With a variable system, it spends most of it's life at partial and low duty. And as I said, with certain protections in place in case you get a sudden loss of pressure, I wouldn't have a problem doing this if it's setup the way these guys are laying it out, boosted with a control/variable strategy that only overtasks the pump on a limited basis once in awhile. I would NOT continuously boost any pump that's meant to run 13.5V at 20+ volts. You're just begging for a failure. But sparingly, sure.

My bigger concern with these returnless setups is the lag time between engine demand, command and actual pump output. If the pump were sitting right in the engine bay, the dampening wouldn't be as much of an issue. Keep in mind that fuel isn't completely incompressible either. Even the open/close of large injectors creates pressure fluctuations which is why guys who run 4 and 6 cylinder motors on gobs of boost tend to have to employ fuel pulse dampeners.

Anything can be tuned, but it's asking a lot of the typical cookie cutter tuners to truly customize your setup and account for part throttle jam on the pedal situations where the demand spikes rapidly and now you have to tune in the ability of the PCM to modulate all this based upon the actual pressure at the rail. Of course it can do this nearly instantaneously (i.e widen or shorten injector pulse based off what's currently available vs what it would like or has commanded). Again, this can all be done, it's just fairly custom. Which is why most tuners just prefer to use a return line and let the physical regulator that's right there close to the rails adjust the return line flow in excess to maintain desired pressures.

I wouldn't run this type of setup unless someone like Mike was tuning my car. At some point, large demand spikes are difficult to manage and smooth out with a dead head, return LESS setup and the tuner would have to put a lot of time and effort into ensuring it's all functioning within the limits of the injector duty adjustments.

Which is again, above certain power levels, most tuners just ask for a return style and call it a day. They know that if they ask for it, the fuel is there. This is much more esoteric.

For me, I have to agree with your analogy and assessment with regard to a return versus a Returnless fuel systems run on E85 at high boost levels, even if the boost levels and fuel demands would not be continuous.

 

[cbrtrx]

Hey Mike. DW said I would have no issue running 800-850whp with their DW400 pump and JMS Fuelmax EX on E85. I hope my tuner agrees.


Hi Doug N,

Your setup will work for that power level.

Levi Graham Technical Product Specialist
DeatschWerks
415 E. Hill St.
Oklahoma City, OK 73105
T: 405-233-3991
E: [email protected]

You'll need aftermarket rails if you don't already have them. The stock gen 3 rails are a big restriction at that power level on E85.

 

[Midwestracer]

I ALSO HAVE FORE RAILS

 

[DougS550]

I ALSO HAVE FORE RAILS

My Whipple Stage 2 came with fuel rails. Whipple said they are good for 1100whp+ E85

 

[Angrey]

My Whipple Stage 2 came with fuel rails. Whipple said they are good for 1100whp+ E85

Then they're changing their tune. The statement is dubious anyway, those rails are good for 10,000 whp if you put enough pressure in the fuel system.

The reality is, 6AN rails aren't optimal. Whipple has probably examined going to an 8AN sized rail and determined it's problematic with some sorta dimensions and mounting. So the answer they gave me (over the phone) is, "we've made 1600 hp with those rails."

The reality is, 6AN will work just fine, dependent upon how hard you have to work the fuel system to deliver the desired flow at each injector.

At some point though, like piglets in a trough, the end piglet is going to get neglected if you run big enough squirters gobbling up enough fuel with each swallow. This is far beyond what most people will encounter and certainly beyond what the 3.0 can deliver (without over spinning it to the moon).

There's not a lot of great data available on hydrodynamics for fuel (vs water). i could calculate the pressure drop restriction going from a large line into a 6AN with water, but not sure it would be wholly accurate with fuel. The reality is, having any part of your feed to the injectors that is 6AN is going to prop the system pressure up a couple psi to achieve the desired flow.

 

[DougS550]

Then they're changing their tune. The statement is dubious anyway, those rails are good for 10,000 whp if you put enough pressure in the fuel system.

The reality is, 6AN rails aren't optimal. Whipple has probably examined going to an 8AN sized rail and determined it's problematic with some sorta dimensions and mounting. So the answer they gave me (over the phone) is, "we've made 1600 hp with those rails."

The reality is, 6AN will work just fine, dependent upon how hard you have to work the fuel system to deliver the desired flow at each injector.

At some point though, like piglets in a trough, the end piglet is going to get neglected if you run big enough squirters gobbling up enough fuel with each swallow. This is far beyond what most people will encounter and certainly beyond what the 3.0 can deliver (without over spinning it to the moon).

There's not a lot of great data available on hydrodynamics for fuel (vs water). i could calculate the pressure drop restriction going from a large line into a 6AN with water, but not sure it would be wholly accurate with fuel. The reality is, having any part of your feed to the injectors that is 6AN is going to prop the system pressure up a couple psi to achieve the desired flow.

I will check but I didn't even think about checking the rail fitting sizes. Good point I will verify for I will not have -8 supplied fuel lines and fittings connect to -6 rails.

 

[HKusp]

There are many Whipple 3.0's and 3.8's running those fuel rails north of 1000whp, pretty "comfortably." I think it's safe to say, many of us here running Whipple rails aren't going to run out of rail before something else becomes an issue.

 

[DougS550]

There are many Whipple 3.0's and 3.8's running those fuel rails north of 1000whp, pretty "comfortably." I think it's safe to say, many of us here running Whipple rails aren't going to run out of rail before something else becomes an issue.

Thank you for your reply. This will help for my future boost.

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